Add parameter to collect obsolete info using plugins.json (#5)

The obsolete information written in `obsolete-plugins.yml` is also
included in `plugins.json`.

In additional, there is a mechanism to automatically update obsolete
information in `plugins.json`.
Ref. fluent/fluentd-website#383

So, we can detect more obsolete plugins by switching to `plugin.json`.

Author: Watson1978

README.md

@@ -30,11 +30,18 @@ $ bundle
 
 ## Configuration
 
-### obsolete_plugins_yml (string) (optional)
+### plugins_json (string) (optional)
 
-Path to obsolete-plugins.yml
+Path to `plugins.json`.
 
-Default value: `https://raw.githubusercontent.com/fluent/fluentd-website/master/scripts/obsolete-plugins.yml`.
+Default value: `https://raw.githubusercontent.com/fluent/fluentd-website/master/scripts/plugins.json`.
+
+
+### Deprecated: obsolete_plugins_yml (string) (optional)
+
+Path to `obsolete-plugins.yml`. This parameter is deprecated. Please use `plugins_json` parameter instead.
+
+Default value: `nil`
 
 ### raise_error (bool) (optional)
 

lib/fluent/plugin/filter_obsolete_plugins.rb

@@ -14,35 +14,33 @@
 # limitations under the License.
 
 require "fluent/plugin/filter"
-require "open-uri"
-require "yaml"
+require "fluent/plugin/obsolete_plugins_utils"
 
 module Fluent
   module Plugin
     class ObsoletePluginsFilter < Fluent::Plugin::Filter
       Fluent::Plugin.register_filter("obsolete_plugins", self)
 
-      OBSOLETE_PLUGINS_URL = "https://raw.githubusercontent.com/fluent/fluentd-website/master/scripts/obsolete-plugins.yml"
+      PLUGINS_JSON_URL = "https://raw.githubusercontent.com/fluent/fluentd-website/master/scripts/plugins.json"
 
       desc "Path to obsolete-plugins.yml"
-      config_param :obsolete_plugins_yml, :string, default: OBSOLETE_PLUGINS_URL
+      config_param :obsolete_plugins_yml, :string, default: nil, deprecated: "use plugins_json parameter instead"
+      desc "Path to plugins.json"
+      config_param :plugins_json, :string, default: PLUGINS_JSON_URL
       desc "Raise error if obsolete plugins are detected"
       config_param :raise_error, :bool, default: false
 
       def configure(conf)
         super
 
-        @obsolete_plugins = URI.open(@obsolete_plugins_yml) do |io|
-          YAML.safe_load(io.read)
-        end
-
-        obsolete_plugins = Gem.loaded_specs.keys & @obsolete_plugins.keys
-        obsolete_plugins.each do |name|
-          log.warn("#{name} is obsolete: #{@obsolete_plugins[name].chomp}")
-        end
-        if @raise_error && !obsolete_plugins.empty?
-          raise Fluent::ConfigError, "Detected obsolete plugins"
-        end
+        obsolete_plugins =
+          if @obsolete_plugins_yml
+            ObsoletePluginsUtils.obsolete_plugins_from_yaml(@obsolete_plugins_yml)
+          else
+            ObsoletePluginsUtils.obsolete_plugins_from_json(@plugins_json)
+          end
+
+        ObsoletePluginsUtils.notify(log, obsolete_plugins, raise_error: @raise_error)
       end
 
       def filter(tag, time, record)

lib/fluent/plugin/obsolete_plugins_utils.rb

@@ -0,0 +1,35 @@
+require "fluent/config/error"
+require "open-uri"
+require "yaml"
+require "json"
+
+class Fluent::Plugin::ObsoletePluginsUtils
+  def self.obsolete_plugins_from_yaml(url)
+    URI.open(url) do |io|
+      YAML.safe_load(io.read)
+    end
+  end
+
+  def self.obsolete_plugins_from_json(url)
+    plugins = URI.open(url) do |io|
+      # io.read causes Encoding::UndefinedConversionError with UTF-8 data when Ruby is started with "-Eascii-8bit:ascii-8bit".
+      # It set the proper encoding to avoid the error.
+      io.set_encoding("UTF-8", "UTF-8")
+      JSON.parse(io.read)
+    end
+    plugins.select { |plugin| plugin["obsolete"] }.reduce({}) do |result, plugin|
+      result[plugin["name"]] = plugin["note"]
+      result
+    end
+  end
+
+  def self.notify(logger, obsolete_plugins, raise_error: false)
+    plugins = Gem.loaded_specs.keys & obsolete_plugins.keys
+    plugins.each do |name|
+      logger.warn("#{name} is obsolete: #{obsolete_plugins[name].chomp}")
+    end
+    if raise_error && !plugins.empty?
+      raise Fluent::ConfigError, "Detected obsolete plugins"
+    end
+  end
+end