synapse/contrib/lnav

lnav config for Synapse logs

lnav is a log-viewing tool. It is particularly useful when you need to interleave multiple log files, or for exploring a large log file with regex filters. The downside is that it is not as ubiquitous as tools like less, grep, etc.

This directory contains an lnav [log format definition](

https://docs.lnav.org/en/v0.10.1/formats.html#defining-a-new-format

) for Synapse logs as emitted by Synapse with the default [logging configuration](

https://matrix-org.github.io/synapse/latest/usage/configuration/config_documentation.html#log_config

). It supports lnav 0.10.1 because that's what's packaged by my distribution.

This should allow lnav:

• to interpret timestamps, allowing log interleaving;
• to interpret log severity levels, allowing colouring by log level(!!!);
• to interpret request IDs, allowing you to skip through a specific request; and
• to highlight room, event and user IDs in logs.

See also https://gist.github.com/benje/e2ab750b0a81d11920d83af637d289f7 for a similar example.

Example

Tips

• lnav -i /path/to/synapse/checkout/contrib/lnav/synapse-log-format.json
• lnav my_synapse_log_file or lnav synapse_log_files.*, etc.
• lnav --help for CLI help.

Within lnav itself:

• ? for help within lnav itself.
• q to quit.
• / to search a-la less and vim, then n and N to continue searching down and up.
• Use o and O to skip through logs based on the request ID (POST-1234, or else the value of the request_id_header header). This may get confused if the same request ID is repeated among multiple files or process restarts.
• ???
• Profit