Class: ScoutApm::Agent
- Inherits:
-
Object
- Object
- ScoutApm::Agent
- Defined in:
- lib/scout_apm/agent.rb,
lib/scout_apm/agent/logging.rb,
lib/scout_apm/agent/reporting.rb
Overview
The agent gathers performance data from a Ruby application. One Agent instance is created per-Ruby process.
Each Agent object creates a worker thread (unless monitoring is disabled or we’re forking). The worker thread wakes up every Agent#period, merges in-memory metrics w/those saved to disk, saves tshe merged data to disk, and sends it to the Scout server.
Defined Under Namespace
Constant Summary collapse
- @@instance =
see self.instance
nil
Instance Attribute Summary collapse
-
#capacity ⇒ Object
Returns the value of attribute capacity.
-
#config ⇒ Object
Returns the value of attribute config.
-
#ignored_uris ⇒ Object
readonly
Returns the value of attribute ignored_uris.
-
#layaway ⇒ Object
Returns the value of attribute layaway.
-
#log_file ⇒ Object
path to the log file.
-
#logger ⇒ Object
Returns the value of attribute logger.
-
#metric_lookup ⇒ Object
Hash used to lookup metric ids based on their name and scope.
-
#options ⇒ Object
options passed to the agent when
#start
is called. -
#process_start_time ⇒ Object
readonly
used when creating slow transactions to report how far from startup the transaction was recorded.
-
#request_histograms ⇒ Object
readonly
Histogram of the cumulative requests since the start of the process.
-
#request_histograms_by_time ⇒ Object
readonly
Histogram of the requests, distinct by reporting period (minute) { StoreReportingPeriodTimestamp => RequestHistograms }.
-
#slow_job_policy ⇒ Object
readonly
Returns the value of attribute slow_job_policy.
-
#slow_request_policy ⇒ Object
readonly
Returns the value of attribute slow_request_policy.
-
#store ⇒ Object
Accessors below are for associated classes.
Class Method Summary collapse
-
.instance(options = {}) ⇒ Object
All access to the agent is thru this class method to ensure multiple Agent instances are not initialized per-Ruby process.
Instance Method Summary collapse
- #apm_enabled? ⇒ Boolean
-
#app_server_load_hook ⇒ Object
Sends a ping to APM right away, smoothes out onboarding Collects up any relevant info (framework, app server, system time, ruby version, etc).
- #app_server_missing?(options = {}) ⇒ Boolean
- #background_job_missing?(options = {}) ⇒ Boolean
- #background_worker_running? ⇒ Boolean
- #clean_old_percentiles ⇒ Object
- #deploy_integration ⇒ Object
- #environment ⇒ Object
- #exit_handler_supported? ⇒ Boolean
-
#force? ⇒ Boolean
If true, the agent will start regardless of safety checks.
-
#initialize(options = {}) ⇒ Agent
constructor
Note - this doesn’t start instruments or the worker thread.
-
#install_exit_handler ⇒ Object
at_exit, calls Agent#shutdown to wrapup metric reporting.
- #install_instrument(instrument_klass) ⇒ Object
-
#load_instruments ⇒ Object
Loads the instrumention logic.
- #preconditions_met?(options = {}) ⇒ Boolean
-
#should_load_instruments?(options = {}) ⇒ Boolean
If we want to skip the app_server_check, then we must load it.
-
#shutdown ⇒ Object
Called via an at_exit handler, it: (1) Stops the background worker (2) Stores metrics locally (forcing current-minute metrics to be written) It does not attempt to actually report metrics.
-
#start(options = {}) ⇒ Object
This is called via
ScoutApm::Agent.instance.start
when ScoutApm is required in a Ruby application. -
#start_background_worker ⇒ Object
Creates the worker thread.
-
#start_background_worker? ⇒ Boolean
The worker thread will automatically start UNLESS: * A supported application server isn’t detected (example: running via Rails console) * A supported application server is detected, but it forks.
- #started? ⇒ Boolean
Methods included from Reporting
#add_metric_ids, #deliver_period, #headers, #log_deliver, #process_metrics, #report_to_server, #reporter
Methods included from Logging
#apply_log_format, #default_log_path, #determine_log_destination, #init_logger, #log_file_path, #log_level, #wants_stderr?, #wants_stdout?
Constructor Details
#initialize(options = {}) ⇒ Agent
Note - this doesn’t start instruments or the worker thread. This is handled via #start
as we don’t want to start the worker thread or install instrumentation if (1) disabled for this environment (2) a worker thread shouldn’t be started (when forking).
