Merge pull request 'Initial testing and improvements of code' (#1) from feature/testing into master

Reviewed-on: #1

.drone.yml

@@ -3,6 +3,18 @@ name: default
 type: docker
 
 steps:
+  - name: test
+    image: golang:alpine
+    volumes:
+      - name: build
+        path: /build
+    commands:
+      - go mod download
+      - go install github.com/onsi/ginkgo/v2/ginkgo
+      - ginkgo --randomize-all --p --cover --coverprofile=cover.out .
+      - go tool cover -func=cover.out
+    environment:
+      CGO_ENABLED: '0'
   - name: build
     image: tystuyfzand/goc:latest
     volumes:
@@ -16,7 +28,7 @@ steps:
     environment:
       GOOS: linux,windows,darwin
       GOARCH: 386,amd64,arm,arm64
-    depends_on: [ clone ]
+    depends_on: [ test ]
   - name: release
     image: plugins/gitea-release
     volumes:
@@ -48,7 +60,7 @@ steps:
         from_secret: docker_password
       repo: registry.meow.tf/tyler/armbian-router
       registry: registry.meow.tf
-    depends_on: [ clone ]
+    depends_on: [ test ]
     when:
       event: tag
 volumes:

.gitignore

@@ -3,3 +3,4 @@ userdata.csv
 dlrouter-apt.yaml
 *.yaml
 !dlrouter.yaml
+*.exe

LICENSE

@@ -1,4 +1,4 @@
-Copyright (c) 2022 Tyler Stuyfzand <admin@meow.tf>
+Copyright (c) 2022 Tyler Stuyfzand <admin@meow.tf>, Armbian Project
 
 Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies.
 

README.md

@@ -0,0 +1,118 @@
+Armbian Redirector
+==================
+
+This repository contains a redirect service for Armbian downloads, apt, etc.
+
+It uses multiple current technologies and best practices, including:
+
+- Go 1.17/1.18
+- GeoIP + Distance routing
+- Server weighting, pooling (top x servers are served instead of a single one)
+- Health checks (HTTP, TLS)
+
+Code Quality
+------------
+
+The code quality isn't the greatest/top tier. All code lives in the "main" package and should be moved at some point.
+
+Regardless, it is meant to be simple and easy to understand.
+
+Configuration
+-------------
+
+### Modes
+
+#### Redirect
+
+Standard redirect functionality
+
+#### Download Mapping
+
+Uses the `dl_map` configuration variable to enable mapping of paths to new paths.
+
+Think symlinks, but in a generated file.
+
+### Mirrors
+Mirror targets with trailing slash are placed in the yaml configuration file.
+
+### Example YAML
+```yaml
+# GeoIP Database Path
+geodb: GeoLite2-City.mmdb
+
+# Comment out to disable
+dl_map: userdata.csv
+
+# LRU Cache Size (in items)
+cacheSize: 1024
+
+# Server definition
+# Weights are just like nginx, where if it's > 1 it'll be chosen x out of x + total times
+# By default, the top 3 servers are used for choosing the best.
+# server = full url or host+path
+# weight = int
+# optional: latitude, longitude (float)
+servers:
+  - server: armbian.12z.eu/apt/
+  - server: armbian.chi.auroradev.org/apt/
+    weight: 15
+    latitude: 41.8879
+    longitude: -88.1995
+````
+
+## API
+
+`/status`
+
+Meant for a simple health check (nginx/etc can 502 or similar if down)
+
+`/reload`
+
+Flushes cache and reloads configuration and mapping. Requires reloadToken to be set in the configuration, and a matching token provided in `Authorization: Bearer TOKEN`
+
+`/mirrors`
+
+Shows all mirrors in the legacy (by region) format
+
+`/mirrors.json`
+
+Shows all mirrors in the new JSON format. Example:
+
+```json
+[
+  {
+    "available":true,
+    "host":"imola.armbian.com",
+    "path":"/apt/",
+    "latitude":46.0503,
+    "longitude":14.5046,
+    "weight":10,
+    "continent":"EU",
+    "lastChange":"2022-08-12T06:52:35.029565986Z"
+  }
+]
+```
+
+`/mirrors/{server}.svg`
+
+Magic SVG path to show badges based on server status, for use in dynamic mirror lists.
+
+`/dl_map`
+
+Shows json-encoded download mappings
+
+`/geoip`
+
+Shows GeoIP information for the requester
+
+`/region/REGIONCODE/PATH`
+
+Using this magic path will redirect to the desired region:
+
+* NA - North America
+* EU - Europe
+* AS - Asia
+
+`/metrics`
+
+Prometheus metrics endpoint. Metrics aren't considered private, thus are exposed to the public.

armbianmirror_suite_test.go

@@ -0,0 +1,13 @@
+package main
+
+import (
+	"testing"
+
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+func TestArmbianMirror(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "ArmbianMirror Suite")
+}

assets/status-down.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="82" height="20" role="img" aria-label="status: down"><title>status: down</title><linearGradient id="s" x2="0" y2="100%"><stop offset="0" stop-color="#bbb" stop-opacity=".1"/><stop offset="1" stop-opacity=".1"/></linearGradient><clipPath id="r"><rect width="82" height="20" rx="3" fill="#fff"/></clipPath><g clip-path="url(#r)"><rect width="43" height="20" fill="#555"/><rect x="43" width="39" height="20" fill="#e05d44"/><rect width="82" height="20" fill="url(#s)"/></g><g fill="#fff" text-anchor="middle" font-family="Verdana,Geneva,DejaVu Sans,sans-serif" text-rendering="geometricPrecision" font-size="110"><text aria-hidden="true" x="225" y="150" fill="#010101" fill-opacity=".3" transform="scale(.1)" textLength="330">status</text><text x="225" y="140" transform="scale(.1)" fill="#fff" textLength="330">status</text><text aria-hidden="true" x="615" y="150" fill="#010101" fill-opacity=".3" transform="scale(.1)" textLength="290">down</text><text x="615" y="140" transform="scale(.1)" fill="#fff" textLength="290">down</text></g></svg>

assets/status-unknown.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="104" height="20" role="img" aria-label="status: unknown"><title>status: unknown</title><linearGradient id="s" x2="0" y2="100%"><stop offset="0" stop-color="#bbb" stop-opacity=".1"/><stop offset="1" stop-opacity=".1"/></linearGradient><clipPath id="r"><rect width="104" height="20" rx="3" fill="#fff"/></clipPath><g clip-path="url(#r)"><rect width="43" height="20" fill="#555"/><rect x="43" width="61" height="20" fill="#9f9f9f"/><rect width="104" height="20" fill="url(#s)"/></g><g fill="#fff" text-anchor="middle" font-family="Verdana,Geneva,DejaVu Sans,sans-serif" text-rendering="geometricPrecision" font-size="110"><text aria-hidden="true" x="225" y="150" fill="#010101" fill-opacity=".3" transform="scale(.1)" textLength="330">status</text><text x="225" y="140" transform="scale(.1)" fill="#fff" textLength="330">status</text><text aria-hidden="true" x="725" y="150" fill="#010101" fill-opacity=".3" transform="scale(.1)" textLength="510">unknown</text><text x="725" y="140" transform="scale(.1)" fill="#fff" textLength="510">unknown</text></g></svg>

assets/status-up.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="66" height="20" role="img" aria-label="status: up"><title>status: up</title><linearGradient id="s" x2="0" y2="100%"><stop offset="0" stop-color="#bbb" stop-opacity=".1"/><stop offset="1" stop-opacity=".1"/></linearGradient><clipPath id="r"><rect width="66" height="20" rx="3" fill="#fff"/></clipPath><g clip-path="url(#r)"><rect width="43" height="20" fill="#555"/><rect x="43" width="23" height="20" fill="#4c1"/><rect width="66" height="20" fill="url(#s)"/></g><g fill="#fff" text-anchor="middle" font-family="Verdana,Geneva,DejaVu Sans,sans-serif" text-rendering="geometricPrecision" font-size="110"><text aria-hidden="true" x="225" y="150" fill="#010101" fill-opacity=".3" transform="scale(.1)" textLength="330">status</text><text x="225" y="140" transform="scale(.1)" fill="#fff" textLength="330">status</text><text aria-hidden="true" x="535" y="150" fill="#010101" fill-opacity=".3" transform="scale(.1)" textLength="130">up</text><text x="535" y="140" transform="scale(.1)" fill="#fff" textLength="130">up</text></g></svg>

