changed assess_jruby! to use block param, added specs & doc

lib/logstash/environment.rb

@@ -7,6 +7,8 @@ module LogStash
     LOGSTASH_HOME = ::File.expand_path(::File.join(::File.dirname(__FILE__), "/../.."))
     JAR_DIR = ::File.join(LOGSTASH_HOME, "/vendor/jar")
 
+    # loads currenly embedded elasticsearch jars
+    # @raise LogStash::EnvironmentError if not runnig under JRuby or if no jar files found
     def load_elasticsearch_jars!
       assess_jruby!
 
@@ -22,8 +24,17 @@ module LogStash
       end
     end
 
-    def assess_jruby!(exception_class = nil, message = nil)
-      raise(exception_class || LogStash::EnvironmentError, message || "JRuby is required") unless jruby?
+    # @yield execute optional block if not currently running under JRuby
+    # @yieldreturn [Exception] exception to raise if Exception class returned otherwise raise default exception
+    # @raise [Exception] yielded exception or default if not runnig under JRuby
+    def assess_jruby!
+      unless  jruby?
+        # grab return value from block if present, use default exception if not an exception class
+        exception = block_given? ? yield : nil
+        exception = LogStash::EnvironmentError.new("JRuby is required") unless exception.is_a?(Exception)
+
+        raise(exception)
+      end
     end
 
     def jruby?

lib/logstash/outputs/elasticsearch.rb

@@ -197,7 +197,7 @@ class LogStash::Outputs::ElasticSearch < LogStash::Outputs::Base
 
     if ["node", "transport"].include?(@protocol)
       # Node or TransportClient; requires JRuby
-      LogStash::Environment.assess_jruby!(LogStash::PluginLoadingError, "This configuration requires JRuby. If you are not using JRuby, you must set 'protocol' to 'http'. For example: output { elasticsearch { protocol => \"http\" } }")
+      LogStash::Environment.assess_jruby!{LogStash::PluginLoadingError.new("This configuration requires JRuby. If you are not using JRuby, you must set 'protocol' to 'http'. For example: output { elasticsearch { protocol => \"http\" } }")}
       LogStash::Environment.load_elasticsearch_jars!
 
       # setup log4j properties for Elasticsearch
@@ -241,7 +241,7 @@ class LogStash::Outputs::ElasticSearch < LogStash::Outputs::Base
                  :protocol => @protocol)
 
     if @embedded
-      LogStash::Environment.assess_jruby!(LogStash::ConfigurationError, "The 'embedded => true' setting is only valid for the elasticsearch output under JRuby. You are running #{RUBY_DESCRIPTION}")
+      LogStash::Environment.assess_jruby!{LogStash::ConfigurationError.new("The 'embedded => true' setting is only valid for the elasticsearch output under JRuby. You are running #{RUBY_DESCRIPTION}")}
       LogStash::Environment.load_elasticsearch_jars!
 
       # Default @host with embedded to localhost. This should help avoid

spec/environmnet.rb

@@ -2,12 +2,39 @@ require "logstash/environment"
 
 describe LogStash::Environment do
 
+  describe "load_elasticsearch_jars!" do
+
     it "should load elasticsarch jars" do
-    expect {LogStash::Environment.load_elasticsearch_jars!}.to_not raise_error
+      expect{LogStash::Environment.load_elasticsearch_jars!}.to_not raise_error
     end
 
     it "should raise when cannot find elasticsarch jars" do
       stub_const("LogStash::Environment::JAR_DIR", "/some/invalid/path")
-    expect {LogStash::Environment.load_elasticsearch_jars!}.to raise_error(LogStash::EnvironmentError)
+      expect{LogStash::Environment.load_elasticsearch_jars!}.to raise_error(LogStash::EnvironmentError)
+    end
+  end
+
+  describe "assess_jruby!" do
+
+    it "should not raise when jruby" do
+      expect(LogStash::Environment).to receive(:jruby?).twice.and_return(true)
+      expect{LogStash::Environment.assess_jruby!}.to_not raise_error
+      expect{LogStash::Environment.assess_jruby!{StandardError.new}}.to_not raise_error
+    end
+
+    it "should raise default exception" do
+      expect(LogStash::Environment).to receive(:jruby?).once.and_return(false)
+      expect{LogStash::Environment.assess_jruby!}.to raise_error(LogStash::EnvironmentError)
+    end
+
+    it "should yield to block and raise returned exception" do
+      expect(LogStash::Environment).to receive(:jruby?).once.and_return(false)
+      expect{LogStash::Environment.assess_jruby!{StandardError.new}}.to raise_error(StandardError)
+    end
+
+    it "should yield to block and raise default exception if exception not returned" do
+      expect(LogStash::Environment).to receive(:jruby?).once.and_return(false)
+      expect{LogStash::Environment.assess_jruby!{nil}}.to raise_error(LogStash::EnvironmentError)
+    end
   end
 end