Ruby:
Logging
How to:
Ruby comes with a built-in module for logging, Logger, that’s super easy to use. Here’s a quick example to get you started:
require 'logger'
# Create a Logger that outputs to STDOUT
logger = Logger.new(STDOUT)
logger.level = Logger::INFO
# Example log messages
logger.info("This is an info message")
logger.warn("This is a warning message")
logger.error("This is an error message")Running the above script will output something like this:
I, [2023-03-15T10:00:00.123456 #1234] INFO -- : This is an info message
W, [2023-03-15T10:00:01.234567 #1234] WARN -- : This is a warning message
E, [2023-03-15T10:00:02.345678 #1234] ERROR -- : This is an error messageYou can configure the log format and level to filter out unnecessary noise, and you can direct logs to different outputs, like a file or even an external logging service.
Deep Dive
Logging is like an age-old tradition in programming. Historically, logs were simple text files, manually parsed with tools like grep. But the concept spiraled into an entire ecosystem of robust logging frameworks and services like Log4j, Syslog on Linux, or Sematext and Loggly in the cloud era.
Ruby’s Logger is a no-frills way to get started, but if you need more horsepower and flexibility, you might check out alternatives like Lograge or Semantic Logger. These libraries play well with Ruby applications, offering more granular control over log formatting, including structured logs (JSON format), better performance, and seamless integration with other services.
Each Ruby logging library has its own way of doing things, but under the hood, they all revolve around the idea of a logger instance that you send messages to. The logger handles these messages based on set levels—DEBUG, INFO, WARN, ERROR, FATAL, and UNKNOWN—and decides what to do with them: print them out, save them to a file, send them over the network, etc.
See Also
For a deep dive into Ruby’s built-in logging module, check out the official docs:
If you’re interested in more advanced logging or want to explore third-party gems:
For general logging practices and philosophy (not Ruby-specific), these articles are timeless reads: