Return 500 on non-zero exit status for Serializing and Streaming modes

[ericstoekl]

Signed-off-by: Eric Stoekl ems5311@gmail.com

Description

This PR is to bubble up non-zero exit code from the fprocess that is run by the of-watchdog as a 500 ISE response to the client which invokes the watchdog.

Motivation and Context

• [X] I have raised an issue to propose this change (required) https://github.com/openfaas-incubator/of-watchdog/issues/12

How Has This Been Tested?

Start the watchdog server with port=8081 mode=serializing fprocess="stat x" ./of-watchdog

Before the update, when you curl the endpoint it will return 200 OK despite the fprocess command failing.

$ curl localhost:8081 -i
HTTP/1.1 200 OK
Content-Type: application/octet-stream
Date: Wed, 04 Apr 2018 14:48:20 GMT
Content-Length: 0

After update, it will return 500 if the fprocess command return non-zero:

$ curl localhost:8081 -i
HTTP/1.1 500 Internal Server Error
Content-Type: application/octet-stream
Date: Wed, 04 Apr 2018 15:11:24 GMT
Content-Length: 13

When running with a working fprocess (use pwd for the fprocess variable for example) I get a 200 response:

$ curl localhost:8081 -i
HTTP/1.1 200 OK
Content-Type: application/octet-stream
Date: Wed, 04 Apr 2018 15:16:00 GMT
Content-Length: 64

/home/s/github/go/src/github.com/openfaas-incubator/of-watchdog

You will see the same results with the streaming (fork) mode.

Types of changes

• [X] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [X] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [X] I've read the CONTRIBUTION guide
• [X] I have signed-off my commits with git commit -s
• [ ] I have added tests to cover my changes.
• [X] All new and existing tests passed.

[alexellis]

I think this will work and have a similar patch on my laptop from when I raised the issue. Let's re-evaluate which modes are needed in the of-watchdog and what else is different in this implementation.

[alexellis]

/close: inactive