tail-jsonl

Tail JSONL/NDJSON Logs

Background

I wanted to find a tool that could:

1. Convert a stream of arbitrary JSONL logs into an easy to skim format
2. Clearly unwrap and display exceptions

If you are looking for more functionality, there are many good alternatives: humanlog, lnav, goaccess, angle-grinder, adapting jq, logss, tailspin, toolong, Nerdlog, loggo, etc.

Installation

Install with pipx, uv tool, mise, or your other tool of choice for Python packages

# Choose one:
pipx install tail-jsonl
uv tool install tail-jsonl # or: uvx tail-jsonl
mise use -g pipx:tail-jsonl

Usage

Pipe JSONL output from any file, kubernetes (such as stern), Docker, etc.

Tip: use |& to ensure that stderr and stdout are formatted (if using latest versions of zsh/bash), but all of these examples only require |

# Example piping input in shell
echo '{"message": "message", "timestamp": "2023-01-01T01:01:01.0123456Z", "level": "debug", "data": true, "more-data": [null, true, -123.123]}' |& tail-jsonl
cat tests/data/logs.jsonl |& tail-jsonl

# Optionally, pre-filter or format with jq, grep, awk, or other tools
cat tests/data/logs.jsonl | jq '.record' --compact-output |& tail-jsonl

# An example stern command (also consider -o=extjson)
stern envvars --context staging --container gateway --since="60m" --output raw |& tail-jsonl

# Or with Docker Compose (note that awk, cut, and grep all buffer. For awk, add '; system("")')
docker compose logs --follow | awk 'match($0, / \| \{.+/) { print substr($0, RSTART+3, RLENGTH); system("") }' |& tail-jsonl

Configuration

Optionally, specify a path to a custom configuration file. For an example configuration file see: ./tests/config_default.toml

echo '...' |& tail-jsonl --config-path=~/.tail-jsonl.toml

Project Status

See the Open Issues and/or the CODE_TAG_SUMMARY. For release history, see the CHANGELOG.

Contributing

We welcome pull requests! For your pull request to be accepted smoothly, we suggest that you first open a GitHub issue to discuss your idea. For resources on getting started with the code base, see the below documentation:

• DEVELOPER_GUIDE
• STYLE_GUIDE

Code of Conduct

We follow the Contributor Covenant Code of Conduct.

Open Source Status

We try to reasonably meet most aspects of the “OpenSSF scorecard” from Open Source Insights

Responsible Disclosure

If you have any security issue to report, please contact the project maintainers privately. You can reach us at [email protected].

License

LICENSE