Class: Flamingo::Daemon::Flamingod
- Inherits:
-
Object
- Object
- Flamingo::Daemon::Flamingod
- Includes:
- TrapKeeper
- Defined in:
- lib/flamingo/daemon/flamingod.rb
Overview
Flamingod is the main overseer of the Flamingo flock.
Starts three sets of children:
-
A wader process: initiates stream request, pushes each response into the queue
-
A Sinatra server: lightweight responder to create and manage subscriptions
-
A set of dispatchers: worker processes that handle each stream response.
You can control the flamingod with the following signals:
-
TERM and INT will kill the flamingod parent process, and signal each child with TERM
-
USR1 will restart the wader gracefully.
Instance Method Summary collapse
- #children ⇒ Object
- #clear_process_meta_data ⇒ Object
- #exit_signaled=(val) ⇒ Object
- #exit_signaled? ⇒ Boolean
- #handle_wader_exit(status) ⇒ Object
- #restart_wader ⇒ Object
- #run ⇒ Object
- #run_as_daemon ⇒ Object
- #set_process_meta_data ⇒ Object
- #signal_children(sig) ⇒ Object
- #start_children ⇒ Object
- #start_new_dispatcher ⇒ Object
- #start_new_wader ⇒ Object
- #start_new_web_server ⇒ Object
- #terminate! ⇒ Object
- #trap_signals ⇒ Object
-
#wait_on_children ⇒ Object
Unless signaled externally, waits in an endless loop.
Methods included from TrapKeeper
Instance Method Details
#children ⇒ Object
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# File 'lib/flamingo/daemon/flamingod.rb', line 90 def children ([@wader,@web_server] + @dispatchers).compact end |
#clear_process_meta_data ⇒ Object
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# File 'lib/flamingo/daemon/flamingod.rb', line 161 def = Flamingo. .delete(:start_time) .delete(:host) .delete(:pid) [:running] = false end |
#exit_signaled=(val) ⇒ Object
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# File 'lib/flamingo/daemon/flamingod.rb', line 27 def exit_signaled=(val) Flamingo.logger.info "Exit signal set to #{val}" @exit_signaled = val end |
#exit_signaled? ⇒ Boolean
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# File 'lib/flamingo/daemon/flamingod.rb', line 23 def exit_signaled? @exit_signaled end |
#handle_wader_exit(status) ⇒ Object
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# File 'lib/flamingo/daemon/flamingod.rb', line 124 def handle_wader_exit(status) if WaderProcess.fatal_exit?(status) Flamingo.logger.error "Wader exited with status "+ "#{status.exitstatus} and cannot be automatically restarted" $stderr.write("Wader exited with fatal error. Check the the log.") terminate! else @wader = start_new_wader end end |
#restart_wader ⇒ Object
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# File 'lib/flamingo/daemon/flamingod.rb', line 60 def restart_wader if @wader Flamingo.logger.info "Flamingod restarting wader pid=#{@wader.pid} with SIGINT" @wader.kill("INT") else Flamingo.logger.info "Wader is not started. Attempting to start new wader." @wader = start_new_wader end end |
#run ⇒ Object
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# File 'lib/flamingo/daemon/flamingod.rb', line 169 def run $0 = 'flamingod' Flamingo.logger.info "Flamingod version: #{Flamingo::VERSION}" trap_signals start_children wait_on_children end |
#run_as_daemon ⇒ Object
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# File 'lib/flamingo/daemon/flamingod.rb', line 135 def run_as_daemon pid_file = PidFile.new if pid_file.running? raise "flamingod process #{pid_file.read} appears to be running" end pid = fork do pid_file.write(Process.pid) [$stdout,$stdin,$stderr].each do |io| io.reopen '/dev/null' rescue nil end run pid_file.delete end Process.detach(pid) pid end |
#set_process_meta_data ⇒ Object
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# File 'lib/flamingo/daemon/flamingod.rb', line 153 def = Flamingo. [:start_time] = Time.now.utc.to_i [:host] = `hostname`.chomp rescue nil [:pid] = Process.pid [:running] = true end |
#signal_children(sig) ⇒ Object
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# File 'lib/flamingo/daemon/flamingod.rb', line 70 def signal_children(sig) pids = (children.map {|c| c.pid}).join(",") Flamingo.logger.info "Flamingod sending SIG#{sig} to pids=#{pids}" children.each do |child| if child.running? begin child.signal(sig) rescue => e Flamingo.logger.info "Failure sending SIG#{sig} to child #{child.pid}: #{e}" end end end end |
#start_children ⇒ Object
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# File 'lib/flamingo/daemon/flamingod.rb', line 94 def start_children Flamingo.logger.info "Flamingod starting children" @wader = start_new_wader @dispatchers = [start_new_dispatcher] @web_server = start_new_web_server end |
#start_new_dispatcher ⇒ Object
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# File 'lib/flamingo/daemon/flamingod.rb', line 39 def start_new_dispatcher Flamingo.logger.info "Flamingod starting new dispatcher" dispatcher = DispatcherProcess.new dispatcher.start dispatcher end |
#start_new_wader ⇒ Object
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# File 'lib/flamingo/daemon/flamingod.rb', line 32 def start_new_wader Flamingo.logger.info "Flamingod starting new wader" wader = WaderProcess.new wader.start wader end |
#start_new_web_server ⇒ Object
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# File 'lib/flamingo/daemon/flamingod.rb', line 46 def start_new_web_server Flamingo.logger.info "Flamingod starting new web server" ws = WebServerProcess.new ws.start ws end |
#terminate! ⇒ Object
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# File 'lib/flamingo/daemon/flamingod.rb', line 84 def terminate! Flamingo.logger.info "Flamingod terminating" self.exit_signaled = true signal_children("INT") end |
#trap_signals ⇒ Object
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# File 'lib/flamingo/daemon/flamingod.rb', line 53 def trap_signals trap("KILL") { terminate! } trap("TERM") { terminate! } trap("INT") { terminate! } trap("USR1") { restart_wader } end |
#wait_on_children ⇒ Object
Unless signaled externally, waits in an endless loop. If any child process terminates, it restarts that process. TODO Needs intelligent behavior so we don’t get endless loops
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# File 'lib/flamingo/daemon/flamingod.rb', line 105 def wait_on_children() until exit_signaled? child_pid = Process.wait(-1) child_status = $? unless exit_signaled? if @wader && @wader.pid == child_pid handle_wader_exit(child_status) elsif @web_server.pid == child_pid @web_server = start_new_web_server elsif (to_delete = @dispatchers.find{|d| d.pid == child_pid}) @dispatchers.delete(to_delete) @dispatchers << start_new_dispatcher else Flamingo.logger.info "Received exit from unknown child #{child_pid}" end end end end |