Spanner Client

Instantiating a Client

To use the API, the Client class defines a high-level interface which handles authorization and creating other objects:

from google.cloud import spanner
client = spanner.Client()

Long-lived Defaults

When creating a Client, the user_agent and timeout_seconds arguments have sensible defaults (DEFAULT_USER_AGENT and DEFAULT_TIMEOUT_SECONDS). However, you may over-ride them and these will be used throughout all API requests made with the client you create.

Configuration

  • For an overview of authentication in google.cloud-python, see Authentication.

  • In addition to any authentication configuration, you can also set the GCLOUD_PROJECT environment variable for the Google Cloud Console project you’d like to interact with. If your code is running in Google App Engine or Google Compute Engine the project will be detected automatically. (Setting this environment variable is not required, you may instead pass the project explicitly when constructing a Client).

  • After configuring your environment, create a Client

>>> from google.cloud import spanner
>>> client = spanner.Client()

or pass in credentials and project explicitly

>>> from google.cloud import spanner
>>> client = spanner.Client(project='my-project', credentials=creds)

Warnings about Multiprocessing

WARNING: When using multiprocessing, the application may hang if a Client instance is created before multiprocessing.Pool or multiprocessing.Process invokes os.fork(). The issue is under investigation, but may be only happening on Macintosh and not Linux. See GRPC/GRPC#12455 for more information.

Next Step

After a Client, the next highest-level object is an Instance. You’ll need one before you can interact with databases.

Next, learn about the Instance Admin.