IndexError in add_rbac_roles

[Kevin W Monroe]

If the migration from known_tokens.csv to k8s secrets fails just right, we'll attempt to parse a csv file that no longer has csv data. This leads to an index error:

-----
Traceback (most recent call last):
  File "/var/lib/juju/agents/unit-kubernetes-master-0/.venv/lib/python3.6/site-packages/charms/reactive/__init__.py", line 74, in main
    bus.dispatch(restricted=restricted_mode)
  File "/var/lib/juju/agents/unit-kubernetes-master-0/.venv/lib/python3.6/site-packages/charms/reactive/bus.py", line 379, in dispatch
    _invoke(hook_handlers)
  File "/var/lib/juju/agents/unit-kubernetes-master-0/.venv/lib/python3.6/site-packages/charms/reactive/bus.py", line 359, in _invoke
    handler.invoke()
  File "/var/lib/juju/agents/unit-kubernetes-master-0/.venv/lib/python3.6/site-packages/charms/reactive/bus.py", line 181, in invoke
    self._action(*args)
  File "/var/lib/juju/agents/unit-kubernetes-master-0/charm/reactive/kubernetes_master.py", line 260, in check_for_upgrade_needed
    add_rbac_roles()
  File "/var/lib/juju/agents/unit-kubernetes-master-0/charm/reactive/kubernetes_master.py", line 307, in add_rbac_roles
    if record[2] == 'admin' and len(record) == 3:
IndexError: list index out of range
-----

This could also happen if a user tries to downgrade to a k8s-master charm revision that predates authn with k8s secrets (before the 1.19 release).

Regardless of how we get there, the k8s-master charm should handle this better.

[Kevin W Monroe (kwmonroe)]

PR for review:

https://github.com/charmed-kubernetes/charm-kubernetes-master/pull/131

[Cory Johns (johnsca)]

Backported to stable: https://github.com/charmed-kubernetes/charm-kubernetes-master/commit/d21d5fdeea79f4247d83269aec5d8e3ebca66298