I've a question regarding capture of "uncaught" exceptions, which appears with stack trace on System.err, circumventing logging configuration: All the other log messages appear properly formatted on System.out (JSON-formatted in my case). But this doesn't happen with Exceptions and stack traces "logged" to System.err!
I've recognized this to happen under at least two circumstances:
Asynchronous execution of tasks (HTTP requests in my case) via ExecutorService (as mentioned in "Scheduled Tasks" chapter). I've added #Retryable annotation to the method; but after all retries fail, "final" Exception thrown by last unsuccessful retry appears on System.err with its stack trace (the other ones thrown by earlier failed retries do not appear, seems they are caught by retry "mechanism" under the hood).
With Exceptions thrown by failed Health indicators (they are implemented by subclassing AbstractHealthIndicator).
I've tried implementing my own TaskExceptionHandler, replacing the default one (also mentioned in "Scheduled Tasks" chapter); and/or by adding System.setErr(System.out) in main method before building/setup of Micronaut Application Context. But nothing seems to help as my test cases attest.
Have I missed a chapter in Micronaut's documentation?
Thanks for any hints.
Regards
Christian
My wager is that Micronaut doesn't provide tools for setting a global uncaught exception handler because that's governed by the wider JRE. We've solved the problem in a few of our services with Thread.html#setDefaultUncaughtExceptionHandler by doing something like this at application startup:
Thread.setDefaultUncaughtExceptionHandler((t, e) -> logger.error("Uncaught exception", e));
Related
What does 'segment' and 'progress' mean in that kind of exception
2) xlang/s engine event log entry: Uncaught exception (see the 'inner exception' below) has suspended an instance of service 'MainEventProcess.MainEvent(5b530a24-7336-4695-78ee-1d4ffdd9f210)'.
The service instance will remain suspended until administratively resumed or terminated.
If resumed the instance will continue from its last persisted state and may re-throw the same unexpected exception.
InstanceId: cf584087-a9d3-4be7-8da7-eae49fd4a108
Shape name: SendDeviationOut
ShapeId: dc5c3484-7955-4d75-b1f9-7e0ca8ecbc1e
Exception thrown from: segment 4, progress 8
Inner exception: Exception occurred when persisting state to the database.
Full details hereon MSDN:
Exception during execution of Orchestration
Can it be helpful in searching errors in code?
First, it's nothing you need to worry about and is not related to your app/code/implementation.
The two items you need to act on are SendDeviationOut and Exception occurred when persisting state to the database. You are most likely publishing a message and there are no Subscribers. This is the "no Subscribers found" error from the Orchestration engine.
Now, to answer your specific question, those are markers to blocks of C# code that XLang compiler generated from your Orchestration. Basically, every statement is organized into a group, segment, and each is executed and tracked individually, progress. If you open the File0.cs, you will see this in action.
In Lablgtk, whenever there is an exception in a callback, the exception is automatically caught and an error message is printed in the console, such as:
(prog:12345) LablGTK-CRITICAL **: gtk_tree_model_foreach_func:
callback raised an exception
This gives no stack trace and no details about the exception, and because it is caught I cannot retrieve this information myself.
Can I enable more detailed logging information for this case? Or prevent the exception from being caught automatically?
I guess the best way to do so is to catch your exception manually and handle it yourself.
let callback_print_exn f () =
try f () with
e -> my_exn_printer e
Assuming val my_exn_printer : exn -> unit is your custom exception printer, you can simply print your callbacks exceptions by replacing ~callback:f by ~callback:(callback_print_exn f) in your code.
Of course, you can also with that method send that exception to another
thread, register a "callback id" that would be passed along with your exception...
About the stack trace, I'm not sure you can retrieve it easily. As it's launched as a callback, you probably want to know the signal used and that can be stored in your callback handler.
I had another similar issue, but this time it was harder to find where to put the calls to intercept the exception.
Fortunately, this time there was a very specific error message coming from the Glib C code:
GLib-CRITICAL **: Source ID ... was not found when attempting to remove it`
Stack Overflow + grep led me to the actual C function, but I could not find which of the several Lablgtk functions bound to this code was the culprit.
So I downloaded the Glib source, added an explicit segmentation fault to the code, compiled it and used LD_LIBRARY_PATH to force my modified Glib version to be loaded.
Then I ran the OCaml binary with gdb, and I got my stack trace, with the precise line number where the Lablgtk function was being called. And from there it was a quick 3-line patch.
Hacks like this one (which was still faster than trying to find where to intercept the call) could be avoided by having a "strict mode" preventing exceptions from being automatically caught. I still believe such a switch should be available for Lablgtk users, and hope it will eventually be available.
