Update all LWRPs to check that docker is alive.

Before issuing any commands that talk to the local docker daemon,
make sure it is running (since its service starts in the background).

attributes/default.rb

@@ -14,6 +14,7 @@
 default['docker']['http_proxy'] = nil
 default['docker']['image_cmd_timeout'] = 300
 default['docker']['registry_cmd_timeout'] = 60
+default['docker']['docker_daemon_timeout'] = 10
 
 default['docker']['init_type'] = value_for_platform(
   %w{ centos debian oracle redhat } => {

libraries/helpers.rb

@@ -1,7 +1,25 @@
+require 'chef/mixin/shell_out'
+include Chef::Mixin::ShellOut
+
 # Helpers module
 module Helpers
   # Helpers::Docker module
   module Docker
+    class DockerNotReady < StandardError
+      def initialize(endpoint, timeout)
+        super <<-EOH
+The Docker daemon did not become ready within #{timeout} seconds.
+This most likely means that Docker failed to start.
+Docker can fail to start if:
+
+  - a configuration file is invalid
+  - permissions are incorrect for the root directory of the docker runtime.
+
+If this problem persists, check your service log files.
+EOH
+      end
+    end
+
     def cli_args(spec)
       cli_line = ''
       spec.each_pair do |arg, value|
@@ -18,5 +36,36 @@ def cli_args(spec)
       end
       cli_line
     end
+
+    def timeout
+      node['docker']['docker_daemon_timeout']
+    end
+
+    # This is based upon wait_until_ready! from the opscode jenkins cookbook.
+    #
+    # Since the docker service returns immediately and the actual docker
+    # process is started as a daemon, we block the Chef Client run until the
+    # daemon is actually ready.
+    #
+    # This method will effectively "block" the current thread until the docker
+    # daemon is ready
+    #
+    # @raise [DockerNotReady]
+    #   if the Docker master does not respond within (+timeout+) seconds
+    #
+    def wait_until_ready!
+      Timeout.timeout(timeout) do
+        while true do
+          result = shell_out('docker info')
+          if not !Array(result.valid_exit_codes).include?(result.exitstatus)
+            break
+          end
+          Chef::Log.debug("Docker daemon is not running - #{result.stdout}\n#{result.stderr}")
+          sleep(0.5)
+        end
+      end
+    rescue Timeout::Error
+      raise DockerNotReady.new(timeout)
+    end
   end
 end

providers/container.rb

@@ -6,6 +6,7 @@ class CommandTimeout < RuntimeError; end
 
 def load_current_resource
   @current_resource = Chef::Resource::DockerContainer.new(new_resource)
+  wait_until_ready!
   dps = docker_cmd('ps -a -notrunc')
   dps.stdout.each_line do |dps_line|
     next unless dps_line.include?(new_resource.image)

providers/image.rb

@@ -5,6 +5,7 @@
 class CommandTimeout < RuntimeError; end
 
 def load_current_resource
+  wait_until_ready!
   @current_resource = Chef::Resource::DockerImage.new(new_resource)
   di = docker_cmd('images -a')
   if di.stdout.include?(new_resource.image_name)

providers/registry.rb

@@ -6,6 +6,7 @@ class CommandTimeout < RuntimeError; end
 
 def load_current_resource
   @current_resource = Chef::Resource::DockerRegistry.new(new_resource)
+  wait_until_ready!
   # TODO: load current resource?
   @current_resource
 end