LANGAR - A web service to work with Docker daemon

Langar is a web service that manage Docker daemon. Langar (لنگر in Persian) means Anchor.

Contents

• Motivations
• How to use
• Configuration
• Endpoints
  • Get all networks
  • Get network info
  • Create network
  • Delete network
  • Health
• To do

Motivations

In SAKKU team we have several modules that needs to make actions in Docker daemon in several servers. Actions like managing container networks, list of containers, manage of swarm and so on. So we need a manager to listen in endpoints and make this actions in Docker daemon servers to prevent issues like:

• Opening Docker API to public networks.
• No control in actions that every module can do with Docker API.

How to use

Building from source:

$ go build -o /usr/bin/langar github.com/SakkuCloud/langar

Running with CLI (stay foreground):

$ langar

Running in debug mode:

$ langar -debug=true

Langar uses some options. These options are listed below.

key	name	default
debug	Debug Mode	false
c	Config File	/etc/langar/config.yml

For production, it's better to use a Systemd service to run Langar. A simple Systemd service shown below. Save this in /lib/systemd/system/langar.service

[Unit]
Description=LANGAR - A web service that manage Docker daemon
After=network.target

[Service]
Type=simple
Restart=on-failure
TimeoutStopSec=10
RestartSec=5
ExecStart=/usr/bin/langar

[Install]
WantedBy=multi-user.target

Run and enable service:

$ systemctl enable langar
$ systemctl start langar

Configuration

Langar uses both YAML format and OS Environment for config. You can see config.yml.example for a sample config file. You can pass config file with:

langar -c config.yml

Below table describes available config file.

config	env	required	default	describe
port	LANGAR_PORT	NO	3000	server will run on this port
logfile	LANGAR_LOGFILE	NO	/var/log/langar.log	logs will store in this file
sentrydsn	LANGAR_SENTRYDSN	NO		DSN of Sentry
accesskey	LANGAR_ACCESSKEY	YES		value of service http header to authorize requests
secretkey	LANGAR_SECRETKEY	YES		value of service-key http header to authorize requests
docker host	LANGAR_DOCKER_SOCKET	NO	/run/docker.sock	Docker socket address

Endpoints

Get all networks

Get all networks in docker daemon (and swarm cluster). A complete curl requests shown below.

curl -X GET \
 http://127.0.0.1:3000/api/network \
 -H 'service: my-awesome-accesss' \
 -H 'service-key: Super$3crT' 

Get network info

Get network info in docker daemon (and swarm cluster). A complete curl requests shown below. you can get network by Id or Name.

curl -X GET \
 http://127.0.0.1:3000/api/network/1234 \
 -H 'service: my-awesome-accesss' \
 -H 'service-key: Super$3crT' 

Create network

Create network info in docker daemon (and swarm cluster). A complete curl requests shown below.

curl -X POST \
 http://127.0.0.1:3000/api/network \
 -H 'Content-Type: application/json' \
 -H 'service: my-awesome-accesss' \
 -H 'service-key: Super$3crT' \
 -d '{
"Name":"test-net",
"CheckDuplicate":true,
"Attachable":true,
"Driver":"overlay",
"IPAM":{
"Driver": "default",
"Config":[
{
"Subnet":"172.20.0.0/16",
"IPRange":"172.20.10.0/24",
"Gateway":"172.20.10.11"
}
]
},
"Internal":true
}
'

Delete network

Delete network in docker daemon (and swarm cluster). A complete curl requests shown below. you can delete network by Id or Name.

curl -X DELETE \
 http://127.0.0.1:3000/api/network/1234 \
 -H 'service: my-awesome-accesss' \
 -H 'service-key: Super$3crT' 

Health

Get Server health (status, uptime and server time).

curl -X GET \
 http://127.0.0.1:3000/api/health 

To do

• Add container to network
• Remove container to network