sap_swpm: Option to enable SWPM observer mode

[rob0d]

#709

[sean-freeman]

@rob0d I'm good to merge this PR, it's non-destructive and can work before the overhaul of the sap_swpm code structure in the coming weeks.

However, in defaults the sap_swpm_swpm_remote_access_user should be uncommented and I would recommend it is by default set to root. If an end user wants to enable this feature and observe using a different OS User, then it can be changed of course. All SWPM executions are otherwise root so I think this default is OK.

[berndfinger]

Hi @rob0d, we are working on finalizing a new version, and your PR can be part of it. Can you please respond to the suggestion from @sean-freeman?

[rob0d]

@sean-freeman @berndfinger apologies, a bit snowed under.
I would prefer not to do that as it will change the role's default behaviour.
Currently when SWPM is executed SAPINST_REMOTE_ACCESS_USER= and SAPINST_REMOTE_ACCESS_USER_IS_TRUSTED=true are not set. This makes SWPM use root (unix) or Administrator(windows) automatically.
By setting the default to root, these two parameters will be set even thought it's not required as they basically emulate the default behaviour. I have never tried to use SAPINST_REMOTE_ACCESS_USER=root and I don't know how will SWPM react. It should behave the same way, but I am not sure and I won't be able to test it for at least 4 weeks.

So setting the default to root, will change the current default behaviour of the role and I am not sure what impact it will have.

[berndfinger]

So setting the default to root, will change the current default behaviour of the role and I am not sure what impact it will have.

@rob0d I think in this case, we better not merge this PR into 1.4.1 but continue this discussion afterwards, for including it into 1.4.2, together with more changes for role sap_swpm.

[sean-freeman]

... in defaults the sap_swpm_swpm_remote_access_user should be uncommented and I would recommend it is by default set to root. If an end user wants to enable this feature and observe using a different OS User, then it can be changed of course. All SWPM executions are otherwise root so I think this default is OK.

Still awaiting this change to be made in defaults, otherwise PR is blocked

[rob0d]

Updated the default to be an empty variable and added code to handle this in a way that it doesn't change SWPM parameters and behaviour.
Unless this is enabled by setting sap_swpm_swpm_observer_mode to true, the behaviour is the same as before, so this is a non breaking change.
If sap_swpm_swpm_remote_access_user is not explicitly set and sap_swpm_swpm_observer_mode = true, it will execute SWPM with standard parameters.
If sap_swpm_swpm_remote_access_user is set, it will add appropriate SWPM command line parameters to use the requested user.

[sean-freeman]

lgtm 👍

[berndfinger]

LGTM