Spanner Batch Query Sample [(#1402)](GoogleCloudPlatform/python-docs-…

…samples#1402)

samples/samples/batch_sample.py

@@ -0,0 +1,89 @@
+# Copyright 2018 Google Inc. All Rights Reserved.
+#
+# 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.
+
+"""This application demonstrates how to do batch operations using Cloud
+Spanner.
+
+For more information, see the README.rst under /spanner.
+"""
+
+import argparse
+import concurrent.futures
+import time
+
+from google.cloud import spanner
+
+
+# [START spanner_batch_client]
+def run_batch_query(instance_id, database_id):
+    """Runs an example batch query."""
+
+    # Expected Table Format:
+    # CREATE TABLE Singers (
+    #   SingerId   INT64 NOT NULL,
+    #   FirstName  STRING(1024),
+    #   LastName   STRING(1024),
+    #   SingerInfo BYTES(MAX),
+    # ) PRIMARY KEY (SingerId);
+
+    spanner_client = spanner.Client()
+    instance = spanner_client.instance(instance_id)
+    database = instance.database(database_id)
+
+    # Create the batch transaction and generate partitions
+    snapshot = database.batch_snapshot()
+    partitions = snapshot.generate_read_batches(
+        table='Singers',
+        columns=('SingerId', 'FirstName', 'LastName',),
+        keyset=spanner.KeySet(all_=True)
+    )
+
+    # Create a pool of workers for the tasks
+    start = time.time()
+    with concurrent.futures.ThreadPoolExecutor() as executor:
+        futures = [executor.submit(process, snapshot, p) for p in partitions]
+
+        for future in concurrent.futures.as_completed(futures, timeout=3600):
+            finish, row_ct = future.result()
+            elapsed = finish - start
+            print(u'Completed {} rows in {} seconds'.format(row_ct, elapsed))
+
+    # Clean up
+    snapshot.close()
+
+
+def process(snapshot, partition):
+    """Processes the requests of a query in an separate process."""
+    print('Started processing partition.')
+    row_ct = 0
+    for row in snapshot.process_read_batch(partition):
+        print(u'SingerId: {}, AlbumId: {}, AlbumTitle: {}'.format(*row))
+        row_ct += 1
+    return time.time(), row_ct
+# [END spanner_batch_client]
+
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser(
+        description=__doc__,
+        formatter_class=argparse.RawDescriptionHelpFormatter)
+    parser.add_argument(
+        'instance_id', help='Your Cloud Spanner instance ID.')
+    parser.add_argument(
+        'database_id', help='Your Cloud Spanner database ID.',
+        default='example_db')
+
+    args = parser.parse_args()
+
+    run_batch_query(args.instance_id, args.database_id)

samples/samples/requirements.txt

@@ -1 +1,2 @@
-google-cloud-spanner==1.1.0
+google-cloud-spanner==1.2.0
+futures ; python_version < '3'