This commit updates the `ScheduledTaskObservationDocumentation` to
better align the contributed KeyValues with OpenTelemetry conventions
for observations of code executions.
Instead of a "target.type" key with the bean class simple name, this
is now contributing the canonical class name of the bean under the
"code.namespace" key.
The "method.name" key is renamed to "code.function" and its values
remain unchanged.
Closes gh-30721
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
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
rstoyanchev
Rob Winch