Explore (Loki datasource): empty log query request on page load resulting in error

[jstaffans]

What happened:

When browsing to the Explore section with a Loki datasource pre-selected but an empty query field, Grafana performs a log query without any query parameters. Loki always returns a HTTP 400.

What you expected to happen:

No log query requests should be sent until something has been entered into the query field.

How to reproduce it (as minimally and precisely as possible):

• Go to the Explore section
• Open browser dev tools
• Select a Loki data source
• Observe a request to /loki/api/v1/query_range without query params, resulting in a HTTP 400 error

Environment:

• Grafana version: 6.7.3
• Data source type & version: Loki 1.4.0

[davkal]

I can't reproduce this in master, so it might be fixed already.