Add a new command that generate a plugin skeleton that can be used to…

… create a new plugin

Fixes #4190

docs/static/plugin-manager.asciidoc

@@ -113,4 +113,4 @@ Once set, plugin commands install, update can be used through this proxy.
 
 include::offline-plugins.asciidoc[]
 
-include::private-gem-repo.asciidoc[]
+include::private-gem-repo.asciidoc[]

lib/pluginmanager/generate.rb

@@ -0,0 +1,90 @@
+# encoding: utf-8
+require "pluginmanager/command"
+require "pluginmanager/templates/render_context"
+require "erb"
+require "ostruct"
+require "fileutils"
+
+class LogStash::PluginManager::Generate < LogStash::PluginManager::Command
+
+  TYPES = [ "input", "filter", "output" ]
+
+  option "--type", "TYPE", "Type of the plugin {input, filter, output}s" do |arg|
+    raise(ArgumentError, "should be one of: input, output or filter") unless TYPES.include?(arg)
+    arg
+  end
+
+  option "--name", "PLUGIN", "Name of the new plugin"
+  option "--path", "PATH", "Location where the plugin skeleton will be created", :default => Dir.pwd
+
+  def execute
+    source = File.join(File.dirname(__FILE__), "templates", "#{type}-plugin")
+    target_path = File.join(path, full_plugin_name)
+    FileUtils.mkdir(target_path)
+    puts " Creating #{target_path}"
+
+    begin
+      create_scaffold(source, target_path)
+    rescue Errno::EACCES => exception
+      report_exception("Permission denied when executing the plugin manager", exception)
+    rescue => exception
+      report_exception("Plugin creation Aborted", exception)
+    end
+  end
+
+  private
+
+  def create_scaffold(source, target)
+    transform_r(source, target)
+  end
+
+  def transform_r(source, target)
+    Dir.entries(source).each do |entry|
+      next if [ ".", ".." ].include?(entry)
+      source_entry = File.join(source, entry)
+      target_entry = File.join(target, entry)
+
+      if File.directory?(source_entry)
+        FileUtils.mkdir(target_entry) unless File.exists?(target_entry)
+        transform_r(source_entry, target_entry)
+      else
+        # copy the new file, in case of being an .erb file should render first
+        if source_entry.end_with?("erb")
+          target_entry = target_entry.gsub(/.erb$/,"").gsub("example", name)
+          File.open(target_entry, "w") { |f| f.write(render(source_entry)) }
+        else
+          FileUtils.cp(source_entry, target_entry)
+        end
+        puts "\t create #{File.join(full_plugin_name, File.basename(target_entry))}"
+      end
+    end
+  end
+
+  def render(source)
+    template = File.read(source)
+    renderer = ERB.new(template)
+    context  = LogStash::PluginManager::RenderContext.new(options)
+    renderer.result(context.get_binding)
+  end
+
+  def options
+    git_data = get_git_info
+    @options ||= {
+      :plugin_name => name,
+      :author => git_data.author,
+      :email  => git_data.email,
+      :min_version => "2.0",
+    }
+  end
+
+  def get_git_info
+    git = OpenStruct.new
+    git.author = %x{ git config --get user.name  }.strip rescue "your_username"
+    git.email  = %x{ git config --get user.email }.strip rescue "[email protected]"
+    git
+  end
+
+  def full_plugin_name
+    @full_plugin_name ||= "logstash-#{type}-#{name.downcase}"
+  end
+end

lib/pluginmanager/main.rb

@@ -20,6 +20,7 @@ module PluginManager
 require "pluginmanager/update"
 require "pluginmanager/pack"
 require "pluginmanager/unpack"
+require "pluginmanager/generate"
 
 module LogStash
   module PluginManager
@@ -32,6 +33,7 @@ class Main < Clamp::Command
       subcommand "pack", "Package currently installed plugins", LogStash::PluginManager::Pack
       subcommand "unpack", "Unpack packaged plugins", LogStash::PluginManager::Unpack
       subcommand "list", "List all installed plugins", LogStash::PluginManager::List
+      subcommand "generate", "Create the foundation for a new plugin", LogStash::PluginManager::Generate
     end
   end
 end

lib/pluginmanager/templates/filter-plugin/CHANGELOG.md

@@ -0,0 +1,2 @@
+## 0.1.0
+  - Plugin created with the logstash plugin generator

lib/pluginmanager/templates/filter-plugin/CONTRIBUTORS.erb

@@ -0,0 +1,10 @@
+The following is a list of people who have contributed ideas, code, bug
+reports, or in general have helped logstash along its way.
+
+Contributors:
+* <%= author %> - <%= email %>
+
+Note: If you've sent us patches, bug reports, or otherwise contributed to
+Logstash, and you aren't on the list above and want to be, please let us know
+and we'll make sure you're here. Contributions from folks like you are what make
+open source awesome.

