1 files changed, 142 insertions, 0 deletions
diff --git a/lib/gitlab/redis/wrapper.rb b/lib/gitlab/redis/wrapper.rb
new file mode 100644
index 00000000000..4178b436acf
--- /dev/null
+++ b/lib/gitlab/redis/wrapper.rb
@@ -0,0 +1,142 @@
+# This file should only be used by sub-classes, not directly by any clients of the sub-classes
+# please require all dependencies below:
+require 'active_support/core_ext/hash/keys'
+require 'active_support/core_ext/module/delegation'
+
+module Gitlab
+  module Redis
+    class Wrapper
+      DEFAULT_REDIS_URL = 'redis://localhost:6379'.freeze
+      REDIS_CONFIG_ENV_VAR_NAME = 'GITLAB_REDIS_CONFIG_FILE'.freeze
+
+      class << self
+        delegate :params, :url, to: :new
+
+        def with
+          @pool ||= ConnectionPool.new(size: pool_size) { ::Redis.new(params) }
+          @pool.with { |redis| yield redis }
+        end
+
+        def pool_size
+          # heuristic constant 5 should be a config setting somewhere -- related to CPU count?
+          size = 5
+          if Sidekiq.server?
+            # the pool will be used in a multi-threaded context
+            size += Sidekiq.options[:concurrency]
+          end
+
+          size
+        end
+
+        def _raw_config
+          return @_raw_config if defined?(@_raw_config)
+
+          @_raw_config =
+            begin
+              if filename = config_file_name
+                ERB.new(File.read(filename)).result.freeze
+              else
+                false
+              end
+            rescue Errno::ENOENT
+              false
+            end
+        end
+
+        def default_url
+          DEFAULT_REDIS_URL
+        end
+
+        # Return the absolute path to a Rails configuration file
+        #
+        # We use this instead of `Rails.root` because for certain tasks
+        # utilizing these classes, `Rails` might not be available.
+        def config_file_path(filename)
+          File.expand_path("../../../config/#{filename}", __dir__)
+        end
+
+        def config_file_name
+          # if ENV set for wrapper class, use it even if it points to a file does not exist
+          file_name = ENV[REDIS_CONFIG_ENV_VAR_NAME]
+          return file_name unless file_name.nil?
+
+          # otherwise, if config files exists for wrapper class, use it
+          file_name = config_file_path('resque.yml')
+          return file_name if File.file?(file_name)
+
+          # nil will force use of DEFAULT_REDIS_URL when config file is absent
+          nil
+        end
+      end
+
+      def initialize(rails_env = nil)
+        @rails_env = rails_env || ::Rails.env
+      end
+
+      def params
+        redis_store_options
+      end
+
+      def url
+        raw_config_hash[:url]
+      end
+
+      def sentinels
+        raw_config_hash[:sentinels]
+      end
+
+      def sentinels?
+        sentinels && !sentinels.empty?
+      end
+
+      private
+
+      def redis_store_options
+        config = raw_config_hash
+        redis_url = config.delete(:url)
+        redis_uri = URI.parse(redis_url)
+
+        if redis_uri.scheme == 'unix'
+          # Redis::Store does not handle Unix sockets well, so let's do it for them
+          config[:path] = redis_uri.path
+          query = redis_uri.query
+          unless query.nil?
+            queries = CGI.parse(redis_uri.query)
+            db_numbers = queries["db"] if queries.key?("db")
+            config[:db] = db_numbers[0].to_i if db_numbers.any?
+          end
+
+          config
+        else
+          redis_hash = ::Redis::Store::Factory.extract_host_options_from_uri(redis_url)
+          # order is important here, sentinels must be after the connection keys.
+          # {url: ..., port: ..., sentinels: [...]}
+          redis_hash.merge(config)
+        end
+      end
+
+      def raw_config_hash
+        config_data = fetch_config
+
+        if config_data
+          config_data.is_a?(String) ? { url: config_data } : config_data.deep_symbolize_keys
+        else
+          { url: self.class.default_url }
+        end
+      end
+
+      def fetch_config
+        return false unless self.class._raw_config
+
+        yaml = YAML.load(self.class._raw_config)
+
+        # If the file has content but it's invalid YAML, `load` returns false
+        if yaml
+          yaml.fetch(@rails_env, false)
+        else
+          false
+        end
+      end
+    end
+  end
+end