Lumberjack DataDog

This gem provides a logging setup for using the lumberjack gem with DataDog. It sets up JSON logging and maps values to DataDog’s standard attributes.

Features

• DataDog Standard Attribute Mapping: Automatically maps Lumberjack log fields to DataDog’s standard attributes:
  • time → timestamp
  • severity → status
  • progname → logger.name
  • pid → pid
• Exception Handling: Structured exception logging with kind, message, and stack fields
• Duration Logging: Automatic conversion of duration values to nanoseconds for DataDog
• Configurable Message Truncation: Limit message length to prevent oversized logs
• Thread Information: Optional thread name logging
• Tag Remapping: Flexible tag transformation and remapping
• Pretty JSON: Optional pretty-printed JSON output for development

Usage

Basic Setup

```ruby require ‘lumberjack_data_dog’

Create a logger that outputs to STDOUT

logger = Lumberjack::DataDog.setup

Log messages

logger.info(“Application started”) logger.warn(“This is a warning”, user_id: 123) logger.error(“Something went wrong”, request_id: “abc-123”) ```

Advanced Configuration

```ruby logger = Lumberjack::DataDog.setup do |config| # Truncate messages longer than 1000 characters config.max_message_length = 1000

# Include thread information config.thread_name = true # or :global for global thread ID

# Disable PID logging config.pid = false

# Remap custom tags to DataDog attributes config.remap_tags( user_id: “usr.id”, request_id: “http.request_id” )

# Enable pretty JSON for development config.pretty = true end ```

Logging to a File

ruby # Log to a file instead of STDOUT File.open("/var/log/app.log", "a") do |file| logger = Lumberjack::DataDog.setup(file) logger.info("Logged to file") end

Exception Logging

Exceptions are automatically structured with DataDog’s error attributes:

ruby begin raise StandardError, "Something went wrong" rescue => e # Results in structured error with error.kind, error.message, and error.stack fields logger.error(e) end

Duration Logging

Duration values are automatically converted to nanoseconds:

```ruby # Log execution time start_time = Time.now # … do some work … duration = Time.now - start_time

logger.info(“Operation completed”, duration: duration) # duration is automatically converted to nanoseconds

You can also use specific duration units

logger.info(“DB query”, duration_ms: 150.5) # milliseconds logger.info(“API call”, duration_micros: 1500) # microseconds logger.info(“Function”, duration_ns: 1500000) # nanoseconds ```

Custom Tag Transformation

```ruby logger = Lumberjack::DataDog.setup do |config| config.remap_tags( # Simple remapping correlation_id: “trace.correlation_id”,

# Transform with a lambda
user_email: ->(email) { {"usr.email" => email.downcase} }   ) end

logger.info(“User logged in”, user_email: “USER@EXAMPLE.COM”) # Results in usr.email: “user@example.com” ```

Installation

Add this line to your application’s Gemfile:

ruby gem "lumberjack_data_dog"

And then execute: bash $ bundle install

Or install it yourself as: bash $ gem install lumberjack_data_dog

Contributing

Open a pull request on GitHub.

Please use the standardrb syntax and lint your code with standardrb --fix before submitting.

License

The gem is available as open source under the terms of the MIT License.