util.mount_cb only supports passing through a single (positional) argument to the wrapped function

[ubuntu-server-builder]

This bug was originally filed in Launchpad as LP: #1884979

Launchpad details

affected_projects = []
assignee = None
assignee_name = None
date_closed = None
date_created = 2020-06-24T14:45:54.248299+00:00
date_fix_committed = None
date_fix_released = None
id = 1884979
importance = undecided
is_complete = False
lp_url = https://bugs.launchpad.net/cloud-init/+bug/1884979
milestone = None
owner = oddbloke
owner_name = Dan Watkins
private = False
status = triaged
submitter = oddbloke
submitter_name = Dan Watkins
tags = []
duplicates = []

Launchpad user Dan Watkins(oddbloke) wrote on 2020-06-24T14:45:54.248299+00:00

This makes it difficult to use with a function that needs to take more than a single positional parameter, or any keyword arguments; you have to partially apply the function before calling mount_cb.

I propose adding args and kwargs parameters, which will be passed to the callback function using *args and **kwargs. (For bonus points, refactor all current callsites to pass args so we can drop the data argument entirely.)

[ubuntu-server-builder]

Launchpad user Dan Watkins(oddbloke) wrote on 2020-06-26T17:45:27.389475+00:00

I haven't started work on this specific feature, but I have started looking at writing tests for mount_cb's current behaviour as it is presently untested.

[ubuntu-server-builder]

Launchpad user Dan Watkins(oddbloke) wrote on 2020-06-26T19:46:45.211155+00:00

That testing is now up at https://github.com/canonical/cloud-init/pull/463