Module: GovukJsonLogging

Defined in:
lib/govuk_app_config/govuk_json_logging.rb

Defined Under Namespace

Classes: Configuration

Class Method Summary collapse

Class Method Details

.configure(&block) ⇒ Object 



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# File 'lib/govuk_app_config/govuk_json_logging.rb', line 18

def self.configure(&block)
  configuration = Configuration.new

  configuration.instance_eval(&block) if block_given?

  # We disable buffering, so that logs aren't lost on crash or delayed
  # indefinitely while troubleshooting.
  $stdout.sync = true

  Rails.logger = ActiveSupport::Logger.new($stdout, level: Rails.logger.level)
  Rails.logger.formatter = proc { |severity, datetime, _progname, msg|
    hash = {
      "@timestamp": datetime.utc.iso8601(3),
      message: msg,
      level: severity,
      tags: %w[rails],
    }

    if defined?(GdsApi::GovukHeaders) && !GdsApi::GovukHeaders.headers[:govuk_request_id].nil?
      hash[:govuk_request_id] = GdsApi::GovukHeaders.headers[:govuk_request_id]
    end

    "#{hash.to_json}\n"
  }

  LogStasher.add_custom_fields do |fields|
    # Mirrors Nginx request logging, e.g. GET /path/here HTTP/1.1
    fields[:request] = "#{request.request_method} #{request.fullpath} #{request.headers['SERVER_PROTOCOL']}"

    fields[:govuk_request_id] = request.headers["GOVUK-Request-Id"]
    fields[:varnish_id] = request.headers["X-Varnish"]
    fields[:govuk_app_config] = GovukAppConfig::VERSION

    instance_exec(fields, &configuration.custom_fields_block) if block_given?
  end

  Rails.application.config.logstasher.enabled = true

  # Log controller actions so that we can graph response times.
  Rails.application.config.logstasher.controller_enabled = true

  # The other loggers are not that interesting in production.
  Rails.application.config.logstasher.mailer_enabled = false
  Rails.application.config.logstasher.record_enabled = false
  Rails.application.config.logstasher.view_enabled = false
  Rails.application.config.logstasher.job_enabled = false

  # Elasticsearch index expect source to be an object and logstash defaults
  # source to be the host IP address causing logs to be dropped.
  Rails.application.config.logstasher.source = {}
  # Elasticsearch index expect error to be an object and logstash defaults
  # error to be a string causing logs to be dropped.
  Rails.application.config.logstasher.field_renaming = {
    error: :error_message,
  }

  Rails.application.config.logstasher.logger = Logger.new(
    $stdout,
    level: Rails.logger.level,
    formatter: proc { |_severity, _datetime, _progname, msg|
      "#{msg.is_a?(String) ? msg : msg.inspect}\n"
    },
  )
  Rails.application.config.logstasher.suppress_app_log = true

  if defined?(GdsApi::Base)
    GdsApi::Base.default_options ||= {}

    # The gds-api-adapters gem logs JSON to describe the requests it makes and
    # the responses it gets, so direct this to the logstasher logger.
    GdsApi::Base.default_options[:logger] = Rails.application.config.logstasher.logger
  end
end