Add AsyncStream support for Remote Config by peterfriese · Pull Request #15352 · firebase/firebase-ios-sdk

peterfriese · 2025-09-22T21:28:04Z

This PR introduces a new configUpdates property to RemoteConfig, providing an AsyncThrowingStream for consuming real-time config updates. This offers a modern, Swift Concurrency-native alternative to the existing closure-based listener, making it easier to integrate real-time updates into async/await workflows.

Motivation

The existing addOnConfigUpdateListener uses a closure-based callback, which can be cumbersome in modern Swift applications that have adopted Swift Concurrency. By providing an AsyncThrowingStream, we offer a more ergonomic and idiomatic way for developers to receive real-time updates, simplifying their code and improving readability.

Implementation Details

FirebaseRemoteConfig/Swift/RemoteConfig+Async.swift: A new file containing an extension on RemoteConfig.
- It adds a public configUpdates property that returns an AsyncThrowingStream<RemoteConfigUpdate, Error>.
- The stream's implementation wraps the existing addOnConfigUpdateListener.
- The listener's lifecycle is automatically managed: it is added when iteration begins and removed when the stream is terminated (e.g., through cancellation).
FirebaseRemoteConfig/Tests/Swift/SwiftAPI/AsyncStreamTests.swift: A new test suite for the async stream functionality.
- Includes mock objects to simulate the real-time service and listener registration.
- Contains tests for various scenarios, including successful updates, error handling, stream cancellation, and handling of multiple updates.

Example usage

Developers can now listen for real-time updates using a simple for try await loop:

func listenForRealtimeUpdates() {
  Task {
    do {
      for try await configUpdate in remoteConfig.configUpdates {
        print("Updated keys: \(configUpdate.updatedKeys)")

        // Activate the new config to make it available
        let status = try await remoteConfig.activate()
        print("Config activated with status: \(status)")
      }
    } catch {
      print("Error listening for remote config updates: \(error)")
    }
  }
}

This change is purely additive and does not affect any existing APIs.

Fix #14539

paulb777

LGTM - thanks @peterfriese !

Leaving approval to @ncooke3 or the RC team

ncooke3 · 2025-10-02T14:28:47Z

Closing and re-opening to trigger all CI checks again.

ncooke3

Left some suggestions to fix current CI errors. Also suggesting to change doc comment and changelog to prefer sequence over stream (impl. detail).

ncooke3 · 2025-10-02T23:25:42Z

Down to one linting failure (unit test flake?). Rerunning:

      - NOTE  | [iOS] xcodebuild:  2025-10-02 22:29:13.149516+0000 AppHost-FirebaseRemoteConfig-Unit-Tests[92144:368595] [[FirebaseRemoteConfig]] 12.4.0 - [FirebaseRemoteConfig][I-RCN000073] Failed to get installations token. Error : Error Domain=com.firebase.installations Code=0 "The server responded with an error:

ncooke3 · 2025-10-03T13:36:48Z

Down to one linting failure (unit test flake?). Rerunning:

      - NOTE  | [iOS] xcodebuild:  2025-10-02 22:29:13.149516+0000 AppHost-FirebaseRemoteConfig-Unit-Tests[92144:368595] [[FirebaseRemoteConfig]] 12.4.0 - [FirebaseRemoteConfig][I-RCN000073] Failed to get installations token. Error : Error Domain=com.firebase.installations Code=0 "The server responded with an error:

Perhaps not a flake. Going to see how to surface which test this is coming from.

ncooke3 · 2025-10-03T14:17:13Z

I haven't been able to reproduce:

