Permit invocation without configuration file, for promoting ad hoc operations

[amotl]

About

The idea of this patch is to make it possible to invoke grafana-import without needing to use a configuration file, in order to promote ad hoc use. We hope it will be received well.

Usage

Instead of defining Grafana connectivity settings within the configuration file, the program now also supports defining it through the command line argument --grafana_url, and the environment variable GRAFANA_URL, in the same way like grafana-client is doing it.

Details

In this spirit, this feature expands into quite the opposite direction what the program was originally conceived for, using a configuration file which can store multiple Grafana connection profiles. We think the program can well be used for both use cases, so this patch relaxes the must-have constraint about having a configuration file.

Trivia

This is a stacked PR, based on GH-8. It can be reviewed independently, but please do not merge prematurely.

References

• Software tests and CI. Ad hoc operation mode. "Builder" and "live reload" features. #7

[peekjef72]

The feature is a good idea.
I build the tool from the grafana-snapshoot "core" program that was using a config file too... a quick and dirty implementation so I didn't even think about it!
But it ise a good idea.

[peekjef72]

I agree.
Everything is fine for me.
You can merge if you are ready.