Logging

Rakiba uses Telemere for structured logging with beautiful ANSI-colored output. Logs are automatically formatted with timestamps, namespaces, and contextual data.

Output

Logs go to both console and file (logs/dev.log):

[INFO]  2024-01-15 10:30:00 app.core server-starting {:port 3000}
[DEBUG] 2024-01-15 10:30:01 app.routes my-handler {:user-id 123}
[WARN]  2024-01-15 10:30:02 app.core - Watch out!
[ERROR] 2024-01-15 10:30:03 app.core - Something broke {:code 500}
[INFO]  2024-01-15 10:30:04 GET /api/users 200 (12ms)

Colors by Level

Log levels are color-coded in the terminal for quick visual scanning:

Level	Color	Use Case
TRACE	White/Gray	Fine-grained debugging
DEBUG	Cyan	Development debugging
INFO	Green	Normal operations
WARN	Yellow	Potential issues
ERROR	Red	Errors that need attention
FATAL	Magenta	Critical failures

HTTP Status Code Colors

HTTP request logs also use color-coded status codes:

Status Range	Color	Meaning
2xx	Green	Success
3xx	Cyan	Redirect
4xx	Yellow	Client error
5xx	Red	Server error

Configuration

Configure logging in your project’s config.edn:

{:logging {:level :info              ; :trace :debug :info :warn :error :fatal
           :file true                ; write to logs/dev.log (default: true)
           :levels {"app.routes" :debug
                    "rakiba.lib" :info}}}

Options explained:

:level - Global minimum log level
:file - Whether to write logs to logs/dev.log
:levels - Per-namespace log level overrides

Environment Variable

Override the log level at startup via environment variable:

LOG_LEVEL=debug bb clj

This is useful for temporarily enabling debug logging without modifying config.edn.

Usage

Use the Telemere API for logging in your application:

(require '[taoensso.telemere :as t])

;; Simple logging
(t/log! :info "Server started")
(t/log! :debug "Processing request" {:user-id 123})
(t/log! :error "Something failed" {:error "timeout"})

;; Structured logging with event IDs
(t/log! {:level :info
         :id ::user-created
         :data {:user-id 123 :email "foo@bar.com"}})

The ::user-created syntax creates a namespaced keyword, making it easy to search and filter logs by event type.

Tailing Logs

Watch logs in real-time with tail:

tail -f logs/dev.log

The file includes ANSI colors, so you’ll see the same beautiful colored output as the console. This is great for monitoring logs in a separate terminal while developing.

Tip: Telemere is included as a core dependency in all Rakiba projects. You don’t need to add it to your deps.edn.

Learn More

Telemere GitHub - Full documentation and advanced features
Configuration - Other config options