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.
-
#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. -
#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).
- #deploy_integration ⇒ Object
- #environment ⇒ Object
- #exit_handler_unsupported? ⇒ Boolean
-
#handle_exit ⇒ Object
at_exit, calls Agent#shutdown to wrapup metric reporting.
-
#initialize(options = {}) ⇒ Agent
constructor
Note - this doesn’t start instruments or the worker thread.
- #install_instrument(instrument_klass) ⇒ Object
-
#load_instruments ⇒ Object
Loads the instrumention logic.
- #preconditions_met? ⇒ Boolean
- #should_load_instruments? ⇒ Boolean
-
#shutdown ⇒ Object
Called via an at_exit handler, it (1) stops the background worker and (2) runs it a final time.
-
#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, #process_metrics, #reporter, #run_samplers
Methods included from Logging
#apply_log_format, #default_log_path, #init_logger, #log_file_path, #log_level, #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).
29 30 31 32 33 34 35 36 37 38 39 40 |
# File 'lib/scout_apm/agent.rb', line 29 def initialize( = {}) @started = false @options ||= @config = ScoutApm::Config.new([:config_path]) @store = ScoutApm::Store.new @layaway = ScoutApm::Layaway.new @metric_lookup = Hash.new @capacity = ScoutApm::Capacity.new @installed_instruments = [] end |
Instance Attribute Details
#capacity ⇒ Object
Returns the value of attribute capacity.
15 16 17 |
# File 'lib/scout_apm/agent.rb', line 15 def capacity @capacity end |
#config ⇒ Object
Returns the value of attribute config.
14 15 16 |
# File 'lib/scout_apm/agent.rb', line 14 def config @config end |
#layaway ⇒ Object
Returns the value of attribute layaway.
13 14 15 |
# File 'lib/scout_apm/agent.rb', line 13 def layaway @layaway end |
#log_file ⇒ Object
path to the log file
17 18 19 |
# File 'lib/scout_apm/agent.rb', line 17 def log_file @log_file end |
#logger ⇒ Object
Returns the value of attribute logger.
16 17 18 |
# 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
19 20 21 |
# 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.
18 19 20 |
# File 'lib/scout_apm/agent.rb', line 18 def @options end |
#store ⇒ Object
Accessors below are for associated classes
12 13 14 |
# 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.
22 23 24 |
# File 'lib/scout_apm/agent.rb', line 22 def self.instance( = {}) @@instance ||= self.new() end |
Instance Method Details
#apm_enabled? ⇒ Boolean
46 47 48 |
# File 'lib/scout_apm/agent.rb', line 46 def apm_enabled? config.value('monitor') and !@options[:force] 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)
116 117 118 |
# File 'lib/scout_apm/agent.rb', line 116 def app_server_load_hook AppServerLoad.new.run end |
#deploy_integration ⇒ Object
207 208 209 |
# File 'lib/scout_apm/agent.rb', line 207 def deploy_integration environment.deploy_integration end |
#environment ⇒ Object
42 43 44 |
# File 'lib/scout_apm/agent.rb', line 42 def environment ScoutApm::Environment.instance end |
#exit_handler_unsupported? ⇒ Boolean
120 121 122 |
# File 'lib/scout_apm/agent.rb', line 120 def exit_handler_unsupported? environment.sinatra? || environment.jruby? || environment.rubinius? end |
#handle_exit ⇒ Object
at_exit, calls Agent#shutdown to wrapup metric reporting.
125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 |
# File 'lib/scout_apm/agent.rb', line 125 def handle_exit logger.debug "Exit handler not supported" and return if exit_handler_unsupported? 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
201 202 203 204 205 |
# File 'lib/scout_apm/agent.rb', line 201 def install_instrument(instrument_klass) instance = instrument_klass.new @installed_instruments << instance instance.install end |
#load_instruments ⇒ Object
Loads the instrumention logic.
180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 |
# File 'lib/scout_apm/agent.rb', line 180 def load_instruments case environment.framework when :rails then install_instrument(ScoutApm::Instruments::ActionControllerRails2) when :rails3_or_4 then install_instrument(ScoutApm::Instruments::ActionControllerRails3) when :sinatra then install_instrument(ScoutApm::Instruments::Sinatra) end install_instrument(ScoutApm::Instruments::ActiveRecord) install_instrument(ScoutApm::Instruments::Moped) install_instrument(ScoutApm::Instruments::Mongoid) install_instrument(ScoutApm::Instruments::NetHttp) if StackProf.respond_to?(:fake?) && StackProf.fake? logger.info 'StackProf not found - add `gem "stackprof"` to your Gemfile to enable advanced code profiling (only for Ruby 2.1+)' end rescue logger.warn "Exception loading instruments:" logger.warn $!. logger.warn $!.backtrace end |
#preconditions_met? ⇒ Boolean
50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 |
# File 'lib/scout_apm/agent.rb', line 50 def preconditions_met? if !apm_enabled? logger.warn "Monitoring isn't enabled for the [#{environment.env}] environment." return false end if !environment.application_name logger.warn "An application name could not be determined. Specify the :name value in scout_apm.yml. Not starting agent." return false end if !environment.app_server_integration.found? logger.warn "Couldn't find a supported app server. Not starting agent." return false end if started? logger.warn "Already started agent." return false end true end |
#should_load_instruments? ⇒ Boolean
175 176 177 |
# File 'lib/scout_apm/agent.rb', line 175 def should_load_instruments? environment.app_server_integration.found? end |
#shutdown ⇒ Object
Called via an at_exit handler, it (1) stops the background worker and (2) runs it a final time. The final run ensures metrics are stored locally to the layaway / reported to scoutapp.com. Otherwise, in-memory metrics would be lost and a gap would appear on restarts.
145 146 147 148 149 |
# File 'lib/scout_apm/agent.rb', line 145 def shutdown return if !started? @background_worker.stop @background_worker.run_once 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).
76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 |
# File 'lib/scout_apm/agent.rb', line 76 def start( = {}) @options.merge!() init_logger logger.info "Attempting to start Scout Agent [#{ScoutApm::VERSION}] on [#{environment.hostname}]" if environment.deploy_integration logger.info "Starting monitoring for [#{environment.deploy_integration.name}]]." return environment.deploy_integration.install end return false unless preconditions_met? @started = true logger.info "Starting monitoring for [#{environment.application_name}]. Framework [#{environment.framework}] App Server [#{environment.app_server}]." load_instruments if should_load_instruments? @samplers = [ ScoutApm::Instruments::Process::ProcessCpu.new(environment.processors, logger), ScoutApm::Instruments::Process::ProcessMemory.new(logger) ] app_server_load_hook # 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 handle_exit 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.
167 168 169 170 171 172 173 |
# File 'lib/scout_apm/agent.rb', line 167 def start_background_worker logger.info "Initializing worker thread." @background_worker = ScoutApm::BackgroundWorker.new @background_worker_thread = Thread.new do @background_worker.start { process_metrics } 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.
159 160 161 162 163 |
# File 'lib/scout_apm/agent.rb', line 159 def start_background_worker? return true if environment.app_server == :thin return true if environment.app_server == :webrick return !environment.forking? end |
#started? ⇒ Boolean
151 152 153 |
# File 'lib/scout_apm/agent.rb', line 151 def started? @started end |