Hang on Windows

[rdilipk]

I have been playing around with benthos with simple input/output mappings. I am experiencing some weird problems when I run it on Windows. A simple mapping to read from stdin, massage the output and print to stdout (from the walkthrough section) takes almost 5 minutes for the application to output any value. Sometimes (~20% of the time) it displays the output quickly. The rest of the time it almost takes the same amount of time: around 5min 50+ seconds but < 6 minutes. Almost feels like it's deliberately waiting for a specified time interval before printing the output. Anybody has seen something like this before? The command line I run is fairly straight forward:

C:/> my_app_that_writes_to_stdout.exe | benthos.exe -c ./myconfig.yaml

I am running this on Windows 10 Enterprise.

[Jeffail]

Hey @rdilipk can you paste the full config you're running?

[Jeffail]

Thanks, yeah that looks pretty straight forward. Ideally I need to find a way to reproduce it to dig in more, but one thing that might be worth trying first is reproducing the hang with the following added to the top of your config:

http:
  debug_endpoints: true

That'll register an HTTP endpoint /debug/stack, which if you access will give you the stack trace of the program while it's blocked. If you paste the full stack here it'll tell me what specifically it's blocked on. More info on debug endpoints here if you're interested: https://www.benthos.dev/docs/components/http/about#debug-endpoints

[rdilipk]

Thanks Jeff. I will do that. FWIW, I am a long time windows programmer. So while benthos is waiting around, I did attach it my debugger (Windbg) and broke into it. It appears one thread is waiting in the kernel after making a user-mode call to NtCreateFile. I have no idea what it's waiting for. Like I said, it does print the output after 5 minutes but it's driving me nuts to wait that long after every invocation :-) I will try your http suggestion and update here.

[rdilipk]

Quick question. where do I use the GET again? One of the INFO outputs said: Listening for HTTP requests at: http://0.0.0.0:4195. That sounds suspicious. Is the endpoint: http://0.0.0.0:4195/debug/stack ?

[Jeffail]

@rdilipk it'll be http://localhost:4195/debug/stack if it's running on your host machine. If it's running on a vm then you'll need the IP address of the host.

[rdilipk]

At this point I am fairly certain benthos hasn't even created a HTTP endpoint in the time its hanging around waiting for something. Neither netstat nor tcpview can show any ports opened by benthos until the very moment it prints the output 5m 58s later. Even then, it's so quick those tools don't show anything. I may have to give up. Spent way too much time trying to get to the bottom of this without any measurable progress. :-(