Extract missing gcs_to_local example DAG from gcs example (#10767)

Co-authored-by: Kamil Breguła <kamil.bregula@polidea.com>

Author: ephraimbuddy

airflow/providers/google/cloud/example_dags/example_gcs_to_local.py

@@ -0,0 +1,37 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you 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.
+
+import os
+
+from airflow import models
+from airflow.providers.google.cloud.transfers.gcs_to_local import GCSToLocalFilesystemOperator
+from airflow.utils.dates import days_ago
+
+PROJECT_ID = os.environ.get("GCP_PROJECT_ID", "example-id")
+BUCKET = os.environ.get("GCP_GCS_BUCKET", "test-gcs-example-bucket")
+
+PATH_TO_REMOTE_FILE = os.environ.get("GCP_GCS_PATH_TO_UPLOAD_FILE", "test-gcs-example-remote.txt")
+PATH_TO_LOCAL_FILE = os.environ.get("GCP_GCS_PATH_TO_SAVED_FILE", "test-gcs-example-local.txt")
+
+with models.DAG(
+    "example_gcs_to_local", start_date=days_ago(1), schedule_interval=None, tags=['example'],
+) as dag:
+    # [START howto_operator_gcs_download_file_task]
+    download_file = GCSToLocalFilesystemOperator(
+        task_id="download_file", object_name=PATH_TO_REMOTE_FILE, bucket=BUCKET, filename=PATH_TO_LOCAL_FILE,
+    )
+    # [END howto_operator_gcs_download_file_task]

docs/howto/operator/google/transfer/gcs_to_local.rst

@@ -42,7 +42,7 @@ data from GCS to local filesystem.
 
 Below is an example of using this operator to upload a file to GCS.
 
-.. exampleinclude:: /../airflow/providers/google/cloud/example_dags/example_gcs.py
+.. exampleinclude:: /../airflow/providers/google/cloud/example_dags/example_gcs_to_local.py
     :language: python
     :dedent: 0
     :start-after: [START howto_operator_gcs_download_file_task]

tests/providers/google/cloud/transfers/test_gcs_to_local_system.py

@@ -0,0 +1,50 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you 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.
+import os
+
+import pytest
+
+from airflow.providers.google.cloud.example_dags.example_gcs_to_local import (
+    BUCKET,
+    PATH_TO_REMOTE_FILE,
+    PATH_TO_LOCAL_FILE,
+)
+from tests.providers.google.cloud.utils.gcp_authenticator import GCP_GCS_KEY
+from tests.test_utils.gcp_system_helpers import CLOUD_DAG_FOLDER, GoogleSystemTest, provide_gcp_context
+
+
+@pytest.mark.backend("mysql", "postgres")
+@pytest.mark.credential_file(GCP_GCS_KEY)
+class GoogleCloudStorageExampleDagsTest(GoogleSystemTest):
+    @provide_gcp_context(GCP_GCS_KEY)
+    def setUp(self):
+        super().setUp()
+        self.create_gcs_bucket(BUCKET)
+        self.upload_content_to_gcs(
+            lines=f"{os.urandom(1 * 1024 * 1024)}", bucket=BUCKET, filename=PATH_TO_REMOTE_FILE
+        )
+
+    @provide_gcp_context(GCP_GCS_KEY)
+    def tearDown(self):
+        self.delete_gcs_bucket(BUCKET)
+        os.remove(PATH_TO_LOCAL_FILE)
+        super().tearDown()
+
+    @provide_gcp_context(GCP_GCS_KEY)
+    def test_run_example_dag(self):
+        self.run_dag('example_gcs_to_local', CLOUD_DAG_FOLDER)

tests/test_project_structure.py

@@ -115,7 +115,6 @@ class TestGoogleProviderProjectStructure(unittest.TestCase):
         ('cloud', 'cassandra_to_gcs'),
         ('cloud', 'mysql_to_gcs'),
         ('cloud', 'mssql_to_gcs'),
-        ('cloud', 'gcs_to_local'),
         ('ads', 'ads_to_gcs'),
     }