Graph data from log

We are capturing our logs with promtail into loki.

We have log lines like this:

...
some prefix duration: 102.03 ms some more text...
some prefix duration: 309.19 ms some more text...
some prefix duration: 426.43 ms some more text...
some prefix duration: 572.82 ms some more text...
...

I want to see a graph of the duration from these log lines.

I entered this query in a Grafana Dashboard in a time series panel with the loki data source:

{host="somehostname",filename="/path/to/some.log"}    # filtering the logfile
|= "some prefix duration:"    # filtering just the lines with duration
| pattern "<_> duration: <duration> ms"    # get the duration from line with a pattern

I used some Transformations:

  • Labels to fields
  • Convert field type
  • Merge

image

I see a graph, but it is cut off at the line limit (default 1000).

Looks like I have to make time series from data coming from a logline. Any suggestions?