    Testing started
 -> FirebaseRemoteConfig (12.4.0)
    - NOTE  | xcodebuild:  note: Using codesigning identity override: -
    - NOTE  | xcodebuild:  note: Building targets in dependency order
    - NOTE  | [iOS] xcodebuild:  note: Target dependency graph (18 targets)
    - NOTE  | xcodebuild:  note: Metadata extraction skipped. No AppIntents.framework dependency found. (in target 'FirebaseSharedSwift' from project 'Pods')
    - NOTE  | xcodebuild:  note: Metadata extraction skipped. No AppIntents.framework dependency found. (in target 'FirebaseRemoteConfigInterop' from project 'Pods')
    - NOTE  | xcodebuild:  note: Metadata extraction skipped. No AppIntents.framework dependency found. (in target 'FirebaseCoreInternal' from project 'Pods')
    - NOTE  | xcodebuild:  note: Metadata extraction skipped. No AppIntents.framework dependency found. (in target 'FirebaseRemoteConfig' from project 'Pods')
    - NOTE  | [iOS] xcodebuild:  note: Signing static framework with --generate-pre-encrypt-hashes (in target 'Pods-App' from project 'Pods')
    - NOTE  | [iOS] xcodebuild:  note: Metadata extraction skipped. No AppIntents.framework dependency found. (in target 'App' from project 'App')
    - NOTE  | [iOS] xcodebuild:  note: Disabling previews because SWIFT_VERSION is set and SWIFT_OPTIMIZATION_LEVEL=-O, expected -Onone (in target 'App' from project 'App')
    - NOTE  | [iOS] xcodebuild:  note: Disabling previews because SWIFT_VERSION is set and SWIFT_OPTIMIZATION_LEVEL=-O, expected -Onone (in target 'Pods-App' from project 'Pods')
    - NOTE  | xcodebuild:  Pods.xcodeproj: warning: The iOS Simulator deployment target 'IPHONEOS_DEPLOYMENT_TARGET' is set to 9.0, but the range of supported deployment target versions is 12.0 to 18.2.99. (in target 'PromisesObjC' from project 'Pods')
    - NOTE  | [iOS] xcodebuild:  note: Disabling previews because SWIFT_VERSION is set and SWIFT_OPTIMIZATION_LEVEL=-O, expected -Onone (in target 'PromisesObjC' from project 'Pods')
    - NOTE  | xcodebuild:  Pods.xcodeproj: warning: The iOS Simulator deployment target 'IPHONEOS_DEPLOYMENT_TARGET' is set to 9.0, but the range of supported deployment target versions is 12.0 to 18.2.99. (in target 'PromisesObjC-FBLPromises_Privacy' from project 'Pods')
    - NOTE  | [iOS] xcodebuild:  note: Disabling previews because SWIFT_VERSION is set and SWIFT_OPTIMIZATION_LEVEL=-O, expected -Onone (in target 'PromisesObjC-FBLPromises_Privacy' from project 'Pods')
    - NOTE  | [iOS] xcodebuild:  note: Disabling previews because SWIFT_VERSION is set and SWIFT_OPTIMIZATION_LEVEL=-O, expected -Onone (in target 'GoogleUtilities-GoogleUtilities_Privacy' from project 'Pods')
    - NOTE  | [iOS] xcodebuild:  note: Disabling previews because SWIFT_VERSION is set and SWIFT_OPTIMIZATION_LEVEL=-O, expected -Onone (in target 'GoogleUtilities' from project 'Pods')
    - NOTE  | [iOS] xcodebuild:  note: Disabling previews because SWIFT_VERSION is set and SWIFT_OPTIMIZATION_LEVEL=-O, expected -Onone (in target 'FirebaseSharedSwift' from project 'Pods')
    - NOTE  | [iOS] xcodebuild:  note: Disabling previews because SWIFT_VERSION is set and SWIFT_OPTIMIZATION_LEVEL=-O, expected -Onone (in target 'FirebaseRemoteConfigInterop' from project 'Pods')