check.go

@@ -0,0 +1,134 @@
+package main
+
+import (
+	"crypto/tls"
+	"crypto/x509"
+	"errors"
+	"fmt"
+	log "github.com/sirupsen/logrus"
+	"net"
+	"net/http"
+	"net/url"
+	"runtime"
+	"time"
+)
+
+var (
+	ErrHttpsRedirect = errors.New("unexpected forced https redirect")
+	ErrCertExpired   = errors.New("certificate is expired")
+)
+
+// checkHttp checks a URL for validity, and checks redirects
+func checkHttp(server *Server, logFields log.Fields) (bool, error) {
+	u := &url.URL{
+		Scheme: "http",
+		Host:   server.Host,
+		Path:   server.Path,
+	}
+
+	req, err := http.NewRequest(http.MethodGet, u.String(), nil)
+
+	req.Header.Set("User-Agent", "ArmbianRouter/1.0 (Go "+runtime.Version()+")")
+
+	if err != nil {
+		return false, err
+	}
+
+	res, err := checkClient.Do(req)
+
+	if err != nil {
+		return false, err
+	}
+
+	logFields["responseCode"] = res.StatusCode
+
+	if res.StatusCode == http.StatusOK || res.StatusCode == http.StatusMovedPermanently || res.StatusCode == http.StatusFound || res.StatusCode == http.StatusNotFound {
+		if res.StatusCode == http.StatusMovedPermanently || res.StatusCode == http.StatusFound {
+			location := res.Header.Get("Location")
+
+			logFields["url"] = location
+
+			// Check that we don't redirect to https from a http url
+			if u.Scheme == "http" {
+				res, err := checkRedirect(location)
+
+				if !res || err != nil {
+					return res, err
+				}
+			}
+		}
+
+		return true, nil
+	}
+
+	logFields["cause"] = fmt.Sprintf("Unexpected http status %d", res.StatusCode)
+
+	return false, nil
+}
+
+// checkRedirect parses a location header response and checks the scheme
+func checkRedirect(locationHeader string) (bool, error) {
+	newUrl, err := url.Parse(locationHeader)
+
+	if err != nil {
+		return false, err
+	}
+
+	if newUrl.Scheme == "https" {
+		return false, ErrHttpsRedirect
+	}
+
+	return true, nil
+}
+
+// checkTLS checks tls certificates from a host, ensures they're valid, and not expired.
+func checkTLS(server *Server, logFields log.Fields) (bool, error) {
+	host, port, err := net.SplitHostPort(server.Host)
+
+	if port == "" {
+		port = "443"
+	}
+
+	conn, err := tls.Dial("tcp", host+":"+port, checkTLSConfig)
+
+	if err != nil {
+		return false, err
+	}
+
+	defer conn.Close()
+
+	err = conn.VerifyHostname(server.Host)
+
+	if err != nil {
+		return false, err
+	}
+
+	now := time.Now()
+
+	state := conn.ConnectionState()
+
+	opts := x509.VerifyOptions{
+		CurrentTime: time.Now(),
+	}
+
+	for _, cert := range state.PeerCertificates {
+		if _, err := cert.Verify(opts); err != nil {
+			logFields["peerCert"] = cert.Subject.String()
+			return false, err
+		}
+		if now.Before(cert.NotBefore) || now.After(cert.NotAfter) {
+			return false, err
+		}
+	}
+
+	for _, chain := range state.VerifiedChains {
+		for _, cert := range chain {
+			if now.Before(cert.NotBefore) || now.After(cert.NotAfter) {
+				logFields["cert"] = cert.Subject.String()
+				return false, ErrCertExpired
+			}
+		}
+	}
+
+	return true, nil
+}

check_test.go

@@ -0,0 +1,202 @@
+package main
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/tls"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/pem"
+	"fmt"
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+	log "github.com/sirupsen/logrus"
+	"math/big"
+	"net"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"strings"
+	"time"
+)
+
+func genTestCerts(notBefore, notAfter time.Time) (*pem.Block, *pem.Block, error) {
+	// Create a Certificate Authority Cert
+	template := x509.Certificate{
+		SerialNumber:          big.NewInt(0),
+		Subject:               pkix.Name{CommonName: "localhost"},
+		SignatureAlgorithm:    x509.SHA256WithRSA,
+		NotBefore:             notBefore,
+		NotAfter:              notAfter,
+		BasicConstraintsValid: true,
+		IPAddresses:           []net.IP{net.ParseIP("127.0.0.1")},
+		KeyUsage:              x509.KeyUsageDigitalSignature | x509.KeyUsageKeyAgreement | x509.KeyUsageKeyEncipherment | x509.KeyUsageDataEncipherment,
+		ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth, x509.ExtKeyUsageClientAuth},
+	}
+
+	// Create a Private Key
+	key, err := rsa.GenerateKey(rand.Reader, 4096)
+	if err != nil {
+		return nil, nil, fmt.Errorf("Could not generate rsa key - %s", err)
+	}
+
+	// Use CA Cert to sign a CSR and create a Public Cert
+	csr := &key.PublicKey
+	cert, err := x509.CreateCertificate(rand.Reader, &template, &template, csr, key)
+	if err != nil {
+		return nil, nil, fmt.Errorf("Could not generate certificate - %s", err)
+	}
+
+	// Convert keys into pem.Block
+	c := &pem.Block{Type: "CERTIFICATE", Bytes: cert}
+	k := &pem.Block{Type: "RSA PRIVATE KEY", Bytes: x509.MarshalPKCS1PrivateKey(key)}
+	return c, k, nil
+}
+
+var _ = Describe("Check suite", func() {
+	var (
+		httpServer *httptest.Server
+		server     *Server
+		handler    http.HandlerFunc
+	)
+	BeforeEach(func() {
+		httpServer = httptest.NewUnstartedServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			handler(w, r)
+		}))
+	})
+	AfterEach(func() {
+		httpServer.Close()
+	})
+	setupServer := func() {
+		u, err := url.Parse(httpServer.URL)
+
+		if err != nil {
+			panic(err)
+		}
+		server = &Server{
+			Host: u.Host,
+			Path: u.Path,
+		}
+	}
+
+	Context("HTTP Checks", func() {
+		BeforeEach(func() {
+			httpServer.Start()
+			setupServer()
+		})
+		It("Should successfully check for connectivity", func() {
+			handler = func(w http.ResponseWriter, r *http.Request) {
+				w.WriteHeader(http.StatusOK)
+			}
+
+			res, err := checkHttp(server, log.Fields{})
+
+			Expect(res).To(BeTrue())
+			Expect(err).To(BeNil())
+		})
+		It("Should return an error when redirected to https", func() {
+			handler = func(w http.ResponseWriter, r *http.Request) {
+				w.Header().Set("Location", strings.Replace(httpServer.URL, "http://", "https://", -1))
+				w.WriteHeader(http.StatusMovedPermanently)
+			}
+
+			res, err := checkHttp(server, log.Fields{})
+
+			Expect(res).To(BeFalse())
+			Expect(err).To(Equal(ErrHttpsRedirect))
+		})
+	})
+	Context("TLS Checks", func() {
+		var (
+			x509Cert *x509.Certificate
+		)
+		setupCerts := func(notBefore, notAfter time.Time) {
+			cert, key, err := genTestCerts(notBefore, notAfter)
+
+			if err != nil {
+				panic("Unable to generate test certs")
+			}
+
+			x509Cert, err = x509.ParseCertificate(cert.Bytes)
+
+			if err != nil {
+				panic("Unable to parse certificate from bytes: " + err.Error())
+			}
+
+			tlsPair, err := tls.X509KeyPair(pem.EncodeToMemory(cert), pem.EncodeToMemory(key))
+
+			if err != nil {
+				panic("Unable to load tls key pair: " + err.Error())
+			}
+
+			httpServer.TLS = &tls.Config{
+				Certificates: []tls.Certificate{tlsPair},
+			}
+
+			httpServer.StartTLS()
+			setupServer()
+		}
+		Context("CA Tests", func() {
+			BeforeEach(func() {
+				setupCerts(time.Now(), time.Now().Add(24*time.Hour))
+			})
+			It("Should fail due to invalid ca", func() {
+				res, err := checkTLS(server, log.Fields{})
+
+				Expect(res).To(BeFalse())
+				Expect(err).ToNot(BeNil())
+			})
+			It("Should successfully validate certificates (valid ca, valid date/times, etc)", func() {
+				pool := x509.NewCertPool()
+
+				pool.AddCert(x509Cert)
+
+				checkTLSConfig = &tls.Config{RootCAs: pool}
+
+				res, err := checkTLS(server, log.Fields{})
+
+				Expect(res).To(BeFalse())
+				Expect(err).ToNot(BeNil())
+
+				checkTLSConfig = nil
+			})
+		})
+		Context("Expiration tests", func() {
+			AfterEach(func() {
+				checkTLSConfig = nil
+			})
+			It("Should fail due to not yet valid certificate", func() {
+				setupCerts(time.Now().Add(5*time.Hour), time.Now().Add(10*time.Hour))
+
+				// Trust our certs
+				pool := x509.NewCertPool()
+
+				pool.AddCert(x509Cert)
+
+				checkTLSConfig = &tls.Config{RootCAs: pool}
+
+				// Check TLS
+				res, err := checkTLS(server, log.Fields{})
+
+				Expect(res).To(BeFalse())
+				Expect(err).ToNot(BeNil())
+			})
+			It("Should fail due to expired certificate", func() {
+				setupCerts(time.Now().Add(-10*time.Hour), time.Now().Add(-5*time.Hour))
+
+				// Trust our certs
+				pool := x509.NewCertPool()
+
+				pool.AddCert(x509Cert)
+
+				checkTLSConfig = &tls.Config{RootCAs: pool}
+
+				// Check TLS
+				res, err := checkTLS(server, log.Fields{})
+
+				Expect(res).To(BeFalse())
+				Expect(err).ToNot(BeNil())
+			})
+		})
+	})
+})

