For safety, Python charm-helpers juju-log command should insert a "--" before the log message.

[Gary Poster]

The Go version of juju-log currently behaves differently than the Python one: see bug 1130771. This breaks the charm-helpers log command, and in particular the log_entry and log_exit functions (see /helpers/python/charmhelpers/__init__.py; excerpt below).

A change that would both work around the issue and be a reasonable long term change would be to make the log command insert a '--' before any log message: "log = command('juju-log', '--')" would work.

Pertinent excerpt follows.

log = command('juju-log')
# We create a juju_status Command here because it makes testing much,
# much easier.
juju_status = lambda: command('juju')('status')

def log_entry():
    log("--> Entering {}".format(script_name()))

def log_exit():
    log("<-- Exiting {}".format(script_name()))