How can I cleanly end a program running under HttpPlatformHandler?

Question

How can I cleanly end a program running under HttpPlatformHandler?

Smith, Roland 40

I wrote a program that runs under HttpPlatformHandler and it works pretty well. The problem I am having is that I added code to exit if the program has been idle for too long. Sometimes after a program exit, the next request coming from a client results in a Bad Gateway error.

It appears that instead of launching another instance of my EXE, it is returning an empty response back to the client.

Is there a preferred way to cleanly shut down the EXE so that the handler can respond to the next request without an error?

Smith, Roland 40 Reputation points

2023-12-05T20:24:03.1066667+00:00

The requestTimeout defaults to 2 minutes. If the request takes longer than 2 minutes to process, the handler kills it before it is done. Most request only take a few seconds so this is a sporadic problem.

I'd like to set requestTimeout to something really long like an hour and have the exe handle timeouts.
Yurong Dai-MSFT 2,846 Reputation points Microsoft External Staff

2023-12-06T10:08:27.2133333+00:00

Hi @Smith, Roland,
You can set the application pool's idle time to 0 to prevent the application pool from automatically shutting down.
Lex Li (Microsoft) 6,032 Reputation points Microsoft Employee

2023-12-06T10:25:21.98+00:00

Not sure what kind of executable you want HttpPlatformHandler to launch, but the typical ones should be application servers themselves, which must be able to handle multiple requests and properly to respond errors. Examples are, Jetty and Tomcat for Java. HttpPlatformHandler is in general a very smart reverse proxy. You might also read my comment to your Stack Overflow post, https://stackoverflow.com/questions/77607812/httpplatformhandler-http-bad-gateway-error
Smith, Roland 40 Reputation points

2023-12-06T13:36:03.5966667+00:00

The program is written in PowerBuilder. I provide the source code to a customer and they add business logic and deploy the exe. My code can run single or multi threaded. It sounds like I should have them use multi threaded mode (or even remove single as an option) so that long running requests don't prevent it from responding within the timeout period.

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Smith, Roland 40 Reputation points

2023-12-05T20:24:03.1066667+00:00

The requestTimeout defaults to 2 minutes. If the request takes longer than 2 minutes to process, the handler kills it before it is done. Most request only take a few seconds so this is a sporadic problem.

I'd like to set requestTimeout to something really long like an hour and have the exe handle timeouts.
Yurong Dai-MSFT 2,846 Reputation points Microsoft External Staff

2023-12-06T10:08:27.2133333+00:00

Hi @Smith, Roland,
You can set the application pool's idle time to 0 to prevent the application pool from automatically shutting down.
Lex Li (Microsoft) 6,032 Reputation points Microsoft Employee

2023-12-06T10:25:21.98+00:00

Not sure what kind of executable you want HttpPlatformHandler to launch, but the typical ones should be application servers themselves, which must be able to handle multiple requests and properly to respond errors. Examples are, Jetty and Tomcat for Java. HttpPlatformHandler is in general a very smart reverse proxy. You might also read my comment to your Stack Overflow post, https://stackoverflow.com/questions/77607812/httpplatformhandler-http-bad-gateway-error
Smith, Roland 40 Reputation points

2023-12-06T13:36:03.5966667+00:00

The program is written in PowerBuilder. I provide the source code to a customer and they add business logic and deploy the exe. My code can run single or multi threaded. It sounds like I should have them use multi threaded mode (or even remove single as an option) so that long running requests don't prevent it from responding within the timeout period.

Answer 1

Based on the discussion via comments, I think the answer is clear.

Different from traditional ISAPI or managed module that dispatch individual requests to an extension, ARR and HttpPlatformHandler (both work as reverse proxy) expect the server administrator to configure a full-feature application server behind. So, for Java that means Tomcat or Jetty, and in your case your program needs to be able to handle multiple incoming requests at the same time.

Since your program will be an application server, you shouldn't expect it to be shut down from time to time, but run continuously over a long period of time. With ARR setup, IIS won't even attempt to shut down your program, while HttpPlatformHandler honors application pool idle shut down and might shut down your program and later start it again.

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How can I cleanly end a program running under HttpPlatformHandler?

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