config.go

@@ -0,0 +1,250 @@
+package main
+
+import (
+	lru "github.com/hashicorp/golang-lru"
+	"github.com/oschwald/maxminddb-golang"
+	"github.com/pkg/errors"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+	log "github.com/sirupsen/logrus"
+	"github.com/spf13/viper"
+	"net"
+	"net/url"
+	"strings"
+	"sync"
+)
+
+func reloadConfig() error {
+	log.Info("Loading configuration...")
+
+	err := viper.ReadInConfig() // Find and read the config file
+
+	if err != nil { // Handle errors reading the config file
+		return errors.Wrap(err, "Unable to read configuration")
+	}
+
+	// db will never be reloaded.
+	if db == nil {
+		// Load maxmind database
+		db, err = maxminddb.Open(viper.GetString("geodb"))
+
+		if err != nil {
+			return errors.Wrap(err, "Unable to open database")
+		}
+	}
+
+	// Refresh server cache if size changed
+	if serverCache == nil {
+		serverCache, err = lru.New(viper.GetInt("cacheSize"))
+	} else {
+		serverCache.Resize(viper.GetInt("cacheSize"))
+	}
+
+	// Purge the cache to ensure we don't have any invalid servers in it
+	serverCache.Purge()
+
+	// Set top choice count
+	topChoices = viper.GetInt("topChoices")
+
+	// Reload map file
+	if err := reloadMap(); err != nil {
+		return errors.Wrap(err, "Unable to load map file")
+	}
+
+	// Reload server list
+	if err := reloadServers(); err != nil {
+		return errors.Wrap(err, "Unable to load servers")
+	}
+
+	// Create mirror map
+	mirrors := make(map[string][]*Server)
+
+	for _, server := range servers {
+		mirrors[server.Continent] = append(mirrors[server.Continent], server)
+	}
+
+	mirrors["default"] = append(mirrors["NA"], mirrors["EU"]...)
+
+	regionMap = mirrors
+
+	hosts := make(map[string]*Server)
+
+	for _, server := range servers {
+		hosts[server.Host] = server
+	}
+
+	hostMap = hosts
+
+	// Check top choices size
+	if topChoices > len(servers) {
+		topChoices = len(servers)
+	}
+
+	// Force check
+	go servers.Check()
+
+	return nil
+}
+
+func reloadServers() error {
+	var serverList []ServerConfig
+
+	if err := viper.UnmarshalKey("servers", &serverList); err != nil {
+		return err
+	}
+
+	var wg sync.WaitGroup
+
+	existing := make(map[string]int)
+
+	for i, server := range servers {
+		existing[server.Host] = i
+	}
+
+	hosts := make(map[string]bool)
+
+	for _, server := range serverList {
+		wg.Add(1)
+
+		var prefix string
+
+		if !strings.HasPrefix(server.Server, "http") {
+			prefix = "https://"
+		}
+
+		u, err := url.Parse(prefix + server.Server)
+
+		if err != nil {
+			log.WithFields(log.Fields{
+				"error":  err,
+				"server": server,
+			}).Warning("Server is invalid")
+			return err
+		}
+
+		hosts[u.Host] = true
+
+		i := -1
+
+		if v, exists := existing[u.Host]; exists {
+			i = v
+		}
+
+		go func(i int, server ServerConfig, u *url.URL) {
+			defer wg.Done()
+
+			s := addServer(server, u)
+
+			if _, ok := existing[u.Host]; ok {
+				s.Redirects = servers[i].Redirects
+
+				servers[i] = s
+			} else {
+				s.Redirects = promauto.NewCounter(prometheus.CounterOpts{
+					Name: "armbian_router_redirects_" + metricReplacer.Replace(u.Host),
+					Help: "The number of redirects for server " + u.Host,
+				})
+
+				servers = append(servers, s)
+
+				log.WithFields(log.Fields{
+					"server":    u.Host,
+					"path":      u.Path,
+					"latitude":  s.Latitude,
+					"longitude": s.Longitude,
+				}).Info("Added server")
+			}
+		}(i, server, u)
+	}
+
+	wg.Wait()
+
+	// Remove servers that no longer exist in the config
+	for i := len(servers) - 1; i >= 0; i-- {
+		if _, exists := hosts[servers[i].Host]; exists {
+			continue
+		}
+
+		log.WithFields(log.Fields{
+			"server": servers[i].Host,
+		}).Info("Removed server")
+
+		servers = append(servers[:i], servers[i+1:]...)
+	}
+
+	return nil
+}
+
+var metricReplacer = strings.NewReplacer(".", "_", "-", "_")
+
+// addServer takes ServerConfig and constructs a server.
+// This will create duplicate servers, but it will overwrite existing ones when changed.
+func addServer(server ServerConfig, u *url.URL) *Server {
+	s := &Server{
+		Available: true,
+		Host:      u.Host,
+		Path:      u.Path,
+		Latitude:  server.Latitude,
+		Longitude: server.Longitude,
+		Continent: server.Continent,
+		Weight:    server.Weight,
+	}
+
+	// Defaults to 10 to allow servers to be set lower for lower priority
+	if s.Weight == 0 {
+		s.Weight = 10
+	}
+
+	ips, err := net.LookupIP(u.Host)
+
+	if err != nil {
+		log.WithFields(log.Fields{
+			"error":  err,
+			"server": s.Host,
+		}).Warning("Could not resolve address")
+		return nil
+	}
+
+	var city City
+	err = db.Lookup(ips[0], &city)
+
+	if err != nil {
+		log.WithFields(log.Fields{
+			"error":  err,
+			"server": s.Host,
+			"ip":     ips[0],
+		}).Warning("Could not geolocate address")
+		return nil
+	}
+
+	if s.Continent == "" {
+		s.Continent = city.Continent.Code
+	}
+
+	if s.Latitude == 0 && s.Longitude == 0 {
+		s.Latitude = city.Location.Latitude
+		s.Longitude = city.Location.Longitude
+	}
+
+	return s
+}
+
+func reloadMap() error {
+	mapFile := viper.GetString("dl_map")
+
+	if mapFile == "" {
+		return nil
+	}
+
+	log.WithField("file", mapFile).Info("Loading download map")
+
+	newMap, err := loadMapFile(mapFile)
+
+	if err != nil {
+		return err
+	}
+
+	dlMap = newMap
+
+	return nil
+}

dlrouter.yaml

@@ -1,16 +1,47 @@
-geodb: GeoIP2-City.mmdb
+# GeoIP Database Path
+geodb: GeoLite2-City.mmdb
+dl_map: userdata.csv
 
+# LRU Cache Size (in items)
+cacheSize: 1024
+
+# Server definition
+# Weights are just like nginx, where if it's > 1 it'll be chosen x out of x + total times
+# By default, the top 3 servers are used for choosing the best.
+# server = full url or host+path
+# weight = int
+# optional: latitude, longitude (float)
 servers:
-    - https://mirrors.tuna.tsinghua.edu.cn/armbian-releases/
+    - server: armbian.12z.eu/apt/
-    - https://mirrors.bfsu.edu.cn/armbian-releases/
+    - server: armbian.chi.auroradev.org/apt/
-    - https://mirrors.nju.edu.cn/armbian-releases/
+      weight: 15
-    - https://mirrors.ustc.edu.cn/armbian-dl/
+      latitude: 41.8879
-    - https://mirror.12z.eu/pub/linux/armbian/dl/
+      longitude: -88.1995
-    - https://armbian.tnahosting.net/dl/
+    - server: armbian.hosthatch.com/apt/
-    - https://stpete-mirror.armbian.com/dl/
+    - server: armbian.lv.auroradev.org/apt/
-    - https://mirror.armbian.de/dl/
+      weight: 15
-    - https://mirrors.netix.net/armbian/dl/
+    - server: armbian.site-meganet.com/apt/
-    - https://mirrors.dotsrc.org/armbian-dl/
+    - server: armbian.systemonachip.net/apt/
-    - https://armbian.hosthatch.com/dl/
+    - server: armbian.tnahosting.net/apt/
-    - https://xogium.performanceservers.nl/dl/
+      weight: 15
-    - https://github.com/armbian/mirror/releases/download/
+    - server: au-mirror.bret.dk/armbian/apt/
+    - server: es-mirror.bret.dk/armbian/apt/
+    - server: imola.armbian.com/apt/
+    - server: mirror.iscas.ac.cn/armbian/
+    - server: mirror.sjtu.edu.cn/armbian/
+    - server: mirrors.aliyun.com/armbian/
+      continent: AS
+    - server: mirrors.bfsu.edu.cn/armbian/
+    - server: mirrors.dotsrc.org/armbian-apt/
+      weight: 15
+    - server: mirrors.netix.net/armbian/apt/
+    - server: mirrors.nju.edu.cn/armbian/
+    - server: mirrors.sustech.edu.cn/armbian/
+    - server: mirrors.tuna.tsinghua.edu.cn/armbian/
+    - server: mirrors.ustc.edu.cn/armbian/
+    - server: mirrors.xtom.de/armbian/
+    - server: sg-mirror.bret.dk/armbian/apt/
+    - server: stpete-mirror.armbian.com/apt/
+    - server: xogium.performanceservers.nl/apt/
+    - server: github.com/armbian/mirror/releases/download/
+      continent: GITHUB