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# File 'lib/scout_apm/agent.rb', line 40 def initialize( = {}) @started = false @process_start_time = Time.now @options ||= # Start up without attempting to load a configuration file. We need to be # able to lookup configuration options like "application_root" which would # then in turn influence where the configuration file came from. # # Later in initialization, we reset @config to include the file. @config = ScoutApm::Config.without_file @slow_request_policy = ScoutApm::SlowRequestPolicy.new @slow_job_policy = ScoutApm::SlowJobPolicy.new @request_histograms = ScoutApm::RequestHistograms.new @request_histograms_by_time = Hash.new { |h, k| h[k] = ScoutApm::RequestHistograms.new } @store = ScoutApm::Store.new @layaway = ScoutApm::Layaway.new(config, environment) @metric_lookup = Hash.new @capacity = ScoutApm::Capacity.new @installed_instruments = [] end |
Instance Attribute Details
#capacity ⇒ Object
Returns the value of attribute capacity.
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# File 'lib/scout_apm/agent.rb', line 15 def capacity @capacity end |
#config ⇒ Object
Returns the value of attribute config.
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# File 'lib/scout_apm/agent.rb', line 14 def config @config end |
#ignored_uris ⇒ Object (readonly)
Returns the value of attribute ignored_uris.
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# File 'lib/scout_apm/agent.rb', line 23 def ignored_uris @ignored_uris end |
#layaway ⇒ Object
Returns the value of attribute layaway.
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# File 'lib/scout_apm/agent.rb', line 13 def layaway @layaway end |
#log_file ⇒ Object
path to the log file
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# File 'lib/scout_apm/agent.rb', line 17 def log_file @log_file end |
#logger ⇒ Object
Returns the value of attribute logger.
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# File 'lib/scout_apm/agent.rb', line 16 def logger @logger end |
#metric_lookup ⇒ Object
Hash used to lookup metric ids based on their name and scope
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# File 'lib/scout_apm/agent.rb', line 19 def metric_lookup @metric_lookup end |
#options ⇒ Object
options passed to the agent when #start
is called.
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# File 'lib/scout_apm/agent.rb', line 18 def @options end |
#process_start_time ⇒ Object (readonly)
used when creating slow transactions to report how far from startup the transaction was recorded.
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# File 'lib/scout_apm/agent.rb', line 22 def process_start_time @process_start_time end |
#request_histograms ⇒ Object (readonly)
Histogram of the cumulative requests since the start of the process
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# File 'lib/scout_apm/agent.rb', line 26 def request_histograms @request_histograms end |
#request_histograms_by_time ⇒ Object (readonly)
Histogram of the requests, distinct by reporting period (minute) { StoreReportingPeriodTimestamp => RequestHistograms }
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# File 'lib/scout_apm/agent.rb', line 30 def request_histograms_by_time @request_histograms_by_time end |
#slow_job_policy ⇒ Object (readonly)
Returns the value of attribute slow_job_policy.
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# File 'lib/scout_apm/agent.rb', line 21 def slow_job_policy @slow_job_policy end |
#slow_request_policy ⇒ Object (readonly)
Returns the value of attribute slow_request_policy.
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# File 'lib/scout_apm/agent.rb', line 20 def slow_request_policy @slow_request_policy end |
#store ⇒ Object
Accessors below are for associated classes
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# File 'lib/scout_apm/agent.rb', line 12 def store @store end |
Class Method Details
.instance(options = {}) ⇒ Object
All access to the agent is thru this class method to ensure multiple Agent instances are not initialized per-Ruby process.
