docker-api

This gem provides an object-oriented interface to the Docker Remote API. Every method listed there is implemented, with the exception of attaching to the STDIN of a Container. At the time of this writing, docker-api is meant to interface with Docker version 0.4.6.

Installation

Add this line to your application's Gemfile:

gem 'docker-api'

And then run:

$ bundle install

Alternatively, if you wish to just use the gem in a script, you can run:

$ gem install docker-api

Finally, just add require 'docker' to the top of the file using this gem.

Usage

docker-api is designed to be very lightweight. Almost no state is cached (aside from id's which are immutable) to ensure that each method call's information is up to date. As such, just about every extrenal method represents an API call.

Starting up

Follow the installation instructions, and then run:

$ sudo docker -d

This will daemonize Docker so that it can be used for the remote API calls.

If you're running Docker locally, there is no setup to do in Ruby. If you're not, you'll have to point the gem to your server. For example:

Docker.url = 'http://example.com'
Docker.options = { :port => 5422 }

Two things to note here. The first is that this gem uses excon, so any of the options that are valid for Excon.new are alse valid for Docker.options. Second, by default Docker runs on port 4243. The gem will assume you want to connnect to port 4243 unless you specify otherwise.

Global calls

All of the following examples require a connection to a Docker server. See the Starting up section above for more information.

require 'docker'
# => true

Docker.version
# => { 'Version' => '0.4.0', 'GoVersion' => 'go1.0.3' }

Docker.info
# => { "Debug" => false, "Containers" => 187, "Images" => 196, "NFd" => 10, "NGoroutines" => 9, "MemoryLimit" => true }

Docker.authenticate!('username' => 'docker-fan-boi', 'password' => 'i<3docker', 'email' => 'dockerboy22@aol.com')
# => true

Images

Just about every method here has a one-to-one mapping with the Images section of the API. If an API call accepts query parameters, these can be passed as an Hash to it's corresponding method.

require 'docker'
# => true

# Instantiate a new Image. Note that this does NOT create the Image.
image = Docker::Image.new
# => Docker::Image { :id => , :connection => Docker::Connection { :url => http://localhost, :options => {:port=>4243} } }

# Test if the Image is created.
image.created?
# => false

# Create the Image.
image.create!('fromRepo' => 'base')
# => Docker::Image { :id => ae7ffbcd1, :connection => Docker::Connection { :url => http://localhost, :options => {:port=>4243} } }

image.created?
# => true

# Insert a file into an Image. Returns a new Image that contains that file.
image.insert('path' => '/google', 'url' => 'http://google.com')
# => Docker::Image { :id => 11ef6c882, :connection => Docker::Connection { :url => http://localhost, :options => {:port=>4243} } }

# Tag an Image.
image.tag('repo' => 'base2', 'force' => true)
# => nil

# Get more information about the Image.
image.json
# => {"id"=>"67859327bf22ef8b5b9b4a6781f72b2015acd894fa03ce07e0db7af170ba468c", "comment"=>"Imported from -", "created"=>"2013-06-19T18:42:58.287944526-04:00", "container_config"=>{"Hostname"=>"", "User"=>"", "Memory"=>0, "MemorySwap"=>0, "CpuShares"=>0, "AttachStdin"=>false, "AttachStdout"=>false, "AttachStderr"=>false, "PortSpecs"=>nil, "Tty"=>false, "OpenStdin"=>false, "StdinOnce"=>false, "Env"=>nil, "Cmd"=>nil, "Dns"=>nil, "Image"=>"", "Volumes"=>nil, "VolumesFrom"=>""}, "docker_version"=>"0.4.0", "architecture"=>"x86_64"}

# View the history of the Image.
image.history
# => [{"Id"=>"67859327bf22", "Created"=>1371681778}]

# Push the Image to the Docker registry. Note that you have to login using
# `Docker.authenticate!` and tag the Image first.
image.push
# => true