go.mod

@@ -5,7 +5,12 @@ go 1.17
 require (
 	github.com/chi-middleware/logrus-logger v0.2.0
 	github.com/go-chi/chi/v5 v5.0.7
+	github.com/hashicorp/golang-lru v0.5.4
+	github.com/jmcvetta/randutil v0.0.0-20150817122601-2bb1b664bcff
+	github.com/onsi/ginkgo/v2 v2.1.4
+	github.com/onsi/gomega v1.20.0
 	github.com/oschwald/maxminddb-golang v1.8.0
+	github.com/pkg/errors v0.9.1
 	github.com/prometheus/client_golang v1.11.0
 	github.com/sirupsen/logrus v1.8.1
 	github.com/spf13/viper v1.10.1
@@ -16,6 +21,7 @@ require (
 	github.com/cespare/xxhash/v2 v2.1.2 // indirect
 	github.com/fsnotify/fsnotify v1.5.1 // indirect
 	github.com/golang/protobuf v1.5.2 // indirect
+	github.com/google/go-cmp v0.5.8 // indirect
 	github.com/hashicorp/hcl v1.0.0 // indirect
 	github.com/magiconair/properties v1.8.5 // indirect
 	github.com/matttproud/golang_protobuf_extensions v1.0.1 // indirect
@@ -29,9 +35,11 @@ require (
 	github.com/spf13/jwalterweatherman v1.1.0 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
 	github.com/subosito/gotenv v1.2.0 // indirect
-	golang.org/x/sys v0.0.0-20211210111614-af8b64212486 // indirect
+	golang.org/x/net v0.0.0-20220425223048-2871e0cb64e4 // indirect
+	golang.org/x/sys v0.0.0-20220422013727-9388b58f7150 // indirect
 	golang.org/x/text v0.3.7 // indirect
-	google.golang.org/protobuf v1.27.1 // indirect
+	google.golang.org/protobuf v1.28.0 // indirect
 	gopkg.in/ini.v1 v1.66.2 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -110,6 +110,8 @@ github.com/envoyproxy/protoc-gen-validate v0.6.2/go.mod h1:2t7qjJNvHPx8IjnBOzl9E
 github.com/fatih/color v1.7.0/go.mod h1:Zm6kSWBoL9eyXnKyktHP6abPY2pDugNf5KwzbycvMj4=
 github.com/fatih/color v1.9.0/go.mod h1:eQcE1qtQxscV5RaZvpXrrb8Drkc3/DdQ+uUYCNjL+zU=
 github.com/fatih/color v1.13.0/go.mod h1:kLAiJbzzSOZDVNGyDpeOxJ47H46qBXwg5ILebYFFOfk=
+github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
+github.com/fsnotify/fsnotify v1.4.9/go.mod h1:znqG4EE+3YCdAaPaxE2ZRY/06pZUdp0tY4IgpuI1SZQ=
 github.com/fsnotify/fsnotify v1.5.1 h1:mZcQUHVQUQWoPXXtuf9yuEXKudkV2sx1E06UadKWpgI=
 github.com/fsnotify/fsnotify v1.5.1/go.mod h1:T3375wBYaZdLLcVNkcVbzGHY7f1l/uK5T5Ai1i3InKU=
 github.com/ghodss/yaml v1.0.0/go.mod h1:4dBDuWmgqj2HViK6kFavaiC9ZROes6MMH2rRYeMEF04=
@@ -126,6 +128,8 @@ github.com/go-logfmt/logfmt v0.3.0/go.mod h1:Qt1PoO58o5twSAckw1HlFXLmHsOX5/0LbT9
 github.com/go-logfmt/logfmt v0.4.0/go.mod h1:3RMwSq7FuexP4Kalkev3ejPJsZTpXXBr9+V4qmtdjCk=
 github.com/go-logfmt/logfmt v0.5.0/go.mod h1:wCYkCAKZfumFQihp8CzCvQ3paCTfi41vtzG1KdI/P7A=
 github.com/go-stack/stack v1.8.0/go.mod h1:v0f6uXyyMGvRgIKkXu+yp6POWl0qKG85gN/melR3HDY=
+github.com/go-task/slim-sprig v0.0.0-20210107165309-348f09dbbbc0 h1:p104kn46Q8WdvHunIJ9dAyjPVtrBPhSr3KT2yUst43I=
+github.com/go-task/slim-sprig v0.0.0-20210107165309-348f09dbbbc0/go.mod h1:fyg7847qk6SyHyPtNmDHnmrv/HOrqktSC+C9fM+CJOE=
 github.com/godbus/dbus/v5 v5.0.4/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
 github.com/gogo/protobuf v1.1.1/go.mod h1:r8qH/GZQm5c6nD/R0oafs1akxWv10x8SbQlK7atdtwQ=
 github.com/gogo/protobuf v1.3.2/go.mod h1:P1XiOD3dCwIKUDQYPy72D8LYyHL2YPYrpS2s69NZV8Q=
@@ -175,8 +179,9 @@ github.com/google/go-cmp v0.5.2/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/
 github.com/google/go-cmp v0.5.3/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.4/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/go-cmp v0.5.6 h1:BKbKCqvP6I+rmFHt06ZmyQtvB8xAkWdhFyr0ZUNZcxQ=
 github.com/google/go-cmp v0.5.6/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/google/go-cmp v0.5.8 h1:e6P7q2lk1O+qJJb4BtCQXlK8vWEO8V1ZeuEdJNOqZyg=
+github.com/google/go-cmp v0.5.8/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/google/martian v2.1.0+incompatible/go.mod h1:9I4somxYTbIHy5NJKHRl3wXiIaQGbYVAs8BPL6v8lEs=
 github.com/google/martian/v3 v3.0.0/go.mod h1:y5Zk1BBys9G+gd6Jrk0W3cC1+ELVxBWuIGO+w/tUAp0=
@@ -193,6 +198,8 @@ github.com/google/pprof v0.0.0-20201023163331-3e6fc7fc9c4c/go.mod h1:kpwsk12EmLe
 github.com/google/pprof v0.0.0-20201203190320-1bf35d6f28c2/go.mod h1:kpwsk12EmLew5upagYY7GY0pfYCcupk39gWOCRROcvE=
 github.com/google/pprof v0.0.0-20210122040257-d980be63207e/go.mod h1:kpwsk12EmLew5upagYY7GY0pfYCcupk39gWOCRROcvE=
 github.com/google/pprof v0.0.0-20210226084205-cbba55b83ad5/go.mod h1:kpwsk12EmLew5upagYY7GY0pfYCcupk39gWOCRROcvE=
+github.com/google/pprof v0.0.0-20210407192527-94a9f03dee38 h1:yAJXTCF9TqKcTiHJAE8dj7HMvPfh66eeA2JYW7eFpSE=
+github.com/google/pprof v0.0.0-20210407192527-94a9f03dee38/go.mod h1:kpwsk12EmLew5upagYY7GY0pfYCcupk39gWOCRROcvE=
 github.com/google/pprof v0.0.0-20210601050228-01bbb1931b22/go.mod h1:kpwsk12EmLew5upagYY7GY0pfYCcupk39gWOCRROcvE=
 github.com/google/pprof v0.0.0-20210609004039-a478d1d731e9/go.mod h1:kpwsk12EmLew5upagYY7GY0pfYCcupk39gWOCRROcvE=
 github.com/google/pprof v0.0.0-20210720184732-4bb14d4b1be1/go.mod h1:kpwsk12EmLew5upagYY7GY0pfYCcupk39gWOCRROcvE=
@@ -224,6 +231,7 @@ github.com/hashicorp/go-uuid v1.0.0/go.mod h1:6SBZvOh/SIDV7/2o3Jml5SYk/TvGqwFJ/b
 github.com/hashicorp/go-uuid v1.0.1/go.mod h1:6SBZvOh/SIDV7/2o3Jml5SYk/TvGqwFJ/bN7x4byOro=
 github.com/hashicorp/golang-lru v0.5.0/go.mod h1:/m3WP610KZHVQ1SGc6re/UDhFvYD7pJ4Ao+sR/qLZy8=
 github.com/hashicorp/golang-lru v0.5.1/go.mod h1:/m3WP610KZHVQ1SGc6re/UDhFvYD7pJ4Ao+sR/qLZy8=
+github.com/hashicorp/golang-lru v0.5.4 h1:YDjusn29QI/Das2iO9M0BHnIbxPeyuCHsjMW+lJfyTc=
 github.com/hashicorp/golang-lru v0.5.4/go.mod h1:iADmTwqILo4mZ8BN3D2Q6+9jd8WM5uGBxy+E8yxSoD4=
 github.com/hashicorp/hcl v1.0.0 h1:0Anlzjpi4vEasTeNFn2mLJgTSwt0+6sfsiTG8qcWGx4=
 github.com/hashicorp/hcl v1.0.0/go.mod h1:E5yfLk+7swimpb2L/Alb/PJmXilQ/rhwaUYs4T20WEQ=
@@ -231,9 +239,12 @@ github.com/hashicorp/logutils v1.0.0/go.mod h1:QIAnNjmIWmVIIkWDTG1z5v++HQmx9WQRO
 github.com/hashicorp/mdns v1.0.4/go.mod h1:mtBihi+LeNXGtG8L9dX59gAEa12BDtBQSp4v/YAJqrc=
 github.com/hashicorp/memberlist v0.3.0/go.mod h1:MS2lj3INKhZjWNqd3N0m3J+Jxf3DAOnAH9VT3Sh9MUE=
 github.com/hashicorp/serf v0.9.6/go.mod h1:TXZNMjZQijwlDvp+r0b63xZ45H7JmCmgg4gpTwn9UV4=
+github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=
 github.com/iancoleman/strcase v0.2.0/go.mod h1:iwCmte+B7n89clKwxIoIXy/HfoL7AsD47ZCWhYzw7ho=
 github.com/ianlancetaylor/demangle v0.0.0-20181102032728-5e5cf60278f6/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
 github.com/ianlancetaylor/demangle v0.0.0-20200824232613-28f6c0f3b639/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
+github.com/jmcvetta/randutil v0.0.0-20150817122601-2bb1b664bcff h1:6NvhExg4omUC9NfA+l4Oq3ibNNeJUdiAF3iBVB0PlDk=
+github.com/jmcvetta/randutil v0.0.0-20150817122601-2bb1b664bcff/go.mod h1:ddfPX8Z28YMjiqoaJhNBzWHapTHXejnB5cDCUWDwriw=
 github.com/jpillora/backoff v1.0.0/go.mod h1:J/6gKK9jxlEcS3zixgDgUAsiuZ7yrSoa/FX5e0EB2j4=
 github.com/json-iterator/go v1.1.6/go.mod h1:+SdeFBvtyEkXs7REEP0seUULqWtbJapLOCVDaaPEHmU=
 github.com/json-iterator/go v1.1.9/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/uOdHXbAo4=
@@ -290,6 +301,21 @@ github.com/modern-go/reflect2 v1.0.1/go.mod h1:bx2lNnkwVCuqBIxFjflWJWanXIb3Rllmb
 github.com/modern-go/reflect2 v1.0.2/go.mod h1:yWuevngMOJpCy52FWWMvUC8ws7m/LJsjYzDa0/r8luk=
 github.com/mwitkow/go-conntrack v0.0.0-20161129095857-cc309e4a2223/go.mod h1:qRWi+5nqEBWmkhHvq77mSJWrCKwh8bxhgT7d/eI7P4U=
 github.com/mwitkow/go-conntrack v0.0.0-20190716064945-2f068394615f/go.mod h1:qRWi+5nqEBWmkhHvq77mSJWrCKwh8bxhgT7d/eI7P4U=
+github.com/nxadm/tail v1.4.4/go.mod h1:kenIhsEOeOJmVchQTgglprH7qJGnHDVpk1VPCcaMI8A=
+github.com/nxadm/tail v1.4.8/go.mod h1:+ncqLTQzXmGhMZNUePPaPqPvBxHAIsmXswZKocGu+AU=
+github.com/onsi/ginkgo v1.6.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
+github.com/onsi/ginkgo v1.12.1/go.mod h1:zj2OWP4+oCPe1qIXoGWkgMRwljMUYCdkwsT2108oapk=
+github.com/onsi/ginkgo v1.16.4 h1:29JGrr5oVBm5ulCWet69zQkzWipVXIol6ygQUe/EzNc=
+github.com/onsi/ginkgo v1.16.4/go.mod h1:dX+/inL/fNMqNlz0e9LfyB9TswhZpCVdJM/Z6Vvnwo0=
+github.com/onsi/ginkgo/v2 v2.1.3/go.mod h1:vw5CSIxN1JObi/U8gcbwft7ZxR2dgaR70JSE3/PpL4c=
+github.com/onsi/ginkgo/v2 v2.1.4 h1:GNapqRSid3zijZ9H77KrgVG4/8KqiyRsxcSxe+7ApXY=
+github.com/onsi/ginkgo/v2 v2.1.4/go.mod h1:um6tUpWM/cxCK3/FK8BXqEiUMUwRgSM4JXG47RKZmLU=
+github.com/onsi/gomega v1.7.1/go.mod h1:XdKZgCCFLUoM/7CFJVPcG8C1xQ1AJ0vpAezJrB7JYyY=
+github.com/onsi/gomega v1.10.1/go.mod h1:iN09h71vgCQne3DLsj+A5owkum+a2tYe+TOCB1ybHNo=
+github.com/onsi/gomega v1.17.0/go.mod h1:HnhC7FXeEQY45zxNK3PPoIUhzk/80Xly9PcubAlGdZY=
+github.com/onsi/gomega v1.19.0/go.mod h1:LY+I3pBVzYsTBU1AnDwOSxaYi9WoWiqgwooUqq9yPro=
+github.com/onsi/gomega v1.20.0 h1:8W0cWlwFkflGPLltQvLRB7ZVD5HuP6ng320w2IS245Q=
+github.com/onsi/gomega v1.20.0/go.mod h1:DtrZpjmvpn2mPm4YWQa0/ALMDj9v4YxLgojwPeREyVo=
 github.com/oschwald/maxminddb-golang v1.8.0 h1:Uh/DSnGoxsyp/KYbY1AuP0tYEwfs0sCph9p/UMXK/Hk=
 github.com/oschwald/maxminddb-golang v1.8.0/go.mod h1:RXZtst0N6+FY/3qCNmZMBApR19cdQj43/NM9VkrNAis=
 github.com/pascaldekloe/goe v0.0.0-20180627143212-57f6aae5913c/go.mod h1:lzWF7FIEvWOWxwDKqyGYQf6ZUaNfKdP144TG7ZOy1lc=
@@ -298,6 +324,7 @@ github.com/pelletier/go-toml v1.9.4 h1:tjENF6MfZAg8e4ZmZTeWaWiT2vXtsoO6+iuOjFhEC
 github.com/pelletier/go-toml v1.9.4/go.mod h1:u1nR/EPcESfeI/szUZKdtJ0xRNbUoANCkoOuaOx1Y+c=
 github.com/pkg/errors v0.8.0/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pkg/sftp v1.10.1/go.mod h1:lYOWFsE0bwd1+KfKJaKeuokY15vzFx25BLbzYYoAxZI=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
@@ -365,6 +392,7 @@ github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9de
 github.com/yuin/goldmark v1.1.32/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/yuin/goldmark v1.3.5/go.mod h1:mwnBkeHKe2W/ZEtQ+71ViKU8L12m81fl3OWwC1Zlc8k=
+github.com/yuin/goldmark v1.4.1/go.mod h1:mwnBkeHKe2W/ZEtQ+71ViKU8L12m81fl3OWwC1Zlc8k=
 go.etcd.io/etcd/api/v3 v3.5.1/go.mod h1:cbVKeC6lCfl7j/8jBhAK6aIYO9XOjdptoxU/nLQcPvs=
 go.etcd.io/etcd/client/pkg/v3 v3.5.1/go.mod h1:IJHfcCEKxYu1Os13ZdwCwIUTUVGYTSAM3YSwc9/Ac1g=
 go.etcd.io/etcd/client/v2 v2.305.1/go.mod h1:pMEacxZW7o8pg4CrFE7pquyCJJzZvkvdD2RibOCCCGs=
@@ -388,6 +416,7 @@ golang.org/x/crypto v0.0.0-20190923035154-9ee001bba392/go.mod h1:/lpIB1dKB+9EgE3
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/crypto v0.0.0-20210817164053-32db794688a5/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
+golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
 golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/exp v0.0.0-20190306152737-a1d7652674e8/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/exp v0.0.0-20190510132918-efd6b22b2522/go.mod h1:ZjyILWgesfNpC6sMxTJOJm9Kp84zZh5NQWvqDGG3Qr8=
