Is there a variable for accessing the version number for a given deployed cloud function

Question

GCP displays the version number of a deployed cloud function in the console. At the moment there isn't a system environment variable which contains information about the deployment - there is no version, nor deployment date.

Given that version updates take considerable time to update (30 seconds +) and propagate, such version information would be useful to wield.

Answer 1

The recently-released nodejs10 runtime environment now includes an officially documented environment variable K_REVISION that contains the deployment version of a cloud function.

From inspection, it also seems that the python37 and older nodejs8 environments include an unofficial environment variable X_GOOGLE_FUNCTION_VERSION that happens to contain the deployment version.

This snippet works on nodejs10 and unofficially works on nodejs8:

exports.helloVersion = (req, res) => {
  console.log(process.env);
  const version = process.env.K_REVISION || process.env.X_GOOGLE_FUNCTION_VERSION || "UNKNOWN";
  console.log(`Running version ${version}`);
  res.status(200).send(`Running version ${version}\n`)
};

Deploying and testing:

$ gcloud functions deploy helloVersion --runtime nodejs8 --trigger-http
versionId: '8'
$ curl https://us-central1-myproject.cloudfunctions.net/helloVersion
Running version 8

$ gcloud functions deploy helloVersion --runtime nodejs10 --trigger-http
versionId: '9'
$ curl https://us-central1-myproject.cloudfunctions.net/helloVersion
Running version 9

Of course, the K_REVISION environment variable on nodejs10 is probably the way to go, given that it's mentioned in the official documentation. The X_GOOGLE_FUNCTION_VERSION environment variable isn't officially mentioned, so it's probably a bad idea to rely on it for something important, but I've found that it might be helpful to display or include opportunistically when debugging, deploying, and testing interactively.