# Remove the Image from the server.
image.remove
# => true

image.created?
# => false

# Given a Container's export, creates a new Image.
image.create_from_file('some-export.tar')
# => Docker::Image { :id => 66b712aef, :connection => Docker::Connection { :url => http://localhost, :options => {:port=>4243} } }

# Load all Images on your Docker server.
Docker::Image.all
# => [Docker::Image { :id => b750fe79269d2ec9a3c593ef05b4332b1d1a02a62b4accb2c21d589ff2f5f2dc, :connection => Docker::Connection { :url => http://localhost, :options => {:port=>4243} } }, Docker::Image { :id => 8dbd9e392a964056420e5d58ca5cc376ef18e2de93b5cc90e868a1bbc8318c1c, :connection => Docker::Connection { :url => http://localhost, :options => {:port=>4243} } }]

# Search the Docker registry.
Docker::Image.search('term' => 'sshd')
# => [Docker::Image { :id => cespare/sshd, :connection => Docker::Connection { :url => http://localhost, :options => {:port=>4243} } }, Docker::Image { :id => johnfuller/sshd, :connection => Docker::Connection { :url => http://localhost, :options => {:port=>4243} } }, Docker::Image { :id => dhrp/mongodb-sshd, :connection => Docker::Connection { :url => http://localhost, :options => {:port=>4243} } }, Docker::Image { :id => rayang2004/sshd, :connection => Docker::Connection { :url => http://localhost, :options => {:port=>4243} } }, Docker::Image { :id => dhrp/sshd, :connection => Docker::Connection { :url => http://localhost, :options => {:port=>4243} } }, Docker::Image { :id => toorop/daemontools-sshd, :connection => Docker::Connection { :url => http://localhost, :options => {:port=>4243} } }, Docker::Image { :id => toorop/daemontools-sshd-nginx, :connection => Docker::Connection { :url => http://localhost, :options => {:port=>4243} } }, Docker::Image { :id => toorop/daemontools-sshd-nginx-php-fpm, :connection => Docker::Connection { :url => http://localhost, :options => {:port=>4243} } }, Docker::Image { :id => mbkan/lamp, :connection => Docker::Connection { :url => http://localhost, :options => {:port=>4243} } }, Docker::Image { :id => toorop/golang, :connection => Docker::Connection { :url => http://localhost, :options => {:port=>4243} } }, Docker::Image { :id => wma55/u1210sshd, :connection => Docker::Connection { :url => http://localhost, :options => {:port=>4243} } }, Docker::Image { :id => jdswinbank/sshd, :connection => Docker::Connection { :url => http://localhost, :options => {:port=>4243} } }, Docker::Image { :id => vgauthier/sshd, :connection => Docker::Connection { :url => http://localhost, :options => {:port=>4243} } }]

# Create an Image from a Dockerfile as a String.
Docker::Image.build("from base\nrun touch /test")
# => Docker::Image { :id => b750fe79269d2ec9a3c593ef05b4332b1d1a02a62b4accb2c21d589ff2f5f2dc, :connection => Docker::Connection { :url => http://localhost, :options => {:port=>4243} } }

# Create an Image from a Dockerfile.
Dockerfile::Image.build_from_dir('.')
# => Docker::Image { :id => 1266dc19e, :connection => Docker::Connection { :url => http://localhost, :options => {:port=>4243} } }

Containers

Much like the Images, this object also has a one-to-one mapping with the Containers section of the API.

require 'docker'

# Instantiate a new Container.
container = Docker::Container.new
# => Docker::Container { :id => , :connection => Docker::Connection { :url => http://localhost, :options => {:port=>4243} } }