@@ -424,8 +453,10 @@ golang.org/x/mod v0.4.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/mod v0.4.1/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/mod v0.4.2/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/mod v0.5.0/go.mod h1:5OXOZSfqPIIbmVBIIKWRFfZjPR0E5r58TLhUjH0a2Ro=
+golang.org/x/mod v0.6.0-dev.0.20220106191415-9b9b3d81d5e3/go.mod h1:3p9vT2HGsQu2K1YbXdKPJLVgG5VJdoTa1poYQBtP1AY=
 golang.org/x/net v0.0.0-20180724234803-3673e40ba225/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20180826012351-8a410e7b638d/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/net v0.0.0-20180906233101-161cd47e91fd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20181114220301-adae6a3d119a/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20190108225652-1e06a53dbb7e/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20190213061140-3a22650c66bd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
@@ -449,6 +480,7 @@ golang.org/x/net v0.0.0-20200324143707-d3edc9973b7e/go.mod h1:qpuaurCH72eLCgpAm/
 golang.org/x/net v0.0.0-20200501053045-e0ff5e5a1de5/go.mod h1:qpuaurCH72eLCgpAm/N6yyVIVM9cpaDIP3A8BGJEC5A=
 golang.org/x/net v0.0.0-20200506145744-7e3656a0809f/go.mod h1:qpuaurCH72eLCgpAm/N6yyVIVM9cpaDIP3A8BGJEC5A=
 golang.org/x/net v0.0.0-20200513185701-a91f0712d120/go.mod h1:qpuaurCH72eLCgpAm/N6yyVIVM9cpaDIP3A8BGJEC5A=
+golang.org/x/net v0.0.0-20200520004742-59133d7f0dd7/go.mod h1:qpuaurCH72eLCgpAm/N6yyVIVM9cpaDIP3A8BGJEC5A=
 golang.org/x/net v0.0.0-20200520182314-0ba52f642ac2/go.mod h1:qpuaurCH72eLCgpAm/N6yyVIVM9cpaDIP3A8BGJEC5A=
 golang.org/x/net v0.0.0-20200625001655-4c5254603344/go.mod h1:/O7V0waA8r7cgGh81Ro3o1hOxt32SMVPicZroKQ2sZA=
 golang.org/x/net v0.0.0-20200707034311-ab3426394381/go.mod h1:/O7V0waA8r7cgGh81Ro3o1hOxt32SMVPicZroKQ2sZA=
@@ -462,8 +494,13 @@ golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v
 golang.org/x/net v0.0.0-20210316092652-d523dce5a7f4/go.mod h1:RBQZq4jEuRlivfhVLdyRGr576XBO4/greRjx4P4O3yc=
 golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4/go.mod h1:p54w0d4576C0XHj96bSt6lcn1PtDYWL6XObtHCRCNQM=
 golang.org/x/net v0.0.0-20210410081132-afb366fc7cd1/go.mod h1:9tjilg8BloeKEkVJvy7fQ90B1CfIiPueXVOjqfkSzI8=
+golang.org/x/net v0.0.0-20210428140749-89ef3d95e781/go.mod h1:OJAsFXCWl8Ukc7SiCT/9KSuxbyM7479/AVlXFRxuMCk=
 golang.org/x/net v0.0.0-20210503060351-7fd8e65b6420/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
 golang.org/x/net v0.0.0-20210813160813-60bc85c4be6d/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
+golang.org/x/net v0.0.0-20211015210444-4f30a5c0130f/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
+golang.org/x/net v0.0.0-20220225172249-27dd8689420f/go.mod h1:CfG3xpIq0wQ8r1q4Su4UZFWDARRcnwPjda9FqA0JpMk=
+golang.org/x/net v0.0.0-20220425223048-2871e0cb64e4 h1:HVyaeDAYux4pnY+D/SiwmLOR36ewZ4iGQIIrtnuCjFA=
+golang.org/x/net v0.0.0-20220425223048-2871e0cb64e4/go.mod h1:CfG3xpIq0wQ8r1q4Su4UZFWDARRcnwPjda9FqA0JpMk=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20190226205417-e64efc72b421/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
 golang.org/x/oauth2 v0.0.0-20190604053449-0f29369cfe45/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
@@ -495,6 +532,7 @@ golang.org/x/sync v0.0.0-20210220032951-036812b2e83c/go.mod h1:RxMgew5VJxzue5/jJ
 golang.org/x/sys v0.0.0-20180823144017-11551d06cbcc/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20180905080454-ebe1bf3edb33/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20180909124046-d0be0721c37e/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20181116152217-5ac8a444bdc5/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190222072716-a9d3bda3a223/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
@@ -506,11 +544,14 @@ golang.org/x/sys v0.0.0-20190507160741-ecd444e8653b/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20190606165138-5da285871e9c/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190624142023-c5567b49c5d0/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190726091711-fc99dfbffb4e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20190904154756-749cb33beabd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190922100055-0a153f010e69/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190924154521-2837fb4f24fe/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20191001151750-bb3f8db39f24/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20191005200804-aed5e4c7ecf9/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20191008105621-543471e840be/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20191026070338-33540a1f6037/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20191120155948-bd437916bb0e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20191204072324-ce4227a45e2e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20191224085550-c709ea063b76/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20191228213918-04cbcbbfeed8/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
@@ -537,6 +578,7 @@ golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20201201145000-ef89a241ccb3/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210104204734-6f8348627aad/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210112080510-489259a85091/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210119212857-b64e53b001e4/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210124154548-22da62e12c0c/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210220050731-9a76102bfb43/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
@@ -561,10 +603,15 @@ golang.org/x/sys v0.0.0-20210823070655-63515b42dcdf/go.mod h1:oPkhp1MJrh7nUepCBc
 golang.org/x/sys v0.0.0-20210908233432-aa78b53d3365/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20210927094055-39ccf1dd6fa6/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20211007075335-d3039528d8ac/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20211019181941-9d821ace8654/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20211124211545-fe61309f8881/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
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 golang.org/x/sys v0.0.0-20211210111614-af8b64212486/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
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 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
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 golang.org/x/text v0.0.0-20170915032832-14c0d48ead0c/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.1-0.20180807135948-17ff2d5776d2/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
@@ -624,6 +671,7 @@ golang.org/x/tools v0.0.0-20200904185747-39188db58858/go.mod h1:Cj7w3i3Rnn0Xh82u
 golang.org/x/tools v0.0.0-20201110124207-079ba7bd75cd/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
 golang.org/x/tools v0.0.0-20201201161351-ac6f37ff4c2a/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
 golang.org/x/tools v0.0.0-20201208233053-a543418bbed2/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
+golang.org/x/tools v0.0.0-20201224043029-2b0845dc783e/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
 golang.org/x/tools v0.0.0-20210105154028-b0ab187a4818/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
 golang.org/x/tools v0.0.0-20210106214847-113979e3529a/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
 golang.org/x/tools v0.1.0/go.mod h1:xkSsbof2nBLbhDlRMhhhyNLN/zl3eTqcnHD5viDpcZ0=
@@ -632,10 +680,11 @@ golang.org/x/tools v0.1.2/go.mod h1:o0xws9oXOQQZyjljx8fwUC0k7L1pTE6eaCbjGeHmOkk=
 golang.org/x/tools v0.1.3/go.mod h1:o0xws9oXOQQZyjljx8fwUC0k7L1pTE6eaCbjGeHmOkk=
 golang.org/x/tools v0.1.4/go.mod h1:o0xws9oXOQQZyjljx8fwUC0k7L1pTE6eaCbjGeHmOkk=
 golang.org/x/tools v0.1.5/go.mod h1:o0xws9oXOQQZyjljx8fwUC0k7L1pTE6eaCbjGeHmOkk=
+golang.org/x/tools v0.1.10 h1:QjFRCZxdOhBJ/UNgnBZLbNV13DlbnK0quyivTnXJM20=
+golang.org/x/tools v0.1.10/go.mod h1:Uh6Zz+xoGYZom868N8YTex3t7RhtHDBrE8Gzo9bV56E=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
-golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 h1:go1bK/D/BFZV2I8cIQd1NKEZ+0owSTG1fDTci4IqFcE=
 golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 google.golang.org/api v0.4.0/go.mod h1:8k5glujaEP+g9n7WNsDg8QP6cUVNI86fCNMcbazEtwE=
 google.golang.org/api v0.7.0/go.mod h1:WtwebWUNSVBH/HAw79HIFXZNqEvBhG+Ra+ax0hx3E3M=
@@ -777,8 +826,9 @@ google.golang.org/protobuf v1.24.0/go.mod h1:r/3tXBNzIEhYS9I1OUVjXDlt8tc493IdKGj
 google.golang.org/protobuf v1.25.0/go.mod h1:9JNX74DMeImyA3h4bdi1ymwjUzf21/xIlbajtzgsN7c=
 google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw=
 google.golang.org/protobuf v1.26.0/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQnmE0givc=
-google.golang.org/protobuf v1.27.1 h1:SnqbnDw1V7RiZcXPx5MEeqPv2s79L9i7BJUlG/+RurQ=
 google.golang.org/protobuf v1.27.1/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQnmE0givc=
+google.golang.org/protobuf v1.28.0 h1:w43yiav+6bVFTBQFZX0r7ipe9JQ1QsbMgHwbBziscLw=
+google.golang.org/protobuf v1.28.0/go.mod h1:HV8QOd/L58Z+nl8r43ehVNZIU/HEI6OcFqwMG9pJV4I=
 gopkg.in/alecthomas/kingpin.v2 v2.2.6/go.mod h1:FMv+mEhP44yOT+4EoQTLFTRgOQ1FBLkstjWtayDeSgw=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
@@ -786,8 +836,10 @@ gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15/go.mod h1:Co6ibVJAznAaIkqp8
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=
 gopkg.in/errgo.v2 v2.1.0/go.mod h1:hNsd1EY+bozCKY1Ytp96fpM3vjJbqLJn88ws8XvfDNI=
+gopkg.in/fsnotify.v1 v1.4.7/go.mod h1:Tz8NjZHkW78fSQdbUxIjBTcgA1z1m8ZHf0WmKUhAMys=
 gopkg.in/ini.v1 v1.66.2 h1:XfR1dOYubytKy4Shzc2LHrrGhU0lDCfDGG1yLPmpgsI=
 gopkg.in/ini.v1 v1.66.2/go.mod h1:pNLf8WUiyNEtQjuu5G5vTm06TEv9tsIgeAvK8hOrP4k=
+gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7/go.mod h1:dt/ZhP58zS4L8KSrWDmTeBkI65Dw0HsyUHuEVlX15mw=
 gopkg.in/yaml.v2 v2.2.1/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.3/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
@@ -798,8 +850,9 @@ gopkg.in/yaml.v2 v2.3.0/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
 gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b h1:h8qDotaEPuJATrMmW04NCwg7v22aHH28wwpauUhK9Oo=
 gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190106161140-3f1c8253044a/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190418001031-e561f6794a2a/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=

