A similar question was asked nearly two years ago, but there was no confirmed answer. Is it now possible to add custom attributes to the automatically generated logs in Cloud Run?

I’m not referring to manually logging additional data (e.g., sending custom logs to Cloud Logging) but rather modifying the default logs to include custom values in the httpRequest or labels section.

For example, if an x-my-custom-header is included in an HTTP request, I would like it to appear in Cloud Logging logs like this:

{
  "httpRequest": {
    "myCustomHeader": "my custom value here",
    "...": "default attributes set by Cloud Run"
  },
  "labels": {
    "instanceId": "someid",
    "mylabel": "mylabelvalue"
  },
  "logName": "projects/my-project/logs/run.googleapis%2Frequests",
  "resource": {
    "type": "cloud_run_revision",
    "labels": {
      "service_name": "myservice"
    }
  }
}

As of 2025, has Google Cloud introduced a way to modify these logs, for example, via middleware in Python? If so, what is the recommended approach?

I created a middleware in Python that adds a custom header to the request before passing it to the application. However, this header does not appear in the automatically generated Cloud Logging logs for Cloud Run.

I expected that modifying the request before it reaches the application would allow the custom header to be included in the httpRequest section of the logs. However, even though the header is present in the request when processed by my application, it does not show up in the Cloud Run logs.

Is there a way to ensure that a custom header added via middleware is included in the automatic Cloud Logging logs?