class Mmtrix::Agent::Configuration::YamlSource

Attributes

failures[RW]
file_path[RW]

Public Class Methods

new(path, env) click to toggle source
# File lib/mmtrix/agent/configuration/yaml_source.rb, line 13
def initialize(path, env)
  config    = {}
  @failures = []

  begin
    @file_path = validate_config_file_path(path)
    return unless @file_path

    ::Mmtrix::Agent.logger.info("Reading configuration from #{path} (#{Dir.pwd})")
    raw_file = File.read(@file_path)
    erb_file = process_erb(raw_file)
    config   = process_yaml(erb_file, env, config, @file_path)
  rescue ScriptError, StandardError => e
    log_failure("Failed to read or parse configuration file at #{path}", e)
  end

  substitute_transaction_threshold(config)
  booleanify_values(config, 'agent_enabled', 'enabled')

  super(config, true)
end

Public Instance Methods

failed?() click to toggle source
# File lib/mmtrix/agent/configuration/yaml_source.rb, line 35
def failed?
  !@failures.empty?
end

Protected Instance Methods

booleanify_values(config, *keys) click to toggle source
# File lib/mmtrix/agent/configuration/yaml_source.rb, line 133
def booleanify_values(config, *keys)
  # auto means defer ro default
  keys.each do |option|
    if config[option] == 'auto'
      config.delete(option)
    elsif !config[option].nil? && !is_boolean?(config[option])
      config[option] = !!(config[option] =~ /yes|on|true/i)
    end
  end
end
is_boolean?(value) click to toggle source
# File lib/mmtrix/agent/configuration/yaml_source.rb, line 144
def is_boolean?(value)
  value == !!value
end
log_failure(*messages) click to toggle source
# File lib/mmtrix/agent/configuration/yaml_source.rb, line 148
def log_failure(*messages)
  ::Mmtrix::Agent.logger.error(*messages)
  @failures << messages
end
process_erb(file) click to toggle source
# File lib/mmtrix/agent/configuration/yaml_source.rb, line 78
def process_erb(file)
  begin
    # Exclude lines that are commented out so failing Ruby code in an
    # ERB template commented at the YML level is fine. Leave the line,
    # though, so ERB line numbers remain correct.
    file.gsub!(/^\s*#.*$/, '#')

    # Next two are for populating the mmtrix.yml via erb binding, necessary
    # when using the default mmtrix.yml file
    generated_for_user = ''
    license_key = ''

    ERB.new(file).result(binding)
  rescue ScriptError, StandardError => e
    log_failure("Failed ERB processing configuration file. This is typically caused by a Ruby error in <% %> templating blocks in your mmtrix.yml file.", e)
    nil
  ensure
    # Avoid warnings by using these again
    generated_for_user = nil
    license_key = nil
  end
end
process_yaml(file, env, config, path) click to toggle source
# File lib/mmtrix/agent/configuration/yaml_source.rb, line 101
def process_yaml(file, env, config, path)
  if file
    confighash = with_yaml_engine { YAML.load(file) }
    unless confighash.key?(env)
      log_failure("Config file at #{path} doesn't include a '#{env}' section!")
    end

    config = confighash[env] || {}
  end

  config
end
substitute_transaction_threshold(config) click to toggle source
# File lib/mmtrix/agent/configuration/yaml_source.rb, line 114
def substitute_transaction_threshold(config)
  if config['transaction_tracer'] &&
      config['transaction_tracer']['transaction_threshold'] =~ /apdex_f/i
    # when value is "apdex_f" remove the config and defer to default
    config['transaction_tracer'].delete('transaction_threshold')
  end
end
validate_config_file_path(path) click to toggle source
# File lib/mmtrix/agent/configuration/yaml_source.rb, line 41
def validate_config_file_path(path)
  expanded_path = File.expand_path(path)

  if path.empty? || !File.exist?(expanded_path)
    warn_missing_config_file(expanded_path)
    return
  end

  expanded_path
end
warn_missing_config_file(path) click to toggle source
# File lib/mmtrix/agent/configuration/yaml_source.rb, line 52
def warn_missing_config_file(path)
  based_on        = 'unknown'
  source          = ::Mmtrix::Agent.config.source(:config_path)
  candidate_paths = [path]

  case source
  when DefaultSource
    based_on = 'defaults'
    candidate_paths = Mmtrix::Agent.config[:config_search_paths].map do |p|
      File.expand_path(p)
    end
  when EnvironmentSource
    based_on = 'environment variable'
  when ManualSource
    based_on = 'API call'
  end

  # This is not a failure, since we do support running without a
  # mmtrix.yml (configured with just ENV). It is, however, uncommon,
  # so warn about it since it's very likely to be unintended.
  Mmtrix::Agent.logger.warn(
    "No configuration file found. Working directory = #{Dir.pwd}",
    "Looked in these locations (based on #{based_on}): #{candidate_paths.join(", ")}"
  )
end
with_yaml_engine() { || ... } click to toggle source
# File lib/mmtrix/agent/configuration/yaml_source.rb, line 122
def with_yaml_engine
  return yield unless Mmtrix::LanguageSupport.needs_syck?

  yamler = ::YAML::ENGINE.yamler
  ::YAML::ENGINE.yamler = 'syck'
  result = yield
  ::YAML::ENGINE.yamler = yamler
  result
end