system_config: support built-in config files

Currently @include directive supports to reuse configuration files,
but no way to apply specific configuration files by default (without
specifying to).

In the previous versions, if you want to manage multiple
configuration files, you must use @include directive explicitly.

In this commit, add an option to specify the directory
(e.g. /etc/fluent/conf.d) which stores additional configuration files.
If there are such files under specified directory, they are loaded by
default without @include directive.

If you want to disable this feature, set empty string
for config_include_dir "".

Signed-off-by: Kentaro Hayashi <[email protected]>

Author: kenhys

lib/fluent/env.rb

@@ -21,6 +21,7 @@
 
 module Fluent
   DEFAULT_CONFIG_PATH = ENV['FLUENT_CONF'] || '/etc/fluent/fluent.conf'
+  DEFAULT_CONFIG_INCLUDE_DIR = ENV["FLUENT_CONF_INCLUDE_DIR"] || '/etc/fluent/conf.d'
   DEFAULT_PLUGIN_DIR = ENV['FLUENT_PLUGIN'] || '/etc/fluent/plugin'
   DEFAULT_SOCKET_PATH = ENV['FLUENT_SOCKET'] || '/var/run/fluent/fluent.sock'
   DEFAULT_BACKUP_DIR = ENV['FLUENT_BACKUP_DIR'] || '/tmp/fluent'

lib/fluent/supervisor.rb

@@ -17,6 +17,7 @@
 require 'fileutils'
 require 'open3'
 require 'pathname'
+require 'find'
 
 require 'fluent/config'
 require 'fluent/counter'
@@ -806,6 +807,10 @@ def configure(supervisor: false)
 
       $log.info :supervisor, 'parsing config file is succeeded', path: @config_path
 
+      build_additional_configurations do |additional_conf|
+        @conf += additional_conf
+      end
+
       @libs.each do |lib|
         require lib
       end
@@ -1090,6 +1095,10 @@ def reload_config
             type: @config_file_type,
           )
 
+          build_additional_configurations do |additional_conf|
+            conf += additional_conf
+          end
+
           Fluent::VariableStore.try_to_reset do
             Fluent::Engine.reload_config(conf)
           end
@@ -1196,6 +1205,28 @@ def build_system_config(conf)
       system_config
     end
 
+    def build_additional_configurations
+      if @system_config.config_include_dir&.empty?
+        $log.info :supervisor, 'default configuration include directory was disabled'
+        return
+      end
+      begin
+        Find.find(@system_config.config_include_dir) do |path|
+          next if File.directory?(path)
+          next unless [".conf", ".yaml", ".yml"].include?(File.extname(path))
+          # NOTE: both types of normal config (.conf) and YAML will be loaded.
+          # Thus, it does not care whether @config_path is .conf or .yml.
+          $log.info :supervisor, 'loading additional configuration file', path: path
+          yield Fluent::Config.build(config_path: path,
+                                         encoding: @conf_encoding,
+                                         use_v1_config: @use_v1_config,
+                                         type: :guess)
+        end
+      rescue Errno::ENOENT
+        $log.info :supervisor, 'inaccessible include directory was specified', path: @system_config.config_include_dir
+      end
+    end
+
     RUBY_ENCODING_OPTIONS_REGEX = %r{\A(-E|--encoding=|--internal-encoding=|--external-encoding=)}.freeze
 
     def build_spawn_command

lib/fluent/system_config.rb

@@ -16,6 +16,7 @@
 
 require 'fluent/configurable'
 require 'fluent/config/element'
+require 'fluent/env'
 
 module Fluent
   class SystemConfig
@@ -28,7 +29,8 @@ class SystemConfig
       :without_source, :with_source_only, :rpc_endpoint, :enable_get_dump, :process_name,
       :file_permission, :dir_permission, :counter_server, :counter_client,
       :strict_config_value, :enable_msgpack_time_support, :disable_shared_socket,
-      :metrics, :enable_input_metrics, :enable_size_metrics, :enable_jit, :source_only_buffer
+      :metrics, :enable_input_metrics, :enable_size_metrics, :enable_jit, :source_only_buffer,
+      :config_include_dir
     ]
 
     config_param :workers,   :integer, default: 1
@@ -58,6 +60,7 @@ class SystemConfig
     config_param :dir_permission, default: nil do |v|
       v.to_i(8)
     end
+    config_param :config_include_dir, default: Fluent::DEFAULT_CONFIG_INCLUDE_DIR
     config_section :log, required: false, init: true, multi: false do
       config_param :path, :string, default: nil
       config_param :format, :enum, list: [:text, :json], default: :text