lib/pluginmanager/templates/filter-plugin/DEVELOPER.md.erb

@@ -0,0 +1,2 @@
+# logstash-filter-<%= plugin_name %>
+Example filter plugin. This should help bootstrap your effort to write your own filter plugin!

lib/pluginmanager/templates/filter-plugin/Gemfile

@@ -0,0 +1,3 @@
+source 'https://rubygems.org'
+gemspec
+

lib/pluginmanager/templates/filter-plugin/LICENSE

@@ -0,0 +1,11 @@
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.

lib/pluginmanager/templates/filter-plugin/README.md

@@ -0,0 +1,86 @@
+# Logstash Plugin
+
+This is a plugin for [Logstash](https://github.com/elastic/logstash).
+
+It is fully free and fully open source. The license is Apache 2.0, meaning you are pretty much free to use it however you want in whatever way.
+
+## Documentation
+
+Logstash provides infrastructure to automatically generate documentation for this plugin. We use the asciidoc format to write documentation so any comments in the source code will be first converted into asciidoc and then into html. All plugin documentation are placed under one [central location](http://www.elastic.co/guide/en/logstash/current/).
+
+- For formatting code or config example, you can use the asciidoc `[source,ruby]` directive
+- For more asciidoc formatting tips, see the excellent reference here https://github.com/elastic/docs#asciidoc-guide
+
+## Need Help?
+
+Need help? Try #logstash on freenode IRC or the https://discuss.elastic.co/c/logstash discussion forum.
+
+## Developing
+
+### 1. Plugin Developement and Testing
+
+#### Code
+- To get started, you'll need JRuby with the Bundler gem installed.
+
+- Create a new plugin or clone and existing from the GitHub [logstash-plugins](https://github.com/logstash-plugins) organization. We also provide [example plugins](https://github.com/logstash-plugins?query=example).
+
+- Install dependencies
+```sh
+bundle install
+```
+
+#### Test
+
+- Update your dependencies
+
+```sh
+bundle install
+```
+
+- Run tests
+
+```sh
+bundle exec rspec
+```
+
+### 2. Running your unpublished Plugin in Logstash
+
+#### 2.1 Run in a local Logstash clone
+
+- Edit Logstash `Gemfile` and add the local plugin path, for example:
+```ruby
+gem "logstash-filter-awesome", :path => "/your/local/logstash-filter-awesome"
+```
+- Install plugin
+```sh
+bin/logstash-plugin install --no-verify
+```
+- Run Logstash with your plugin
+```sh
+bin/logstash -e 'filter {awesome {}}'
+```
+At this point any modifications to the plugin code will be applied to this local Logstash setup. After modifying the plugin, simply rerun Logstash.
+
+#### 2.2 Run in an installed Logstash
+
+You can use the same **2.1** method to run your plugin in an installed Logstash by editing its `Gemfile` and pointing the `:path` to your local plugin development directory or you can build the gem and install it using:
+
+- Build your plugin gem
+```sh
+gem build logstash-filter-awesome.gemspec
+```
+- Install the plugin from the Logstash home
+```sh
+bin/logstash-plugin install /your/local/plugin/logstash-filter-awesome.gem
+```
+- Start Logstash and proceed to test the plugin
+
+## Contributing
+
+All contributions are welcome: ideas, patches, documentation, bug reports, complaints, and even something you drew up on a napkin.
+
+Programming is not a required skill. Whatever you've seen about open source and maintainers or community members  saying "send patches or die" - you will not see that here.
+
+It is more important to the community that you are able to contribute.
+
+For more information about contributing, see the [CONTRIBUTING](https://github.com/elastic/logstash/blob/master/CONTRIBUTING.md) file.

