The main component of the Simple RPC client system, this wraps around MCollective::Client and just brings in a lot of convention and standard approached.
Creates a stub for a remote agent, you can pass in an options array in the flags which will then be used else it will just create a default options array with filtering enabled based on the standard command line use.
rpc = RPC::Client.new("rpctest", :configfile => "client.cfg", :options => options)
You typically would not call this directly you’d use MCollective::RPC#rpcclient instead which is a wrapper around this that can be used as a Mixin
# File lib/mcollective/rpc/client.rb, line 19 def initialize(agent, flags = {}) if flags.include?(:options) options = flags[:options] elsif @@initial_options options = Marshal.load(@@initial_options) else oparser = MCollective::Optionparser.new({:verbose => false, :progress_bar => true, :mcollective_limit_targets => false}, "filter") options = oparser.parse do |parser, options| if block_given? yield(parser, options) end Helpers.add_simplerpc_options(parser, options) end @@initial_options = Marshal.dump(options) end @stats = Stats.new @agent = agent @discovery_timeout = options[:disctimeout] @timeout = options[:timeout] @verbose = options[:verbose] @filter = options[:filter] @config = options[:config] @discovered_agents = nil @progress = options[:progress_bar] @limit_targets = options[:mcollective_limit_targets] agent_filter agent @client = MCollective::Client.new(@config) @client.options = options @collective = @client.collective # if we can find a DDL for the service override # the timeout of the client so we always magically # wait appropriate amounts of time. # # We add the discovery timeout to the ddl supplied # timeout as the discovery timeout tends to be tuned # for local network conditions and fact source speed # which would other wise not be accounted for and # some results might get missed. # # We do this only if the timeout is the default 5 # seconds, so that users cli overrides will still # get applied begin @ddl = DDL.new(agent) @timeout = @ddl.meta[:timeout] + @discovery_timeout if @timeout == 5 rescue Exception => e Log.debug("Could not find DDL: #{e}") @ddl = nil end STDERR.sync = true STDOUT.sync = true end
Sets the agent filter
# File lib/mcollective/rpc/client.rb, line 292 def agent_filter(agent) @filter["agent"] << agent @filter["agent"].compact! reset end
Sets the class filter
# File lib/mcollective/rpc/client.rb, line 268 def class_filter(klass) @filter["cf_class"] << klass @filter["cf_class"].compact! reset end
Sets the collective we are communicating with
# File lib/mcollective/rpc/client.rb, line 356 def collective=(c) @collective = c @client.options[:collective] = c end
Constructs custom requests with custom filters and discovery data the idea is that this would be used in web applications where you might be using a cached copy of data provided by a registration agent to figure out on your own what nodes will be responding and what your filter would be.
This will help you essentially short circuit the traditional cycle of:
mc discover / call / wait for discovered nodes
by doing discovery however you like, contructing a filter and a list of nodes you expect responses from.
Other than that it will work exactly like a normal call, blocks will behave the same way, stats will be handled the same way etcetc
If you just wanted to contact one machine for example with a client that already has other filter options setup you can do:
puppet.custom_request(“runonce”, {}, {:identity => “your.box.com”},
["your.box.com"])
This will do runonce action on just ‘your.box.com’, no discovery will be done and after receiving just one response it will stop waiting for responses
# File lib/mcollective/rpc/client.rb, line 226 def custom_request(action, args, expected_agents, filter = {}, &block) @ddl.validate_request(action, args) if @ddl @stats.reset custom_filter = Util.empty_filter custom_options = options.clone # merge the supplied filter with the standard empty one # we could just use the merge method but I want to be sure # we dont merge in stuff that isnt actually valid ["identity", "fact", "agent", "cf_class"].each do |ftype| if filter.include?(ftype) custom_filter[ftype] = [filter[ftype], custom_filter[ftype]].flatten end end # ensure that all filters at least restrict the call to the agent we're a proxy for custom_filter["agent"] << @agent unless custom_filter["agent"].include?(@agent) custom_options[:filter] = custom_filter # Fake out the stats discovery would have put there @stats.discovered_agents([expected_agents].flatten) # Handle fire and forget requests if args.include?(:process_results) && args[:process_results] == false @filter = custom_filter return fire_and_forget_request(action, args) end # Now do a call pretty much exactly like in method_missing except with our own # options and discovery magic if block_given? call_agent(action, args, custom_options, [expected_agents].flatten) do |r| block.call(r) end else call_agent(action, args, custom_options, [expected_agents].flatten) end end
Disconnects cleanly from the middleware
# File lib/mcollective/rpc/client.rb, line 84 def disconnect @client.disconnect end
Does discovery based on the filters set, i a discovery was previously done return that else do a new discovery.
Will show a message indicating its doing discovery if running verbose or if the :verbose flag is passed in.
