add back --pluginpath option

support adding plugin paths

support --pluginpath option

missing doc

refactor using @purbon suggestions

Agent#configure_plugin_paths spec

solves elastic#3580

lib/logstash/agent.rb

@@ -39,6 +39,11 @@ class LogStash::Agent < Clamp::Command
   option ["-V", "--version"], :flag,
     I18n.t("logstash.agent.flag.version")
 
+ option ["-p", "--pluginpath"] , "PATH",
+   I18n.t("logstash.agent.flag.pluginpath"),
+   :multivalued => true,
+   :attribute_name => :plugin_paths
+
   option ["-t", "--configtest"], :flag,
     I18n.t("logstash.agent.flag.configtest"),
     :attribute_name => :config_test
@@ -204,6 +209,7 @@ def show_gems
   # Log file stuff, plugin path checking, etc.
   def configure
     configure_logging(log_file)
+    configure_plugin_paths(plugin_paths)
   end # def configure
 
   # Point logging at a specific path.
@@ -229,7 +235,6 @@ def configure_logging(path)
       else
         @logger.level = :warn
       end
-
     end
 
     if log_file
@@ -254,6 +259,15 @@ def configure_logging(path)
     # http://jira.codehaus.org/browse/JRUBY-7003
   end # def configure_logging
 
+  # add the given paths for ungemified/bare plugins lookups
+  # @param paths [String, Array<String>] plugins path string or list of path strings to add
+  def configure_plugin_paths(paths)
+    Array(paths).each do |path|
+      fail(I18n.t("logstash.agent.configuration.plugin_path_missing", :path => path)) unless File.directory?(path)
+      LogStash::Environment.add_plugin_path(path)
+    end
+  end
+
   def load_config(path)
     begin
       uri = URI.parse(path)

lib/logstash/environment.rb

@@ -99,6 +99,14 @@ def load_locale!
       I18n.reload!
       fail "No locale? This is a bug." if I18n.available_locales.empty?
     end
+
+    # add path for bare/ungemified plugins lookups. the path must be the base path that will include
+    # the dir structure 'logstash/TYPE/NAME.rb' where TYPE is 'inputs' 'filters', 'outputs' or 'codecs'
+    # and NAME is the name of the plugin
+    # @param path [String] plugins path to add
+    def add_plugin_path(path)
+      $LOAD_PATH << path
+    end
   end
 end
 

spec/core/environment_spec.rb

@@ -38,7 +38,18 @@
         allow(Dir).to receive(:glob).and_return([])
         expect { subject.load_runtime_jars! }.to raise_error
       end
+    end
+  end
+
+  context "add_plugin_path" do
+    let(:path) { "/some/path" }
+
+    before(:each) { expect($LOAD_PATH).to_not include(path) }
+    after(:each) { $LOAD_PATH.delete(path) }
 
+    it "should add the path to $LOAD_PATH" do
+      expect{subject.add_plugin_path(path)}.to change{$LOAD_PATH.size}.by(1)
+      expect($LOAD_PATH).to include(path)
     end
   end
 end

spec/logstash/agent_spec.rb

@@ -22,7 +22,7 @@
         end
       end
     end
-    
+
     context "when remote" do
       context 'supported scheme' do
         let(:path) { "http://test.local/superconfig.conf" }
@@ -34,4 +34,28 @@
       end
     end
   end
+
+  context "--pluginpath" do
+    let(:single_path) { "/some/path" }
+    let(:multiple_paths) { ["/some/path1", "/some/path2"] }
+
+    it "should add single valid dir path to the environment" do
+      expect(File).to receive(:directory?).and_return(true)
+      expect(LogStash::Environment).to receive(:add_plugin_path).with(single_path)
+      subject.configure_plugin_paths(single_path)
+    end
+
+    it "should fail with single invalid dir path" do
+      expect(File).to receive(:directory?).and_return(false)
+      expect(LogStash::Environment).not_to receive(:add_plugin_path)
+      expect{subject.configure_plugin_paths(single_path)}.to raise_error(LogStash::ConfigurationError)
+    end
+
+    it "should add multiple valid dir path to the environment" do
+      expect(File).to receive(:directory?).exactly(multiple_paths.size).times.and_return(true)
+      multiple_paths.each{|path| expect(LogStash::Environment).to receive(:add_plugin_path).with(path)}
+      subject.configure_plugin_paths(multiple_paths)
+    end
+  end
 end
+