lib/pluginmanager/templates/filter-plugin/Rakefile

@@ -0,0 +1 @@
+require "logstash/devutils/rake"

lib/pluginmanager/templates/filter-plugin/lib/logstash/filters/example.rb.erb

@@ -0,0 +1,43 @@
+# encoding: utf-8
+require "logstash/filters/base"
+require "logstash/namespace"
+
+# This <%= @plugin_name %> filter will replace the contents of the default 
+# message field with whatever you specify in the configuration.
+#
+# It is only intended to be used as an <%= @plugin_name %>.
+class LogStash::Filters::<%= classify(plugin_name) %> < LogStash::Filters::Base
+
+  # Setting the config_name here is required. This is how you
+  # configure this filter from your Logstash config.
+  #
+  # filter {
+  #   <%= @plugin_name %> {
+  #     message => "My message..."
+  #   }
+  # }
+  #
+  config_name "<%= plugin_name %>"
+
+  # Replace the message with this value.
+  config :message, :validate => :string, :default => "Hello World!"
+
+
+  public
+  def register
+    # Add instance variables 
+  end # def register
+
+  public
+  def filter(event)
+
+    if @message
+      # Replace the event message with our message as configured in the
+      # config file.
+      event["message"] = @message
+    end
+
+    # filter_matched should go in the last line of our successful code
+    filter_matched(event)
+  end # def filter
+end # class LogStash::Filters::<%= classify(plugin_name) %>

lib/pluginmanager/templates/filter-plugin/logstash-filter-example.gemspec.erb

@@ -0,0 +1,23 @@
+Gem::Specification.new do |s|
+  s.name          = 'logstash-filter-<%= plugin_name %>'
+  s.version       = '0.1.0'
+  s.licenses      = ['Apache License (2.0)']
+  s.summary       = 'TODO: Write a short summary, because Rubygems requires one.'
+  s.description   = 'TODO: Write a longer description or delete this line.'
+  s.homepage      = 'TODO: Put your plugin's website or public repo URL here.'
+  s.authors       = ['<%= author %>']
+  s.email         = '<%= email %>'
+  s.require_paths = ['lib']
+
+  # Files
+  s.files = Dir['lib/**/*','spec/**/*','vendor/**/*','*.gemspec','*.md','CONTRIBUTORS','Gemfile','LICENSE','NOTICE.TXT']
+   # Tests
+  s.test_files = s.files.grep(%r{^(test|spec|features)/})
+
+  # Special flag to let us know this is actually a logstash plugin
+  s.metadata = { "logstash_plugin" => "true", "logstash_group" => "filter" }
+
+  # Gem dependencies
+  s.add_runtime_dependency "logstash-core-plugin-api", "~> <%= min_version %>"
+  s.add_development_dependency 'logstash-devutils'
+end

lib/pluginmanager/templates/filter-plugin/spec/filters/example_spec.rb.erb

@@ -0,0 +1,21 @@
+# encoding: utf-8
+require_relative '../spec_helper'
+require "logstash/filters/<%= plugin_name %>"
+
+describe LogStash::Filters::<%= classify(plugin_name) %> do
+  describe "Set to Hello World" do
+    let(:config) do <<-CONFIG
+      filter {
+        <%= plugin_name %> {
+          message => "Hello World"
+        }
+      }
+    CONFIG
+    end
+
+    sample("message" => "some text") do
+      expect(subject).to include("message")
+      expect(subject['message']).to eq('Hello World')
+    end
+  end
+end

lib/pluginmanager/templates/filter-plugin/spec/spec_helper.rb

@@ -0,0 +1,2 @@
+# encoding: utf-8
+require "logstash/devutils/rspec/spec_helper"

lib/pluginmanager/templates/input-plugin/CHANGELOG.md

@@ -0,0 +1,2 @@
+## 0.1.0
+  - Plugin created with the logstash plugin generator

lib/pluginmanager/templates/input-plugin/CONTRIBUTORS.erb

@@ -0,0 +1,10 @@
+The following is a list of people who have contributed ideas, code, bug
+reports, or in general have helped logstash along its way.
+
+Contributors:
+* <%= author %> - <%= email %>
+
+Note: If you've sent us patches, bug reports, or otherwise contributed to
+Logstash, and you aren't on the list above and want to be, please let us know
+and we'll make sure you're here. Contributions from folks like you are what make
+open source awesome.

lib/pluginmanager/templates/input-plugin/DEVELOPER.md.erb

@@ -0,0 +1,2 @@
+# logstash-input-<%= plugin_name %>
+Example input plugin. This should help bootstrap your effort to write your own input plugin!

lib/pluginmanager/templates/input-plugin/Gemfile

@@ -0,0 +1,3 @@
+source 'https://rubygems.org'
+gemspec
+

lib/pluginmanager/templates/input-plugin/LICENSE

@@ -0,0 +1,11 @@
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.