use of charmhelpers log function raise exception if not under juju environment

[Thierry FAUCK]

When creating a python script with charmhelpers, the problem is that log() function calls a juju-log() function which is only integrated in juju.
As such trying to execute
                                 python -v hooks/install
will raise an exception: OSError: [Errno 2] No such file or directory

[Thierry FAUCK (thierry-j)]

For people willing to use charmhelpers out of juju, bypass is to use a script called juju-log located in the default search path.

[Marco Ceppi (marcoceppi)]

This doesn't seem like a charm-tools issue as much as an issue with the setup. You shouldn't be invoking hooks outside of a hook context. This is really a limitation in Juju not so much charm-tools. You /can/ execute hooks on remote systems using `juju run` and `juju-run`

juju help run

There is also a `juju-run` installed on deployed machines that let you execute code in a hook environment. If you're trying to do testing you'll want to mock these interfaces instead.