    - NOTE  | [iOS] xcodebuild:  note: Disabling previews because SWIFT_VERSION is set and SWIFT_OPTIMIZATION_LEVEL=-O, expected -Onone (in target 'FirebaseRemoteConfig-FirebaseRemoteConfig_Privacy' from project 'Pods')
    - NOTE  | [iOS] xcodebuild:  note: Disabling previews because SWIFT_VERSION is set and SWIFT_OPTIMIZATION_LEVEL=-O, expected -Onone (in target 'FirebaseRemoteConfig' from project 'Pods')
    - NOTE  | [iOS] xcodebuild:  note: Disabling previews because SWIFT_VERSION is set and SWIFT_OPTIMIZATION_LEVEL=-O, expected -Onone (in target 'FirebaseInstallations-FirebaseInstallations_Privacy' from project 'Pods')
    - NOTE  | [iOS] xcodebuild:  note: Disabling previews because SWIFT_VERSION is set and SWIFT_OPTIMIZATION_LEVEL=-O, expected -Onone (in target 'FirebaseInstallations' from project 'Pods')
    - NOTE  | [iOS] xcodebuild:  note: Disabling previews because SWIFT_VERSION is set and SWIFT_OPTIMIZATION_LEVEL=-O, expected -Onone (in target 'FirebaseCoreInternal-FirebaseCoreInternal_Privacy' from project 'Pods')
    - NOTE  | [iOS] xcodebuild:  note: Disabling previews because SWIFT_VERSION is set and SWIFT_OPTIMIZATION_LEVEL=-O, expected -Onone (in target 'FirebaseCoreInternal' from project 'Pods')
    - NOTE  | [iOS] xcodebuild:  note: Disabling previews because SWIFT_VERSION is set and SWIFT_OPTIMIZATION_LEVEL=-O, expected -Onone (in target 'FirebaseCore-FirebaseCore_Privacy' from project 'Pods')
    - NOTE  | [iOS] xcodebuild:  note: Disabling previews because SWIFT_VERSION is set and SWIFT_OPTIMIZATION_LEVEL=-O, expected -Onone (in target 'FirebaseCore' from project 'Pods')
    - NOTE  | [iOS] xcodebuild:  note: Disabling previews because SWIFT_VERSION is set and SWIFT_OPTIMIZATION_LEVEL=-O, expected -Onone (in target 'FirebaseABTesting-FirebaseABTesting_Privacy' from project 'Pods')
    - NOTE  | [iOS] xcodebuild:  note: Disabling previews because SWIFT_VERSION is set and SWIFT_OPTIMIZATION_LEVEL=-O, expected -Onone (in target 'FirebaseABTesting' from project 'Pods')
    - NOTE  | xcodebuild:  note: Target dependency graph (19 targets)
    - NOTE  | xcodebuild:  note: Using stub executor library without Swift entry point. (in target 'AppHost-FirebaseRemoteConfig-Unit-Tests' from project 'Pods')
    - NOTE  | [iOS] xcodebuild:  note: Metadata extraction skipped. No AppIntents.framework dependency found. (in target 'FirebaseRemoteConfig-Unit-unit' from project 'Pods')
    - NOTE  | [iOS] xcodebuild:  The server responded with an error: 
    - NOTE  | [iOS] xcodebuild:  2025-10-03 10:15:06.050224-0400 AppHost-FirebaseRemoteConfig-Unit-Tests[52071:8570339] [[FirebaseRemoteConfig]] 12.4.0 - [FirebaseRemoteConfig][I-RCN000073] Failed to get installations token. Error : Error Domain=com.firebase.installations Code=0 "The server responded with an error: 
    - NOTE  | [iOS] xcodebuild:  " UserInfo={NSLocalizedFailureReason=The server responded with an error: 
    - NOTE  | [iOS] xcodebuild:  note: Metadata extraction skipped. No AppIntents.framework dependency found. (in target 'FirebaseRemoteConfig-Unit-swift-api-tests' from project 'Pods')
    - NOTE  | [iOS] xcodebuild:  note: Metadata extraction skipped. No AppIntents.framework dependency found. (in target 'FirebaseRemoteConfig-Unit-fake-console-tests' from project 'Pods')

