Class: ScoutApm::Agent::Preconditions

Inherits:
Object
  • Object
show all
Defined in:
lib/scout_apm/agent/preconditions.rb

Constant Summary collapse

PRECONDITIONS =

The preconditions here must be a 2 element hash, with :message and :check. message: Proc that takes the environment, and returns a string check: Proc that takes an AgentContext and returns true if precondition was met, if false, we shouldn’t start. severity: Severity of the log message (one of: :debug, :info, :warn, :error or :fatal)

[
  PRECONDITION_ENABLED = {
    :message => proc {|environ| "Monitoring isn't enabled for the [#{environ.env}] environment." },
    :check => proc { |context| context.config.value('monitor') },
    :severity => :info,
  },

  PRECONDITION_APP_NAME = {
    :message => proc {|environ| "An application name could not be determined. Specify the :name value in scout_apm.yml." },
    :check => proc { |context| context.environment.application_name },
    :severity => :warn,
  },

  PRECONDITION_INTERACTIVE = {
    :message => proc {|environ| "Agent attempting to load in interactive mode." },
    :check => proc { |context| ! context.environment.interactive? },
    :severity => :info,
  },

  PRECONDITION_DETECTED_SERVER = {
    :message => proc {|environ| "Deferring agent start. Standing by for first request" },
    :check => proc { |context|
      app_server_missing = !context.environment.app_server_integration(true).found?
      background_job_missing = context.environment.background_job_integrations.length == 0

      !app_server_missing && !background_job_missing
    },
    :severity => :info,
  },

  PRECONDITION_ALREADY_STARTED = {
    :message => proc {|environ| "Already started agent." },
    :check => proc { |context| !context.started? },
    :severity => :info,
  },

  PRECONDITION_OLD_SCOUT_RAILS = {
    :message => proc {|environ| "ScoutAPM is incompatible with the old Scout Rails plugin. Please remove scout_rails from your Gemfile" },
    :check => proc { !defined?(::ScoutRails) },
    :severity => :warn,
  },
]

Instance Method Summary collapse

Instance Method Details

#check?(context) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/scout_apm/agent/preconditions.rb', line 51

def check?(context)
  @check_result ||=
    begin
      failed_preconditions = PRECONDITIONS.inject(Array.new) { |errors, condition|
        unless condition[:check].call(context)
          errors << {
            :severity => condition[:severity],
            :message => condition[:message].call(context.environment),
          }
        end

        errors
      }

      if failed_preconditions.any?
        failed_preconditions.each {|error| context.logger.send(error[:severity], error[:message]) }
        force? # if forced, return true anyway
      else
        # No errors, we met preconditions
        true
      end
    end
end

#force? ⇒ Boolean

XXX: Wire up options here and below in the appserver & bg server detections

Returns:

  • (Boolean) 


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# File 'lib/scout_apm/agent/preconditions.rb', line 76

def force?
  false
end