test/command/test_fluentd.rb

@@ -1536,4 +1536,76 @@ def send_end(port)
       end_thread&.kill
     end
   end
+
+  def create_config_include_dir_configuration(config_path, config_dir, yaml_format = false)
+    if yaml_format
+      conf = <<CONF
+      system:
+        config_include_dir: "#{config_dir}"
+CONF
+    else
+      conf = <<CONF
+      <system>
+        config_include_dir #{config_dir}
+      </system>
+CONF
+    end
+    create_conf_file(config_path, conf)
+  end
+
+  sub_test_case "test additional configuration directory" do
+    setup do
+      FileUtils.mkdir_p(File.join(@tmp_dir, "conf.d"))
+    end
+
+    test "disable additional configuration directory" do
+      conf_path = create_config_include_dir_configuration("disabled_config_include_dir.conf", "")
+      assert_log_matches(create_cmdline(conf_path),
+                         "[info]: default configuration include directory was disabled")
+    end
+
+    test "inaccessible include directory error" do
+      conf_path = create_config_include_dir_configuration("inaccessible_include.conf", "/nonexistent")
+      assert_log_matches(create_cmdline(conf_path),
+                         "[info]: inaccessible include directory was specified")
+    end
+
+    data("include additional configuration with relative conf.d" => [{"relative_path" => true}],
+         "include additional configuration with full-path conf.d" => [{"relative_path" => false}])
+    test "additional configuration file (conf.d/child.conf) was loaded" do |(option)|
+      conf_dir = option["relative_path"] ? "conf.d" : "#{@tmp_dir}/conf.d"
+      conf_path = create_config_include_dir_configuration("parent.conf", conf_dir)
+      create_conf_file('conf.d/child.conf', "")
+      assert_log_matches(create_cmdline(conf_path),
+                         "[info]: loading additional configuration file path=\"#{conf_dir}/child.conf\"")
+    end
+  end
+
+  sub_test_case "test additional configuration directory (YAML)" do
+    setup do
+      FileUtils.mkdir_p(File.join(@tmp_dir, "conf.d"))
+    end
+
+    test "disable additional configuration directory" do
+      conf_path = create_config_include_dir_configuration("disabled_config_include_dir.yml", "", true)
+      assert_log_matches(create_cmdline(conf_path),
+                         "[info]: default configuration include directory was disabled")
+    end
+
+    test "inaccessible include directory error" do
+      conf_path = create_config_include_dir_configuration("inaccessible_include.yml", "/nonexistent", true)
+      assert_log_matches(create_cmdline(conf_path),
+                         "[info]: inaccessible include directory was specified")
+    end
+
+    data("include additional YAML configuration with relative conf.d" => [{"relative_path" => true}],
+         "include additional YAML configuration with full path conf.d" => [{"relative_path" => false}])
+    test "additional relative configuration file (conf.d/child.yml) was loaded" do |(option)|
+      conf_dir = option["relative_path"] ? "conf.d" : "#{@tmp_dir}/conf.d"
+      conf_path = create_config_include_dir_configuration("parent.yml", conf_dir, true)
+      create_conf_file('conf.d/child.yml', "")
+      assert_log_matches(create_cmdline(conf_path),
+                         "[info]: loading additional configuration file path=\"#{conf_dir}/child.yml\"")
+    end
+  end
 end

test/test_supervisor.rb

@@ -1054,6 +1054,129 @@ def test_stop_parallel_old_supervisor_after_delay
     end
   end
 
