telemere

# Telemere

Structured logging and telemetry library for Clojure and ClojureScript. Next-generation successor to Timbre with unified API for logging, tracing, and performance monitoring.

## Overview

Telemere provides a unified approach to application observability, handling traditional logging, structured telemetry, distributed tracing, and performance monitoring through a single consistent API.

**Key Features:**
- Structured data throughout pipeline (no string parsing)
- Compile-time signal elision (zero runtime cost for disabled signals)
- Runtime filtering (namespace, level, ID, rate limiting, sampling)
- Async and sync handler dispatch
- OpenTelemetry, SLF4J, and tools.logging interoperability
- Zero-configuration defaults
- ClojureScript support

**Artifact:** `com.taoensso/telemere`
**Latest Version:** 1.1.0
**License:** EPL-1.0
**Repository:** https://github.com/taoensso/telemere

## Installation

Add to `deps.edn`:
```clojure
{:deps {com.taoensso/telemere {:mvn/version "1.1.0"}}}
```

Or Leiningen `project.clj`:
```clojure
[com.taoensso/telemere "1.1.0"]
```

Import in namespace:
```clojure
(ns my-app
  (:require [taoensso.telemere :as t]))
```

## Core Concepts

### Signals

Signals are structured telemetry events represented as Clojure maps with standardized attributes. They preserve data types throughout the logging pipeline rather than converting to strings.

Signal attributes include: namespace, level, ID, timestamp, thread info, line number, form data, return values, custom data maps.

### Default Configuration

Out-of-the-box settings:
- Minimum level: `:info`
- Handler: Console output to `*out*` or browser console
- Automatic interop with SLF4J, tools.logging when present

### Filtering Philosophy

Two-stage filtering:
1. **Call-time** (compile + runtime): Determines if signal is created
2. **Handler-time** (runtime): Determines which handlers process signal

Effective filtering reduces noise and improves performance.

## API Reference

### Signal