A helper used by RPC::Agent#implemented_by to delegate an action to an external script. At present only JSON based serialization is supported in future ones based on key=val pairs etc will be added
It serializes the request object into an input file and creates an empty output file. It then calls the external command reading the output file at the end.
any STDERR gets logged at error level and any STDOUT gets logged at info level.
It will interpret the exit code from the application the same way RPC::Reply#fail! and fail handles their codes creating a consistent interface, the message part of the fail message will come from STDERR
Generally externals should just exit with code 1 on failure and print to STDERR, this is exactly what Perl die() does and translates perfectly to our model
It uses the MCollective::Shell wrapper to call the external application
# File lib/mcollective/rpc/actionrunner.rb, line 26 def initialize(command, request, format=:json) @agent = request.agent @action = request.action @format = format @request = request @command = path_to_command(command) @stdout = "" @stderr = "" end
# File lib/mcollective/rpc/actionrunner.rb, line 117 def canrun?(command) File.executable?(command) end
# File lib/mcollective/rpc/actionrunner.rb, line 91 def load_json_results(file) return {} unless File.readable?(file) JSON.load(File.read(file)) || {} rescue JSON::ParserError {} end
# File lib/mcollective/rpc/actionrunner.rb, line 73 def load_results(file) Log.debug("Attempting to load results in #{format} format from #{file}") data = {} if respond_to?("load_#{format}_results") tempdata = send("load_#{format}_results", file) tempdata.each_pair do |k,v| data[k.to_sym] = v end end data rescue Exception => e {} end
# File lib/mcollective/rpc/actionrunner.rb, line 129 def path_to_command(command) unless command[0,1] == File::SEPARATOR Config.instance.libdir.each do |libdir| command_file = File.join(libdir, "agent", agent, command) return command_file if File.exist?(command_file) end end return command end
# File lib/mcollective/rpc/actionrunner.rb, line 36 def run unless canrun?(command) Log.warn("Cannot run #{to_s}") raise RPCAborted, "Cannot execute #{to_s}" end Log.debug("Running #{to_s}") request_file = saverequest(request) reply_file = tempfile("reply") reply_file.close runner = shell(command, request_file.path, reply_file.path) runner.runcommand Log.debug("#{command} exited with #{runner.status.exitstatus}") stderr.each_line {|l| Log.error("#{to_s}: #{l.chomp}")} unless stderr.empty? stdout.each_line {|l| Log.info("#{to_s}: #{l.chomp}")} unless stdout.empty? {:exitstatus => runner.status.exitstatus, :stdout => runner.stdout, :stderr => runner.stderr, :data => load_results(reply_file.path)} ensure request_file.close! if request_file.respond_to?("close!") reply_file.close! if reply_file.respond_to?("close") end
# File lib/mcollective/rpc/actionrunner.rb, line 113 def save_json_request(req) req.to_json end
# File lib/mcollective/rpc/actionrunner.rb, line 99 def saverequest(req) Log.debug("Attempting to save request in #{format} format") if respond_to?("save_#{format}_request") data = send("save_#{format}_request", req) request_file = tempfile("request") request_file.puts data request_file.close end request_file end
# File lib/mcollective/rpc/actionrunner.rb, line 66 def shell(command, infile, outfile) env = {"MCOLLECTIVE_REQUEST_FILE" => infile, "MCOLLECTIVE_REPLY_FILE" => outfile} Shell.new("#{command} #{infile} #{outfile}", :cwd => Dir.tmpdir, :stdout => stdout, :stderr => stderr, :environment => env) end
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