Add GCF Python SQL samples (GoogleCloudPlatform#1655)

* Add GCF Python SQL samples

Change-Id: Ib60712a5f3808b1fb99088e5e637304ef21e98c7

* Update test SQL instance name

Change-Id: I0c6ca84695a1a593f46ddd922507eb0cb1e56879

* Add SQL Kokoro test files

Change-Id: Ia59f803bb2bd50842f047a6570ebbc86171d2898

* Address comments

Change-Id: I0bad3298fa138430a4073ce108412fd4a6af5854

* Switch python samples to pools

Change-Id: Ibf5a90b3b8c02596f441b7d77cdf11b416260437

* Use connections for Python MySQL, as libraries don't support pooling

Change-Id: I3efeabd192be9c2c987846b0df7dcced016ddc49

* Fix lint + tests

Change-Id: I9d2901a737ab0bb7d74edefa69876704846fdf10

* Fix nits

Change-Id: I0bbcf8e32e6fd2f8fa8ef942d3b089418f01f502

* Make Python config consistent with Node samples

Change-Id: Ibb0341f51861ec5adcba136903c1df0567e97398

Author: Ace Nassri

.kokoro/presubmit_tests_functions_sql.cfg

@@ -0,0 +1,15 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+# Download secrets from Cloud Storage.
+gfile_resources: "/bigstore/cloud-devrel-kokoro-resources/python-docs-samples"
+
+# Tell the trampoline which build file to use.
+env_vars: {
+    key: "TRAMPOLINE_BUILD_FILE"
+    value: "github/python-docs-samples/.kokoro/system_tests.sh"
+}
+
+env_vars: {
+    key: "NOX_SESSION"
+    value: "functions and sql and py36 and not venv"
+}

.kokoro/system_tests.sh

@@ -26,9 +26,19 @@ source ./testing/test-env.sh
 export GOOGLE_APPLICATION_CREDENTIALS=$(pwd)/testing/service-account.json
 export GOOGLE_CLIENT_SECRETS=$(pwd)/testing/client-secrets.json
 
+# Run Cloud SQL proxy, if required
+if [ -n "${CLOUD_SQL_PROXY}" ]; then
+  cloud_sql_proxy -instances="${MYSQL_INSTANCE}"=tcp:3306 &
+  cloud_sql_proxy -instances="${POSTGRES_INSTANCE}"=tcp:5432 &
+fi
+
 # Run tests
 nox -k "${NOX_SESSION}" || ret_code=$?
 
+if [ -n "${CLOUD_SQL_PROXY}" ]; then
+  killall cloud_sql_proxy || true
+fi
+
 # Workaround for Kokoro permissions issue: delete secrets
 rm testing/{test-env.sh,client-secrets.json,service-account.json}
 

functions/sql/mysql_sample.py

@@ -0,0 +1,68 @@
+# Copyright 2018 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 functions_sql_mysql]
+from os import getenv
+
+import pymysql
+
+is_production = getenv('SUPERVISOR_HOSTNAME') is not None
+
+# TODO(developer): specify SQL connection details
+CONNECTION_NAME = getenv(
+  'INSTANCE_CONNECTION_NAME',
+  '<YOUR INSTANCE CONNECTION NAME>')
+DB_USER = getenv('MYSQL_USER', '<YOUR DB USER>')
+DB_PASSWORD = getenv('MYSQL_PASSWORD', '<YOUR DB PASSWORD>')
+DB_NAME = getenv('MYSQL_DATABASE', '<YOUR DB NAME>')
+
+mysql_config = {
+  'user': DB_USER,
+  'password': DB_PASSWORD,
+  'db': DB_NAME,
+  'charset': 'utf8mb4',
+  'cursorclass': pymysql.cursors.DictCursor,
+  'autocommit': True
+}
+
+if is_production:
+    mysql_config['unix_socket'] = \
+      '/cloudsql/' + CONNECTION_NAME
+
+# Create SQL connection globally to enable reuse
+# PyMySQL does not include support for connection pooling
+mysql_conn = pymysql.connect(**mysql_config)
+
+
+def __get_cursor():
+    """
+    Helper function to get a cursor
+      PyMySQL does NOT automatically reconnect,
+      so we must reconnect explicitly using ping()
+    """
+    try:
+        return mysql_conn.cursor()
+    except Exception:
+        mysql_conn.ping(reconnect=True)
+        return mysql_conn.cursor()
+
+
+def mysql_demo(request):
+    # Remember to close SQL resources declared while running this function.
+    # Keep any declared in global scope (e.g. mysql_conn) for later reuse.
+    with __get_cursor() as cursor:
+        cursor.execute('SELECT NOW() as now')
+        results = cursor.fetchone()
+        return str(results['now'])
+# [END functions_sql_mysql]

