feat: Add the FDv2 data source orchestrator to the client SDK by beekld · Pull Request #612 · launchdarkly/cpp-sdks

beekld · 2026-09-11T18:00:53Z

Summary

Adds the client SDK's FDv2 data source -- the orchestrator that runs initializers to load a basis, then rotates synchronizers to keep it current.

Implemented here:

Runs initializers to a basis, then rotates synchronizers on fallback and recovery conditions.
Reports data-source status, records the environment id, and tags applied data as cache- or network-sourced.

Also moves the shared orchestration primitives out of the server SDK into libs/internal so both SDKs can share them. That server change is a behavior-neutral relocation.

Notes:

Start() blocks on cache initialization, so cached flags are immediately evaluable. This matches the behavior of the FDv1 client. It also matches Android. However, Flutter loads the cache asynchronously instead.
FDv1 fallback directive handling is out of scope.

Note

Overview
Adds FDv2DataSource to the client SDK: an IDataSource orchestrator that chains initializers (basis + optional inline cache load on Start()), then synchronizers with fallback/recovery timers, status reporting, environment ID, and from_cache on applies. Shutdown/GuardShutdown blocks late results from overwriting store or status after identify-style restarts.

Shared FDv2 orchestration moves from the server SDK into libs/internal (Conditions, templated SourceManager, condition interfaces). Conditions now take a reduced SourceSignal instead of full source results; server FDv2DataSystem is updated to classify results and link the internal library (local conditions/source_manager sources removed).

Adds broad client unit tests for lifecycle, initializer/synchronizer phases, cache-only mode, and tier rotation; internal tests adjusted for the new APIs. Minor .gitignore entries for .env and .claude.

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beekld · 2026-09-17T00:08:31Z

This PR needs some more work on thread safety. Because the store can outlive the data source, the mechanism that worked in the server code isn't 100% sufficient for client code. I'll comment again when it's ready.

beekld · 2026-09-17T22:09:29Z

Okay, I think I fixed the fence issues by adding a future that gets taken and not resolved until any outstanding writes finish.

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kinyoklion · 2026-09-29T20:47:55Z

 #include <vector>

-namespace launchdarkly::server_side::data_systems {
+namespace launchdarkly::internal::data_sources {


Should these be internal::data_system?

Done. And I'll clean up the similar inconsistencies in the other files in a later step.

kinyoklion

Approved, but a couple comments inline for things that might need addressed.

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…pace

beekld added this pull request to stack #608 September 11, 2026 18:04

beekld force-pushed the bklimt/SDK-3032/client-fdv2-orchestrator branch from e03fed7 to d3da070 Compare September 11, 2026 21:23

beekld force-pushed the bklimt/SDK-3032/client-fdv2-orchestrator branch 2 times, most recently from 22c46d4 to ae8dc46 Compare September 12, 2026 00:21

beekld marked this pull request as ready for review September 12, 2026 00:21

beekld requested a review from a team as a code owner September 12, 2026 00:21

cursor Bot reviewed Sep 12, 2026

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Comment thread libs/client-sdk/src/data_sources/fdv2/fdv2_data_source.cpp

Comment thread libs/client-sdk/src/data_sources/fdv2/fdv2_data_source.cpp

beekld force-pushed the bklimt/SDK-3032/client-fdv2-orchestrator branch 2 times, most recently from 7d79b26 to c3faa16 Compare September 16, 2026 20:56

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Comment thread libs/client-sdk/src/data_sources/fdv2/fdv2_data_source.cpp

beekld force-pushed the bklimt/SDK-3032/client-fdv2-orchestrator branch from c3faa16 to b53a79c Compare September 16, 2026 21:25

beekld force-pushed the bklimt/SDK-3032/client-fdv2-orchestrator branch from b53a79c to f52848a Compare September 17, 2026 00:03

beekld force-pushed the bklimt/SDK-3032/client-fdv2-orchestrator branch from f52848a to b387a57 Compare September 17, 2026 22:09

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Comment thread libs/client-sdk/src/data_sources/fdv2/fdv2_data_source.cpp

beekld force-pushed the bklimt/SDK-3032/client-fdv2-orchestrator branch from ab7869c to 4b40610 Compare September 18, 2026 16:57

beekld force-pushed the bklimt/SDK-3032/client-fdv2-orchestrator branch from 4b40610 to bb64e46 Compare September 24, 2026 21:14

Base automatically changed from bklimt/SDK-3031/client-fdv2-streaming to main September 24, 2026 21:26

beekld force-pushed the bklimt/SDK-3032/client-fdv2-orchestrator branch 2 times, most recently from 56b64c8 to d43a97c Compare September 24, 2026 21:29

kinyoklion reviewed Sep 29, 2026

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Comment thread libs/client-sdk/src/data_sources/fdv2/fdv2_data_source.cpp

kinyoklion reviewed Sep 29, 2026

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Comment thread libs/client-sdk/src/data_sources/fdv2/fdv2_data_source.cpp Outdated

kinyoklion reviewed Sep 29, 2026

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Comment thread libs/client-sdk/src/data_sources/fdv2/fdv2_data_source.cpp Outdated

kinyoklion approved these changes Sep 29, 2026

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Comment thread libs/client-sdk/src/data_sources/fdv2/fdv2_data_source.cpp

beekld force-pushed the bklimt/SDK-3032/client-fdv2-orchestrator branch from 9b7fdd4 to 912d436 Compare October 2, 2026 23:36

beekld removed this pull request from stack #608 October 3, 2026 01:24

beekld added 11 commits October 5, 2026 10:59

refactor: Share the FDv2 orchestration primitives between the SDKs

6595a13

feat: Orchestrate the client FDv2 initializers and synchronizers

92f7fbc

test: Put the cache-miss comment on the right FDv2 data source test

411008f

refactor: Rename the FDv2 result-to-signal helper to ClassifyResult

a554877

fix: Drop FDv2 data source applies after shutdown

0006367

fix: Defer FDv2 data source shutdown until in-flight writes finish

6bdd8af

fix: Defer the FDv2 shutdown callback until Start finishes

cdd9745

maint: add some .gitignore entries

dcf45c4

fix: Gate client FDv2 initialization on the payload selector

42130a1

refactor: Pass from_cache to OnInitializerResult instead of a member

e75e90a

refactor: Move the shared FDv2 primitives into the data_systems names…

223736f

…pace

beekld force-pushed the bklimt/SDK-3032/client-fdv2-orchestrator branch from ee65761 to 223736f Compare October 5, 2026 18:00

beekld added this pull request to stack #627 October 5, 2026 18:00

beekld removed this pull request from stack #627 October 5, 2026 18:05

beekld added this pull request to stack #628 October 5, 2026 18:10

beekld removed this pull request from stack #628 October 5, 2026 19:18

beekld added this pull request to stack #629 October 5, 2026 19:24

beekld merged commit 7633334 into main Oct 5, 2026
53 checks passed

beekld deleted the bklimt/SDK-3032/client-fdv2-orchestrator branch October 5, 2026 23:25

github-actions Bot mentioned this pull request Oct 5, 2026

chore: release main #630

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beekld commented Sep 17, 2026

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beekld commented Sep 11, 2026 •

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