Add support for pid_mode

Also adds a bit of coverage for network_mode.

README.md

@@ -271,6 +271,17 @@ In `host` and `container...` network modes, you may specify a
 for container health checks. The mapping itself, while still passed via the API,
 will be ignored by Docker.
 
+### PID modes
+
+You may specify the PID mode you would like a container to use via:
+
+```ruby
+set :pid_mode, 'pidmode'
+```
+
+Docker (and therefore Centurion) supports one of nothing (the default), `host`,
+and `container:<container-id>` for this argument.
+
 ### CGroup Resource Constraints
 
 Limits on memory and CPU can be specified with the `memory` and `cpu_shares`

lib/centurion/service.rb

@@ -5,7 +5,7 @@ module Centurion
   class Service
     extend ::Capistrano::DSL
 
-    attr_accessor :command, :dns, :extra_hosts, :image, :name, :volumes, :port_bindings, :network_mode, :cap_adds, :cap_drops, :ipc_mode, :security_opt
+    attr_accessor :command, :dns, :extra_hosts, :image, :name, :volumes, :port_bindings, :network_mode, :pid_mode, :cap_adds, :cap_drops, :ipc_mode, :security_opt
     attr_reader :memory, :cpu_shares, :env_vars, :labels
 
     def initialize(name)
@@ -35,6 +35,7 @@ def self.from_env
         s.volumes       = fetch(:binds, [])
         s.port_bindings = fetch(:port_bindings, [])
         s.network_mode  = fetch(:network_mode, 'bridge')
+        s.pid_mode      = fetch(:pid_mode, nil)
         s.command       = fetch(:command, nil)
         s.memory        = fetch(:memory, 0)
         s.cpu_shares    = fetch(:cpu_shares, 0)
@@ -76,10 +77,6 @@ def cap_drops=(capabilites)
       @cap_drops = capabilites
     end
 
-    def network_mode=(mode)
-      @network_mode = mode
-    end
-
     def memory=(bytes)
       if !bytes || !is_a_uint64?(bytes)
         raise ArgumentError, "invalid value for cgroup memory constraint: #{bytes}, value must be a between 0 and 18446744073709551615"
@@ -159,6 +156,9 @@ def build_host_config(restart_policy = nil)
       # Set the network mode
       host_config['NetworkMode'] = network_mode
 
+      # Set the pid mode if specified
+      host_config['PidMode'] = pid_mode if pid_mode
+
       # DNS if specified
       host_config['Dns'] = dns if dns
 

lib/centurion/version.rb

@@ -1,3 +1,3 @@
 module Centurion
-  VERSION = '1.9.2'
+  VERSION = '1.10.0'
 end

spec/service_spec.rb

@@ -18,6 +18,8 @@
     set(:port_bindings, [ Centurion::Service::PortBinding.new(12340, 80, 'tcp') ])
     set(:labels, labels)
     set(:security_opt, ['seccomp=unconfined'])
+    set(:network_mode, 'host')
+    set(:pid_mode, 'host')
 
     svc = Centurion::Service.from_env
     expect(svc.name).to eq('mycontainer')
@@ -29,6 +31,8 @@
     expect(svc.port_bindings.first.container_port).to eq(80)
     expect(svc.labels).to eq(labels)
     expect(svc.security_opt).to eq(['seccomp=unconfined'])
+    expect(svc.network_mode).to eq('host')
+    expect(svc.pid_mode).to eq('host')
   end
 
   it 'starts with a command' do
@@ -64,6 +68,14 @@
     expect(service.dns).to eq('redis.example.com')
   end
 
+  it 'has a default network mode' do
+    expect(service.network_mode).to eq('bridge')
+  end
+
+  it 'has no default pid mode' do
+    expect(service.pid_mode).to be(nil)
+  end
+
   it 'boots from a docker image' do
     service.image = 'registry.hub.docker.com/library/redis'
     expect(service.image).to eq('registry.hub.docker.com/library/redis')
@@ -309,4 +321,35 @@
    })
   end
 
+  it 'builds docker configuration for container-linked pids' do
+    service.pid_mode = 'container:a2e8937b'
+    expect(service.build_host_config(Centurion::Service::RestartPolicy.new('on-failure', 50))).to eq({
+      'Binds' => [],
+      'CapAdd' => [],
+      'CapDrop' => [],
+      'NetworkMode' => 'bridge',
+      'PidMode' => 'container:a2e8937b',
+      'PortBindings' => {},
+       'RestartPolicy' => {
+         'Name' => 'on-failure',
+         'MaximumRetryCount' => 50
+      }
+   })
+  end
+
+  it 'builds docker configuration for host pids' do
+    service.pid_mode = 'host'
+    expect(service.build_host_config(Centurion::Service::RestartPolicy.new('on-failure', 50))).to eq({
+      'Binds' => [],
+      'CapAdd' => [],
+      'CapDrop' => [],
+      'NetworkMode' => 'bridge',
+      'PidMode' => 'host',
+      'PortBindings' => {},
+       'RestartPolicy' => {
+         'Name' => 'on-failure',
+         'MaximumRetryCount' => 50
+      }
+   })
+  end
 end