A simple, go-based DNS resolver/caching server

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kenshinx 81450a3983 Update hosts records as a regular interval 1. /etc/hosts will be update cycle instead of update once at the progress run 2. Avoid access redis in each requests		2015-02-12 14:09:49 +08:00
.gitignore	add IPv6 support	2015-02-03 20:33:54 +08:00
README.md	Add link to blog	2015-02-11 11:13:05 +08:00
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godns_test.go	CodeReviewComments#imports	2015-02-10 17:04:57 +08:00
handler.go	Update hosts records as a regular interval	2015-02-12 14:09:49 +08:00
hosts.go	Update hosts records as a regular interval	2015-02-12 14:09:49 +08:00
hosts_test.go	add IPv6 support	2015-02-03 20:33:54 +08:00
main.go	add benchmark test	2013-07-25 12:32:57 +08:00
resolver.go	#CodeReviewComments# imports standard library in the first group	2015-02-10 17:00:59 +08:00
server.go	#CodeReviewComments# imports standard library in the first group	2015-02-10 17:00:59 +08:00
settings.go	#CodeReviewComments# imports standard library in the first group	2015-02-10 17:00:59 +08:00

README.md

GODNS

A simple and fast dns cache server written by go.

Similar to dnsmasq ,but support some difference features:

Keep hosts records in redis instead of the local file /etc/hosts
Auto-Reloads when hosts configuration is changed. (Yes, dnsmasq needs to be reloaded)
Cache records save in memory or redis configurable

Installation & Running

Install
```
 $ go get github.com/kenshinx/godns
```

Build

 $ cd $GOPATH/src/github.com/kenshinx/godns 
 $ go build -o godns *.go

Running
```
 $ sudo ./godns -c godns.conf
```
Test
```
 $ dig www.github.com @127.0.0.1
```

More details about how to install and running godns can reference my blog (Chinese)

Use godns

	$ sudo vi /etc/resolv.conf
	nameserver #the ip of godns running

Configuration

All the configuration in godns.conf is a TOML format config file.
More about Toml :https://github.com/mojombo/toml

resolv.conf

Upstream server can be configured by changing file from somewhere other than "/etc/resolv.conf"

[resolv]
resolv-file = "/etc/resolv.conf"

If multiple namerservers are set in resolv.conf, the upsteam server will try in a top to bottom order

cache

Only the local memory storage backend is currently implemented. The redis backend is in the todo list

[cache]
backend = "memory"   
expire = 600  # default expire time 10 minutes
maxcount = 100000

hosts

Force resolve domain to assigned ip, support two types hosts configuration:

locale hosts file
remote redis hosts

hosts file

can be assigned at godns.conf,default : /etc/hosts

[hosts]
host-file = "/etc/hosts"

redis hosts

This is a special requirment in our system. Must maintain a global hosts configuration, and support update the hosts record from other remote server. so "redis-hosts" will be supported, and will query the redis db when each dns request is reached.

The hosts record is organized with redis hash map. and the key of the map is configured.

[hosts]
redis-key = "godns:hosts"

Insert hosts records into redis

redis > hset godns:hosts www.sina.com.cn 1.1.1.1

Benchmak

Debug close

$ go test -bench=.

testing: warning: no tests to run
PASS
BenchmarkDig-8     50000             57945 ns/op
ok      _/usr/home/keqiang/godns        3.259s

The result : 15342 queries/per second

The test environment:

CentOS release 6.4

CPU:
Intel Xeon 2.40GHZ 4 cores
MEM:
46G

Web console

Joke: A web console for godns

https://github.com/kenshinx/joke

screenshot

Deployment

Deployment in productive supervisord highly recommended.


[program:godns]
command=/usr/local/bin/godns -c /etc/godns.conf
autostart=true
autorestart=true
user=root
stdout_logfile_maxbytes = 50MB
stdoiut_logfile_backups = 20
stdout_logfile = /var/log/godns.log

TODO

The redis cache backend
Update ttl