Class | MCollective::RPC::Client |
In: |
lib/mcollective/rpc/client.rb
|
Parent: | Object |
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.
agent | [R] | |
client | [R] | |
config | [RW] | |
ddl | [R] | |
discovery_timeout | [RW] | |
filter | [RW] | |
limit_targets | [R] | |
progress | [RW] | |
stats | [R] | |
timeout | [RW] | |
verbose | [RW] |
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 19: def initialize(agent, flags = {}) 20: if flags.include?(:options) 21: options = flags[:options] 22: 23: elsif @@initial_options 24: options = Marshal.load(@@initial_options) 25: 26: else 27: oparser = MCollective::Optionparser.new({:verbose => false, :progress_bar => true, :mcollective_limit_targets => false}, "filter") 28: 29: options = oparser.parse do |parser, options| 30: if block_given? 31: yield(parser, options) 32: end 33: 34: Helpers.add_simplerpc_options(parser, options) 35: end 36: 37: @@initial_options = Marshal.dump(options) 38: end 39: 40: @stats = Stats.new 41: @agent = agent 42: @discovery_timeout = options[:disctimeout] 43: @timeout = options[:timeout] 44: @verbose = options[:verbose] 45: @filter = options[:filter] 46: @config = options[:config] 47: @discovered_agents = nil 48: @progress = options[:progress_bar] 49: @limit_targets = options[:mcollective_limit_targets] 50: 51: agent_filter agent 52: 53: @client = client = MCollective::Client.new(@config) 54: @client.options = options 55: 56: # if we can find a DDL for the service override 57: # the timeout of the client so we always magically 58: # wait appropriate amounts of time. 59: # 60: # We add the discovery timeout to the ddl supplied 61: # timeout as the discovery timeout tends to be tuned 62: # for local network conditions and fact source speed 63: # which would other wise not be accounted for and 64: # some results might get missed. 65: # 66: # We do this only if the timeout is the default 5 67: # seconds, so that users cli overrides will still 68: # get applied 69: begin 70: @ddl = DDL.new(agent) 71: @timeout = @ddl.meta[:timeout] + @discovery_timeout if @timeout == 5 72: rescue Exception => e 73: Log.instance.debug("Could not find DDL: #{e}") 74: @ddl = nil 75: end 76: 77: STDERR.sync = true 78: STDOUT.sync = true 79: end
Sets the agent filter
# File lib/mcollective/rpc/client.rb, line 280 280: def agent_filter(agent) 281: @filter["agent"] << agent 282: @filter["agent"].compact! 283: reset 284: end
Sets the class filter
# File lib/mcollective/rpc/client.rb, line 266 266: def class_filter(klass) 267: @filter["cf_class"] << klass 268: @filter["cf_class"].compact! 269: reset 270: 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 224 224: def custom_request(action, args, expected_agents, filter = {}, &block) 225: @ddl.validate_request(action, args) if @ddl 226: 227: @stats.reset 228: 229: custom_filter = Util.empty_filter 230: custom_options = options.clone 231: 232: # merge the supplied filter with the standard empty one 233: # we could just use the merge method but I want to be sure 234: # we dont merge in stuff that isnt actually valid 235: ["identity", "fact", "agent", "cf_class"].each do |ftype| 236: if filter.include?(ftype) 237: custom_filter[ftype] = [filter[ftype], custom_filter[ftype]].flatten 238: end 239: end 240: 241: # ensure that all filters at least restrict the call to the agent we're a proxy for 242: custom_filter["agent"] << @agent unless custom_filter["agent"].include?(@agent) 243: custom_options[:filter] = custom_filter 244: 245: # Fake out the stats discovery would have put there 246: @stats.discovered_agents([expected_agents].flatten) 247: 248: # Handle fire and forget requests 249: if args.include?(:process_results) && args[:process_results] == false 250: @filter = custom_filter 251: return fire_and_forget_request(action, args) 252: end 253: 254: # Now do a call pretty much exactly like in method_missing except with our own 255: # options and discovery magic 256: if block_given? 257: call_agent(action, args, custom_options, [expected_agents].flatten) do |r| 258: block.call(r) 259: end 260: else 261: call_agent(action, args, custom_options, [expected_agents].flatten) 262: end 263: end
Disconnects cleanly from the middleware
# File lib/mcollective/rpc/client.rb, line 82 82: def disconnect 83: @client.disconnect 84: 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 312 312: def discover(flags={}) 313: flags.include?(:verbose) ? verbose = flags[:verbose] : verbose = @verbose 314: 315: if @discovered_agents == nil 316: @stats.time_discovery :start 317: 318: STDERR.print("Determining the amount of hosts matching filter for #{discovery_timeout} seconds .... ") if verbose 319: @discovered_agents = @client.discover(@filter, @discovery_timeout) 320: STDERR.puts(@discovered_agents.size) if verbose 321: 322: @stats.time_discovery :end 323: 324: end 325: 326: @stats.discovered_agents(@discovered_agents) 327: RPC.discovered(@discovered_agents) 328: 329: @discovered_agents 330: end
Sets the fact filter
# File lib/mcollective/rpc/client.rb, line 273 273: def fact_filter(fact, value) 274: @filter["fact"] << {:fact => fact, :value => value} 275: @filter["fact"].compact! 276: reset 277: end
Sets the identity filter
# File lib/mcollective/rpc/client.rb, line 287 287: def identity_filter(identity) 288: @filter["identity"] << identity 289: @filter["identity"].compact! 290: reset 291: 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 344 344: def limit_targets=(limit) 345: if limit.is_a?(String) 346: raise "Invalid limit specified: #{limit} valid limits are /^\d+%*$/" unless limit =~ /^\d+%*$/ 347: @limit_targets = limit 348: elsif limit.respond_to?(:to_i) 349: limit = limit.to_i 350: limit = 1 if limit == 0 351: @limit_targets = limit 352: else 353: raise "Don't know how to handle limit of type #{limit.class}" 354: end 355: end
Magic handler to invoke remote methods
Once the stub is created using the constructor or the 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 175 175: def method_missing(method_name, *args, &block) 176: # set args to an empty hash if nothings given 177: args = args[0] 178: args = {} if args.nil? 179: 180: action = method_name.to_s 181: 182: @stats.reset 183: 184: @ddl.validate_request(action, args) if @ddl 185: 186: # Handle single target requests by doing discovery and picking 187: # a random node. Then do a custom request specifying a filter 188: # that will only match the one node. 189: if @limit_targets 190: target_nodes = pick_nodes_from_discovered(@limit_targets) 191: Log.instance.debug("Picked #{target_nodes.join(',')} as limited target(s)") 192: 193: custom_request(action, args, target_nodes, {"identity" => /^(#{target_nodes.join('|')})$/}, &block) 194: else 195: # Normal agent requests as per client.action(args) 196: call_agent(action, args, options, &block) 197: end 198: 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 114 114: def new_request(action, data) 115: callerid = PluginManager["security_plugin"].callerid 116: 117: {:agent => @agent, 118: :action => action, 119: :caller => callerid, 120: :data => data} 121: end
Provides a normal options hash like you would get from Optionparser
# File lib/mcollective/rpc/client.rb, line 334 334: def options 335: {:disctimeout => @discovery_timeout, 336: :timeout => @timeout, 337: :verbose => @verbose, 338: :filter => @filter, 339: :config => @config} 340: end
Resets various internal parts of the class, most importantly it clears out the cached discovery
# File lib/mcollective/rpc/client.rb, line 295 295: def reset 296: @discovered_agents = nil 297: end