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# File 'lib/scout_apm/agent.rb', line 33 def self.instance( = {}) @@instance ||= self.new() end |
Instance Method Details
#apm_enabled? ⇒ Boolean
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# File 'lib/scout_apm/agent.rb', line 69 def apm_enabled? config.value('monitor') end |
#app_server_load_hook ⇒ Object
Sends a ping to APM right away, smoothes out onboarding Collects up any relevant info (framework, app server, system time, ruby version, etc)
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# File 'lib/scout_apm/agent.rb', line 162 def app_server_load_hook AppServerLoad.new.run end |
#app_server_missing?(options = {}) ⇒ Boolean
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# File 'lib/scout_apm/agent.rb', line 331 def app_server_missing?( = {}) !environment.app_server_integration(true).found? && ![:skip_app_server_check] end |
#background_job_missing?(options = {}) ⇒ Boolean
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# File 'lib/scout_apm/agent.rb', line 335 def background_job_missing?( = {}) environment.background_job_integration.nil? && ![:skip_background_job_check] end |
#background_worker_running? ⇒ Boolean
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# File 'lib/scout_apm/agent.rb', line 238 def background_worker_running? !! @background_worker_thread end |
#clean_old_percentiles ⇒ Object
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# File 'lib/scout_apm/agent.rb', line 263 def clean_old_percentiles request_histograms_by_time. keys. select {|| .age_in_seconds > 60 * 10 }. each {|| request_histograms_by_time.delete() } end |
#deploy_integration ⇒ Object
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# File 'lib/scout_apm/agent.rb', line 327 def deploy_integration environment.deploy_integration end |
#environment ⇒ Object
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# File 'lib/scout_apm/agent.rb', line 65 def environment ScoutApm::Environment.instance end |
#exit_handler_supported? ⇒ Boolean
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# File 'lib/scout_apm/agent.rb', line 166 def exit_handler_supported? if environment.sinatra? logger.debug "Exit handler not supported for Sinatra" false elsif environment.jruby? logger.debug "Exit handler not supported for JRuby" false elsif environment.rubinius? logger.debug "Exit handler not supported for Rubinius" false else true end end |
#force? ⇒ Boolean
If true, the agent will start regardless of safety checks. Currently just used for testing.
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# File 'lib/scout_apm/agent.rb', line 74 def force? @options[:force] end |
#install_exit_handler ⇒ Object
at_exit, calls Agent#shutdown to wrapup metric reporting.
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# File 'lib/scout_apm/agent.rb', line 182 def install_exit_handler logger.debug "Shutdown handler not supported" and return unless exit_handler_supported? logger.debug "Installing Shutdown Handler" at_exit do logger.info "Shutting down Scout Agent" # MRI 1.9 bug drops exit codes. # http://bugs.ruby-lang.org/issues/5218 if environment.ruby_19? status = $!.status if $!.is_a?(SystemExit) shutdown exit status if status else shutdown end end end |
#install_instrument(instrument_klass) ⇒ Object
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# File 'lib/scout_apm/agent.rb', line 311 def install_instrument(instrument_klass) # Don't attempt to install the same instrument twice return if @installed_instruments.any? { |already_installed_instrument| instrument_klass === already_installed_instrument } # Allow users to skip individual instruments via the config file instrument_short_name = instrument_klass.name.split("::").last if (config.value("disabled_instruments") || []).include?(instrument_short_name) logger.info "Skipping Disabled Instrument: #{instrument_short_name} - To re-enable, change `disabled_instruments` key in scout_apm.yml" return end instance = instrument_klass.new @installed_instruments << instance instance.install end |
#load_instruments ⇒ Object
Loads the instrumention logic.
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# File 'lib/scout_apm/agent.rb', line 279 def load_instruments if !background_job_missing? case environment.background_job_name when :delayed_job install_instrument(ScoutApm::Instruments::DelayedJob) end else case environment.framework when :rails then install_instrument(ScoutApm::Instruments::ActionControllerRails2) when :rails3_or_4 then install_instrument(ScoutApm::Instruments::ActionControllerRails3Rails4) install_instrument(ScoutApm::Instruments::MiddlewareSummary) install_instrument(ScoutApm::Instruments::RailsRouter) # when :sinatra then install_instrument(ScoutApm::Instruments::Sinatra) end end install_instrument(ScoutApm::Instruments::ActiveRecord) install_instrument(ScoutApm::Instruments::Moped) install_instrument(ScoutApm::Instruments::Mongoid) install_instrument(ScoutApm::Instruments::NetHttp) install_instrument(ScoutApm::Instruments::HttpClient) install_instrument(ScoutApm::Instruments::Redis) install_instrument(ScoutApm::Instruments::InfluxDB) install_instrument(ScoutApm::Instruments::Elasticsearch) install_instrument(ScoutApm::Instruments::Grape) rescue logger.warn "Exception loading instruments:" logger.warn $!. logger.warn $!.backtrace end |
#preconditions_met?(options = {}) ⇒ Boolean
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# File 'lib/scout_apm/agent.rb', line 78 def preconditions_met?(={}) if !apm_enabled? logger.warn "Monitoring isn't enabled for the [#{environment.env}] environment. #{force? ? 'Forcing agent to start' : 'Not starting agent'}" return false unless force? end if !environment.application_name logger.warn "An application name could not be determined. Specify the :name value in scout_apm.yml. #{force? ? 'Forcing agent to start' : 'Not starting agent'}." return false unless force? end if app_server_missing?() && background_job_missing? if force? logger.warn "Agent starting (forced)" else logger.warn "Deferring agent start. Standing by for first request" end return false unless force? end if started? logger.warn "Already started agent." return false end if defined?(::ScoutRails) logger.warn "ScoutAPM is incompatible with the old Scout Rails plugin. Please remove scout_rails from your Gemfile" return false unless force? end true end |
#should_load_instruments?(options = {}) ⇒ Boolean
If we want to skip the app_server_check, then we must load it.
