Cloud Functions locations

Cloud Functions is regional, which means the infrastructure that runs your Cloud Function is located in specific regions and is managed by Google to be redundantly available across all the zones within those regions.

When selecting what regions to run your functions in, your primary considerations should be latency and availability. You can generally select regions close to your users, but you should also consider the location of the other products and services that your app uses. Using services across multiple regions can affect your app's latency, as well as pricing.

Cloud Functions is available in the following regions:

• us-central1 (Iowa)
• us-east1 (South Carolina)
• europe-west1 (Belgium)
• europe-west2 (London)
• asia-east2 (Hong Kong)
• asia-northeast1 (Tokyo)

Functions in a given region in a given project must have unique (case insensitive) names, but functions across regions or across projects may share the same name.

Best practices for changing region

By default, functions run in the us-central1 region. Note that this may be different from the region of an event source, such as a Storage bucket. If you need to change the region where a function runs, follow the recommendations in this section for each function trigger type.

To set the region where a function runs, set the region parameter in the function definition as shown:

exports.myStorageFunction = functions
    .region('europe-west1')
    .storage
    .object()
    .onFinalize((object) => {
      // ...
    });

You can specify multiple regions by passing multiple comma-separated region strings in functions.region(). See change a function's region for more information on recommended procedures.

HTTP and client-callable functions

For HTTP and callable functions, we recommend that you first set your function to the destination region, or closest to where most expected customers are located, and then alter your original function to redirect its HTTP request to the new function (they can have the same name). If clients of your HTTP function support redirects, you can simply change your original function to return an HTTP redirect status (301) along with the URL of your new function. If your clients do not handle redirects well, you can proxy the request from the original function to the new function by initiating a new request from the original function to the new function. The final step is to ensure that all clients are calling the new function.

Client-side location selection for callable functions

Regarding the callable function, client callable setups should follow the same guidelines as HTTP functions. The client can also specify a region, and must do so if the function runs in any region other than us-central1.

To set regions on the client, specify the desired region at initialization:

lazy var functions = Functions.functions(region:"us-central1")

@property(strong, nonatomic) FIRFunctions *functions;
// ...
self.functions = [FIRFunctions functionsWithRegion:@"us-central1"];

var functions = firebase.app().functions('us-central1');

private FirebaseFunctions mFunctions;
// ...
mFunctions = FirebaseFunctions.getInstance("us-central1");

firebase::functions::Functions* functions;
// ...
functions = firebase::functions::Functions::GetInstance("us-central1");

firebase.Functions.FirebaseFunctions functions;

functions = Firebase.Functions.FirebaseFunctions.GetInstance("us-central1");

Background functions

Background functions adopt an at-least-once event delivery semantic, which means that under some circumstances they may receive duplicate events. So, you should implement functions to be idempotent. If your function is already idempotent, then you can redeploy the function in the new region with the same event trigger and remove the old function after you verify that the new function is correctly receiving traffic. During this transition, both functions will receive events. See change a function's region for the recommended sequence of commands to change regions for functions.

If your function is not currently idempotent, or its idempotency does not extend beyond the region, then we recommend that you first implement idempotency before moving the function.

Optimal region recommendations differ by event trigger type:

Selecting regions based on Cloud Firestore and Storage locations

The available regions for functions do not match precisely with the regions available for your Cloud Firestore database and your Cloud Storage buckets.

Note that if your function and your resource (database instance or Storage bucket) are in different locations, then you could potentially experience increased latency and billing costs.

Here's a mapping of the closest functions-supported regions for Cloud Firestore and Cloud Storage: