Class: Timber::Logger

Inherits:
Logger
  • Object
show all
Includes:
ActiveSupport::LoggerThreadSafeLevel, LoggerSilence
Defined in:
lib/timber/logger.rb

Overview

The Timber Logger behaves exactly like ‘::Logger`, except that it supports a transparent API for logging structured messages. It ensures your log messages are communicated properly with the Timber.io API.

To adhere to our no code debt / no lock-in promise, the Timber Logger will never deviate from the ‘::Logger` interface. That is, it will never add methods, or alter any method signatures. This ensures Timber can be removed without consequence.

Examples:

Basic example (the original ::Logger interface remains untouched):

logger.info "Payment rejected for customer #{customer_id}"

Using a Hash

# The :message key is required, the other additional key is your event type and data
# :type is the namespace used in timber for the :data
logger.info "Payment rejected", payment_rejected: {customer_id: customer_id, amount: 100}

Using a Struct (a simple, more structured way, to define events)

PaymentRejectedEvent = Struct.new(:customer_id, :amount, :reason) do
  # `#message` and `#type` are required, otherwise they will not be logged properly.
  # `#type` is the namespace used in timber for the struct data
  def message; "Payment rejected for #{customer_id}"; end
  def type; :payment_rejected; end
end
Logger.info PaymentRejectedEvent.new("abcd1234", 100, "Card expired")

Using typed Event classes

# Event implementation is left to you. Events should be simple classes.
# The only requirement is that it responds to #to_timber_event and return the
# appropriate Timber::Events::* type.
class Event
  def to_hash
    hash = {}
    instance_variables.each { |var| hash[var.to_s.delete("@")] = instance_variable_get(var) }
    hash
  end
  alias to_h to_hash

  def to_timber_event
    Timber::Events::Custom.new(type: type, message: message, data: to_hash)
  end

  def message; raise NotImplementedError.new; end
  def type; raise NotImplementedError.new; end
end

class PaymentRejectedEvent < Event
  attr_accessor :customer_id, :amount
  def initialize(customer_id, amount)
    @customer_id = customer_id
    @amount = amount
  end
  def message; "Payment rejected for customer #{customer_id}"; end
  def type; :payment_rejected_event; end
end

Logger.info PymentRejectedEvent.new("abcd1234", 100)

Defined Under Namespace

Classes: AugmentedFormatter, JSONFormatter, MessageOnlyFormatter, PassThroughFormatter

Instance Method Summary collapse

Constructor Details

#initialize(*io_devices) ⇒ Logger

Creates a new Timber::Logger instance where the passed argument is an IO device. That is, anything that responds to ‘#write` and `#close`.

Note, this method does not accept the same arguments as the standard Ruby ‘::Logger`. The Ruby `::Logger` accepts additional options controlling file rotation if the first argument is a file name. This is a design flaw that Timber does not assume. Logging to a file, or multiple IO devices is demonstrated in the examples below.

Examples:

Logging to STDOUT

logger = Timber::Logger.new(STDOUT)

Logging to the Timber HTTP device

http_device = Timber::LogDevices::HTTP.new("my-timber-api-key")
logger = Timber::Logger.new(http_device)

Logging to a file (with rotation)

file_device = Logger::LogDevice.new("path/to/file.log")
logger = Timber::Logger.new(file_device)

Logging to a file and the Timber HTTP device (multiple log devices)

http_device = Timber::LogDevices::HTTP.new("my-timber-api-key")
file_device = Logger::LogDevice.new("path/to/file.log")
logger = Timber::Logger.new(http_device, file_device)


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# File 'lib/timber/logger.rb', line 211

def initialize(*io_devices)
  io_device = \
    if io_devices.size == 0
      raise ArgumentError.new("At least one IO device must be provided when instantiating " +
        "a Timber::Logger. Ex: Timber::Logger.new(STDOUT).")
    elsif io_devices.size > 1
      LogDevices::Multi.new(io_devices)
    else
      io_devices.first
    end

  super(io_device)

  # Ensure we sync STDOUT to avoid buffering
  if io_device.respond_to?(:"sync=")
    io_device.sync = true
  end

  # Set the default formatter. The formatter cannot be set during
  # initialization, and can be changed with #formatter=.
  if io_device.is_a?(LogDevices::HTTP)
    self.formatter = PassThroughFormatter.new
  elsif Config.instance.development? || Config.instance.test?
    self.formatter = MessageOnlyFormatter.new
  else
    self.formatter = AugmentedFormatter.new
  end

  self.level = environment_level

  after_initialize if respond_to?(:after_initialize)

  Timber::Config.instance.debug { "Timber::Logger instantiated, level: #{level}, formatter: #{formatter.class}" }

  @initialized = true
end

Instance Method Details

#add(severity, message = nil, progname = nil, &block) ⇒ Object

Patch to ensure that the #level method is used instead of ‘@level`. This is required because of Rails’ monkey patching on Logger via ‘::LoggerSilence`.



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# File 'lib/timber/logger.rb', line 276

def add(severity, message = nil, progname = nil, &block)
  return true if @logdev.nil? || (severity || UNKNOWN) < level
  super
end

#formatter=(value) ⇒ Object

Note:

The formatter cannot be changed if you are using the HTTP logger backend.

Sets a new formatted on the logger.



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# File 'lib/timber/logger.rb', line 251

def formatter=(value)
  if @initialized && @logdev && @logdev.dev.is_a?(Timber::LogDevices::HTTP) && !value.is_a?(PassThroughFormatter)
    raise ArgumentError.new("The formatter cannot be changed when using the " +
      "Timber::LogDevices::HTTP log device. The PassThroughFormatter must be used for proper " +
      "delivery.")
  end

  super
end

#level=(value) ⇒ Object 



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# File 'lib/timber/logger.rb', line 261

def level=(value)
  if value.is_a?(Symbol)
    value = level_from_symbol(value)
  end
  super
end

#with_context(context, &block) ⇒ Object

Convenience method for adding context. Please see Timber::Logger.{Timber{Timber::CurrentContext{Timber::CurrentContext.with} for a more detailed description and examples.



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# File 'lib/timber/logger.rb', line 270

def with_context(context, &block)
  Timber::CurrentContext.with(context, &block)
end