Timeout

---

Computing features associated with third-party services can be unpredictably slow. Chalk helps you manage such uncertainty by specifying a resolver timeout duration.

Chalk will instantaneously (±1ms) cease waiting for a resolver whose runtime has exceeded the specified timeout duration. Simultaneously, via parallel execution, Chalk will return other crucial features whose resolvers did not time out.

---

To specify a timeout, use the timeout keyword argument to either @online or @offline:

---

​

Example

from chalk.features import online, offline

@online(timeout="200ms")
def resolve_australian_credit_score(
    driver_id: User.driver_id_aus,
) -> User.credit_score_aus:
    return experian_client.get_score(driver_id)

@offline(timeout=timedelta(milliseconds=50))
def resolve_canadian_credit_score(
    user_si_number: User.social_insurance_number,
) -> User.credit_score_can:
    return equifax_client.get_score(user_si_number)

See Duration for supported durations.

---

​

Behavior upon timeout

​

Direct timeout

If a query’s output feature is directly resolved by a resolver that timed out, Chalk will return an error with the error code RESOLVER_TIMED_OUT, and its message will contain the name of the timed-out resolver.

​

Upstream timeout

If a query’s output feature is resolved by a resolver whose upstream resolver has timed out, Chalk will return an error with the error code UPSTREAM_FAILED.

The resolver that directly outputs the requested feature will not be run (unless it marks its inputs as optional).

​

Multiple output features

If your query contains multiple output features, Chalk will still return the other features whose resolver did not time out.