godns/hosts/hosts.go

118 lines
2.3 KiB
Go

package hosts
import (
"github.com/miekg/dns"
"time"
)
type HostMap map[string][]Host
type Host struct {
Type uint16 `json:"type"`
TTL time.Duration `json:"ttl"`
Values []string `json:"values"`
}
func (h *Host) TypeString() string {
return dns.TypeToString[h.Type]
}
type ProviderList struct {
providers []Provider
}
// Provider is an interface specifying a host source
// Each source should support AT LEAST List and Get, but can support Writer as well
type Provider interface {
List() (HostMap, error)
Get(queryType uint16, domain string) (*Host, error)
}
// Writer is an interface to modify hosts.
// Examples of this include Redis, Bolt, MySQL, etc.
type Writer interface {
Set(domain string, host *Host) error
Delete(domain string) error
}
type ProviderWriter interface {
Provider
Writer
}
func NewHosts(providers []Provider) *ProviderList {
return &ProviderList{providers}
}
// List returns all results, merged into one HostMap
func (h *ProviderList) List() (HostMap, error) {
hostMap := make(HostMap)
for _, provider := range h.providers {
hosts, err := provider.List()
if err != nil {
continue
}
for k, v := range hosts {
if existing, ok := hostMap[k]; ok {
existing = append(existing, v...)
hostMap[k] = existing
} else {
hostMap[k] = v
}
}
}
return hostMap, nil
}
// Get Matches values to providers, loping each in order
func (h *ProviderList) Get(queryType uint16, domain string) (*Host, error) {
var host *Host
var err error
for _, provider := range h.providers {
host, err = provider.Get(queryType, domain)
if host != nil {
break
}
}
return host, err
}
// Set invokes each provider, setting the host on the first one to return a nil error
func (h *ProviderList) Set(domain string, host *Host) (err error) {
for _, provider := range h.providers {
if writer, ok := provider.(Writer); ok {
err = writer.Set(domain, host)
if err == nil {
return
}
}
}
err = errUnsupportedOperation
return
}
// Delete invokes each provider, removing the host on the first one to return a nil error
func (h *ProviderList) Delete(domain string) (err error) {
for _, provider := range h.providers {
if writer, ok := provider.(Writer); ok {
err = writer.Delete(domain)
if err == nil {
return
}
}
}
err = errUnsupportedOperation
return
}