Use reset to force a new discovery
# File lib/mcollective/rpc/client.rb, line 324 def discover(flags={}) flags.include?(:verbose) ? verbose = flags[:verbose] : verbose = @verbose if @discovered_agents == nil @stats.time_discovery :start STDERR.print("Determining the amount of hosts matching filter for #{discovery_timeout} seconds .... ") if verbose @discovered_agents = @client.discover(@filter, @discovery_timeout) STDERR.puts(@discovered_agents.size) if verbose @stats.time_discovery :end end @stats.discovered_agents(@discovered_agents) RPC.discovered(@discovered_agents) @discovered_agents end
Sets the fact filter
# File lib/mcollective/rpc/client.rb, line 275 def fact_filter(fact, value=nil, operator="=") return if fact.nil? return if fact == false if value.nil? parsed = Util.parse_fact_string(fact) @filter["fact"] << parsed unless parsed == false else parsed = Util.parse_fact_string("#{fact}#{operator}#{value}") @filter["fact"] << parsed unless parsed == false end @filter["fact"].compact! reset end
Returns help for an agent if a DDL was found
# File lib/mcollective/rpc/client.rb, line 89 def help(template) if @ddl @ddl.help(template) else return "Can't find DDL for agent '#{@agent}'" end end
Sets the identity filter
# File lib/mcollective/rpc/client.rb, line 299 def identity_filter(identity) @filter["identity"] << identity @filter["identity"].compact! reset end
Sets and sanity checks the #limit_targets variable used to restrict how many nodes we’ll target
# File lib/mcollective/rpc/client.rb, line 363 def limit_targets=(limit) if limit.is_a?(String) raise "Invalid limit specified: #{limit} valid limits are /^\d+%*$/" unless limit =~ %r^\d+%*$/ @limit_targets = limit elsif limit.respond_to?(:to_i) limit = limit.to_i limit = 1 if limit == 0 @limit_targets = limit else raise "Don't know how to handle limit of type #{limit.class}" end end
Magic handler to invoke remote methods
Once the stub is created using the constructor or the MCollective::RPC#rpcclient helper you can call remote actions easily:
ret = rpc.echo(:msg => "hello world")
This will call the ‘echo’ action of the ‘rpctest’ agent and return the result as an array, the array will be a simplified result set from the usual full MCollective::Client#req with additional error codes and error text:
{
:sender => "remote.box.com", :statuscode => 0, :statusmsg => "OK", :data => "hello world"
}
If :statuscode is 0 then everything went find, if it’s 1 then you supplied the correct arguments etc but the request could not be completed, you’ll find a human parsable reason in :statusmsg then.
Codes 2 to 5 maps directly to UnknownRPCAction, MissingRPCData, InvalidRPCData and UnknownRPCError see below for a description of those, in each case :statusmsg would be the reason for failure.
To get access to the full result of the MCollective::Client#req calls you can pass in a block:
rpc.echo(:msg => "hello world") do |resp| pp resp end
In this case resp will the result from MCollective::Client#req. Instead of returning simple text and codes as above you’ll also need to handle the following exceptions:
UnknownRPCAction - There is no matching action on the agent MissingRPCData - You did not supply all the needed parameters for the action InvalidRPCData - The data you did supply did not pass validation UnknownRPCError - Some other error prevented the agent from running
During calls a progress indicator will be shown of how many results we’ve received against how many nodes were discovered, you can disable this by setting progress to false:
rpc.progress = false
This supports a 2nd mode where it will send the SimpleRPC request and never handle the responses. It’s a bit like UDP, it sends the request with the filter attached and you only get back the requestid, you have no indication about results.
You can invoke this using:
puts rpc.echo(:process_results => false)
This will output just the request id.
# File lib/mcollective/rpc/client.rb, line 177 def method_missing(method_name, *args, &block) # set args to an empty hash if nothings given args = args[0] args = {} if args.nil? action = method_name.to_s @stats.reset @ddl.validate_request(action, args) if @ddl # Handle single target requests by doing discovery and picking # a random node. Then do a custom request specifying a filter # that will only match the one node. if @limit_targets target_nodes = pick_nodes_from_discovered(@limit_targets) Log.debug("Picked #{target_nodes.join(',')} as limited target(s)") custom_request(action, args, target_nodes, {"identity" => %r^(#{target_nodes.join('|')})$/}, &block) else # Normal agent requests as per client.action(args) call_agent(action, args, options, &block) end end
Creates a suitable request hash for the SimpleRPC agent.
You’d use this if you ever wanted to take care of sending requests on your own - perhaps via Client#sendreq if you didn’t care for responses.
In that case you can just do:
msg = your_rpc.new_request("some_action", :foo => :bar) filter = your_rpc.filter your_rpc.client.sendreq(msg, msg[:agent], filter)
This will send a SimpleRPC request to the action some_action with arguments :foo = :bar, it will return immediately and you will have no indication at all if the request was receieved or not
Clearly the use of this technique should be limited and done only if your code requires such a thing
# File lib/mcollective/rpc/client.rb, line 116 def new_request(action, data) callerid = PluginManager["security_plugin"].callerid {:agent => @agent, :action => action, :caller => callerid, :data => data} end
Provides a normal options hash like you would get from Optionparser
# File lib/mcollective/rpc/client.rb, line 346 def options {:disctimeout => @discovery_timeout, :timeout => @timeout, :verbose => @verbose, :filter => @filter, :collective => @collective, :config => @config} end
Resets various internal parts of the class, most importantly it clears out the cached discovery
# File lib/mcollective/rpc/client.rb, line 307 def reset @discovered_agents = nil end
Reet the filter to an empty one
# File lib/mcollective/rpc/client.rb, line 312 def reset_filter @filter = Util.empty_filter agent_filter @agent end