krapslog

Visualize a log file with sparklines

When troubleshooting a problem with a production service, I often need to get the general shape of a log file. Are there any spikes? Was the load higher during the incident than it was beforehand? Does anything else stand out? Without tooling to help you, a large log file is little more than a blob of data. This tool is designed to quickly surface key features of the log — and then get out of your way.

Installing

$ go get -u github.com/acj/krapslog

Usage

$ krapslog -h
Usage of krapslog:
  -format string
        date format to look for (see https://golang.org/pkg/time/#Time.Format) (default "02/Jan/2006:15:04:05.000")
  -markers int
        number of time markers to display
  -progress
        display progress while scanning the log file

Examples

Get the basic shape:

$ krapslog /var/log/haproxy.log 
▂▂▂▂▂▁▂▁▁▁▁▂▁▁▁▁▂▂▂▁▁▁▁▁▁▁▁▁▂▂▂▂▂▂▂▂▂▃▂▂▂▃▂▂▂▂▃▃▃▃▃▄▅▅▅▄▅▃▄▃▄▄▅▅▆▇▆▆▆▆▆▆▆▆▇▇▇▇██

Add points in time:

$ krapslog -markers 10 /var/log/haproxy.log
                                                             Sat Nov 23 14:15:56
                                                    Sat Nov 23 13:22:29        |
                                           Sat Nov 23 12:29:01        |        |
                                  Sat Nov 23 11:35:33        |        |        |
                          Sat Nov 23 10:48:02       |        |        |        |
                                            |       |        |        |        |
▂▂▂▂▂▁▂▁▁▁▁▂▁▁▁▁▂▂▂▁▁▁▁▁▁▁▁▁▂▂▂▂▂▂▂▂▂▃▂▂▂▃▂▂▂▂▃▃▃▃▃▄▅▅▅▄▅▃▄▃▄▄▅▅▆▇▆▆▆▆▆▆▆▆▇▇▇▇██
|        |        |       |        |
|        |        |       |        Sat Nov 23 09:54:34
|        |        |       Sat Nov 23 09:01:07
|        |        Sat Nov 23 08:13:36
|        Sat Nov 23 07:20:08
Sat Nov 23 06:26:40

Custom date formats

By default, krapslog assumes that log timestamps are in the format "02/Jan/2006:15:04:05.000". However, you can use the format parameter to find timestamps in other formats. The parameter value must use the format given in the documentation for Go's Time.Format type.

For example, if your log contains dates that look like "Jan 1, 2020 15:04:05", you can run krapslog as follows:

$ krapslog -format "Jan 2, 2006 15:04:05"

Contributing

Please be kind. We're all trying to do our best.

If you find a bug, please open an issue. (Or, better, submit a pull request that fixes it!)