http.go

@@ -3,23 +3,28 @@ package main
 import (
 	"encoding/json"
 	"fmt"
+	"github.com/jmcvetta/randutil"
+	"github.com/spf13/viper"
 	"net"
 	"net/http"
 	"net/url"
+	"os"
 	"path"
 	"strings"
 )
 
+// statusHandler is a simple handler that will always return 200 OK with a body of "OK"
 func statusHandler(w http.ResponseWriter, r *http.Request) {
 	w.WriteHeader(http.StatusOK)
+
+	if r.Method != http.MethodHead {
+		w.Write([]byte("OK"))
+	}
 }
 
-func mirrorsHandler(w http.ResponseWriter, r *http.Request) {
+// redirectHandler is the default "not found" handler which handles redirects
-	w.Header().Set("Content-Type", "application/json")
+// if the environment variable OVERRIDE_IP is set, it will use that ip address
-
+// this is useful for local testing when you're on the local network
-	json.NewEncoder(w).Encode(servers)
-}
-
 func redirectHandler(w http.ResponseWriter, r *http.Request) {
 	ipStr, _, err := net.SplitHostPort(r.RemoteAddr)
 
@@ -30,26 +35,75 @@ func redirectHandler(w http.ResponseWriter, r *http.Request) {
 
 	ip := net.ParseIP(ipStr)
 
-	// TODO: This is temporary to allow testing on private addresses.
+	if ip.IsLoopback() || ip.IsPrivate() {
-	if ip.IsPrivate() {
+		overrideIP := os.Getenv("OVERRIDE_IP")
-		ip = net.ParseIP("1.1.1.1")
+
+		if overrideIP == "" {
+			overrideIP = "1.1.1.1"
 		}
 
-	server, distance, err := servers.Closest(ip)
+		ip = net.ParseIP(overrideIP)
+	}
+
+	var server *Server
+	var distance float64
+
+	// If the path has a prefix of region/NA, it will use specific regions instead
+	// of the default geographical distance
+	if strings.HasPrefix(r.URL.Path, "/region") {
+		parts := strings.Split(r.URL.Path, "/")
+
+		// region = parts[2]
+		if mirrors, ok := regionMap[parts[2]]; ok {
+			choices := make([]randutil.Choice, len(mirrors))
+
+			for i, item := range mirrors {
+				if !item.Available {
+					continue
+				}
+
+				choices[i] = randutil.Choice{
+					Weight: item.Weight,
+					Item:   item,
+				}
+			}
+
+			choice, err := randutil.WeightedChoice(choices)
 
 			if err != nil {
 				http.Error(w, err.Error(), http.StatusInternalServerError)
 				return
 			}
 
+			server = choice.Item.(*Server)
+
+			r.URL.Path = strings.Join(parts[3:], "/")
+		}
+	}
+
+	// If none of the above exceptions are matched, we use the geographical distance based on IP
+	if server == nil {
+		server, distance, err = servers.Closest(ip)
+
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+	}
+
+	// If we don't have a scheme, we'll use https by default
 	scheme := r.URL.Scheme
 
 	if scheme == "" {
 		scheme = "https"
 	}
 
+	// redirectPath is a combination of server path (which can be something like /armbian)
+	// and the URL path.
+	// Example: /armbian + /some/path = /armbian/some/path
 	redirectPath := path.Join(server.Path, r.URL.Path)
 
+	// If we have a dlMap, we map the url to a final path instead
 	if dlMap != nil {
 		if newPath, exists := dlMap[strings.TrimLeft(r.URL.Path, "/")]; exists {
 			downloadsMapped.Inc()
@@ -57,6 +111,11 @@ func redirectHandler(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
+	if strings.HasSuffix(r.URL.Path, "/") && !strings.HasSuffix(redirectPath, "/") {
+		redirectPath += "/"
+	}
+
+	// We need to build the final url now
 	u := &url.URL{
 		Scheme: scheme,
 		Host:   server.Host,
@@ -66,13 +125,44 @@ func redirectHandler(w http.ResponseWriter, r *http.Request) {
 	server.Redirects.Inc()
 	redirectsServed.Inc()
 
+	// If we used geographical distance, we add an X-Geo-Distance header for debug.
+	if distance > 0 {
 		w.Header().Set("X-Geo-Distance", fmt.Sprintf("%f", distance))
+	}
+
 	w.Header().Set("Location", u.String())
 	w.WriteHeader(http.StatusFound)
 }
 
