# erlang-lager/lager

A logging framework for Erlang/OTP

Repository: https://github.com/erlang-lager/lager
Canonical: https://ross.abutalabs.com/products/lager
Language: Erlang
License: Apache-2.0
License Family: permissive
Topics: erlang, logging, otp
Last push: 2025-08-26T16:09:45+00:00

## Health v2 (maintenance only)
Score: 40/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 38, release rhythm 8, longevity 100
- inputs: {"age_days": 5549, "days_push": 372, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1130, forks 445 (observed 2026-08-28T04:03:42.399907+00:00)

## What it is
Lager is a logging framework for Erlang/OTP that provides fine-grained log levels, multiple backends and sinks, and integration with UNIX tools like syslog and logrotate. It uses a parse transform to capture module/function/line/pid context and includes features like load shedding and log rotation.

## Use cases
- add structured logging to an Erlang/OTP application
- rotate log files by time or size
- integrate Erlang logging with syslog
- filter log messages by severity level
- prevent log flooding from crashing the node
- pretty-print records in log output

## When to choose
- you are building an Erlang/OTP application and need robust, configurable logging
- you want syslog/logrotate compatibility and multiple log backends
- you need protection against oversized log volumes via load shedding

## When to avoid
- you are using Erlang/OTP's built-in logger (OTP 21+) and prefer standard library logging
- your project is not written in Erlang
- you need logging for a platform outside the BEAM ecosystem

## Facets
- artifact type: library
- maturity: active
- function: logging
- domain: developer-tools, backend
- platform: windows, elixir
- tags: erlang, otp, log-rotation, syslog, parse-transform, linux, macos

## Member repositories
- erlang-lager/lager (main) score 40

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:42.399907+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T06:38:14.774941+00:00, confidence not recorded.
  - readme: https://github.com/erlang-lager/lager (fetched 2026-08-28T04:03:42.399907+00:00, sha c852bd31784d)
- Data as of 2026-08-30T08:39:29.467469+00:00.