module TingYun::Agent::InstanceMethods::Start
Public Instance Methods
This method should be called in a forked process after a fork. It assumes the parent process initialized the agent, but does not assume the agent started.
The call is idempotent, but not re-entrant.
-
It clears any metrics carried over from the parent process
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Restarts the sampler thread if necessary
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Initiates a new agent run and worker loop unless that was done in the parent process and
:force_reconnect
is not true
Options:
-
:force_reconnect => true
to force the spawned process to establish a new connection, such as when forking a long running process. The default is falseāit will only connect to the server if the parent had not connected. -
:keep_retrying => false
if we try to initiate a new connection, this tells me to only try it once so this method returns quickly if there is some kind of latency with the server.
# File lib/ting_yun/agent/instance_methods/start.rb, line 131 def after_fork(options={}) needs_restart = false @after_fork_lock.synchronize do needs_restart = @dispatcher.needs_restart? @dispatcher.mark_started end return if !needs_restart || !Agent.config[:'agent_enabled'] || disconnected? ::TingYun::Agent.logger.debug "Starting the worker thread in #{Process.pid} (parent #{Process.ppid}) after forking." # Clear out locks and stats left over from parent process reset_objects_with_locks drop_buffered_data setup_and_start_agent(options) end
Check to see if the agent should start, returning true
if it should. should hava the vaild app_name, unstart-state and able to start The agent is disabled when it is not force enabled by the 'agent_enabled' option (e.g. in a manual start), or enabled normally through the configuration file
# File lib/ting_yun/agent/instance_methods/start.rb, line 17 def agent_should_start? return false if already_started? || !TingYun::Agent.config[:'agent_enabled'] unless app_name_configured? TingYun::Agent.logger.error "No application name configured.", "The Agent cannot start without at least one. Please check your ", "tingyun.yml and ensure that it is valid and has at least one ", "value set for app_name in the", "environment." return false end return true end
Check whether we have already started, which is an error condition
# File lib/ting_yun/agent/instance_methods/start.rb, line 35 def already_started? if started? TingYun::Agent.logger.info("Agent Started Already!") true end end
Logs the configured application names
# File lib/ting_yun/agent/instance_methods/start.rb, line 67 def app_name_configured? names = TingYun::Agent.config.app_names return names.respond_to?(:any?) && names.any? end
Sanity-check the agent configuration and start the agent, setting up the worker thread and the exit handler to shut down the agent
# File lib/ting_yun/agent/instance_methods/start.rb, line 88 def check_config_and_start_agent return unless has_correct_license_key? return if is_using_forking_dispatcher? setup_and_start_agent end
A correct license key exists and is of the proper length
# File lib/ting_yun/agent/instance_methods/start.rb, line 56 def has_correct_license_key? if TingYun::Agent.config[:license_key] && TingYun::Agent.config[:license_key].length > 0 true else TingYun::Agent.logger.warn("No license key found. " + "This often means your tingyun.yml file was not found, or it lacks a section for the running environment,'#{::TingYun::Frameworks.framework.env}'. You may also want to try linting your tingyun.yml to ensure it is valid YML.") false end end
If we're using a dispatcher that forks before serving requests, we need to wait until the children are forked before connecting, otherwise the parent process sends useless data
# File lib/ting_yun/agent/instance_methods/start.rb, line 76 def is_using_forking_dispatcher? if [:puma, :passenger, :rainbows, :unicorn].include? TingYun::Agent.config[:dispatcher] TingYun::Agent.logger.info "Deferring startup of agent reporting thread because #{TingYun::Agent.config[:dispatcher]} may fork." true else false end end
# File lib/ting_yun/agent/instance_methods/start.rb, line 43 def log_startup Agent.logger.info "Environment: #{::TingYun::Frameworks.framework.env}" # log_environment dispatcher_name = TingYun::Agent.config[:dispatcher].to_s if dispatcher_name.empty? TingYun::Agent.logger.info 'No known dispatcher detected.' else TingYun::Agent.logger.info "Dispatcher: #{dispatcher_name}" end # log_dispatcher TingYun::Agent.logger.info "Application: #{TingYun::Agent.config.app_names.join(", ")}" # log_app_name end
This is the shared method between the main agent startup and the after_fork
call restarting the thread in deferred dispatchers.
Treatment of @started and env report is important to get right.
# File lib/ting_yun/agent/instance_methods/start.rb, line 98 def setup_and_start_agent(options={}) @started = true @dispatcher.mark_started generate_environment_report install_exit_handler @middleware.load_samplers # cpu and memory load if TingYun::Agent.config[:sync_startup] connect_in_sync else start_worker_thread(options) end end
# File lib/ting_yun/agent/instance_methods/start.rb, line 30 def started? @started end