salutem.core.checks — io.logicblocks/salutem.core 0.1.0-RC20

Provides constructors, predicates and evaluation functions for checks.

attempt clj

(attempt check context)

(attempt dependencies trigger-id check context result-channel)

background-check clj

(background-check check-name check-fn)

(background-check check-name check-fn opts)

Constructs a background check with the provided name and check function.

A background check is one that is evaluated periodically with the result cached until the next evaluation, which will occur once the time-to-live (TTL) of the check has passed.

Background checks are useful for external dependencies where it is important not to perform the check too frequently and where the health status only needs to be accurate to within the TTL.

Takes the following parameters:

• check-name: a keyword representing the name of the check
• check-fn: an arity-2 function, with with the first argument being a context map as provided during evaluation or at maintenance pipeline construction and the second argument being a callback function which should be called with the result fo the check to signal the check is complete; note, check functions must be non-blocking.
• opts: an optional map of additional options for the check, containing:
  • :ttl: a [[duration]] representing the TTL for a result of this check, defaulting to 10 seconds
  • :timeout: a [[duration]] representing the amount of time to wait for the check to complete before considering it failed, defaulting to 10 seconds

background? clj

(background? check)

Returns true if the provided check is a background check, false otherwise.

evaluate clj

(evaluate check)

(evaluate check context)

Evaluates the provided check synchronously, returning the result of the evaluation.

Optionally takes a context map containing arbitrary context required by the check in order to run and passed to the check function as the first argument.

realtime-check clj

(realtime-check check-name check-fn)

(realtime-check check-name check-fn opts)

Constructs a realtime check with the provided name and check function.

A realtime check is one that is re-evaluated whenever the check is resolved, with no caching of results taking place.

Realtime checks are useful when the accuracy of the check needs to be very accurate or where the check itself is inexpensive.

Takes the following parameters:

• check-name: a keyword representing the name of the check
• check-fn: an arity-2 function, with with the first argument being a context map as provided during evaluation or at maintenance pipeline construction and the second argument being a callback function which should be called with the result fo the check to signal the check is complete; note, check functions must be non-blocking.
• opts: an optional map of additional options for the check, containing:
  • :timeout: a [[duration]] representing the amount of time to wait for the check to complete before considering it failed, defaulting to 10 seconds

realtime? clj

(realtime? check)

Returns true if the provided check is a realtime check, false otherwise.