juju_exe() fails to parse JUJU_VERSION

[Junien F]

Hi,

If you run mojo with the JUJU_VERSION environment variable set to "latest-1.25.x", mojo will try to run the "juju-latest" executable, which doesn't exist.

This is because juju_exe() (in mojo/juju/wait.py) is bugged, and is expecting JUJU_VERSION to have a proper formatting.

Not sure why this exists and why mojo doesn't simply use juju from PATH.

At any rate, this error should be caught up and displayed more appropriately, because right now, here's what's displayed :

2017-06-29 12:10:29 [INFO] Waiting for environment to reach steady state
2017-06-29 12:10:29 [ERROR] juju-latest status --format=json failed: 2
2017-06-29 12:10:29 [ERROR] Juju Status: environment: my-super-env
machines:
[juju status follows]
2017-06-29 12:10:29 [ERROR] 2

Not easy to understand what's going on :)

Thanks

[William Grant (wgrant)]

(2 is ENOENT here, not actually the exit code of the process.)

[Stuart Bishop (stub)]

JUJU_VERSION was added to support Openstack workflows. AFAIK it isn't anything official, so there is no definition of 'proper formatting' except for what works for the Openstack Charmers (because they got here first).

Does juju-wait need to cope with weird JUJU_VERSION's, or make using JUJU_VERSION opt in? Or is the fix simply to emit the juju executable to be used and why so 'bogus' JUJU_VERSION settings can be fixed?

[Junien F (axino)]

mojo should tell the operator that it tried to run juju-latest because of JUJU_VERSION, and should advise the operator to fix or unset this variable.