Class: Bluepill::Process
- Inherits:
-
Object
- Object
- Bluepill::Process
- Defined in:
- lib/bluepill/process.rb
Constant Summary collapse
- CONFIGURABLE_ATTRIBUTES =
[ :start_command, :stop_command, :restart_command, :stdout, :stderr, :stdin, :daemonize, :pid_file, :working_dir, :environment, :start_grace_time, :stop_grace_time, :restart_grace_time, :uid, :gid, :cache_actual_pid, :monitor_children, :child_process_factory, :pid_command, :auto_start, :supplementary_groups, :stop_signals ]
Instance Attribute Summary collapse
-
#children ⇒ Object
readonly
Returns the value of attribute children.
-
#logger ⇒ Object
Returns the value of attribute logger.
-
#name ⇒ Object
Returns the value of attribute name.
-
#process_running ⇒ Object
Returns the value of attribute process_running.
-
#skip_ticks_until ⇒ Object
Returns the value of attribute skip_ticks_until.
-
#statistics ⇒ Object
readonly
Returns the value of attribute statistics.
-
#triggers ⇒ Object
Returns the value of attribute triggers.
-
#watches ⇒ Object
Returns the value of attribute watches.
Instance Method Summary collapse
- #actual_pid ⇒ Object
- #actual_pid=(pid) ⇒ Object
- #add_trigger(name, options = {}) ⇒ Object
-
#add_watch(name, options = {}) ⇒ Object
Watch related methods.
- #cache_actual_pid? ⇒ Boolean
- #clean_threads ⇒ Object
- #clear_pid ⇒ Object
- #daemonize? ⇒ Boolean
- #determine_initial_state ⇒ Object
-
#dispatch!(event, reason = nil) ⇒ Object
State machine methods.
- #handle_user_command(cmd) ⇒ Object
-
#initialize(process_name, checks, options = {}) ⇒ Process
constructor
A new instance of Process.
- #monitor_children? ⇒ Boolean
- #notify_triggers(transition) ⇒ Object
- #pid_from_command ⇒ Object
- #pid_from_file ⇒ Object
- #prepare_command(command) ⇒ Object
-
#process_running?(force = false) ⇒ Boolean
System Process Methods.
- #record_transition(transition) ⇒ Object
- #refresh_children! ⇒ Object
- #restart_process ⇒ Object
- #run_watches ⇒ Object
- #signal_process(code) ⇒ Object
-
#skip_ticks_for(seconds) ⇒ Object
Internal State Methods.
- #skipping_ticks? ⇒ Boolean
- #start_process ⇒ Object
- #stop_process ⇒ Object
- #system_command_options ⇒ Object
- #tick ⇒ Object
- #unlink_pid ⇒ Object
- #with_timeout(secs, &blk) ⇒ Object
Constructor Details
#initialize(process_name, checks, options = {}) ⇒ Process
Returns a new instance of Process.
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# File 'lib/bluepill/process.rb', line 103 def initialize(process_name, checks, = {}) @name = process_name @event_mutex = Monitor.new @watches = [] @triggers = [] @children = [] @threads = [] @statistics = ProcessStatistics.new @actual_pid = [:actual_pid] self.logger = [:logger] checks.each do |name, opts| if Trigger[name] self.add_trigger(name, opts) else self.add_watch(name, opts) end end # These defaults are overriden below if it's configured to be something else. @monitor_children = false @cache_actual_pid = true @start_grace_time = @stop_grace_time = @restart_grace_time = 3 @environment = {} CONFIGURABLE_ATTRIBUTES.each do |attribute_name| self.send("#{attribute_name}=", [attribute_name]) if .has_key?(attribute_name) end # Let state_machine do its initialization stuff super() # no arguments intentional end |
Instance Attribute Details
#children ⇒ Object (readonly)
Returns the value of attribute children.
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# File 'lib/bluepill/process.rb', line 47 def children @children end |
#logger ⇒ Object
Returns the value of attribute logger.
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# File 'lib/bluepill/process.rb', line 45 def logger @logger end |
#name ⇒ Object
Returns the value of attribute name.
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# File 'lib/bluepill/process.rb', line 45 def name @name end |
#process_running ⇒ Object
Returns the value of attribute process_running.
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# File 'lib/bluepill/process.rb', line 45 def process_running @process_running end |
#skip_ticks_until ⇒ Object
Returns the value of attribute skip_ticks_until.
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# File 'lib/bluepill/process.rb', line 45 def skip_ticks_until @skip_ticks_until end |
#statistics ⇒ Object (readonly)
Returns the value of attribute statistics.
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# File 'lib/bluepill/process.rb', line 47 def statistics @statistics end |
#triggers ⇒ Object
Returns the value of attribute triggers.
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# File 'lib/bluepill/process.rb', line 45 def triggers @triggers end |
#watches ⇒ Object
Returns the value of attribute watches.
