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#

# 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 uuid

from sqlalchemy import create_engine

from sqlalchemy.orm import Session

from sample_helper import run_sample

from model import Singer

# Shows how to transaction tags and statement tags with Spanner and SQLAlchemy.

def tags_sample():

engine = create_engine(

"spanner:///projects/sample-project/"

"instances/sample-instance/"

"databases/sample-database",

echo=True,

)

# Set a transaction_tag in the execution options for the session to set

# a transaction tag.

with Session(

engine.execution_options(transaction_tag="my_transaction_tag")

) as session:

# The transaction that is automatically started by SQLAlchemy will use the

# transaction tag that is specified in the execution options.

# Execute a query with a request tag.

singer_id = str(uuid.uuid4())

singer = session.get(

Singer, singer_id, execution_options={"request_tag": "my_tag_1"}

)

# Add the singer if it was not found.

if singer is None:

# The session.Add(..) function does not support execution_options, but we can

# set the execution_options on the connection of this session. This will be

# propagated to the next statement that is executed on the connection.

session.connection().execution_options(request_tag="insert_singer")

singer = Singer(id=singer_id, first_name="John", last_name="Doe")

session.add(singer)

session.commit()

if __name__ == "__main__":

run_sample(tags_sample)