A collection of agents, loads them, reloads them and dispatches messages to them. It uses the PluginManager to store, load and manage instances of plugins.
Get a list of agents that we have
# File lib/mcollective/agents.rb, line 145 145: def self.agentlist 146: @@agents.keys 147: end
(Not documented)
# File lib/mcollective/agents.rb, line 5 5: def initialize(agents = {}) 6: @config = Config.instance 7: raise ("Configuration has not been loaded, can't load agents") unless @config.configured 8: 9: @@agents = agents 10: 11: loadagents 12: end
Checks if a plugin should be activated by calling activate? on it if it responds to that method else always activate it
# File lib/mcollective/agents.rb, line 85 85: def activate_agent?(agent) 86: klass = Kernel.const_get("MCollective").const_get("Agent").const_get(agent.capitalize) 87: 88: if klass.respond_to?("activate?") 89: return klass.activate? 90: else 91: Log.debug("#{klass} does not have an activate? method, activating as default") 92: return true 93: end 94: rescue Exception => e 95: Log.warn("Agent activation check for #{agent} failed: #{e.class}: #{e}") 96: return false 97: end
Builds a class name string given a Agent name
# File lib/mcollective/agents.rb, line 78 78: def class_for_agent(agent) 79: "MCollective::Agent::#{agent.capitalize}" 80: end
Deletes all agents
# File lib/mcollective/agents.rb, line 15 15: def clear! 16: @@agents.each_key do |agent| 17: PluginManager.delete "#{agent}_agent" 18: Util.unsubscribe(Util.make_subscriptions(agent, :broadcast)) 19: end 20: 21: @@agents = {} 22: end
Dispatches a message to an agent, accepts a block that will get run if there are any replies to process from the agent
# File lib/mcollective/agents.rb, line 118 118: def dispatch(request, connection) 119: Log.debug("Dispatching a message to agent #{request.agent}") 120: 121: Thread.new do 122: begin 123: agent = PluginManager["#{request.agent}_agent"] 124: 125: Timeout::timeout(agent.timeout) do 126: replies = agent.handlemsg(request.payload, connection) 127: 128: # Agents can decide if they wish to reply or not, 129: # returning nil will mean nothing goes back to the 130: # requestor 131: unless replies == nil 132: yield(replies) 133: end 134: end 135: rescue Timeout::Error => e 136: Log.warn("Timeout while handling message for #{request.agent}") 137: rescue Exception => e 138: Log.error("Execution of #{request.agent} failed: #{e}") 139: Log.error(e.backtrace.join("\n\t\t")) 140: end 141: end 142: end
searches the libdirs for agents
# File lib/mcollective/agents.rb, line 100 100: def findagentfile(agentname) 101: @config.libdir.each do |libdir| 102: agentfile = File.join([libdir, "mcollective", "agent", "#{agentname}.rb"]) 103: if File.exist?(agentfile) 104: Log.debug("Found #{agentname} at #{agentfile}") 105: return agentfile 106: end 107: end 108: return false 109: end
Determines if we have an agent with a certain name
# File lib/mcollective/agents.rb, line 112 112: def include?(agentname) 113: PluginManager.include?("#{agentname}_agent") 114: end
Loads a specified agent from disk if available
# File lib/mcollective/agents.rb, line 42 42: def loadagent(agentname) 43: agentfile = findagentfile(agentname) 44: return false unless agentfile 45: classname = class_for_agent(agentname) 46: 47: PluginManager.delete("#{agentname}_agent") 48: 49: begin 50: single_instance = ["registration", "discovery"].include?(agentname) 51: 52: PluginManager.loadclass(classname) 53: 54: if activate_agent?(agentname) 55: PluginManager << {:type => "#{agentname}_agent", :class => classname, :single_instance => single_instance} 56: 57: # Attempt to instantiate the agent once so any validation and hooks get run 58: # this does a basic sanity check on the agent as a whole, if this fails it 59: # will be removed from the plugin list 60: PluginManager["#{agentname}_agent"] 61: 62: Util.subscribe(Util.make_subscriptions(agentname, :broadcast)) unless @@agents.include?(agentname) 63: 64: @@agents[agentname] = {:file => agentfile} 65: return true 66: else 67: Log.debug("Not activating agent #{agentname} due to agent policy in activate? method") 68: return false 69: end 70: rescue Exception => e 71: Log.error("Loading agent #{agentname} failed: #{e}") 72: PluginManager.delete("#{agentname}_agent") 73: return false 74: end 75: end
Loads all agents from disk
# File lib/mcollective/agents.rb, line 25 25: def loadagents 26: Log.debug("Reloading all agents from disk") 27: 28: clear! 29: 30: @config.libdir.each do |libdir| 31: agentdir = "#{libdir}/mcollective/agent" 32: next unless File.directory?(agentdir) 33: 34: Dir.new(agentdir).grep(/\.rb$/).each do |agent| 35: agentname = File.basename(agent, ".rb") 36: loadagent(agentname) unless PluginManager.include?("#{agentname}_agent") 37: end 38: end 39: end
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