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Active Support Error Reporter

ActiveSupport::ErrorReporter is a common interface for error reporting services.

To rescue and report any unhandled error, you can use the handle method:

Rails.error.handle do
  do_something!
end

If an error is raised, it will be reported and swallowed.

Alternatively, if you want to report the error but not swallow it, you can use record:

Rails.error.record do
  do_something!
end

Both methods can be restricted to handle only a specific error class:

maybe_tags = Rails.error.handle(Redis::BaseError) { redis.get("tags") }
Namespace
Methods
D
H
N
R
S
U

Constants

DEFAULT_SOURCE = "application"
 
SEVERITIES = %i(error warning info)
 

Attributes

[RW] logger

Class Public methods

new(*subscribers, logger: nil)

Source: show | on GitHub 

# File activesupport/lib/active_support/error_reporter.rb, line 32
def initialize(*subscribers, logger: nil)
  @subscribers = subscribers.flatten
  @logger = logger
end

Instance Public methods

disable(subscriber)

Prevent a subscriber from being notified of errors for the duration of the block. You may pass in the subscriber itself, or its class.

This can be helpful for error reporting service integrations, when they wish to handle any errors higher in the stack.

Source: show | on GitHub 

# File activesupport/lib/active_support/error_reporter.rb, line 147
def disable(subscriber)
  disabled_subscribers = (ActiveSupport::IsolatedExecutionState[self] ||= [])
  disabled_subscribers << subscriber
  begin
    yield
  ensure
    disabled_subscribers.delete(subscriber)
  end
end

handle(*error_classes, severity: :warning, context: {}, fallback: nil, source: DEFAULT_SOURCE)

Evaluates the given block, reporting and swallowing any unhandled error. If no error is raised, returns the return value of the block. Otherwise, returns the result of fallback.call, or nil if fallback is not specified.

# Will report a TypeError to all subscribers and return nil.
Rails.error.handle do
  1 + '1'
end

Can be restricted to handle only specific error classes:

maybe_tags = Rails.error.handle(Redis::BaseError) { redis.get("tags") }

Options

  • :severity - This value is passed along to subscribers to indicate how important the error report is. Can be :error, :warning, or :info. Defaults to :warning.

  • :context - Extra information that is passed along to subscribers. For example:

    Rails.error.handle(context: { section: "admin" }) do
  # ...
end

  • :fallback - A callable that provides handle‘s return value when an unhandled error is raised. For example:

    user = Rails.error.handle(fallback: -> { User.anonymous }) do
  User.find_by(params)
end

  • :source - This value is passed along to subscribers to indicate the source of the error. Subscribers can use this value to ignore certain errors. Defaults to "application".

Source: show | on GitHub 

# File activesupport/lib/active_support/error_reporter.rb, line 74
def handle(*error_classes, severity: :warning, context: {}, fallback: nil, source: DEFAULT_SOURCE)
  error_classes = [StandardError] if error_classes.blank?
  yield
rescue *error_classes => error
  report(error, handled: true, severity: severity, context: context, source: source)
  fallback.call if fallback
end

record(*error_classes, severity: :error, context: {}, source: DEFAULT_SOURCE)

Evaluates the given block, reporting and re-raising any unhandled error. If no error is raised, returns the return value of the block.

# Will report a TypeError to all subscribers and re-raise it.
Rails.error.record do
  1 + '1'
end

Can be restricted to handle only specific error classes:

tags = Rails.error.record(Redis::BaseError) { redis.get("tags") }

Options

  • :severity - This value is passed along to subscribers to indicate how important the error report is. Can be :error, :warning, or :info. Defaults to :error.

  • :context - Extra information that is passed along to subscribers. For example:

    Rails.error.record(context: { section: "admin" }) do
  # ...
end

  • :source - This value is passed along to subscribers to indicate the source of the error. Subscribers can use this value to ignore certain errors. Defaults to "application".

Source: show | on GitHub 

# File activesupport/lib/active_support/error_reporter.rb, line 110
def record(*error_classes, severity: :error, context: {}, source: DEFAULT_SOURCE)
  error_classes = [StandardError] if error_classes.blank?
  yield
rescue *error_classes => error
  report(error, handled: false, severity: severity, context: context, source: source)
  raise
end

report(error, handled: true, severity: handled ? :warning : :error, context: {}, source: DEFAULT_SOURCE)

Report an error directly to subscribers. You can use this method when the block-based handle and record methods are not suitable.

Rails.error.report(error)

Source: show | on GitHub 

# File activesupport/lib/active_support/error_reporter.rb, line 172
def report(error, handled: true, severity: handled ? :warning : :error, context: {}, source: DEFAULT_SOURCE)
  return if error.instance_variable_defined?(:@__rails_error_reported)

  unless SEVERITIES.include?(severity)
    raise ArgumentError, "severity must be one of #{SEVERITIES.map(&:inspect).join(", ")}, got: #{severity.inspect}"
  end

  full_context = ActiveSupport::ExecutionContext.to_h.merge(context)
  disabled_subscribers = ActiveSupport::IsolatedExecutionState[self]
  @subscribers.each do |subscriber|
    unless disabled_subscribers&.any? { |s| s === subscriber }
      subscriber.report(error, handled: handled, severity: severity, context: full_context, source: source)
    end
  rescue => subscriber_error
    if logger
      logger.fatal(
        "Error subscriber raised an error: #{subscriber_error.message} (#{subscriber_error.class})\n" +
        subscriber_error.backtrace.join("\n")
      )
    else
      raise
    end
  end

  unless error.frozen?
    error.instance_variable_set(:@__rails_error_reported, true)
  end

  nil
end

set_context(...)

Update the execution context that is accessible to error subscribers. Any context passed to handle, record, or report will be merged with the context set here.

Rails.error.set_context(section: "checkout", user_id: @user.id)

Source: show | on GitHub 

# File activesupport/lib/active_support/error_reporter.rb, line 163
def set_context(...)
  ActiveSupport::ExecutionContext.set(...)
end

subscribe(subscriber)

Register a new error subscriber. The subscriber must respond to

report(Exception, handled: Boolean, severity: (:error OR :warning OR :info), context: Hash, source: String)

The report method should never raise an error.

Source: show | on GitHub 

# File activesupport/lib/active_support/error_reporter.rb, line 123
def subscribe(subscriber)
  unless subscriber.respond_to?(:report)
    raise ArgumentError, "Error subscribers must respond to #report"
  end
  @subscribers << subscriber
end

unsubscribe(subscriber)

Unregister an error subscriber. Accepts either a subscriber or a class.

subscriber = MyErrorSubscriber.new
Rails.error.subscribe(subscriber)

Rails.error.unsubscribe(subscriber)
# or
Rails.error.unsubscribe(MyErrorSubscriber)

Source: show | on GitHub 

# File activesupport/lib/active_support/error_reporter.rb, line 138
def unsubscribe(subscriber)
  @subscribers.delete_if { |s| subscriber === s }
end