Play nice with authorization

[bmorg]

When adding a source, the provided user seems to need admin privileges in order to not get an error.

Otherwise there will be a "Unable to connect to source" error displayed in both the host list and a host's graphs, which both seem to otherwise work just fine.

Specifically, a READ grant on the telegraf database should be more than enough for Chronograf to work.

[goller]

Hi @bmorg, thanks for writing in! Yes, I agree. We'll take a look at which queries are causing this problem. At the very least we should state what permissions the chronograf user needs (for example it would need to READ kapacitor).

[bmorg]

Thanks @goller! I for one haven't even gotten around to installing Kapacitor yet, so I don't have a kapacitor database.

[goller]

@bmorg we found out that SHOW DATABASES for a read-only user is a limitation of influxdb at the moment. However, @mark-rushakoff is writing support for SHOW DATABASES right now for InfluxDB 1.3.

[mark-rushakoff]

It's already merged in master of open source InfluxDB: influxdata/influxdb#7974

[nhaugo]

Fixed by InfluxDB 1.3