Add buffered device to write to Logstash HTTP input

README.md

@@ -257,6 +257,24 @@ LogStashLogger.new \
   verify_hostname: false
 ```
 
+## HTTP
+Supports rudimentary writes (buffered, non-persistent connections) to the[ Logstash HTTP Input](https://www.elastic.co/guide/en/logstash/current/plugins-inputs-http.html):
+```ruby
+input {
+  http {
+    port => 8080
+  }
+}
+```
+
+```ruby
+LogStashLogger.new \
+  type: :http,
+  url: 'http://localhost:8080'
+```
+
+Note the parameter is `url` and not `uri`.  Relies on [Net:HTTP](https://ruby-doc.org/stdlib-2.7.1/libdoc/net/http/rdoc/Net/HTTP.html#class-Net::HTTP-label-HTTPS) to auto-detect SSL usage from the scheme.
+
 ## Custom Log Fields
 
 `LogStashLogger` by default will log a JSON object with the format below.

lib/logstash-logger/device.rb

@@ -20,6 +20,7 @@ module Device
     autoload :Stderr, 'logstash-logger/device/stderr'
     autoload :Balancer, 'logstash-logger/device/balancer'
     autoload :MultiDelegator, 'logstash-logger/device/multi_delegator'
+    autoload :HTTP, 'logstash-logger/device/http'
 
     def self.new(opts)
       opts = opts.dup
@@ -60,6 +61,7 @@ def self.device_klass_for(type)
         when :stderr then Stderr
         when :multi_delegator then MultiDelegator
         when :balancer then Balancer
+        when :http then HTTP
         else fail ArgumentError, 'Invalid device type'
       end
     end

lib/logstash-logger/device/http.rb

@@ -0,0 +1,33 @@
+require 'uri'
+require 'net/http'
+
+module LogStashLogger
+  module Device
+
+    # Rudimentary write to Logstash HTTP Input relying on buffering
+    # rather than persistent HTTP connections for efficiency.
+    class HTTP < Connectable
+
+      def initialize(opts)
+        super
+        @url = URI(opts[:url])
+      end
+
+      def connect
+        # no-op
+      end
+
+      def write_one(message)
+        write_batch([message])
+      end
+
+      def write_batch(messages, group = nil)
+        # Logstash HTTP input expects JSON array instead of lines of JSON
+        body = "[#{messages.join(',')}]"
+        resp = Net::HTTP.post @url, body, {"Content-Type" => "application/json"}
+        raise resp.message if Net::HTTPError === resp
+      end
+
+    end
+  end
+end

spec/device/http_spec.rb

@@ -0,0 +1,11 @@
+require 'logstash-logger'
+
+describe LogStashLogger::Device::HTTP do
+  include_context 'device'
+
+  it "Post event to HTTP" do
+    expect(Net::HTTP).to receive(:post)
+    http_device.write('test')
+  end
+
+end

spec/spec_helper.rb

@@ -53,6 +53,7 @@ def connection_type
   let(:tcp_device) { LogStashLogger::Device.new(type: :tcp, port: port, sync: true) }
   let(:ssl_tcp_device) { LogStashLogger::Device.new(type: :tcp, port: port, ssl_enable: true, sync: true) }
   let(:unix_device) { LogStashLogger::Device.new(type: :unix, path: '/tmp/logstash', sync: true) }
+  let(:http_device) { LogStashLogger::Device.new(type: :http, url: 'http://localhost', sync: true) }
 
   let(:file) { Tempfile.new('test') }
   let(:file_device) { LogStashLogger::Device.new(type: :file, path: file.path)}