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In my app, I'm using RTDB multiple instances, together with RTDB management APIs, to try to dynamically balance the load.

So my point is, because I don't know future load, I will just start with one RTDB instance, and create multiple ones if a specified threshold of usage is exceeded.

In my case, this requires the following:

  1. create new RTDB instance through management API
  2. apply rules to that RTDB instance
  3. apply cloud functions to that RTDB instance

1 and 2 could be programmatically done inside a cloud function, but I'm having troubles with 3.

Is this possible? Are there any workaround or future plans to support 3?

I'm thinking about two options: deploy a function from a function, or allow RTDB triggers to apply to every instances.

Alberto Di Gioacchino
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1 Answers1

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As you can check here in the management API documentation, the response body of the create method returns a DatabaseInstance object which has the following structure:

{
  "name": string,
  "project": string,
  "databaseUrl": string,
  "type": enum (DatabaseInstanceType),
  "state": enum (State)
}

So, you can get the databaseUrl value, store it somewhere in your code and send it to your cloud function as a parameter later, assuming it is a http function. In the function all you have to do is use the following code to access it:

let app = admin.app();
let ref = app.database('YOUR_SECOND_INSTANCE_URL_HERE').ref();

EDIT

For triggered functions this is not possible, since you would need to know the instances names or URL when deploying to function to apply the trigger to them. If you already have the instances names you could try doing something like this community answer, although I am not sure it will suit your app's needs.

Ralemos
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  • I think you missed the point. I need to have cloud functions on every RTDB instance triggers, with the instances created dynamically. – Alberto Di Gioacchino Jan 26 '21 at 20:09
  • The answer is still valid in that case, if you are going to create the instance with the management API dynamically, you can store the URL of the currently active instances somewhere, say a config file stored in GCS for example, and access that information with the cloud function and connect and operate in all of them, as described in this [community answer](https://stackoverflow.com/a/51193586/12857703) – Ralemos Jan 27 '21 at 13:06
  • It's valid for a different issue maybe, not mine. For mine, I need to deploy trigger functions on multiple rtdb instances dynamically created. – Alberto Di Gioacchino Jan 27 '21 at 16:16
  • Oh, got it, it's a trigger. In that case this is not possible since you would have to know the instaces names or urls to do it. – Ralemos Jan 28 '21 at 17:11