Monitoring wrapped ThreadPoolExecutor returned from Executors
dl at cs.oswego.edu
Thu Jan 7 13:09:27 UTC 2021
On 1/5/21 10:11 PM, Tommy Ludwig wrote:
> In the Micrometer project, we provide metrics instrumentation of `ExectorService`s. For `ThreadPoolExecutor`s, we track the number of completed tasks, active tasks, thread pool sizes, task queue size and remaining capacity via methods from `ThreadPoolExecutor`. We are currently using a brittle reflection hack to do this for the wrapped `ThreadPoolExecutor` returned from `Executors` methods `newSingleThreadExecutor` and `newSingleThreadScheduledExecutor`. With the introduction of JEP-396 in JDK 16, our reflection hack throws an InaccessibleObjectException by default.
> I am not seeing a proper way to get at the methods we use for the metrics (e.g. `ThreadPoolExecutor::getCompletedTaskCount`) in this case. Is there a way that I am missing?
There's no guarantee that newSingleThreadExecutor returns a restricted
view of a ThreadPoolExecutor, so there can't be a guaranteed way of
But I'm sympathetic to the idea that under the current implementation
(which is unlikely to change anytime soon), the stats are available, and
should be available to monitoring tools. But none of the ways to do this
are very attractive: Creating a MonitorableExecutorService interface and
returning that? Making the internal view class public with a protected
More information about the core-libs-dev