CLI sessions: handle case where retry is not passed as an argument

[sbesson]

Some logic was introduced in #283 to allow auto-retries in the CLI sessions plugin. This new functionality is disabled by default. As can be seen in the original PR, most of the testing has been done using omero sessions login where the functionality was introduced.

Most CLI plugins can inherit the login mechanism: the addition of add_login_arguments() in the CLI plugin sub-parser means the self.ctx.conn(args) can then use self.controls["sessions"].login(args).

As the --retry argument was only added to the sessions plugin, a misleading error message can be printed under some scenarios. The most typical ones and the easiest to reproduce is to enter an incorrect password. The login command produces the expected behavior with 3 tries by defaut:

(venv3) [sbesson@prod114-omeroreadwrite ~]$ omero login public@localhost -C
Password:
Password check failed for 'public': [id=52]
Password:
Password check failed for 'public': [id=52]
Password:
3 incorrect password attempts

But any other command will fail immediately with a cryptic InternalException

(venv3) [sbesson@prod114-omeroreadwrite ~]$ omero hql 'select * from Image i' -u public -s localhost -C
Password:
InternalException: Failed to connect: 'Namespace' object has no attribute 'retry'

e5ac9c6 proposes one way to fix this issue by adding an additional check for the existence of the retry in the var(args) dictionary and would make the two examples above behave identically.
An alternate strategy would be to add --retry to Parser. add_login_arguments and allow all sub-commands to set the value.

[joshmoore]

I wouldn't have any objections to also adding to the add_login_arguments method but I can't immediately think of a case where I would use it. (Perhaps some form of one-liner...)

[sbesson]

but I can't immediately think of a case where I would use it.

Agreed and this is likely why I didn't go and implement this solution at first. The omero sessions login --retry logic was introduced for a fairly specific use case. I'd be fine with waiting until someone comes with a concrete scenario before adding an optional argument to almost all CLI plugins

[sbesson]

We had some users stumbling across the InternalException: Failed to connect: 'Namespace' object has no attribute 'retry' error and I just realised this has been merged but not released yet.

@joshmoore @jburel is there a roadmap/timeline for the next OMERO.py release? I realise there are a few ongoing investigations including #371 and #370 but looking at v5.13.1...d5ca72f, we could certainly cut a patch release with the integrated changes.

[jburel]

It will make sense to cut a patch release. Do you want to take care of it?

[sbesson]

Sure, I'll open a changelog PR shortly