This commit enhances the `ScheduledAnnotationBeanPostProcessor` to
instrument `@Scheduled` methods declared on beans. This will create
`"tasks.scheduled.execution"` observations for each execution of a
scheduled method. This supports both blocking and reactive variants.
By default, observations are no-ops; developers must configure the
current `ObservationRegistry` on the `ScheduledTaskRegistrar` by using a
`SchedulingConfigurer`.
Closes gh-29883
This commit adds a note in the reference documentation stating that
`ErrorHandler` infrastructure is not involved when reactive methods send
an error signal: the exception is sent as a message in the pipeline and
is not thrown from the task `Runnable`.
See gh-23533
This commit adds support for `@Scheduled` annotation on reactive
methods and Kotlin suspending functions.
Reactive methods are methods that return a `Publisher` or a subclass
of `Publisher`. The `ReactiveAdapterRegistry` is used to support many
implementations, such as `Flux`, `Mono`, `Flow`, `Single`, etc.
Methods should not take any argument and published values will be
ignored, as they are already with synchronous support.
This is implemented in `ScheduledAnnotationReactiveSupport`, which
"converts" Publishers to `Runnable`. This strategy keeps track of
active Subscriptions in the `ScheduledAnnotationBeanPostProcessor`,
in order to cancel them all in case of shutdown.
The existing scheduling support for tasks is reused, aligning the
triggering behavior with the existing support: cron, fixedDelay and
fixedRate are all supported strategies.
If the `Publisher` errors, the exception is logged at warn level and
otherwise ignored. As a result new `Runnable` instances will be
created for each execution and scheduling will continue.
The only difference with synchronous support is that error signals
will not be thrown by those `Runnable` tasks and will not be made
available to the `org.springframework.util.ErrorHandler` contract.
This is due to the asynchronous and lazy nature of Publishers.
Closes gh-23533
Closes gh-28515
Prior to this commit, the Observation instrumentation for Reactive
server applications was implemented with a `WebFilter`. This allowed to
record observations and set up a tracing context for the controller
handlers.
The limitation of this approach is that all processing happening at a
lower level is not aware of any observation. Here, the
`HttpWebHandlerAdapter` handles several interesting aspects:
* logging of HTTP requests and responses at the TRACE level
* logging of client disconnect errors
* handling of unresolved errors
With the current instrumentation, these logging statements will miss the
tracing context information. As a result, this commit deprecates the
`ServerHttpObservationFilter` in favor of a more direct instrumentation
of the `HttpWebHandlerAdapter`. This enables a more precise
instrumentattion and allows to set up the current observation earlier in
the reactor context: log statements will now contain the relevant
information.
Fixes gh-30013
Brian Clozel
Juergen Hoeller
Sébastien Deleuze
Sam Brannen
Simon Baslé
rstoyanchev
Stephane Nicoll
Olga MaciaszekSharma
Rob Winch