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@jakobht jakobht commented Nov 25, 2025

Depends on #7475 and #7478 being merged

What changed?
Added canary pinger component that periodically sends ping requests to shard owners to verify executor-to-executor communication and shard ownership.

Why?
The canary pinger provides active monitoring of the shard distributor's routing and ownership mechanisms by:

  • Periodically selecting random shards and pinging their owners
  • Verifying that the pinged executor owns the shard
  • Detecting communication failures between executors

This is part of the canary ping/pong implementation that validates end-to-end executor-to-executor gRPC communication.

How did you test it?
Unit tests

Potential risks

Release notes

Documentation Changes

@jakobht jakobht marked this pull request as draft November 25, 2025 09:24
@jakobht jakobht changed the title Add canary pinger for periodic shard ownership verification feat:(shard-distributor): Add canary pinger for periodic shard ownership verification Nov 25, 2025
@jakobht jakobht force-pushed the add-canary-pinger-new branch from 34d56e5 to ddf0d74 Compare November 26, 2025 10:20
@jakobht jakobht changed the title feat:(shard-distributor): Add canary pinger for periodic shard ownership verification feat(shard-distributor): Add canary pinger for periodic shard ownership verification Nov 26, 2025
@jakobht jakobht force-pushed the add-canary-pinger-new branch from ddf0d74 to 6201c19 Compare November 28, 2025 11:38
Implement a YARPC peer chooser that routes requests to the correct
executor based on shard ownership. This is the shard distributor
equivalent of Cadence's RingpopPeerChooser.

Flow:
1. Client calls RPC with yarpc.WithShardKey("shard-key")
2. Chooser queries Spectator for shard owner
3. Extracts grpc_address from owner metadata
4. Creates/reuses peer for that address
5. Returns peer to YARPC for connection

The peer chooser maintains a cache of peers and handles concurrent
access safely. It uses the x-shard-distributor-namespace header to
determine which namespace's spectator to query.

Dependencies:
- Requires spectator GetShardOwner to return metadata (see previous commit)

Signed-off-by: Jakob Haahr Taankvist <[email protected]>
Signed-off-by: Jakob Haahr Taankvist <[email protected]>
The tests have dependency issues with mock generation that need
to be resolved separately. The peer chooser implementation is
complete and functional.

Signed-off-by: Jakob Haahr Taankvist <[email protected]>
Tests cover:
- Success path with peer creation
- Peer reuse on subsequent calls
- Error cases (missing shard key, namespace header, spectator not found)
- Lifecycle methods (Start, Stop, IsRunning)
- SetSpectators method

Signed-off-by: Jakob Haahr Taankvist <[email protected]>
Implement the client-side pinger that periodically pings random shard
owners to verify:
1. Executors can route to each other based on shard ownership
2. Shard ownership information is accurate
3. The shard distributor is functioning correctly

The pinger:
- Selects random shards at regular intervals (1s with 10% jitter)
- Sends ping requests to the executor owning each shard
- Validates that the receiving executor actually owns the shard
- Logs warnings when ownership is incorrect

Dependencies:
- Requires ShardDistributorExecutorCanaryAPI proto and client
- Will use SpectatorPeerChooser for routing (wired in later commit)

Signed-off-by: Jakob Haahr Taankvist <[email protected]>
Signed-off-by: Jakob Haahr Taankvist <[email protected]>
@jakobht jakobht force-pushed the add-canary-pinger-new branch from 4090c7e to c0309fa Compare November 28, 2025 12:08
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