FirebaseRemoteConfig passed validation.
nickcooke@nickcooke-mac2 firebase (peterfriese/asyncsequences/remoteconfig) % xcode-select -p
/Applications/Xcode_16.2.app/Contents/Developer

ncooke3 · 2025-10-03T14:37:55Z

Should be OK to ignore, I verified that the new test suite you added is running and passing.

Introduces `AsyncSequence` support for `Query.snapshots` and `DocumentReference.snapshots`, enabling developers to handle Firestore real-time updates using Swift's structured concurrency. - Provides a modern, async-await compatible alternative to `addSnapshotListener`. - Supports both `Query` and `DocumentReference` snapshot streams. - Automatically handles listener registration and cleanup on task cancellation. - Configured with an unbounded buffering policy to ensure no snapshot events are lost. This work follows similar patterns introduced for Firebase Auth and Remote Config, bringing consistency to the developer experience across the Firebase Apple SDKs. Related Projects: - Firebase Auth AsyncSequence (#15362) - Remote Config AsyncSequence (#15352) Public API: - `DocumentReference.snapshots(includeMetadataChanges:) -> DocumentSnapshotsSequence` - `Query.snapshots(includeMetadataChanges:) -> QuerySnapshotsSequence` Tested on iOS, macOS, tvOS, and watchOS. Signed-off-by: Peter Friese <peter@peterfriese.dev> Co-authored-by: Nick Cooke <36927374+ncooke3@users.noreply.github.com>

Co-authored-by: Nick Cooke <36927374+ncooke3@users.noreply.github.com>

…the naming scheme

Removed performance-tuning attributes and Sendable conformances to match the established SDK patterns. Retained the 2025 copyright year.

peterfriese self-assigned this Sep 22, 2025

peterfriese added the api: remoteconfig label Sep 22, 2025

peterfriese linked an issue Sep 22, 2025 that may be closed by this pull request

Implement AsyncStream support for Remote Config #15351

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peterfriese requested review from ncooke3 and paulb777 September 22, 2025 21:49

peterfriese marked this pull request as ready for review September 22, 2025 21:52

paulb777 reviewed Sep 23, 2025

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peterfriese requested review from ncooke3 and paulb777 September 24, 2025 14:29

ncooke3 reviewed Sep 24, 2025

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Comment thread docs/AsyncStreams/api-design-proposal.md

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Comment thread FirebaseRemoteConfig/Tests/Swift/SwiftAPI/AsyncStreamTests.swift Outdated

paulb777 approved these changes Sep 29, 2025

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ncooke3 closed this Oct 2, 2025

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Comment thread FirebaseRemoteConfig/Swift/RemoteConfig+Async.swift Outdated

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ncooke3 added the needs-jules-review Label for manually marking PRs as ready for a review from Jules. label Jan 28, 2026

peterfriese force-pushed the peterfriese/asyncsequences/remoteconfig branch from 66f5df1 to 7a321e3 Compare March 30, 2026 13:57

Add design document

ad7fa44

peterfriese and others added 18 commits March 31, 2026 14:13

Cleanup

c5bc110

Initial implementation of AsyncStream for RC + basic test

e49bdbd

Add more complete unit tests

a9b4528

Formatting

7fe0b01

Fix copyright and add Sendable conformance

0b186c1

Add changelog entry

d9cf44f

Update FirebaseRemoteConfig/CHANGELOG.md

5690f52

Co-authored-by: Nick Cooke <36927374+ncooke3@users.noreply.github.com>

Fix conflicting API in API design proposal for Cloud Storage

9e7830b

Simplify listener attachment syncronisation

5d2a7d5

Fix styling

296cab3

Remove design doc in favour of adding it via a separate PR

c03199b

Rename stream from updates to configUpdates to better align with …

b44ff13

…the naming scheme

Return stream as an AsyncSequence

4ea371e

Update tests

51d9c63

Implement feedback from review

96a1f8c

Add concrete sequence for RemoteConfig

fff5d19

Fix styling

7637cfd

feat(RemoteConfig): align AsyncSequence with Firestore patterns

7c62aea

Removed performance-tuning attributes and Sendable conformances to match the established SDK patterns. Retained the 2025 copyright year.

peterfriese force-pushed the peterfriese/asyncsequences/remoteconfig branch from 7a321e3 to 7c62aea Compare March 31, 2026 12:39

ncooke3 approved these changes Mar 31, 2026

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peterfriese merged commit d250c11 into main Mar 31, 2026
85 checks passed

peterfriese deleted the peterfriese/asyncsequences/remoteconfig branch March 31, 2026 16:21

github-actions Bot mentioned this pull request Apr 7, 2026

Update to Firebase 12.12.0 afresh-technologies/firebase-ios-sdk-xcframeworks#107

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Add AsyncStream support for Remote Config#15352

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peterfriese commented Sep 22, 2025 •

edited by ncooke3

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