+  sub_test_case "include additional configuration" do
+    setup do
+      @config_include_dir = File.join(@tmp_dir, "conf.d")
+      FileUtils.mkdir_p(@config_include_dir)
+    end
+
+    test "no additional configuration" do
+      c = Fluent::Config::Element.new('system', '', { 'config_include_dir' => '' }, [])
+      stub(Fluent::Config).build { config_element('ROOT', '', {}, [c]) }
+      supervisor = Fluent::Supervisor.new({})
+      stub(supervisor).build_spawn_command { "dummy command line" }
+      supervisor.configure(supervisor: true)
+      assert_equal([c], supervisor.instance_variable_get(:@conf).elements)
+    end
+
+    data(
+      "single source" => ["forward"],
+      "multiple sources" => ["forward", "tcp"])
+    test "additional configuration" do |sources|
+      c = Fluent::Config::Element.new('system', '',
+                                      { 'config_include_dir' => @config_include_dir }, [])
+      config_path = "#{@config_include_dir}/dummy.conf"
+      stub(Fluent::Config).build(config_path: "/etc/fluent/fluent.conf", encoding: "utf-8",
+                                 additional_config: anything, use_v1_config: anything,
+                                 type: anything) { config_element('ROOT', '', {}, [c]) }
+      sources.each do |type|
+        config = <<~EOF
+        <source>
+          @type #{type}
+        </source>
+        EOF
+        additional_config_path = "#{@config_include_dir}/#{type}.yml"
+        write_config(additional_config_path, config)
+        stub(Fluent::Config).build(config_path: additional_config_path, encoding: "utf-8",
+                                   use_v1_config: true, type: :guess) {
+          Fluent::Config.parse(File.read(additional_config_path), File.dirname(config_path), true)
+        }
+      end
+      supervisor = Fluent::Supervisor.new({})
+      stub(supervisor).build_spawn_command { "dummy command line" }
+      supervisor.configure(supervisor: true)
+      expected = [c].concat(sources.collect { |type| {"@type" => type} })
+      assert_equal(expected, supervisor.instance_variable_get(:@conf).elements)
+    end
+
+    data(
+      "single YAML source" => ["forward"],
+      "multiple YAML sources" => ["forward", "tcp"])
+    test "additional YAML configuration" do |sources|
+      c = Fluent::Config::Element.new('system', '',
+                                      { 'config_include_dir' => @config_include_dir }, [])
+      config_path = "#{@config_include_dir}/dummy.yml"
+      stub(Fluent::Config).build(config_path: "/etc/fluent/fluent.conf", encoding: "utf-8",
+                                 additional_config: anything, use_v1_config: anything,
+                                 type: anything) { config_element('ROOT', '', {}, [c]) }
+      sources.each do |type|
+        config = <<~EOF
+        config:
+          - source:
+              $type: #{type}
+        EOF
+        additional_config_path = "#{@config_include_dir}/#{type}.yml"
+        write_config(additional_config_path, config)
+        stub(Fluent::Config).build(config_path: additional_config_path, encoding: "utf-8",
+                                   use_v1_config: true, type: :guess) {
+          Fluent::Config::YamlParser.parse(additional_config_path)
+      }
+      end
+      supervisor = Fluent::Supervisor.new({})
+      stub(supervisor).build_spawn_command { "dummy command line" }
+      supervisor.configure(supervisor: true)
+      expected = [c].concat(sources.collect { |type| {"@type" => type} })
+      assert_equal(expected, supervisor.instance_variable_get(:@conf).elements)
+    end
+
+    data(
+      "single source" => [false, ["forward"]],
+      "multiple sources" => [false, ["forward", "tcp"]],
+      "single YAML source" => [true, ["forward"]],
+      "multiple YAML sources" => [true, ["forward", "tcp"]])
+    test "reload with additional configuration" do |(yaml, sources)|
+      c = Fluent::Config::Element.new('system', '',
+                                      { 'config_include_dir' => @config_include_dir }, [])
+      config_path = "#{@config_include_dir}/dummy.yml"
+      stub(Fluent::Config).build(config_path: "/etc/fluent/fluent.conf", encoding: "utf-8",
+                                 additional_config: anything, use_v1_config: anything,
+                                 type: anything) { config_element('ROOT', '', {}, [c]) }
+      sources.each do |type|
+        if yaml
+          config = <<~EOF
+          config:
+            - source:
+                $type: #{type}
+          EOF
+          additional_config_path = "#{@config_include_dir}/#{type}.yml"
+          write_config(additional_config_path, config)
+          stub(Fluent::Config).build(config_path: additional_config_path, encoding: "utf-8",
+                                     use_v1_config: true, type: :guess) {
+            Fluent::Config::YamlParser.parse(additional_config_path)
+          }
+        else
+          config = <<~EOF
+          <source>
+            @type #{type}
+          </source>
+          EOF
+          additional_config_path = "#{@config_include_dir}/#{type}.conf"
+          write_config(additional_config_path, config)
+          stub(Fluent::Config).build(config_path: additional_config_path, encoding: "utf-8",
+                                   use_v1_config: true, type: :guess) {
+            Fluent::Config.parse(File.read(additional_config_path), File.dirname(config_path), true)
+          }
+        end
+      end
+      supervisor = Fluent::Supervisor.new({})
+      stub(supervisor).build_spawn_command { "dummy command line" }
+      supervisor.configure(supervisor: true)
+      supervisor.__send__(:reload_config)
+      expected = [c].concat(sources.collect { |type| {"@type" => type} })
+      assert_equal(expected, supervisor.instance_variable_get(:@conf).elements)
+    end
+  end
+
   def create_debug_dummy_logger
     dl_opts = {}
     dl_opts[:log_level] = ServerEngine::DaemonLogger::DEBUG