Update firebasedatabase event conversion logic (#107)

* Update firebasedatabase event conversion logic

Recently the format of Firebase RTDB event was updated to include
location information in the source. When upcasting, this can be
derived from the domain field of a legacy event as described here:

https://github.com/GoogleCloudPlatform/functions-framework-conformance/blob/master/docs/mapping.md#firebase-rtdb-events-tentative

* fix lint errors

* review feedback

* added test for firebase-dbdelete2.json

Author: matthewrobertson

.github/workflows/conformance.yml

@@ -27,13 +27,13 @@ jobs:
     - name: Bundle install
       run: 'bundle install'
     - name: Run HTTP conformance tests
-      uses: GoogleCloudPlatform/functions-framework-conformance/action@v0.3.9
+      uses: GoogleCloudPlatform/functions-framework-conformance/action@v0.3.12
       with:
         functionType: 'http'
         useBuildpacks: false
         cmd: "'bundle exec functions-framework-ruby --source test/conformance/app.rb --target http_func --signature-type http'"
     - name: Run CloudEvent conformance tests
-      uses: GoogleCloudPlatform/functions-framework-conformance/action@v0.3.11
+      uses: GoogleCloudPlatform/functions-framework-conformance/action@v0.3.12
       with:
         functionType: 'cloudevent'
         useBuildpacks: false

lib/functions_framework/legacy_event_converter.rb

@@ -84,10 +84,11 @@ def normalized_context input
       id = normalized_context_field input, "eventId"
       timestamp = normalized_context_field input, "timestamp"
       type = normalized_context_field input, "eventType"
+      domain = normalized_context_field input, "domain"
       service, resource = analyze_resource normalized_context_field input, "resource"
       service ||= service_from_type type
       return nil unless id && timestamp && type && service && resource
-      { id: id, timestamp: timestamp, type: type, service: service, resource: resource }
+      { id: id, timestamp: timestamp, type: type, service: service, resource: resource, domain: domain }
     end
 
     def normalized_context_field input, field
@@ -114,7 +115,7 @@ def service_from_type type
     end
 
     def construct_cloud_event context, data
-      source, subject = convert_source context[:service], context[:resource]
+      source, subject = convert_source context[:service], context[:resource], context[:domain]
       type = LEGACY_TYPE_TO_CE_TYPE[context[:type]]
       return nil unless type && source
       ce_data, data_subject = convert_data context, data
@@ -129,12 +130,24 @@ def construct_cloud_event context, data
                                time:              context[:timestamp]
     end
 
-    def convert_source service, resource
+    def convert_source service, resource, domain
       return ["//#{service}/#{resource}", nil] unless CE_SERVICE_TO_RESOURCE_RE.key? service
 
       match = CE_SERVICE_TO_RESOURCE_RE[service].match resource
       return [nil, nil] unless match
-      ["//#{service}/#{match[1]}", match[2]]
+
+      if service == "firebasedatabase.googleapis.com"
+        return [nil, nil] if domain.nil?
+        location = "us-central1"
+        if domain != "firebaseio.com"
+          location_match = domain.match(/^([\w-]+)\.firebasedatabase\.app$/)
+          return [nil, nil] unless location_match
+          location = location_match[1]
+        end
+        ["//#{service}/projects/_/locations/#{location}/#{match[1]}", match[2]]
+      else
+        ["//#{service}/#{match[1]}", match[2]]
+      end
     end
 
     def convert_data context, data
@@ -192,7 +205,7 @@ def convert_data context, data
 
     CE_SERVICE_TO_RESOURCE_RE = {
       "firebase.googleapis.com"         => %r{^(projects/[^/]+)/(events/[^/]+)$},
-      "firebasedatabase.googleapis.com" => %r{^(projects/_/instances/[^/]+)/(refs/.+)$},
+      "firebasedatabase.googleapis.com" => %r{^projects/_/(instances/[^/]+)/(refs/.+)$},
       "firestore.googleapis.com"        => %r{^(projects/[^/]+/databases/\(default\))/(documents/.+)$},
       "storage.googleapis.com"          => %r{^(projects/[^/]+/buckets/[^/]+)/([^#]+)(?:#.*)?$}
     }.freeze

test/legacy_events_data/firebase-db1.json

@@ -6,6 +6,7 @@
   "auth": {
     "admin": true
   },
+  "domain":"firebaseio.com",
   "data": {
     "data": null,
     "delta": {

test/legacy_events_data/firebase-dbdelete1.json

@@ -6,6 +6,7 @@
   "auth": {
     "admin": true
   },
+  "domain":"europe-west1.firebasedatabase.app",
   "data": {
     "data": {
       "grandchild": "other changed"

test/legacy_events_data/firebase-dbdelete2.json

@@ -6,6 +6,7 @@
   "auth": {
     "admin": true
   },
+  "domain":"firebaseio.com",
   "data": {
     "data": 10,
     "delta": null

test/test_legacy_event_converter.rb

@@ -186,10 +186,36 @@ def load_legacy_event filename, url_path: nil, encoding: "utf-8"
     event = load_legacy_event "firebase-db1.json"
     assert_equal "1.0", event.spec_version
     assert_equal "/SnHth9OSlzK1Puj85kk4tDbF90=", event.id
-    assert_equal "//firebasedatabase.googleapis.com/projects/_/instances/my-project-id", event.source.to_s
+    assert_equal \
+      "//firebasedatabase.googleapis.com/projects/_/locations/us-central1/instances/my-project-id",
+      event.source.to_s
     assert_equal "google.firebase.database.document.v1.written", event.type
     assert_equal "refs/gcf-test/xyz", event.subject
     assert_equal "2020-05-21T11:15:34+00:00", event.time.rfc3339
     assert_equal "other", event.data["delta"]["grandchild"]
   end
+
+  it "converts firebase-dbdelete1.json" do
+    event = load_legacy_event "firebase-dbdelete1.json"
+    assert_equal "1.0", event.spec_version
+    assert_equal "oIcVXHEMZfhQMNs/yD4nwpuKE0s=", event.id
+    assert_equal \
+      "//firebasedatabase.googleapis.com/projects/_/locations/europe-west1/instances/my-project-id",
+      event.source.to_s
+    assert_equal "google.firebase.database.document.v1.deleted", event.type
+    assert_equal "refs/gcf-test/xyz", event.subject
+    assert_equal "2020-05-21T11:53:45+00:00", event.time.rfc3339
+  end
+
+  it "converts firebase-dbdelete2.json" do
+    event = load_legacy_event "firebase-dbdelete2.json"
+    assert_equal "1.0", event.spec_version
+    assert_equal "KVLKeFKjFP2jepddr+EPGC0ZQ20=", event.id
+    assert_equal \
+      "//firebasedatabase.googleapis.com/projects/_/locations/us-central1/instances/my-project-id",
+      event.source.to_s
+    assert_equal "google.firebase.database.document.v1.deleted", event.type
+    assert_equal "refs/gcf-test/abc", event.subject
+    assert_equal "2020-05-21T11:56:12+00:00", event.time.rfc3339
+  end
 end