# Google Cloud Logging driver The Google Cloud Logging driver sends container logs to Google Cloud Logging. ## Usage You can configure the default logging driver by passing the `--log-driver` option to the Docker daemon: docker daemon --log-driver=gcplogs You can set the logging driver for a specific container by using the `--log-driver` option to `docker run`: docker run --log-driver=gcplogs ... This log driver does not implement a reader so it is incompatible with `docker logs`. If Docker detects that it is running in a Google Cloud Project, it will discover configuration from the instance metadata service. Otherwise, the user must specify which project to log to using the `--gcp-project` log option and Docker will attempt to obtain credentials from the Google Application Default Credential. The `--gcp-project` takes precedence over information discovered from the metadata server so a Docker daemon running in a Google Cloud Project can be overriden to log to a different Google Cloud Project using `--gcp-project`. ## gcplogs options You can use the `--log-opt NAME=VALUE` flag to specify these additional Google Cloud Logging driver options: | Option | Required | Description | |-----------------------------|----------|---------------------------------------------------------------------------------------------------------------------------------------------| | `gcp-project` | optional | Which GCP project to log to. Defaults to discovering this value from the GCE metadata service. | | `gcp-log-cmd` | optional | Whether to log the command that the container was started with. Defaults to false. | | `labels` | optional | Comma-separated list of keys of labels, which should be included in message, if these labels are specified for container. | | `env` | optional | Comma-separated list of keys of environment variables, which should be included in message, if these variables are specified for container. | If there is collision between `label` and `env` keys, the value of the `env` takes precedence. Both options add additional fields to the attributes of a logging message. Below is an example of the logging options required to log to the default logging destination which is discovered by querying the GCE metadata server. docker run --log-driver=gcplogs \ --log-opt labels=location --log-opt env=TEST --log-opt gcp-log-cmd=true --env "TEST=false" --label location=west your/application This configuration also directs the driver to include in the payload the label `location`, the environment variable `ENV`, and the command used to start the container.