Unable to write-file on google cloud function workspace

The library I have used is node-persist -- link

The idea is to save a token in a file using the above library for a particular time period, which can be used while the google cloud function trigger.

But I'm getting below error while saving fresh token in google function workspace.

error => [Error: EROFS: read-only file system, unlink '/workspace/tmp/94c8aa2452bccd82ee129b46f7c4be79'] {
     errno: -30,
     code: 'EROFS',
     syscall: 'unlink',
     path: '/workspace/tmp/94c8aa2452bccd82ee129b46f7c4be79'
}

Got the Solution

Can do file system operation on /tmp or os.tmpdir() https://cloud.google.com/appengine/docs/standard/nodejs/using-temp-files