- Add support for agent '-e' flag - lets you specify a configuration

  in a simple string.

  If no inputs are specified, it assumes: stdin { type => stdin }
  If no outputs are specified, it assumes: stdout { debug => true }
  Any given filters default with 'type => stdin' unless otherwise specified.

  https://logstash.jira.com/browse/LOGSTASH-105

bin/logstash

@@ -10,5 +10,4 @@ if ARGV[0] =~ /^-/
   ARGV.unshift("agent")
 end
 
-p :bin => ARGV
 LogStash::Runner.new.main(ARGV)

lib/logstash/agent.rb

@@ -67,7 +67,15 @@ def options(opts)
     opts.on("-f CONFIGFILE", "--config CONFIGFILE",
             "Load the logstash config from a specific file") do |arg|
       @config_file = arg
-    end
+    end # -f / --config
+
+    opts.on("-e CONFIGSTRING",
+            "Use the given string as the configuration data. Same syntax as " \
+            "the config file. If not input is specified, " \
+            "'stdin { type => stdin }' is default. If no output is " \
+            "specified, 'stdout { debug => true }}' is default.") do |arg|
+      @config_string = arg
+    end # -e
 
     opts.on("-d", "--daemonize", "Daemonize (default is run in foreground)") do 
       @daemonize = true
@@ -173,13 +181,16 @@ def parse_options(args)
 
   private
   def configure
-    if @config_file.nil? || @config_file.empty?
+    if @config_file && @config_string
+      @logger.fatal "Can't use -f and -e at the same time"
+      raise "Configuration problem"
+    elsif (@config_file.nil? || @config_file.empty?) && @config_string.nil?
       @logger.fatal "No config file given. (missing -f or --config flag?)"
       @logger.fatal @opts.help
       raise "Configuration problem"
     end
 
-    if !File.exist?(@config_file)
+    if @config_file and !File.exist?(@config_file)
       @logger.fatal "Config file '#{@config_file}' does not exist."
       raise "Configuration problem"
     end
@@ -224,7 +235,11 @@ def run(args, &block)
     configure
 
     # Load the config file
-    config = LogStash::Config::File.new(@config_file)
+    if @config_file
+      config = LogStash::Config::File.new(@config_file, nil)
+    elsif @config_string
+      config = LogStash::Config::File.new(nil, @config_string)
+    end
 
     @thread = Thread.new do
       run_with_config(config, &block)
@@ -266,6 +281,26 @@ def run_with_config(config)
       end # case type
     end # config.parse
 
+    # If we are given a config string (run usually with 'agent -e "some config string"')
+    # then set up some defaults.
+    if @config_string
+      require "logstash/inputs/stdin"
+      require "logstash/outputs/stdout"
+
+      # set defaults if necessary
+
+      # All filters default to 'stdin' type
+      @filters.each do |filter|
+        filter.type = "stdin" if filter.type.nil?
+      end
+
+      # If no inputs are specified, use stdin by default.
+      @inputs = [LogStash::Inputs::Stdin.new("type" => [ "stdin" ])] if @inputs.length == 0
+
+      # If no outputs are specified, use stdout in debug mode.
+      @outputs = [LogStash::Outputs::Stdout.new("debug" => [ "true" ])] if @outputs.length == 0
+    end
+
     if @inputs.length == 0 or @outputs.length == 0
       raise "Must have both inputs and outputs configured."
     end

lib/logstash/config/file.rb

@@ -27,7 +27,7 @@ def parse
     @config = grammar.config
 
     registry = LogStash::Config::Registry::registry
-    self.each do |o|
+    each do |o|
       # Load the base class for the type given (like inputs/base, or filters/base)
       # TODO(sissel): Error handling
       tryload o[:type], :base

lib/logstash/config/mixin.rb

@@ -77,6 +77,8 @@ def config_init(params)
       # set @foo
       #ivar = "@#{key}"
       instance_variable_set("@#{key}", value)
+      #define_method(key.to_sym) { value }
+      #define_method("#{key}=".to_sym) { |v| instance_variable_set("@#{key}", v) }
     end
 
     @config = params
@@ -100,6 +102,11 @@ def config(name, opts={})
 
       name = name.to_s if name.is_a?(Symbol)
       @config[name] = opts  # ok if this is empty
+
+      if name.is_a?(String)
+        define_method(name) { instance_variable_get("@#{name}") }
+        define_method("#{name}=") { |v| instance_variable_set("@#{name}", v) }
+      end
     end # def config
 
     def get_config

lib/logstash/runner.rb

@@ -7,7 +7,7 @@ def main(args)
 
     @runners = []
     while !args.empty?
-      p :args => args
+      #p :args => args
       args = run(args)
     end