I have a problem in catching the exceptions in my spring integration application.
Flow of operations in my application.
Http:inbound gateway which receives the request (error-channel defined to my custom error channel)
Service Activator for basic validations (Exceptions which are thrown from here are handled by error-channel defined on the GW)
splitter
Aggregator
Exceptions on my splitter or Aggregator are not handled by my error channel. why?
Steps taken:
I added a chain and included a header enricher and specified an error channel just before the splitter.
After this, any exception on my splitter is handled by my error channel mentioned in the header enricher.
<chain input-channel="invitations">
<header-enricher>
<error-channel ref="failed-invitations" />
</header-enricher>
<int:splitter ref="payloadSplitter" />
</chain>
But the same doesnt work when do the same on my Aggregator. why?
Whenever there is an exception in my code, it retries and gets executed more than one time. why?
I have a "errorChannel" defined which logs the exceptions. it doesnt work.
I know the thread is too old, but I was also facing a similar issue and found I declared error-channel in header-enricher but not provide 'overwrite="true"' as a parameter. And after providing 'overwrite="true"'it is working as needed. I am surprised why spring integration does not provide an overwrite=true by default.
Let us know this is what solution you did in your old code? So everyone can find out the solution for such a scenario.
Does anybody know how to print full stack trace on the Browser, when a Runtime Exception occurs in MULE..??
When a runtime Exception occurs, MULE throws a 500 Server Error to the client , but shows no details to the client. It prints the whole stack trace in Console or Log Files (like the following) :
Root Exception stack trace:
java.sql.SQLException: Invalid column name
at oracle.jdbc.driver.OracleStatement.getColumnIndex(OracleStatement.java:3677)
at oracle.jdbc.driver.OracleResultSetImpl.findColumn(OracleResultSetImpl.java:2749)
at oracle.jdbc.driver.OracleResultSet.getString(OracleResultSet.java:494)
+ 3 more (set debug level logging or '-Dmule.verbose.exceptions=true'
for everything)
Can i show the same stack Trace on the Browser (to the client)..??
And if possible , then also tell me how to switch ON or OFF printing of Stack Trace on Browser..??
(It may be possible that sometime in future , i dont want to show stack trace on browser)
Yes this is possible. I assume you are using a regular HTTP endpoint and this is a REST type service(?) If so, you can simply put a try/catch around the code causing the exception and return whatever text you want.
There are also exception strategies (http://www.mulesoft.org/documentation/display/MULE3USER/Error+Handling) for doing more sophisticated error handling, but it sounds like you are looking for the simple answer above.
If this doesn't answer your question, please provide more info about your mule config and the service that is raising the exception.
There is nothing out of the box in Mule to do that. You have to implement an exception handler that will format the stacktrace in the Message exception payload and return it to the caller.
In your case, the HTTP transport has a particularity that can be found in the HttpMessageReceiver code:
try
{
conn.writeResponse(processRequest(request));
}
catch (Exception e)
{
...
conn.writeResponse(buildFailureResponse(request.getRequestLine().getHttpVersion(), httpStatus, e.getMessage()));
This means that when an exception crops-up to the top level, the creation of the failure message response is not customizable: you get this pretty technical message back and that is all.
I see two options to solve your problem:
sub-class HttpMessageReceiver and make the response message customizable in your version,
drop the HTTP transport in favor of the Jetty one (look at the bookstore example) and customize the response error messages at the web container level.
Does throwing an exception in a windows service crash the service?
i.e. it will have to be restarted manually
Note:
I am throwing the exception from within the catch clause.
Not strictly so -- it'd only cause problems if the exception is unhandled.
If the exception is uncaught and bubbles back up to the OnStart() method it will crash the service. You will typically see a message in the Windows Event Log similar to the following:
"The MyServiceName Service service terminated unexpectedly. It has done this x time(s).
If you're throwing the exception in Catch, and there's nothing above it to recatch it, then that will cause your service to stop. The OnStart() method needs a try/catch. If you don't want to stop the service when an Exception occurs, then you need to handle it (log it and move on, or whatever).
My preference woudld be to handle expected exceptions, and to have unexpected exceptions either cause the service to stop, or at least stop/restart automatically. If something unexpected happens your service will be running in an unknown state, and who knows what it will do.
We ran into the problem of an untrapped exception on a child thread causing the service to stop without providing any information about what was causing the exception. We used this method to find out the source of the exception.
You can put a Handler to the service to catch all unhandled exceptions (including all sub threads of the service). In VB.NET, you will need to add a handler for AppDomain.CurrentDomain.UnhandledException. It is likely similar in C#. It will then catch anything that does bubble up past your onStart. You can choose to consume it there or allow it to crash the service from there.