I have log lines of the following form in my Google Cloud Console:
Updated blacklist info about 123 minions. max_blacklist_per_minion=20, median_blacklist_per_minion=8, blacklist_free_minions=31
And I'm trying to set up some log-based metrics to get a longer-term overview of the values (ie. how are they changing? is it lower or higher than yesterday? etc).
However I didn't find any examples for this scenario in the documentation and what I could think of doesn't seem to work. Specifically I'm trying to understand what I need to select in "Field name" to have access to the log line (so that I can write a regular expression against).
I tried textPayload but that seems to be empty for this log entry. Looking at the actual log entry there should also be a protoPayload.line[0], but that doesn't seem to work either
In the "Metric Editor" built into the logs viewer UI you can use "protoPayload.line.logMessage" as the field name. For some reason the UI doesn't want to suggest 'line' (seems like a bug; same behavior in the filter box).
The log based metric won't distinguish based on the index of the app log line, so something like 'line[0]' won't work. For a distribution all values are extracted. A count metric would count the log entry (ie 1 regardless the number of 'line' matches).