functions/sql/mysql_test.py

@@ -0,0 +1,19 @@
+# Copyright 2018 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.
+
+import mysql_sample
+
+
+def test_mysql():
+    mysql_sample.mysql_demo(None)

functions/sql/postgres_sample.py

@@ -0,0 +1,61 @@
+# Copyright 2018 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 functions_sql_postgres]
+from os import getenv
+
+from psycopg2.pool import SimpleConnectionPool
+
+is_production = getenv('SUPERVISOR_HOSTNAME') is not None
+
+# TODO(developer): specify SQL connection details
+CONNECTION_NAME = getenv(
+  'INSTANCE_CONNECTION_NAME',
+  '<YOUR INSTANCE CONNECTION NAME>')
+DB_USER = getenv('POSTGRES_USER', '<YOUR DB USER>')
+DB_PASSWORD = getenv('POSTGRES_PASSWORD', '<YOUR DB PASSWORD>')
+DB_NAME = getenv('POSTGRES_DATABASE', '<YOUR DB NAME>')
+
+pg_config = {
+  'user': DB_USER,
+  'password': DB_PASSWORD,
+  'dbname': DB_NAME,
+}
+
+if is_production:
+    pg_config['host'] = '/cloudsql/' + CONNECTION_NAME
+else:
+    pg_config['host'] = 'localhost'
+
+# Connection pools reuse connections between invocations,
+# and handle dropped or expired connections automatically.
+pg_pool = None
+
+
+def postgres_demo(request):
+    global pg_pool
+
+    # Initialize the pool lazily, in case SQL access isn't needed for this
+    # GCF instance. Doing so minimizes the number of active SQL connections,
+    # which helps keep your GCF instances under SQL connection limits.
+    if not pg_pool:
+        pg_pool = SimpleConnectionPool(1, 1, **pg_config)
+
+    # Remember to close SQL resources declared while running this function.
+    # Keep any declared in global scope (e.g. pg_pool) for later reuse.
+    with pg_pool.getconn().cursor() as cursor:
+        cursor.execute('SELECT NOW() as now')
+        results = cursor.fetchone()
+        return str(results[0])
+# [END functions_sql_postgres]

functions/sql/postgres_test.py

@@ -0,0 +1,19 @@
+# Copyright 2018 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.
+
+import postgres_sample
+
+
+def test_postgres():
+    postgres_sample.postgres_demo(None)

functions/sql/requirements.txt

@@ -0,0 +1,2 @@
+psycopg2==2.7.5
+PyMySQL==0.9.2

testing/secrets.tar.enc

@@ -1,13 +1,25 @@
 # Environment variables for system tests.
 export GCLOUD_PROJECT=your-project-id
 export GOOGLE_CLOUD_PROJECT=$GCLOUD_PROJECT
+export FIRESTORE_PROJECT=
+
 export CLOUD_STORAGE_BUCKET=$GCLOUD_PROJECT
 export API_KEY=
 export BIGTABLE_CLUSTER=bigtable-test
 export BIGTABLE_ZONE=us-central1-c
 export SPANNER_INSTANCE=
 export COMPOSER_LOCATION=us-central1
 export COMPOSER_ENVIRONMENT=
+export CLOUD_KMS_KEY=
+
+export MYSQL_INSTANCE=
+export MYSQL_USER=
+export MYSQL_PASSWORD=
+export MYSQL_DATABASE=
+export POSTGRES_INSTANCE=
+export POSTGRES_USER=
+export POSTGRES_PASSWORD=
+export POSTGRES_DATABASE=
 
 # Environment variables for App Engine Flexible system tests.
 export GA_TRACKING_ID=