Merge pull request #384 from alphagov/models

Refactor Discovery Engine resource handling

Author: csutter

.github/workflows/ci.yml

@@ -45,9 +45,7 @@ jobs:
       RAILS_ENV: test
       # All Google client library calls are mocked, but the application needs this set to boot
       GOOGLE_CLOUD_PROJECT_ID: not-used
-      DISCOVERY_ENGINE_SERVING_CONFIG: not-used
-      DISCOVERY_ENGINE_DATASTORE: not-used
-      DISCOVERY_ENGINE_DATASTORE_BRANCH: not-used
+      DISCOVERY_ENGINE_DEFAULT_COLLECTION_NAME: not-used
       # Redis running through govuk-infrastructure action
       REDIS_URL: redis://localhost:6379
     steps:

app/models/branch.rb

@@ -0,0 +1,21 @@
+# Represents a branch on a Discovery Engine data store.
+#
+# Currently, every data store on Discovery Engine has exactly *one* branch (the default branch), and
+# we are not able to make any changes to that resource. However, we still need to model it here
+# because documents are children of the branch, not the datastore itself.
+#
+# see https://cloud.google.com/ruby/docs/reference/google-cloud-discovery_engine-v1/latest/Google-Cloud-DiscoveryEngine-V1-DocumentService-Client
+# (there is no documentation specific to branches)
+Branch = Data.define(:remote_resource_id) do
+  include DiscoveryEngineNameable
+
+  # The default branch automatically available on a data store
+  def self.default
+    new("default_branch")
+  end
+
+  def parent
+    # We only use a single data store in our architecture, so we can hardcode it here.
+    DataStore.default
+  end
+end

app/models/concerns/discovery_engine_nameable.rb

@@ -0,0 +1,31 @@
+# Enhances models with a `#name` method returning their fully qualified Google Cloud Platform
+# resource name (like a path).
+#
+# For example, for a `Control`, this would be:
+#   projects/{project}/locations/{location}/collections/{collection_id}/engines/
+#   {engine_id}/controls/{control_id}
+#
+# Requires the including class to implement `#remote_resource_id`, and optionally `#parent` if the
+# parent resource is not the default collection.
+module DiscoveryEngineNameable
+  # The name (fully qualified path) of this Discovery Engine resource on GCP
+  def name
+    [parent_name, resource_path_fragment, remote_resource_id].join("/")
+  end
+
+private
+
+  def resource_path_fragment
+    # For example: `DataStore` -> `dataStores`
+    self.class.name.downcase_first.pluralize
+  end
+
+  def parent_name
+    if respond_to?(:parent)
+      parent.name
+    else
+      # The default collection is the parent of all root-level resources
+      Rails.configuration.discovery_engine_default_collection_name
+    end
+  end
+end

app/models/data_store.rb

@@ -0,0 +1,15 @@
+# Represents a data store on Discovery Engine.
+#
+# A data store contains the indexed documents that can be searched through an engine.
+#
+# Our architecture currently only has a single data store, so we do not need the ability to manage
+# data stores through Search Admin.
+#
+# see https://cloud.google.com/ruby/docs/reference/google-cloud-discovery_engine-v1/latest/Google-Cloud-DiscoveryEngine-V1-DataStore
+DataStore = Data.define(:remote_resource_id) do
+  include DiscoveryEngineNameable
+
+  def self.default
+    new("govuk_content")
+  end
+end

app/models/engine.rb

@@ -0,0 +1,18 @@
+# Represents an engine on Discovery Engine.
+#
+# An engine (called "app" in the Google Cloud UI) is an abstraction over the data stores that
+# contain our searchable documents, and is used for querying. It is the parent resource of several
+# other resources such as controls and serving configs.
+#
+# Our architecture currently only has a single engine, so we do not need the ability to manage
+# engines through Search Admin.
+#
+# see https://cloud.google.com/ruby/docs/reference/google-cloud-discovery_engine-v1/latest/Google-Cloud-DiscoveryEngine-V1-Engine
+Engine = Data.define(:remote_resource_id) do
+  include DiscoveryEngineNameable
+
+  # The default engine created through Terraform in `govuk-infrastructure`
+  def self.default
+    new("govuk")
+  end
+end

app/models/serving_config.rb

@@ -0,0 +1,21 @@
+# Represents a serving config on Discovery Engine.
+#
+# A serving config is an endpoint on an engine that can be used for
+# querying. Each serving config can have different configuration (in particular, different sets of
+# active controls), which allows us to test out new configuration changes outside of the default
+# serving config.
+#
+# see https://cloud.google.com/ruby/docs/reference/google-cloud-discovery_engine-v1beta/latest/Google-Cloud-DiscoveryEngine-V1beta-ServingConfig
+ServingConfig = Data.define(:remote_resource_id) do
+  include DiscoveryEngineNameable
+
+  # The default serving config automatically available on an engine
+  def self.default
+    new("default_search")
+  end
+
+  def parent
+    # We only use a single engine in our architecture, so we can hardcode it here.
+    Engine.default
+  end
+end

app/services/discovery_engine/autocomplete/complete.rb

@@ -32,14 +32,10 @@ def suggestions
 
     def complete_query_request
       {
-        data_store:,
+        data_store: DataStore.default.name,
         query:,
         query_model: QUERY_MODEL,
       }
     end
-
-    def data_store
-      Rails.configuration.discovery_engine_datastore
-    end
   end
 end

app/services/discovery_engine/autocomplete/update_denylist.rb

@@ -54,7 +54,7 @@ def bucket_name
     end
 
     def parent
-      Rails.configuration.discovery_engine_datastore
+      DataStore.default.name
     end
   end
 end

app/services/discovery_engine/query/search.rb

@@ -56,7 +56,7 @@ def query
     end
 
     def serving_config
-      Rails.configuration.discovery_engine_serving_config
+      ServingConfig.default.name
     end
 
     def page_size

app/services/discovery_engine/sync/operation.rb

@@ -60,7 +60,7 @@ def version_cache
     end
 
     def document_name
-      "#{Rails.configuration.discovery_engine_datastore_branch}/documents/#{content_id}"
+      [Branch.default.name, "documents", content_id].join("/")
     end
 
     def log(level, message)