1 files changed, 98 insertions, 4 deletions

diff --git a/lib/gitlab/webpack/manifest.rb b/lib/gitlab/webpack/manifest.rb
index d2c01bbd55e..6a8a7e24ebd 100644
--- a/lib/gitlab/webpack/manifest.rb
+++ b/lib/gitlab/webpack/manifest.rb
@@ -1,16 +1,33 @@
 # frozen_string_literal: true
 
-require 'webpack/rails/manifest'
+require 'net/http'
+require 'uri'
 
 module Gitlab
   module Webpack
-    class Manifest < ::Webpack::Rails::Manifest
-      # Raised if a supplied asset does not exist in the webpack manifest
+    class Manifest
+      # Raised if we can't read our webpack manifest for whatever reason
+      class ManifestLoadError < StandardError
+        def initialize(message, orig)
+          super "#{message} (original error #{orig})"
+        end
+      end
+
+      # Raised if webpack couldn't build one of your entry points
+      class WebpackError < StandardError
+        def initialize(errors)
+          super "Error in webpack compile, details follow below:\n#{errors.join("\n\n")}"
+        end
+      end
+
+      # Raised if a supplied entry point does not exist in the webpack manifest
       AssetMissingError = Class.new(StandardError)
 
       class << self
+        include Gitlab::Utils::StrongMemoize
+
         def entrypoint_paths(source)
-          raise ::Webpack::Rails::Manifest::WebpackError, manifest["errors"] unless manifest_bundled?
+          raise WebpackError, manifest["errors"] unless manifest_bundled?
 
           dll_assets = manifest.fetch("dllAssets", [])
           entrypoint = manifest["entrypoints"][source]
@@ -21,9 +38,86 @@ module Gitlab
               "/#{::Rails.configuration.webpack.public_path}/#{p}"
             end
           else
+            raise AssetMissingError, "Can't find asset '#{source}' in webpack manifest"
+          end
+        end
+
+        def asset_paths(source)
+          raise WebpackError, manifest["errors"] unless manifest_bundled?
+
+          paths = manifest["assetsByChunkName"][source]
+          if paths
+            # Can be either a string or an array of strings.
+            # Do not include source maps as they are not javascript
+            [paths].flatten.reject { |p| p =~ /.*\.map$/ }.map do |p|
+              "/#{::Rails.configuration.webpack.public_path}/#{p}"
+            end
+          else
             raise AssetMissingError, "Can't find entry point '#{source}' in webpack manifest"
           end
         end
+
+        def clear_manifest!
+          clear_memoization(:manifest)
+        end
+
+        private
+
+        def manifest_bundled?
+          !manifest["errors"].any? { |error| error.include? "Module build failed" }
+        end
+
+        def manifest
+          if ::Rails.configuration.webpack.dev_server.enabled
+            # Don't cache if we're in dev server mode, manifest may change ...
+            load_manifest
+          else
+            # ... otherwise cache at class level, as JSON loading/parsing can be expensive
+            strong_memoize(:manifest) { load_manifest }
+          end
+        end
+
+        def load_manifest
+          data = if ::Rails.configuration.webpack.dev_server.enabled
+                   load_dev_server_manifest
+                 else
+                   load_static_manifest
+                 end
+
+          Gitlab::Json.parse(data)
+        end
+
+        def load_dev_server_manifest
+          host = ::Rails.configuration.webpack.dev_server.manifest_host
+          port = ::Rails.configuration.webpack.dev_server.manifest_port
+          uri = Addressable::URI.new(scheme: 'http', host: host, port: port, path: dev_server_path)
+
+          # localhost could be blocked via Gitlab::HTTP
+          response = HTTParty.get(uri.to_s, verify: false) # rubocop:disable Gitlab/HTTParty
+
+          return response.body if response.code == 200
+
+          raise "HTTP error #{response.code}"
+        rescue => e
+          raise ManifestLoadError.new("Could not load manifest from webpack-dev-server at #{uri} - is it running, and is stats-webpack-plugin loaded?", e)
+        end
+
+        def load_static_manifest
+          File.read(static_manifest_path)
+        rescue => e
+          raise ManifestLoadError.new("Could not load compiled manifest from #{static_manifest_path} - have you run `rake webpack:compile`?", e)
+        end
+
+        def static_manifest_path
+          ::Rails.root.join(
+            ::Rails.configuration.webpack.output_dir,
+            ::Rails.configuration.webpack.manifest_filename
+          )
+        end
+
+        def dev_server_path
+          "/#{::Rails.configuration.webpack.public_path}/#{::Rails.configuration.webpack.manifest_filename}"
+        end
       end
     end
   end