Cloud Spanner is the world’s first fully managed relational database service to offer both strong consistency and horizontal scalability for mission-critical online transaction processing (OLTP) applications. With Cloud Spanner you enjoy all the traditional benefits of a relational database; but unlike any other relational database service, Cloud Spanner scales horizontally to hundreds or thousands of servers to handle the biggest transactional workloads.

  • Client Library Documentation

  • Product Documentation

  • Quick Start

    In order to use this library, you first need to go through the following steps:

  • Select or create a Cloud Platform project.

  • Enable billing for your project.

  • Enable the Google Cloud Spanner API.

  • Setup Authentication.

  • Installation

    Install this library in a virtualenv using pip. virtualenv is a tool to create isolated Python environments. The basic problem it addresses is one of dependencies and versions, and indirectly permissions.

    With virtualenv , it’s possible to install this library without needing system install permissions, and without clashing with the installed system dependencies.

    Supported Python Versions

    Python >= 3.7

    Deprecated Python Versions

    Python == 2.7. Python == 3.5. Python == 3.6.

    Mac/Linux

    pip install virtualenv
    virtualenv <your-env>
    source <your-env>/bin/activate
    <your-env>/bin/pip install google-cloud-spanner

    Windows

    pip install virtualenv
    virtualenv <your-env>
    <your-env>\Scripts\activate
    <your-env>\Scripts\pip.exe install google-cloud-spanner

    Executing Arbitrary SQL in a Transaction

    Generally, to work with Cloud Spanner, you will want a transaction. The preferred mechanism for this is to create a single function, which executes as a callback to database.run_in_transaction :

    # First, define the function that represents a single "unit of work"
    # that should be run within the transaction.
    def update_anniversary(transaction, person_id, unix_timestamp):
        # The query itself is just a string.
        # The use of @parameters is recommended rather than doing your
        # own string interpolation; this provides protections against
        # SQL injection attacks.
        query = """SELECT anniversary FROM people
            WHERE id = @person_id"""
        # When executing the SQL statement, the query and parameters are sent
        # as separate arguments. When using parameters, you must specify
        # both the parameters themselves and their types.
        row = transaction.execute_sql(
            query=query,
            params={'person_id': person_id},
            param_types={
                'person_id': types.INT64_PARAM_TYPE,
        ).one()
        # Now perform an update on the data.
        old_anniversary = row[0]
        new_anniversary = _compute_anniversary(old_anniversary, years)
        transaction.update(
            'people',
            ['person_id', 'anniversary'],
            [person_id, new_anniversary],
    # Actually run the `update_anniversary` function in a transaction.
    database.run_in_transaction(update_anniversary,
        person_id=42,
        unix_timestamp=1335020400,
    

    Select records using a Transaction

    Once you have a transaction object (such as the first argument sent to run_in_transaction), reading data is easy:

    # Define a SELECT query.
    query = """SELECT e.first_name, e.last_name, p.telephone
        FROM employees as e, phones as p
        WHERE p.employee_id == e.employee_id"""
    # Execute the query and return results.
    result = transaction.execute_sql(query)
    for row in result.rows:
        print(row)

    Insert records using Data Manipulation Language (DML) with a Transaction

    Use the execute_update() method to execute a DML statement:

    spanner_client = spanner.Client()
    instance = spanner_client.instance(instance_id)
    database = instance.database(database_id)
    def insert_singers(transaction):
        row_ct = transaction.execute_update(
            "INSERT Singers (SingerId, FirstName, LastName) "
            " VALUES (10, 'Virginia', 'Watson')"
        print("{} record(s) inserted.".format(row_ct))
    database.run_in_transaction(insert_singers)

    Insert records using Mutations with a Transaction

    To add one or more records to a table, use insert:

    transaction.insert(
        'citizens',
        columns=['email', 'first_name', 'last_name', 'age'],
        values=[
            ['phred@exammple.com', 'Phred', 'Phlyntstone', 32],
            ['bharney@example.com', 'Bharney', 'Rhubble', 31],
    

    Update records using Data Manipulation Language (DML) with a Transaction

    spanner_client = spanner.Client()
    instance = spanner_client.instance(instance_id)
    database = instance.database(database_id)
    def update_albums(transaction):
        row_ct = transaction.execute_update(
            "UPDATE Albums "
            "SET MarketingBudget = MarketingBudget * 2 "
            "WHERE SingerId = 1 and AlbumId = 1"
        print("{} record(s) updated.".format(row_ct))
    database.run_in_transaction(update_albums)

    Update records using Mutations with a Transaction

    Transaction.update updates one or more existing records in a table. Fails if any of the records does not already exist.

    transaction.update(
        'citizens',
        columns=['email', 'age'],
        values=[
            ['phred@exammple.com', 33],
            ['bharney@example.com', 32],
    

    Connection API

    Connection API represents a wrap-around for Python Spanner API, written in accordance with PEP-249, and provides a simple way of communication with a Spanner database through connection objects:

    from google.cloud.spanner_dbapi.connection import connect
    connection = connect("instance-id", "database-id")
    connection.autocommit = True
    cursor = connection.cursor()
    cursor.execute("SELECT * FROM table_name")
    result = cursor.fetchall()

    Aborted Transactions Retry Mechanism

    In !autocommit mode, transactions can be aborted due to transient errors. In most cases retry of an aborted transaction solves the problem. To simplify it, connection tracks SQL statements, executed in the current transaction. In case the transaction aborted, the connection initiates a new one and re-executes all the statements. In the process, the connection checks that retried statements are returning the same results that the original statements did. If results are different, the transaction is dropped, as the underlying data changed, and auto retry is impossible.

    Auto-retry of aborted transactions is enabled only for !autocommit mode, as in autocommit mode transactions are never aborted.

    Next Steps

  • See the Client Library Documentation to learn how to connect to Cloud Spanner using this Client Library.

  • Read the Product documentation to learn more about the product and see How-to Guides.

  • Download files

    Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

    Source Distribution