# Test if the has been created.
container.created?
# => false

# Create the Container. 
container.create!('Cmd' => ['ls'], 'Image' => 'base')
# => Docker::Container { :id => 492510dd38e4, :connection => Docker::Connection { :url => http://localhost, :options => {:port=>4243} } }

container.created?
# => true

# Get more information about the Container.
container.json
# => {"Id"=>"492510dd38e4da7703f36dfccd013de672b8250f57f59d1555ced647766b5e82", "Created"=>"2013-06-20T10:46:02.897548-04:00", "Path"=>"ls", "Args"=>[], "Config"=>{"Hostname"=>"492510dd38e4", "User"=>"", "Memory"=>0, "MemorySwap"=>0, "CpuShares"=>0, "AttachStdin"=>false, "AttachStdout"=>false, "AttachStderr"=>false, "PortSpecs"=>nil, "Tty"=>false, "OpenStdin"=>false, "StdinOnce"=>false, "Env"=>nil, "Cmd"=>["ls"], "Dns"=>nil, "Image"=>"base", "Volumes"=>nil, "VolumesFrom"=>""}, "State"=>{"Running"=>false, "Pid"=>0, "ExitCode"=>0, "StartedAt"=>"0001-01-01T00:00:00Z", "Ghost"=>false}, "Image"=>"b750fe79269d2ec9a3c593ef05b4332b1d1a02a62b4accb2c21d589ff2f5f2dc", "NetworkSettings"=>{"IpAddress"=>"", "IpPrefixLen"=>0, "Gateway"=>"", "Bridge"=>"", "PortMapping"=>nil}, "SysInitPath"=>"/usr/bin/docker", "ResolvConfPath"=>"/etc/resolv.conf", "Volumes"=>nil}

# Start running the Container.
container.start
# => nil

# Stop running the Container.
container.stop
# => nil

# Restart the Container.
container.restart
# => nil

# Kill the command running in the Container.
container.kill
# => nil

# Export a Container. Since an export is typically at least 300M, chunks of the
# export are yielded instead of just returning the whole thing.
File.open('export.tar', 'w') do |f|
  container.export { |chunk| file.write(chunk) }
end
# => nil

# Inspect a Container's changes to the file system.
container.changes
# => [{'Path'=>'/dev', 'Kind'=>0}, {'Path'=>'/dev/kmsg', 'Kind'=>1}]

# Wait for the current command to finish executing.
container.wait
# => {'StatusCode'=>0}

# Attach to the Container. Currently, the below options are the only valid ones.
container.attach(:stream => true, :stdout => true, :stderr => true, :logs => true)
# => "bin\nboot\ndev\netc\nhome\nlib\nlib64\nmedia\nmnt\nopt\nproc\nroot\nrun\nsbin\nselinux\nsrv\nsys\ntmp\nusr\nvar"

# Create an Image from a Container's changes.
container.commit
# => Docker::Image { :id => eaeb8d00efdf, :connection => Docker::Connection { :url => http://localhost, :options => {:port=>4243} } }

# Request all of the Containers. By default, will only return the running Containers.
Docker::Container.all(:all => true)
# => [Docker::Container { :id => , :connection => Docker::Connection { :url => http://localhost, :options => {:port=>4243} } }]

Connecting to Multiple Servers

By default, each object connects to the connection specified by Docker.connection. If you need to connect to multiple servers, you can do so by specifying the connection on #new or in the utilizing class method. Examples:

require 'docker'

Docker::Container.new(:connection => Docker::Connection.new(:url => 'http://example.com'))
Docker::Container.all({}, Docker::Connection.new(:url => 'http://example.com'))

Docker::Image.new(:connection => Docker::Connection.new(:url => 'http://example.com'))
Docker::Image.all({}, Docker::Connection.new(:url => 'http://example.com'))
Docker::Image.build('from base', Docker::Connection.new(:url => 'http://example.com'))
Docker::Image.build_from_dir('.', Docker::Connection.new(:url => 'http://example.com'))
Docker::Image.search({ :term => 'sshd' }, Docker::Connection.new(:url => 'http://example.com'))

Known Issues

• Docker::Container#attach cannot attach to STDIN