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# File 'lib/scout_apm/agent.rb', line 271 def should_load_instruments?(={}) return true if [:skip_app_server_check] return true if config.value('dev_trace') return false if !apm_enabled? environment.app_server_integration.found? || !background_job_missing? end |
#shutdown ⇒ Object
Called via an at_exit handler, it: (1) Stops the background worker (2) Stores metrics locally (forcing current-minute metrics to be written) It does not attempt to actually report metrics.
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# File 'lib/scout_apm/agent.rb', line 204 def shutdown logger.info "Shutting down ScoutApm" return if !started? return if @shutdown @shutdown = true if @background_worker logger.info("Stopping background worker") @background_worker.stop store.write_to_layaway(layaway, :force) if @background_worker_thread.alive? @background_worker_thread.wakeup @background_worker_thread.join end end end |
#start(options = {}) ⇒ Object
This is called via ScoutApm::Agent.instance.start
when ScoutApm is required in a Ruby application. It initializes the agent and starts the worker thread (if appropiate).
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# File 'lib/scout_apm/agent.rb', line 113 def start( = {}) @options.merge!() @config = ScoutApm::Config.with_file(@config.value("config_file")) layaway.config = config init_logger logger.info "Attempting to start Scout Agent [#{ScoutApm::VERSION}] on [#{environment.hostname}]" @ignored_uris = ScoutApm::IgnoredUris.new(config.value('ignore')) if environment.deploy_integration logger.info "Starting monitoring for [#{environment.deploy_integration.name}]]." return environment.deploy_integration.install end load_instruments if should_load_instruments?() return false unless preconditions_met?() @started = true logger.info "Starting monitoring for [#{environment.application_name}]. Framework [#{environment.framework}] App Server [#{environment.app_server}] Background Job Framework [#{environment.background_job_name}]." [ ScoutApm::Instruments::Process::ProcessCpu.new(environment.processors, logger), ScoutApm::Instruments::Process::ProcessMemory.new(logger), ScoutApm::Instruments::PercentileSampler.new(logger, 95), ].each { |s| store.add_sampler(s) } app_server_load_hook if environment.background_job_integration environment.background_job_integration.install logger.info "Installed Background Job Integration [#{environment.background_job_name}]" end # start_background_worker? is true on non-forking servers, and directly # starts the background worker. On forking servers, a server-specific # hook is inserted to start the background worker after forking. if start_background_worker? start_background_worker logger.info "Scout Agent [#{ScoutApm::VERSION}] Initialized" else environment.app_server_integration.install logger.info "Scout Agent [#{ScoutApm::VERSION}] loaded in [#{environment.app_server}] master process. Monitoring will start after server forks its workers." end end |
#start_background_worker ⇒ Object
Creates the worker thread. The worker thread is a loop that runs continuously. It sleeps for Agent#period and when it wakes, processes data, either saving it to disk or reporting to Scout.
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# File 'lib/scout_apm/agent.rb', line 244 def start_background_worker if !apm_enabled? logger.debug "Not starting background worker as monitoring isn't enabled." return false end logger.info "Not starting background worker, already started" and return if background_worker_running? logger.info "Initializing worker thread." install_exit_handler @background_worker = ScoutApm::BackgroundWorker.new @background_worker_thread = Thread.new do @background_worker.start { ScoutApm::Agent.instance.process_metrics clean_old_percentiles } end end |
#start_background_worker? ⇒ Boolean
The worker thread will automatically start UNLESS:
-
A supported application server isn’t detected (example: running via Rails console)
-
A supported application server is detected, but it forks. In this case, the agent is started in the forked process.
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# File 'lib/scout_apm/agent.rb', line 231 def start_background_worker? return true if environment.app_server == :thin return true if environment.app_server == :webrick return true if force? return !environment.forking? end |
#started? ⇒ Boolean
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# File 'lib/scout_apm/agent.rb', line 223 def started? @started end |