I'm new to logstash and testing
filebeat -> logstash -> elasticsearch -> kibana
for viewing log data.
I have managed to use logstash to parse and format log formats,
but I am worried that some log lines may be in a format that I did not consider and my parser will miss and not store in elasticsearch.
How can I find out if some of my log lines are not matching and not processed with the grok patterns I am using?
If the mapping of the some log data and elasticsearch doesn't match, how would I find out and view or log such errors?
I noticed the --debug command line option gives more information.
What is the --debug equivalent in logstash.yml?
Other than the --debug command line option, logs stored by logstash in /var/log/* what other useful tips for debugging and problem solving can you suggest?