CODEWITHSUNDEEP
firebasegoogle-cloud-platformgoogle-cloud-firestoregoogle-cloud-functions
TSR
TSR

Reputation: 20396

Understanding Firebase cloud function "cold start"

It is mentionned in the doc that

Functions are stateless, and the execution environment is often initialized from scratch, which is called a cold start.

This statement implies that * sometimes *, functions are not initialized from scracth and the state can be reused.

Is this a reliable assumption ?

Illustration

var count = 0; // global variable

functiion mycouldFunction(){
  count ++;
  return count;

}

If I call myCloudFunction twice with X amount of time apart, should I expect it to return '1' then '2'

Then a 3rd call after Y amount time, I should expect it to return '1' again ?

If that is true, what is the value of X and Y ?

Upvotes: 1

Views: 616

Answers (2)

Doug Stevenson
Doug Stevenson

Reputation: 317352

Cloud Functions will indeed sometimes reuse server instances to handle multiple requests, as an optimization. There is no guarantee if or when this can happen. Unless you are implementing some sort of optimization on your own (memory caching, for example), it's not advisable to store anything in global memory, since your function could be subject to a cold start for any one of its invocations.

Upvotes: 2

Brian Burton
Brian Burton

Reputation: 3842

No, cloud functions are stateless so every time you call myCloudFunction it would return 1.

To achieve what you want you would need to store the updated value in Firestore or RTDB or similar and read the updated value on each load.

What "Cold Start" refers to has nothing to do with the above, it's in reference to how functions are served. GCF will "turn off" functions that are infrequently used so they may respond slower than functions that are "turned on" and ready to receive requests.

Upvotes: -1

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