Make mode=serializing be fully backwards compatible with the original watchdog

[thomasjpfan]

For of-watchdog to take the place of the original watchdog, it should be fully backwards compatible with the original watchdog.

Expected Behavior

Support environmental variables cgi_headers, marshal_request, and combine_output with their corresponding feature.

Current Behavior

The above features are not fully supported.

Possible Solution

Migrate over the tests and code from the original watchdog.

Context

Maintaining two versions of watchdog doubles the amount of work one needs to do. Once of-watchdog in serializing mode becomes backwards compatible, it can replace the original watchdog while the other modes can get worked on.

[sargun]

@alexellis is this and #10 the only remaining items to be able to supplant the old watchdog?

[alexellis]

Hi I am not clear what the question is. There are two supported watchdogs at present.

For the forking mode we have the classic watchdog and for HTTP mode we are using this watchdog. Both watchdogs are used by the end user community in templates.

https://docs.openfaas.com/architecture/watchdog/