Timeouts, retries and pools · hard

A pool that actually pools

Six requests against an API that closes the connection after each response. Get them all through inside the budget, and leave nothing half-open behind.

How this is graded

Every request returns successfully inside 60 ms
Leaves no connection half-open
Leaves at most 6 sockets in TIME_WAIT

The budget is measured, not chosen: it is what a configuration that solves this actually cost, plus a little room.

The client

Timeouts

connectTimeoutMsGetting a connection, handshake includedreadTimeoutMsIdle time waiting for bytes; restarts when some arrivetotalBudgetMsThe whole request, every retry and backoff included

Retries

maxAttemptsIncluding the first. 1 means no retriesjitterHow the delay is spread across clientsrespectRetryAfterWait as long as the server askedgenerateIdempotencyKeysAttach a key to non-idempotent requestshonourIdempotencyKeyRetry a non-idempotent request that carries oneretryPostTreat POST as safe to repeatretryOn429Treat 429 as worth another attempt

Pool

keepAliveReuse a connection for more than one requestmaxConnectionsHow many may be open at oncemaxPerHost…and how many to any one hostacquireTimeoutMsHow long a request waits for a free slot

Capture

Nothing has run yet. Configure the client and run it — the capture is what you will be graded on.