A simple and fast dns cache server written by go.

Similar to dnsmasq, but supports some difference features:

• Keep hosts records in redis and the local file /etc/hosts

• Auto-Reloads when hosts configuration is changed. (Yes, dnsmasq needs to be reloaded)

1. Install

    $ go get github.com/kenshinx/godns
   

2. Build

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

3. Running

    $ sudo ./godns -c ./etc/godns.conf
   

4. Test

    $ dig www.github.com @127.0.0.1
   

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

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

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

Domain-specific nameservers configuration, formatting keep compatible with Dnsmasq.

server=/google.com/8.8.8.8

More cases please refererence dnsmasq-china-list

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

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"

Hosts file format is described in linux man pages. More than that , *. wildcard is supported additional.

redis hosts

This is a special requirment in our system. Must maintain a global hosts configuration, and support update the host records from other remote server. Therefore, while "redis-hosts" be enabled, 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.test.com 1.1.1.1

Compared with file-backend records, redis-backend hosts support multiple A entries.

redis > hset godns:hosts www.test.com 1.1.1.1,2.2.2.2

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

Joke: A web console for godns

https://github.com/kenshinx/joke

screenshot

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

• The redis cache backend
• Update ttl

godns is under the MIT license. See the LICENSE file for details.