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 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.
# File lib/mcollective/rpc/agent.rb, line 62 def handlemsg(msg, connection) @request = RPC::Request.new(msg) @reply = RPC::Reply.new(@request.action, @ddl) 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
# File lib/mcollective/rpc/agent.rb, line 52 def load_ddl @ddl = DDL.new(@agent_name, :agent) @meta = @ddl.meta @timeout = @meta[:timeout] || 10 rescue Exception => e Log.error("Failed to load DDL for the '%s' agent, DDLs are required: %s: %s" % [@agent_name, e.class, e.to_s]) raise DDLValidationError end
Returns an array of actions this agent support
# File lib/mcollective/rpc/agent.rb, line 148 def self.actions public_instance_methods.sort.grep(/_action$/).map do |method| $1 if method =~ /(.+)_action$/ end end
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 130 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
# File lib/mcollective/rpc/agent.rb, line 37 def initialize @agent_name = self.class.to_s.split("::").last.downcase load_ddl @logger = Log.instance @config = Config.instance # 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
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