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MCollective::RPC::Agent

A wrapper around the traditional agent, it takes care of a lot of the tedious setup you would do for each agent allowing you to just create methods following a naming standard leaving the heavy lifting up to this clas.

See marionette-collective.org/simplerpc/agents.html

It only really makes sense to use this with a Simple RPC client on the other end, basic usage would be:

module MCollective
   module Agent
      class Helloworld<RPC::Agent
         matadata :name        => "Test SimpleRPC Agent",
                  :description => "A simple test",
                  :author      => "You",
                  :license     => "1.1",
                  :url         => "http://your.com/,
                  :timeout     => 60

         action "hello" do
             reply[:msg] = "Hello #{request[:name]}"
         end

         action "foo" do
             implemented_by "/some/script.sh"
         end
      end
   end
end

If you wish to implement the logic for an action using an external script use the implemented_by method that will cause your script to be run with 2 arguments.

The first argument is a file containing JSON with the request and the 2nd argument is where the script should save its output as a JSON hash.

We also currently have the validation code in here, this will be moved to plugins soon.

Attributes

config[R]
ddl[R]
logger[R]
meta[RW]
reply[RW]
request[RW]
timeout[R]

Public Instance Methods

handlemsg(msg, connection) click to toggle source
# File lib/mcollective/rpc/agent.rb, line 75
def handlemsg(msg, connection)
  @request = RPC.request(msg)
  @reply = RPC.reply

  begin
    # Calls the authorization plugin if any is defined
    # if this raises an exception we wil just skip processing this
    # message
    authorization_hook(@request) if respond_to?("authorization_hook")


    # Audits the request, currently continues processing the message
    # we should make this a configurable so that an audit failure means
    # a message wont be processed by this node depending on config
    audit_request(@request, connection)

    before_processing_hook(msg, connection)

    if respond_to?("#{@request.action}_action")
      send("#{@request.action}_action")
    else
      raise UnknownRPCAction, "Unknown action: #{@request.action}"
    end
  rescue RPCAborted => e
    @reply.fail e.to_s, 1

  rescue UnknownRPCAction => e
    @reply.fail e.to_s, 2

  rescue MissingRPCData => e
    @reply.fail e.to_s, 3

  rescue InvalidRPCData => e
    @reply.fail e.to_s, 4

  rescue UnknownRPCError => e
    @reply.fail e.to_s, 5

  rescue Exception => e
    @reply.fail e.to_s, 5

  end

  after_processing_hook

  if @request.should_respond?
    return @reply.to_hash
  else
    Log.debug("Client did not request a response, surpressing reply")
    return nil
  end
end
help() click to toggle source

to auto generate help

# File lib/mcollective/rpc/agent.rb, line 171
def help
  self.help("#{@config[:configdir]}/rpc-help.erb")
end

Public Class Methods

actions() click to toggle source

Returns an array of actions this agent support

# File lib/mcollective/rpc/agent.rb, line 176
def self.actions
  public_instance_methods.sort.grep(/_action$/).map do |method|
    $1 if method =~ /(.+)_action$/
  end
end
activate?() click to toggle source

By default RPC Agents support a toggle in the configuration that can enable and disable them based on the agent name

Example an agent called Foo can have:

plugin.foo.activate_agent = false

and this will prevent the agent from loading on this particular machine.

Agents can use the activate_when helper to override this for example:

activate_when do

File.exist?("/usr/bin/puppet")

end

# File lib/mcollective/rpc/agent.rb, line 143
def self.activate?
  agent_name = self.to_s.split("::").last.downcase

  Log.debug("Starting default activation checks for #{agent_name}")

  should_activate = Config.instance.pluginconf["#{agent_name}.activate_agent"]

  if should_activate
    Log.debug("Found plugin config #{agent_name}.activate_agent with value #{should_activate}")
    unless should_activate =~ /^1|y|true$/
      return false
    end
  end

  return true
end
help(template) click to toggle source

Generates help using the template based on the data created with metadata and input

# File lib/mcollective/rpc/agent.rb, line 162
def self.help(template)
  if @ddl
    @ddl.help(template)
  else
    "No DDL defined"
  end
end
new() click to toggle source
# File lib/mcollective/rpc/agent.rb, line 44
def initialize
  # Default meta data unset
  @meta = {:timeout     => 10,
           :name        => "Unknown",
           :description => "Unknown",
           :author      => "Unknown",
           :license     => "Unknown",
           :version     => "Unknown",
           :url         => "Unknown"}

  @timeout = meta[:timeout] || 10
  @logger = Log.instance
  @config = Config.instance
  @agent_name = self.class.to_s.split("::").last.downcase

  # Loads the DDL so we can later use it for validation
  # and help generation
  begin
    @ddl = DDL.new(@agent_name)
  rescue Exception => e
    Log.debug("Failed to load DDL for agent: #{e.class}: #{e}")
    @ddl = nil
  end

  # if we have a global authorization provider enable it
  # plugins can still override it per plugin
  self.class.authorized_by(@config.rpcauthprovider) if @config.rpcauthorization

  startup_hook
end

[Validate]

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