No such file or directory: 'htpasswd': 'htpasswd' since apache2-utils is not installed

[Nobuto Murata]

I'm following the following doc:
https://www.ubuntu.com/kubernetes/docs/docker-registry

How to reproduce:

juju deploy ~containers/docker-registry
juju config docker-registry \
  auth-basic-user='admin' \
  auth-basic-password='password'

Then unit error "FileNotFoundError: [Errno 2] No such file or directory: 'htpasswd': 'htpasswd'" happens.

apache2-utils including htpasswd is supposed to be installed with apt layer:
https://github.com/CanonicalLtd/docker-registry-charm/blob/master/layer.yaml
But it's not installed when reactive/docker_registry.py is executed.

unit-docker-registry-0: 22:00:26 ERROR unit.docker-registry/0.juju-log Hook error:
Traceback (most recent call last):
  File "/var/lib/juju/agents/unit-docker-registry-0/.venv/lib/python3.6/site-packages/charms/reactive/__init__.py", line 73, in main
    bus.dispatch(restricted=restricted_mode)
  File "/var/lib/juju/agents/unit-docker-registry-0/.venv/lib/python3.6/site-packages/charms/reactive/bus.py", line 390, in dispatch
    _invoke(other_handlers)
  File "/var/lib/juju/agents/unit-docker-registry-0/.venv/lib/python3.6/site-packages/charms/reactive/bus.py", line 359, in _invoke
    handler.invoke()
  File "/var/lib/juju/agents/unit-docker-registry-0/.venv/lib/python3.6/site-packages/charms/reactive/bus.py", line 181, in invoke
    self._action(*args)
  File "/var/lib/juju/agents/unit-docker-registry-0/charm/reactive/docker_registry.py", line 25, in start
    layer.docker_registry.configure_registry()
  File "lib/charms/layer/docker_registry.py", line 32, in configure_registry
    auth_basic = _get_auth_basic()
  File "lib/charms/layer/docker_registry.py", line 201, in _get_auth_basic
    if _write_htpasswd(htpasswd_file, user, password):
  File "lib/charms/layer/docker_registry.py", line 273, in _write_htpasswd
    subprocess.check_call(cmd)
  File "/usr/lib/python3.6/subprocess.py", line 286, in check_call
    retcode = call(*popenargs, **kwargs)
  File "lib/charms/layer/status.py", line 186, in _patched_call
    return _orig_call(cmd, *args, **kwargs)
  File "/usr/lib/python3.6/subprocess.py", line 267, in call
    with Popen(*popenargs, **kwargs) as p:
  File "/usr/lib/python3.6/subprocess.py", line 709, in __init__
    restore_signals, start_new_session)
  File "/usr/lib/python3.6/subprocess.py", line 1344, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)
FileNotFoundError: [Errno 2] No such file or directory: 'htpasswd': 'htpasswd'

[Nobuto Murata (nobuto)]

https://github.com/CanonicalLtd/docker-registry-charm/pull/35

[Kevin W Monroe (kwmonroe)]

Fix is available in rev 143 and higher:

cs:~containers/docker-registry-143