+// reloadHandler is an http handler which lets us reload the server configuration
+// It is only enabled when the reloadToken is set in the configuration
 func reloadHandler(w http.ResponseWriter, r *http.Request) {
-	reloadMap()
+	expectedToken := viper.GetString("reloadToken")
+
+	if expectedToken == "" {
+		w.WriteHeader(http.StatusUnauthorized)
+		return
+	}
+
+	token := r.Header.Get("Authorization")
+
+	if token == "" || !strings.HasPrefix(token, "Bearer") || !strings.Contains(token, " ") {
+		w.WriteHeader(http.StatusUnauthorized)
+		return
+	}
+
+	token = token[strings.Index(token, " ")+1:]
+
+	if token != expectedToken {
+		w.WriteHeader(http.StatusUnauthorized)
+		return
+	}
+
+	if err := reloadConfig(); err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		w.Write([]byte(err.Error()))
+		return
+	}
 
 	w.WriteHeader(http.StatusOK)
 	w.Write([]byte("OK"))
@@ -88,3 +178,25 @@ func dlMapHandler(w http.ResponseWriter, r *http.Request) {
 
 	json.NewEncoder(w).Encode(dlMap)
 }
+
+func geoIPHandler(w http.ResponseWriter, r *http.Request) {
+	ipStr, _, err := net.SplitHostPort(r.RemoteAddr)
+
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	ip := net.ParseIP(ipStr)
+
+	var city City
+	err = db.Lookup(ip, &city)
+
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	json.NewEncoder(w).Encode(city)
+}

main.go

@@ -4,27 +4,26 @@ import (
 	"flag"
 	"github.com/chi-middleware/logrus-logger"
 	"github.com/go-chi/chi/v5"
+	lru "github.com/hashicorp/golang-lru"
 	"github.com/oschwald/maxminddb-golang"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 	log "github.com/sirupsen/logrus"
 	"github.com/spf13/viper"
-	"net"
 	"net/http"
-	"net/url"
 	"os"
 	"os/signal"
-	"strings"
-	"sync"
 	"syscall"
 )
 
 var (
 	db         *maxminddb.Reader
 	servers    ServerList
-
+	regionMap  map[string][]*Server
+	hostMap    map[string]*Server
 	dlMap      map[string]string
+	topChoices int
 
 	redirectsServed = promauto.NewCounter(prometheus.CounterOpts{
 		Name: "armbian_router_redirects",
@@ -35,24 +34,65 @@ var (
 		Name: "armbian_router_download_maps",
 		Help: "The total number of mapped download paths",
 	})
+
+	serverCache *lru.Cache
 )
 
-// City represents a MaxmindDB city
+type LocationLookup struct {
-type City struct {
 	Location struct {
 		Latitude  float64 `maxminddb:"latitude"`
 		Longitude float64 `maxminddb:"longitude"`
 	} `maxminddb:"location"`
 }
 
+// City represents a MaxmindDB city
+type City struct {
+	Continent struct {
+		Code      string            `maxminddb:"code" json:"code"`
+		GeoNameID uint              `maxminddb:"geoname_id" json:"geoname_id"`
+		Names     map[string]string `maxminddb:"names" json:"names"`
+	} `maxminddb:"continent" json:"continent"`
+	Country struct {
+		GeoNameID uint              `maxminddb:"geoname_id" json:"geoname_id"`
+		IsoCode   string            `maxminddb:"iso_code" json:"iso_code"`
+		Names     map[string]string `maxminddb:"names" json:"names"`
+	} `maxminddb:"country" json:"country"`
+	Location struct {
+		AccuracyRadius uint16  `maxminddb:"accuracy_radius" json:'accuracy_radius'`
+		Latitude       float64 `maxminddb:"latitude" json:"latitude"`
+		Longitude      float64 `maxminddb:"longitude" json:"longitude"`
+	} `maxminddb:"location"`
+	RegisteredCountry struct {
+		GeoNameID uint              `maxminddb:"geoname_id" json:"geoname_id"`
+		IsoCode   string            `maxminddb:"iso_code" json:"iso_code"`
+		Names     map[string]string `maxminddb:"names" json:"names"`
+	} `maxminddb:"registered_country" json:"registered_country"`
+}
+
+type ServerConfig struct {
+	Server    string  `mapstructure:"server" yaml:"server"`
+	Latitude  float64 `mapstructure:"latitude" yaml:"latitude"`
+	Longitude float64 `mapstructure:"longitude" yaml:"longitude"`
+	Continent string  `mapstructure:"continent"`
+	Weight    int     `mapstructure:"weight" yaml:"weight"`
+}
+
 var (
 	configFlag = flag.String("config", "", "configuration file path")
+	flagDebug  = flag.Bool("debug", false, "Enable debug logging")
 )
 
 func main() {
 	flag.Parse()
 
+	if *flagDebug {
+		log.SetLevel(log.DebugLevel)
+	}
+
 	viper.SetDefault("bind", ":8080")
+	viper.SetDefault("cacheSize", 1024)
+	viper.SetDefault("topChoices", 3)
+	viper.SetDefault("reloadKey", randSeq(32))
 
 	viper.SetConfigName("dlrouter")        // name of config file (without extension)
 	viper.SetConfigType("yaml")            // REQUIRED if the config file does not have the extension in the name
@@ -64,46 +104,10 @@ func main() {
 		viper.SetConfigFile(*configFlag)
 	}
 
-	err := viper.ReadInConfig() // Find and read the config file
+	if err := reloadConfig(); err != nil {
-
+		log.WithError(err).Fatalln("Unable to load configuration")
-	if err != nil { // Handle errors reading the config file
-		log.WithError(err).Fatalln("Unable to load config file")
 	}
 
-	db, err = maxminddb.Open(viper.GetString("geodb"))
-
-	if err != nil {
-		log.WithError(err).Fatalln("Unable to open database")
-	}
-
-	if mapFile := viper.GetString("dl_map"); mapFile != "" {
-		log.WithField("file", mapFile).Info("Loading download map")
-
-		dlMap, err = loadMap(mapFile)
-
-		if err != nil {
-			log.WithError(err).Fatalln("Unable to load download map")
-		}
-	}
-
-	serverList := viper.GetStringSlice("servers")
-
-	var wg sync.WaitGroup
-
-	for _, server := range serverList {
-		wg.Add(1)
-
-		go func(server string) {
-			defer wg.Done()
-
-			addServer(server)
-		}(server)
-	}
-
-	wg.Wait()
-
-	log.Info("Servers added, checking statuses")
-
 	// Start check loop
 	go servers.checkLoop()
 
@@ -114,15 +118,22 @@ func main() {
 	r.Use(RealIPMiddleware)
 	r.Use(logger.Logger("router", log.StandardLogger()))
 
+	r.Head("/status", statusHandler)
 	r.Get("/status", statusHandler)
-	r.Get("/mirrors", mirrorsHandler)
+	r.Get("/mirrors", legacyMirrorsHandler)
+	r.Get("/mirrors/{server}.svg", mirrorStatusHandler)
+	r.Get("/mirrors.json", mirrorsHandler)
 	r.Post("/reload", reloadHandler)
 	r.Get("/dl_map", dlMapHandler)
+	r.Get("/geoip", geoIPHandler)
 	r.Get("/metrics", promhttp.Handler().ServeHTTP)
-	r.HandleFunc("/*", redirectHandler)
+
+	r.NotFound(redirectHandler)
 
 	go http.ListenAndServe(viper.GetString("bind"), r)
 
+	log.Info("Ready")
+
 	c := make(chan os.Signal)
 
 	signal.Notify(c, syscall.SIGKILL, syscall.SIGTERM, syscall.SIGHUP)
@@ -134,85 +145,10 @@ func main() {
 			break
 		}
 
-		reloadMap()
+		err := reloadConfig()
+
+		if err != nil {
+			log.WithError(err).Warning("Did not reload configuration due to error")
+		}
 	}
 }
-
-var metricReplacer = strings.NewReplacer(".", "_", "-", "_")
-
-func addServer(server string) {
-	var prefix string
-
-	if !strings.HasPrefix(server, "http") {
-		prefix = "https://"
-	}
-
-	u, err := url.Parse(prefix + server)
-
-	if err != nil {
-		log.WithFields(log.Fields{
-			"error":  err,
-			"server": server,
-		}).Warning("Server is invalid")
-		return
-	}
-
-	ips, err := net.LookupIP(u.Host)
-
-	if err != nil {
-		log.WithFields(log.Fields{
-			"error":  err,
-			"server": server,
-		}).Warning("Could not resolve address")
-		return
-	}
-
-	var city City
-	err = db.Lookup(ips[0], &city)
-
-	if err != nil {
-		log.WithFields(log.Fields{
-			"error":  err,
-			"server": server,
-		}).Warning("Could not geolocate address")
-		return
-	}
-
-	redirects := promauto.NewCounter(prometheus.CounterOpts{
-		Name: "armbian_router_redirects_" + metricReplacer.Replace(u.Host),
-		Help: "The number of redirects for server " + u.Host,
-	})
-
-	servers = append(servers, &Server{
-		Host:      u.Host,
-		Path:      u.Path,
-		Latitude:  city.Location.Latitude,
-		Longitude: city.Location.Longitude,
-		Redirects: redirects,
-	})
-
-	log.WithFields(log.Fields{
-		"server":    u.Host,
-		"path":      u.Path,
-		"latitude":  city.Location.Latitude,
-		"longitude": city.Location.Longitude,
-	}).Info("Added server")
-}
-
-func reloadMap() {
-	mapFile := viper.GetString("dl_map")
-
-	if mapFile == "" {
-		return
-	}
-
-	log.WithField("file", mapFile).Info("Loading download map")
-
-	newMap, err := loadMap(mapFile)
-
-	if err != nil {
-		return
-	}
-
-	dlMap = newMap
-}

map.go

@@ -7,7 +7,8 @@ import (
 	"strings"
 )
 
-func loadMap(file string) (map[string]string, error) {
+// loadMapFile loads a file as a map
+func loadMapFile(file string) (map[string]string, error) {
 	f, err := os.Open(file)
 
 	if err != nil {
@@ -16,6 +17,11 @@ func loadMap(file string) (map[string]string, error) {
 
 	defer f.Close()
 
+	return loadMap(f)
+}
+
+// loadMap loads a pipe separated file of mappings
+func loadMap(f io.Reader) (map[string]string, error) {
 	m := make(map[string]string)
 
 	r := csv.NewReader(f)

map_test.go

@@ -0,0 +1,16 @@
+package main
+
+import (
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+	"strings"
+)
+
+var _ = Describe("Map", func() {
+	It("Should successfully load the map", func() {
+		m, err := loadMap(strings.NewReader(`bananapi/Bullseye_current|bananapi/archive/Armbian_21.08.1_Bananapi_bullseye_current_5.10.60.img.xz|Aug 26 2021|332M`))
+
+		Expect(err).To(BeNil())
+		Expect(m["bananapi/Bullseye_current"]).To(Equal("bananapi/archive/Armbian_21.08.1_Bananapi_bullseye_current_5.10.60.img.xz"))
+	})
+})

middleware.go

@@ -29,7 +29,9 @@ func RealIPMiddleware(f http.Handler) http.Handler {
 			return
 		}
 
