cwltail

cwltail

tail -f for cloudwatch logs and with custom highlighting.

Supports tailing all streams for cloudwatch log group with following capabilities:

• Highlight parts of log message based on regular expression
• Highlight warning and error log messages, pattern to detect log level can be customized
• Filter log lines by matching or not matching regular expression
• Including short (last 6 character) name of log stream in the log message
• Include Cloudwatch event timestamp (either time or full timestamp) in the log message
• Use AWS profile name for credentials

Usage

Highlighting based on log level

-w option enables highlighting based on log level. Default regex to detect log level is

(?i)\b((?P<warning>warn|warning)|(?P<error>error))\b

Custom regex can be provided with -l option.

Custom regex must contain named capture groups with names warning and error. If any of these groups are not empty for any given line of code, then that line will be highlighted with yellow for warning or red for errors. If both groups match, then line will be highlighted as an error.

Highlighting parts of the log message

-c option allows to pass a regular expression to highlight certain parts of the log messages. If expression matches the log line, then each capturing group of the expression will be displayed in a distinct color.

Example of the regexp to highlight time, then something in square brackets then sequence of non-whitespace characters and then sequence of alphanumeric characters and '.'

`(\d{2}:\d{2}:\d{2}.\d{3})\s+\[(.*)\]\s+(\S+)\s+([a-zA-Z0-9_.]+).*`

Filtering the log

-f option allows to pass regular expression to filter log lines. If the log line matches the expression then it will be displayed and the matching part will be highlighted.

If the expression is prefixed with exclamation mark that it will work as grep -v, i.e. all the lines that match the expression will be discarded.

-f Exception will match all the lines containing the sequence "Exception"

-f !Exception will match all the lines that do not contain the sequence "Exception"

Download

Download the latest binaries on releases page. That contains precompiled binaries for Linux and MacOS x86. Sorry, no Windows binaries, use Linux binary with WSL2.