[Maas-devel] Allow API to use <system_id | hostname> for all operations that currently require the system_id

[Raphaël Badin]

[...]
> For this reason, I think we need to look at this in the context of some of the
> upcoming work on general usability.
>
> My opinion is that changing the API is the wrong thing to do here.  If we want
> to make the command line more usable, I think we need to move maas back to
> maas-cli and write a wrapper (called maas) around it to add a sugary layer for
> end users.  This can include something that accepts hostnames for operations
> involving nodes.  It can also include something that makes the parameters to
> some of the operations a lot easier to understand.

I agree with the idea that changing the API would be wrong.

Even though the CLI is a bit rough to use right now (mostly because the 
inline (maas -h) documentation is a bit vague and the online 
documentation non-existant — two things that we've been wanting to fix 
for a long time, see 
https://bugs.launchpad.net/maas/+bugs?field.tag=cli), keeping its 
behaviour close to the API's behaviour has clear advantages.

I wonder if, instead of changing the core *behaviour* by adding the 
option to look up the nodes using hostnames, we shouldn't improve the 
CLI so that it's easier to *extract* information from the returned 
responses.  This is based on the idea that most of the pain we feel when 
using the CLI comes from the awkwardness of having to deal with 
JSON-formatted output.  While this is fine when using the API in Python, 
JSON is clumsy to use on the command-line (even though I know that they 
are workarounds, for instance by piping the JSON blob into a Python 
command).

More precisely, it would make it very easy to get the system id of a 
node whose hostname you know;  I'm thinking about something along the 
lines of:

$ maas <profile> nodes list hostname=<hostname> *limit=1 
get-field=system_id* → system_id

The main functionality already exists (getting the filtered list of 
nodes); the part the we would need to add would be the limitation and 
the field extraction.

@Andres & al. don't you think that, if you had access (through a very 
clear call to the CLI) to the system_id of a node using its hostname, 
this would solve your usability problem?

R.