-		if !net.ParseIP(host).IsPrivate() {
+		netIP := net.ParseIP(host)
+
+		if !netIP.IsLoopback() && !netIP.IsPrivate() {
 			f.ServeHTTP(w, r)
 			return
 		}

mirrors.go

@@ -0,0 +1,94 @@
+package main
+
+import (
+	_ "embed"
+	"encoding/json"
+	"github.com/go-chi/chi/v5"
+	"net/http"
+	"strconv"
+	"strings"
+)
+
+// legacyMirrorsHandler will list the mirrors by region in the legacy format
+// it is preferred to use mirrors.json, but this handler is here for build support
+func legacyMirrorsHandler(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "application/json")
+
+	mirrorOutput := make(map[string][]string)
+
+	for region, mirrors := range regionMap {
+		list := make([]string, len(mirrors))
+
+		for i, mirror := range mirrors {
+			list[i] = r.URL.Scheme + "://" + mirror.Host + "/" + strings.TrimLeft(mirror.Path, "/")
+		}
+
+		mirrorOutput[region] = list
+	}
+
+	json.NewEncoder(w).Encode(mirrorOutput)
+}
+
+// mirrorsHandler is a simple handler that will return the list of servers
+func mirrorsHandler(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "application/json")
+	json.NewEncoder(w).Encode(servers)
+}
+
+var (
+	//go:embed assets/status-up.svg
+	statusUp []byte
+
+	//go:embed assets/status-down.svg
+	statusDown []byte
+
+	//go:embed assets/status-unknown.svg
+	statusUnknown []byte
+)
+
+// mirrorStatusHandler is a fancy svg-returning handler.
+// it is used to display mirror statuses on a config repo of sorts
+func mirrorStatusHandler(w http.ResponseWriter, r *http.Request) {
+	serverHost := chi.URLParam(r, "server")
+
+	w.Header().Set("Content-Type", "image/svg+xml;charset=utf-8")
+	w.Header().Set("Cache-Control", "max-age=120")
+
+	if serverHost == "" {
+		w.Write(statusUnknown)
+		return
+	}
+
+	serverHost = strings.Replace(serverHost, "_", ".", -1)
+
+	server, ok := hostMap[serverHost]
+
+	if !ok {
+		w.Header().Set("Content-Length", strconv.Itoa(len(statusUnknown)))
+		w.Write(statusUnknown)
+		return
+	}
+
+	key := "offline"
+
+	if server.Available {
+		key = "online"
+	}
+
+	w.Header().Set("ETag", "\""+key+"\"")
+
+	if match := r.Header.Get("If-None-Match"); match != "" {
+		if strings.Trim(match, "\"") == key {
+			w.WriteHeader(http.StatusNotModified)
+			return
+		}
+	}
+
+	if server.Available {
+		w.Header().Set("Content-Length", strconv.Itoa(len(statusUp)))
+		w.Write(statusUp)
+	} else {
+		w.Header().Set("Content-Length", strconv.Itoa(len(statusDown)))
+		w.Write(statusDown)
+	}
+}

servers.go

@@ -1,81 +1,86 @@
 package main
 
 import (
+	"crypto/tls"
+	"github.com/jmcvetta/randutil"
 	"github.com/prometheus/client_golang/prometheus"
 	log "github.com/sirupsen/logrus"
 	"math"
 	"net"
 	"net/http"
-	"runtime"
+	"sort"
-	"strings"
 	"sync"
 	"time"
 )
 
 var (
 	checkClient = &http.Client{
-		Timeout: 10 * time.Second,
+		Timeout: 20 * time.Second,
+		CheckRedirect: func(req *http.Request, via []*http.Request) error {
+			return http.ErrUseLastResponse
+		},
+	}
+
+	checkTLSConfig *tls.Config = nil
+
+	checks = []serverCheck{
+		checkHttp,
+		checkTLS,
 	}
 )
 
+// Server represents a download server
 type Server struct {
-	Available bool
+	Available  bool               `json:"available"`
-	Host      string
+	Host       string             `json:"host"`
-	Path      string
+	Path       string             `json:"path"`
-	Latitude  float64
+	Latitude   float64            `json:"latitude"`
-	Longitude float64
+	Longitude  float64            `json:"longitude"`
-	Redirects prometheus.Counter
+	Weight     int                `json:"weight"`
+	Continent  string             `json:"continent"`
+	Redirects  prometheus.Counter `json:"-"`
+	LastChange time.Time          `json:"lastChange"`
 }
 
+type serverCheck func(server *Server, logFields log.Fields) (bool, error)
+
+// checkStatus runs all status checks against a server
 func (server *Server) checkStatus() {
-	req, err := http.NewRequest(http.MethodGet, "https://"+server.Host+"/"+strings.TrimLeft(server.Path, "/"), nil)
+	logFields := log.Fields{
-
+		"host": server.Host,
-	req.Header.Set("User-Agent", "ArmbianRouter/1.0 (Go "+runtime.Version()+")")
-
-	if err != nil {
-		// This should never happen.
-		log.WithFields(log.Fields{
-			"server": server.Host,
-			"error":  err,
-		}).Warning("Invalid request! This should not happen, please check config.")
-		return
 	}
 
-	res, err := checkClient.Do(req)
+	var res bool
+	var err error
+
+	for _, check := range checks {
+		res, err = check(server, logFields)
 
 		if err != nil {
+			logFields["error"] = err
+		}
+
+		if !res {
+			break
+		}
+	}
+
+	if !res {
 		if server.Available {
-			log.WithFields(log.Fields{
+			log.WithFields(logFields).Info("Server went offline")
-				"server": server.Host,
-				"error":  err,
-			}).Info("Server went offline")
 
 			server.Available = false
+			server.LastChange = time.Now()
 		} else {
-			log.WithFields(log.Fields{
+			log.WithFields(logFields).Debug("Server is still offline")
-				"server": server.Host,
-				"error":  err,
-			}).Debug("Server is still offline")
 		}
+
 		return
-	}
+	} else {
-
-	responseFields := log.Fields{
-		"server":       server.Host,
-		"responseCode": res.StatusCode,
-	}
-
-	if res.StatusCode == http.StatusOK || res.StatusCode == http.StatusMovedPermanently || res.StatusCode == http.StatusFound || res.StatusCode == http.StatusNotFound {
 		if !server.Available {
 			server.Available = true
-			log.WithFields(responseFields).Info("Server is online")
+			server.LastChange = time.Now()
-		}
+			log.WithFields(logFields).Info("Server is online")
-	} else {
-		log.WithFields(responseFields).Debug("Server status not known")
-
-		if server.Available {
-			log.WithFields(responseFields).Info("Server went offline")
-			server.Available = false
 		}
 	}
 }
@@ -86,8 +91,8 @@ func (s ServerList) checkLoop() {
 	t := time.NewTicker(60 * time.Second)
 
 	for {
-		s.Check()
 		<-t.C
+		s.Check()
 	}
 }
 
@@ -110,33 +115,89 @@ func (s ServerList) Check() {
 	wg.Wait()
 }
 
-// Closest will use GeoIP on the IP provided and find the closest server.
+// ComputedDistance is a wrapper that contains a Server and Distance.
+type ComputedDistance struct {
+	Server   *Server
+	Distance float64
+}
+
+// DistanceList is a list of Computed Distances with an easy "Choices" func
+type DistanceList []ComputedDistance
+
+// Closest will use GeoIP on the IP provided and find the closest servers.
+// When we have a list of x servers closest, we can choose a random or weighted one.
 // Return values are the closest server, the distance, and if an error occurred.
 func (s ServerList) Closest(ip net.IP) (*Server, float64, error) {
-	var city City
+	choiceInterface, exists := serverCache.Get(ip.String())
+
+	if !exists {
+		var city LocationLookup
 		err := db.Lookup(ip, &city)
 
 		if err != nil {
 			return nil, -1, err
 		}
 
-	var closest *Server
+		c := make(DistanceList, len(s))
-	var closestDistance float64 = -1
 
-	for _, server := range s {
+		for i, server := range s {
 			if !server.Available {
 				continue
 			}
 
 			distance := Distance(city.Location.Latitude, city.Location.Longitude, server.Latitude, server.Longitude)
 
-		if closestDistance == -1 || distance < closestDistance {
+			c[i] = ComputedDistance{
-			closestDistance = distance
+				Server:   server,
-			closest = server
+				Distance: distance,
 			}
 		}
 
-	return closest, closestDistance, nil
+		// Sort by distance
+		sort.Slice(c, func(i int, j int) bool {
+			return c[i].Distance < c[j].Distance
+		})
+
+		choiceCount := topChoices
+
+		if len(c) < topChoices {
+			choiceCount = len(c)
+		}
+
+		choices := make([]randutil.Choice, choiceCount)
+
+		for i, item := range c[0:choiceCount] {
+			if item.Server == nil {
+				continue
+			}
+
+			choices[i] = randutil.Choice{
+				Weight: item.Server.Weight,
+				Item:   item,
+			}
+		}
+
+		choiceInterface = choices
+
+		serverCache.Add(ip.String(), choiceInterface)
+	}
+
+	choice, err := randutil.WeightedChoice(choiceInterface.([]randutil.Choice))
+
+	if err != nil {
+		return nil, -1, err
+	}
+
+	dist := choice.Item.(ComputedDistance)
+
+	if !dist.Server.Available {
+		// Choose a new server and refresh cache
+		serverCache.Remove(ip.String())
+
+		return s.Closest(ip)
+	}
+
+	return dist.Server, dist.Distance, nil
 }
 
 // haversin(θ) function
@@ -146,7 +207,7 @@ func hsin(theta float64) float64 {
 
 // Distance function returns the distance (in meters) between two points of
 //     a given longitude and latitude relatively accurately (using a spherical
-//     approximation of the Earth) through the Haversin Distance Formula for
+//     approximation of the Earth) through the Haversine Distance Formula for
 //     great arc distance on a sphere with accuracy for small distances
 //
 // point coordinates are supplied in degrees and converted into rad. in the func

util.go

@@ -0,0 +1,13 @@
+package main
+
+import "math/rand"
+
+var letters = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
+
+func randSeq(n int) string {
+	b := make([]rune, n)
+	for i := range b {
+		b[i] = letters[rand.Intn(len(letters))]
+	}
+	return string(b)
+}