When adding chatd tests to route through a real in-process `aibridged`
daemon (#26658), found two races:
- **Pool:** `CachedBridgePool.Shutdown` calls `cache.Close()` while an
in-flight `Acquire` runs `cache.Wait()`. ristretto closes the channel
`Wait` sends on.
- **Bridge:** `RequestBridge.ServeHTTP` does `inflightWG.Add(1)` after
the `b.closed` check, racing `Shutdown`'s `inflightWG.Wait()`.
## Fix
- `RequestBridge`: adds `admitMu` RWMutex to order `inflightWG.Add`
(ServeHTTP, read) before `close(b.closed)` (Shutdown, write).
- `CachedBridgePool`: adds `opsMu` + `opsWG` so `Shutdown` drains
in-flight `Acquire`/`ReplaceProviders` before `cache.Close()`
- Adds tests `TestRequestBridgeShutdownAdmissionRace` and
`TestPoolShutdownReplaceProviders` for above. (Note:
`TestRequestBridgeShutdownAdmissionRace` leverages a `serve_admission`
quartz trap added to `RequestBridge`).
---
> 🤖 Created by Coder Agents on behalf of @johnstcn.
## Description
This PR adds Prometheus metrics for aibridge's API-key failover, giving visibility into key pool health and failover behavior per provider.
The following metrics are introduced:
- **`key_pool_state`** (gauge): number of keys currently in each state (`valid`, `temporary`, `permanent`) per provider, sampled at scrape time.
- **`key_pool_state_transitions_total`** (counter): key state transitions during failover, labeled by `reason` (`rate_limited`, `unauthorized`, `forbidden`).
- **`key_pool_exhaustions_total`** (counter): times a pool ran out of usable keys, labeled by `outcome` (`rate_limited`, `auth_failed`).
- **`key_pool_failover_attempts`** (histogram): keys attempted before success or exhaustion (per interception for bridged requests, per request for passthrough).
## Changes
- Moves `MarkKeyOnStatus` and key-pool error handling onto `*keypool.Pool`.
- Attaches metrics to each provider's key pool at install time, on construction and on provider reload.
- Adds a scrape-time state collector and a `KeyPools()` accessor on the bridge pool to feed it.
- Tracks per-request key attempts in the bridged and passthrough failover paths.
- Adds test coverage for the new metrics across the keypool unit tests, the bridged intercept failover tests, and the passthrough failover test.
Closes https://github.com/coder/internal/issues/1447
Closes https://linear.app/codercom/issue/AIGOV-198/aibridge-key-failover-observability
> [!NOTE]
> Initially generated by Claude Opus 4.7, modified and reviewed by @ssncferreira
_Disclosure: created with Coder Agents._
When providers are disabled, we should serve a sentinel error so the
requesting client (Claude Code, Coder Agents, etc) is informed. Coder
Agents can also conditionalize its display to show a helpful error
message.
---------
Signed-off-by: Danny Kopping <danny@coder.com>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Previously the in-process aibridge daemon and the enterprise aibridgeproxy daemon both snapshotted their provider routing once at boot. Any `ai_providers` or `ai_provider_keys` mutation required a restart for either to pick it up.
Add an `ai_providers_changed` pubsub channel that the CRUD handlers publish on after Create / Update / Delete. Both daemons subscribe:
- **aibridged** rebuilds its `[]aibridge.Provider` snapshot via `BuildProviders` and swaps it into the pool atomically. Inflight requests keep serving against the bridge they already acquired; new acquires build against the new snapshot. Per-provider construction errors stay scoped to the offending row.
- **aibridgeproxyd** rebuilds its routing snapshot from `GetAIProviders` and swaps the host→provider map atomically. The MITM listener picks up new providers without restart.
DB read for aibridgeproxyd uses the existing `AsAIProviderMetadataReader` subject for routing-only access.
In order to allow Coder Agents to use AI Gateway in OSS, we need to rehome the `aibridged`\-related code into the AGPL path.
The HTTP API is only registered under enterprise so will still require the AI Governance Add-on to be present in order to use it, whereas Coder Agents uses an in-memory pipe to the same handlers.
Cian Johnston