Observe_lwt_unix (observe-lwt-unix.Observe_lwt

type id_generator = unit -> string

A synchronous source of fresh operation occurrence identifiers.

Observe serializes calls to the configured generator. Each call must return a fresh, non-empty, valid UTF-8 identifier and should complete promptly. Raised exceptions and invalid results are contained and diagnosed; the affected operation is not published.

type sampling_draw = unit -> float

A synchronous source of independent probabilistic draws. Each call must return a finite value greater than or equal to zero and less than one. Observe serializes a configured custom source. Raised exceptions and invalid results are contained and cause the affected log to be retained. A source that recursively emits a sampled Observe log is rejected instead of deadlocking.

val init : 
  ?id_generator:id_generator ->
  ?sampling_draw:sampling_draw ->
  Observe.Config.t ->
  (unit, Observe.init_error) Stdlib.result

Install the process-wide Observe engine with Lwt dynamic context, the OS wall clock, cryptographically random UUID v4 operation identities, and automatic standard-error output. Configured sampling uses runtime-owned random draws. Custom identity and sampling sources are useful for deterministic tests or application-specific policy. Importing this package allocates no writer or background work. See id_generator and sampling_draw for their contracts. Returns Error Runtime_closed after shutdown has begun.

val init_exn : 
  ?id_generator:id_generator ->
  ?sampling_draw:sampling_draw ->
  Observe.Config.t ->
  unit

Like init, but raises Observe.Init_error on failure.

val with_operation : 
  name:string ->
  ?using:('record, 'builder) Observe.Schema.t ->
  ?error:exn Observe.Error.t ->
  (unit -> 'a Lwt.t) ->
  'a Lwt.t

Run one scoped wide operation, make it current during callback, and make one final publication attempt on success, exception, or cancellation. Escaping exceptions are contributed using error, which defaults to Observe.Error.exn, then re-raised with their original backtrace. Failed error interpretation seals and withholds the invalid observation.

val fork : 
  name:string ->
  ?using:('record, 'builder) Observe.Schema.t ->
  ?error:exn Observe.Error.t ->
  (unit -> 'a Lwt.t) ->
  'a Lwt.t

Run one scoped, independently emitted child of the current operation. The child records its parent's complete reference; it does not copy or modify the parent's event. The prior current operation is restored when callback finishes. Raises Observe.Logs.Current_error Not_bound outside an operation scope.

val flush : unit -> unit Lwt.t

Resolve when all console and registered output records accepted before the call have reached their effect boundary. On an incomplete finite wait or participant outcome, raises Lifecycle.Incomplete report; preserves Lwt.Canceled. A complete report means all participants settled without a reported problem, but only to their owned effect boundaries, not durability. This uses a 30-second finite caller wait; timed-out shared work continues. Ordinary application-defined drains are not registered automatically.

val shutdown : unit -> unit Lwt.t

Close production logging admission, drain accepted records, and stop every output worker. On an incomplete finite wait or participant outcome, raises Lifecycle.Incomplete report; preserves Lwt.Canceled. A complete report means all participants settled without a reported problem, but only to their owned effect boundaries, not durability. This uses a 30-second finite caller wait; timed-out shared work continues. Repeated calls share one idempotent state machine. Shutdown is terminal even when called before initialization. Logging after shutdown does not evaluate author callbacks.

module Lifecycle : sig ... end

Expert registration for independently installed Lwt-Unix outputs. Reports distinguish rejected, lost, failed, timed-out, and cancelled delivery; problem output labels are bounded runtime identities. Duration bounds are finite caller waits only; shared work continues after timeout.

module Test : sig ... end