feat(eventarc): new sample for storage event receiver

eventarc/storage_handler/Procfile

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+web: gunicorn --bind :$PORT --workers 1 --threads 8 --timeout 0 main:app

eventarc/storage_handler/main.py

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+# Copyright 2023 Google LLC.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# [START eventarc_storage_cloudevent_server]
+import os
+
+from cloudevents.http import from_http
+
+from flask import Flask, request
+
+from google.events.cloud.storage import StorageObjectData
+
+
+app = Flask(__name__)
+# [END eventarc_storage_cloudevent_server]
+
+
+# [START eventarc_storage_cloudevent_handler]
+@app.route("/", methods=["POST"])
+def index():
+    event = from_http(request.headers, request.get_data())
+
+    # Gets the GCS bucket name from the CloudEvent data
+    # Example: "storage.googleapis.com/projects/_/buckets/my-bucket"
+    try:
+        storage_obj = StorageObjectData(event.data)
+        gcs_object = os.path.join(storage_obj.bucket, storage_obj.name)
+        update_time = storage_obj.updated
+        return (
+            f"Cloud Storage object changed: {gcs_object}"
+            + f" updated at {update_time}",
+            200,
+        )
+    except ValueError as e:
+        return (f"Failed to parse event data: {e}", 400)
+
+
+# [END eventarc_storage_cloudevent_handler]
+
+
+# [START eventarc_storage_cloudevent_server]
+if __name__ == "__main__":
+    app.run(debug=True, host="0.0.0.0", port=int(os.environ.get("PORT", 8080)))
+# [END eventarc_storage_cloudevent_server]

eventarc/storage_handler/main_test.py

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+# Copyright 2023 Google LLC.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# [START eventarc_testing_cloudevent]
+from uuid import uuid4
+
+from cloudevents.conversion import to_binary
+from cloudevents.http import CloudEvent
+
+from google.events.cloud.storage import StorageObjectData
+
+import pytest
+
+import main
+
+
+ce_attributes = {
+    "id": str(uuid4),
+    "type": "com.pytest.sample.event",
+    "source": "<my-test-source>",
+    "specversion": "1.0",
+}
+
+
+@pytest.fixture
+def client():
+    main.app.testing = True
+    return main.app.test_client()
+
+
+def test_endpoint(client):
+    storagedata = StorageObjectData(bucket="test-bucket", name="my-file.txt")
+    event = CloudEvent(ce_attributes, StorageObjectData.to_dict(storagedata))
+    headers, body = to_binary(event)
+
+    r = client.post("/", headers=headers, data=body)
+    assert r.status_code == 200
+    assert "Cloud Storage object changed: test-bucket/my-file.txt" in r.text
+
+
+# [END eventarc_testing_cloudevent]
+
+
+def test_invalid_data(client):
+    event = CloudEvent(ce_attributes, {"an_unknown_field": "some_value"})
+    headers, body = to_binary(event)
+
+    r = client.post("/", headers=headers, data=body)
+    assert r.status_code == 400

eventarc/storage_handler/requirements-test.txt

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+pytest==7.0.1

eventarc/storage_handler/requirements.txt

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+Flask==2.1.0
+gunicorn==20.1.0
+google-events==0.7.0
+cloudevents==1.9.0