The type for builder values. A builder generates values from inputs (keys). A builder is typically used with a cache.
module Key : sig ... endInput describing what is to be built. Any change to the key will trigger a rebuild. If you want to use some value in the build but not rebuild when it changes, put it in the context instead.
For passing context parameters to the builder which aren't part of the key (e.g. timeouts or resource pools).
val name : t -> stringA unique name for this builder. This is used for metric reporting.
title t key is a one-line summary of the operation that is performed by generate. It is used as the reason string for the pending state and as the title of the log.
val generate :
t ->
switch:Lwt_switch.t ->
log:Live_log.t ->
DK.Transaction.t ->
context ->
Key.t ->
(value, [ `Failure of string ]) result Lwt.tgenerate t ~log trans ctx key generates the value for key and stores it in trans under the "value" directory. It is called when the value is not in the cache, or when a rebuild has been requested. The value returned must be the same as the value that would be loaded by load. If the build is cancelled, switch will be turned off. If generate throws an exception then it is caught and treated as an error result.
load t tr key is the value v previously saved by generate.