Cache.Make creates a cache module that exposes a simple with_ interface over its resources. The cache has the following properties:
Resource reuse: When a resource r is opened, it will remain open until one of the following:
f r raised an exception where f was a function passed to with_r has been idle for idle_cleanup_afterr has been used max_resource_reuse timesclose_and_flush has been called on the cacheWhen a resource is closed, either because of one of the above conditions, or because it was closed by other means, it no longer counts towards the limits.
Limits: The cache respects the following limits:
max_resources are open simultaneouslymax_resources_per_id are open simultaneously for a given id (args)module R : Resource.Sval with_ :
?open_timeout:Core.Time_ns.Span.t ->
?give_up:unit Async_kernel.Deferred.t ->
t ->
R.Key.t ->
f:(R.t -> 'a Async_kernel.Deferred.t) ->
'a Async_kernel.Deferred.Or_error.twith_ t key ~f calls f resource where resource is either:
1) An existing cached resource that was opened with key' such that R.Key.equal key key' 2) A newly opened resource created by R.open_ key common_args, respecting the limits of t.config
Returns an error if:
R.open_ returned an errorgive_up is determinedIf f raises, the exception is not caught, but the resource will be closed and the Cache will remain in a working state (no resources are lost).
val with_' :
?open_timeout:Core.Time_ns.Span.t ->
?give_up:unit Async_kernel.Deferred.t ->
t ->
R.Key.t ->
f:(R.t -> 'a Async_kernel.Deferred.t) ->
[ `Ok of 'a
| `Gave_up_waiting_for_resource
| `Error_opening_resource of Core.Error.t
| `Cache_is_closed ]
Async_kernel.Deferred.tLike with_ but classify the different errors
val with_any :
?open_timeout:Core.Time_ns.Span.t ->
?give_up:unit Async_kernel.Deferred.t ->
?load_balance:bool ->
t ->
R.Key.t list ->
f:(R.t -> 'a Async_kernel.Deferred.t) ->
(R.Key.t * 'a) Async_kernel.Deferred.Or_error.tLike with_ and with_' except f is run on the first matching available resource (or the first resource that has availability to be opened).
Preference is given towards resources earlier in the list, unless ~load_balance:true has been specified, in which case preference is given to ensure that load is approximately balanced. The key with the least number of open connections will be favored.
val with_any' :
?open_timeout:Core.Time_ns.Span.t ->
?give_up:unit Async_kernel.Deferred.t ->
?load_balance:bool ->
t ->
R.Key.t list ->
f:(R.t -> 'a Async_kernel.Deferred.t) ->
[ `Ok of R.Key.t * 'a
| `Error_opening_resource of R.Key.t * Core.Error.t
| `Gave_up_waiting_for_resource
| `Cache_is_closed ]
Async_kernel.Deferred.tval with_any_loop :
?open_timeout:Core.Time_ns.Span.t ->
?give_up:unit Async_kernel.Deferred.t ->
?load_balance:bool ->
t ->
R.Key.t list ->
f:(R.t -> 'a Async_kernel.Deferred.t) ->
[ `Ok of R.Key.t * 'a
| `Error_opening_all_resources of (R.Key.t * Core.Error.t) list
| `Gave_up_waiting_for_resource
| `Cache_is_closed ]
Async_kernel.Deferred.tTries with_any' in a loop (removing args that have open errors) until receiving an `Ok, or until it has failed to open all resources in args_list.
val close_started : t -> boolval close_finished : t -> unit Async_kernel.Deferred.tval close_and_flush : t -> unit Async_kernel.Deferred.tClose all currently open resources and prevent the creation of new ones. All subsequent calls to with_ and immediate fail with `Cache_is_closed. Any jobs that are waiting for a connection will return with `Cache_is_closed. The returned Deferred.t is determined when all jobs have finished running and all resources have been closed.