24 log to stderr

README.md

@@ -8,7 +8,7 @@ writing to a file or syslog since logstash can receive the structured data direc
 ## Features
 
 * Can write directly to logstash over a UDP or TCP/SSL connection.
-* Can write to a file, Redis, a unix socket, or stdout.
+* Can write to a file, Redis, a unix socket, stdout or stderr.
 * Always writes in logstash JSON format.
 * Logger can take a string message, a hash, a `LogStash::Event`, an object, or a JSON string as input.
 * Events are automatically populated with message, timestamp, host, and severity.
@@ -45,6 +45,7 @@ file_logger = LogStashLogger.new(type: :file, path: 'log/development.log', sync:
 unix_logger = LogStashLogger.new(type: :unix, path: '/tmp/sock')
 redis_logger = LogStashLogger.new(type: :redis)
 stdout_logger = LogStashLogger.new(type: :stdout)
+stderr_logger = LogStashLogger.new(type: :stderr)
 io_logger = LogStashLogger.new(type: :io, io: io)
 
 # The following messages are written to UDP port 5228:
@@ -78,6 +79,7 @@ unix:///tmp/socket
 file:///path/to/file        
 redis://localhost:6379     
 stdout:/
+stderr:/
 ```
 
 Pass the URI into your logstash logger like so:

lib/logstash-logger/device.rb

@@ -14,6 +14,7 @@ module Device
     autoload :File, 'logstash-logger/device/file'
     autoload :IO, 'logstash-logger/device/io'
     autoload :Stdout, 'logstash-logger/device/stdout'
+    autoload :Stderr, 'logstash-logger/device/stderr'
 
     def self.new(opts)
       opts = opts.dup
@@ -43,6 +44,7 @@ def self.device_klass_for(type)
         when :redis then Redis
         when :io then IO
         when :stdout then Stdout
+        when :stderr then Stderr
         else fail ArgumentError, 'Invalid type'
       end
     end

lib/logstash-logger/device/stderr.rb

@@ -0,0 +1,13 @@
+module LogStashLogger
+  module Device
+    class Stderr < IO
+      def initialize(opts={})
+        super({io: $stderr}.merge(opts))
+      end
+
+      def close
+        # no-op
+      end
+    end
+  end
+end

spec/device/stderr_spec.rb

@@ -0,0 +1,16 @@
+require 'logstash-logger'
+
+describe LogStashLogger::Device::Stderr do
+  let(:stderr) { $stderr }
+
+  it 'writes to stderr' do
+    expect(subject.to_io).to eq stderr
+    expect(stderr).to receive(:write).once
+    subject.write("test")
+  end
+
+  it 'ignores #close' do
+    expect(stderr).not_to receive(:close)
+    subject.close
+  end
+end

spec/device_spec.rb

@@ -76,6 +76,11 @@
       let(:uri_config) { stdout_uri_config }
       it { is_expected.to be_a LogStashLogger::Device::Stdout }
     end
+
+    context 'when URI config is stderr' do
+      let(:uri_config) { stderr_uri_config }
+      it { is_expected.to be_a LogStashLogger::Device::Stderr }
+    end
   end
 
 end

spec/spec_helper.rb

@@ -53,6 +53,7 @@ def connection_type
   let(:file_uri) { "file://#{file.path}" }
   let(:redis_uri) { "redis://localhost:6379" }
   let(:stdout_uri) { "stdout://localhost" }
+  let(:stderr_uri) { "stderr://localhost" }
 
   let(:invalid_uri_config) { {uri: "non parsable uri"} }
   let(:udp_uri_config)     { {uri: udp_uri} }
@@ -61,4 +62,5 @@ def connection_type
   let(:file_uri_config)    { {uri: file_uri} }
   let(:redis_uri_config)   { {uri: redis_uri} }
   let(:stdout_uri_config)  { {uri: stdout_uri} }
+  let(:stderr_uri_config)  { {uri: stderr_uri} }
 end