A malformed endpoint URL panicked inside Transport, crashing the host app
(often at startup from external config). Capture the parse error and surface
it from the transport on first use instead. Add the previously untested
HealthChecker coverage (initial probe, recovery, Stop termination, unknown
endpoint), raising balancer coverage from ~41% to ~87%. Default the health
probe path to /healthz to match this library's own server.
- Deduplicate sentinel errors: httpx.ErrNoHealthy, ErrCircuitOpen, and
ErrRetryExhausted are now aliases to the canonical sub-package values
so errors.Is works across package boundaries
- Retry transport returns ErrRetryExhausted only when all attempts are
actually exhausted, not on early policy exit
- Balancer: pre-parse endpoint URLs at construction, replace req.Clone
with cheap shallow struct copy to avoid per-request allocations
- Circuit breaker: Load before LoadOrStore to avoid allocating a Breaker
on every request for known hosts
- Health checker: drain response body before close for connection reuse,
probe endpoints concurrently, run initial probe synchronously in Start
- Client: add Close() to shut down health checker goroutine, propagate
URL resolution errors instead of silently discarding them
- MockClock: fix lock ordering in Reset (clock.mu before t.mu), fix
timer slice compaction to avoid backing-array aliasing, extract
fireExpired to deduplicate Advance/Set
Implements balancer middleware with URL rewriting per-request:
- RoundRobin, Failover, and WeightedRandom endpoint selection strategies
- Background HealthChecker with configurable probe interval and path
- Thread-safe health state tracking with sync.RWMutex