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# File 'lib/bluepill/process.rb', line 45 def watches @watches end |
Instance Method Details
#actual_pid ⇒ Object
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# File 'lib/bluepill/process.rb', line 380 def actual_pid pid_command ? pid_from_command : pid_from_file end |
#actual_pid=(pid) ⇒ Object
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# File 'lib/bluepill/process.rb', line 404 def actual_pid=(pid) @actual_pid = pid end |
#add_trigger(name, options = {}) ⇒ Object
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# File 'lib/bluepill/process.rb', line 198 def add_trigger(name, = {}) self.triggers << Trigger[name].new(self, .merge(:logger => self.logger)) end |
#add_watch(name, options = {}) ⇒ Object
Watch related methods
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# File 'lib/bluepill/process.rb', line 194 def add_watch(name, = {}) self.watches << ConditionWatch.new(name, .merge(:logger => self.logger)) end |
#cache_actual_pid? ⇒ Boolean
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# File 'lib/bluepill/process.rb', line 376 def cache_actual_pid? !!@cache_actual_pid end |
#clean_threads ⇒ Object
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# File 'lib/bluepill/process.rb', line 356 def clean_threads @threads.each { |t| t.kill } @threads.clear end |
#clear_pid ⇒ Object
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# File 'lib/bluepill/process.rb', line 408 def clear_pid @actual_pid = nil end |
#daemonize? ⇒ Boolean
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# File 'lib/bluepill/process.rb', line 361 def daemonize? !!self.daemonize end |
#determine_initial_state ⇒ Object
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# File 'lib/bluepill/process.rb', line 226 def determine_initial_state if self.process_running?(true) self.state = 'up' else self.state = (auto_start == false) ? 'unmonitored' : 'down' # we need to check for false value end end |
#dispatch!(event, reason = nil) ⇒ Object
State machine methods
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# File 'lib/bluepill/process.rb', line 166 def dispatch!(event, reason = nil) @event_mutex.synchronize do @statistics.record_event(event, reason) self.send("#{event}") end end |
#handle_user_command(cmd) ⇒ Object
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# File 'lib/bluepill/process.rb', line 234 def handle_user_command(cmd) case cmd when "start" if self.process_running?(true) logger.warning("Refusing to re-run start command on an already running process.") else dispatch!(:start, "user initiated") end when "stop" stop_process dispatch!(:unmonitor, "user initiated") when "restart" restart_process when "unmonitor" # When the user issues an unmonitor cmd, reset any triggers so that # scheduled events gets cleared triggers.each {|t| t.reset! } dispatch!(:unmonitor, "user initiated") end end |
#monitor_children? ⇒ Boolean
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# File 'lib/bluepill/process.rb', line 365 def monitor_children? !!self.monitor_children end |
#notify_triggers(transition) ⇒ Object
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# File 'lib/bluepill/process.rb', line 189 def notify_triggers(transition) self.triggers.each {|trigger| trigger.notify(transition)} end |
#pid_from_command ⇒ Object
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# File 'lib/bluepill/process.rb', line 399 def pid_from_command pid = %x{#{pid_command}}.strip (pid =~ /\A\d+\z/) ? pid.to_i : nil end |
#pid_from_file ⇒ Object
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# File 'lib/bluepill/process.rb', line 384 def pid_from_file return @actual_pid if cache_actual_pid? && @actual_pid @actual_pid = begin if pid_file if File.exists?(pid_file) str = File.read(pid_file) str.to_i if str.size > 0 else logger.warning("pid_file #{pid_file} does not exist or cannot be read") nil end end end end |
#prepare_command(command) ⇒ Object
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# File 'lib/bluepill/process.rb', line 449 def prepare_command(command) command.to_s.gsub("{{PID}}", actual_pid.to_s) end |
#process_running?(force = false) ⇒ Boolean
System Process Methods
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# File 'lib/bluepill/process.rb', line 256 def process_running?(force = false) @process_running = nil if force # clear existing state if forced @process_running ||= signal_process(0) # the process isn't running, so we should clear the PID self.clear_pid unless @process_running @process_running end |
#record_transition(transition) ⇒ Object
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# File 'lib/bluepill/process.rb', line 173 def record_transition(transition) unless transition.loopback? @transitioned = true # When a process changes state, we should clear the memory of all the watches self.watches.each { |w| w.clear_history! } # Also, when a process changes state, we should re-populate its child list if self.monitor_children? self.logger.warning "Clearing child list" self.children.clear end logger.info "Going from #{transition.from_name} => #{transition.to_name}" end end |
#refresh_children! ⇒ Object
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# File 'lib/bluepill/process.rb', line 428 def refresh_children! # First prune the list of dead children @children.delete_if {|child| !child.process_running?(true) } # Add new found children to the list new_children_pids = System.get_children(self.actual_pid) - @children.map {|child| child.actual_pid} unless new_children_pids.empty? logger.info "Existing children: #{@children.collect{|c| c.actual_pid}.join(",")}. Got new children: #{new_children_pids.inspect} for #{actual_pid}" end # Construct a new process wrapper for each new found children new_children_pids.each do |child_pid| name = "<child(pid:#{child_pid})>" logger = self.logger.prefix_with(name) child = self.child_process_factory.create_child_process(name, child_pid, logger) @children << child end end |
#restart_process ⇒ Object
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# File 'lib/bluepill/process.rb', line 333 def restart_process if restart_command cmd = self.prepare_command(restart_command) logger.warning "Executing restart command: #{cmd}" with_timeout(restart_grace_time) do result = System.execute_blocking(cmd, self.) unless result[:exit_code].zero? logger.warning "Restart command execution returned non-zero exit code:" logger.warning result.inspect end end self.skip_ticks_for(restart_grace_time) else logger.warning "No restart_command specified. Must stop and start to restart" self.stop_process # the tick will bring it back. end end |
#run_watches ⇒ Object
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# File 'lib/bluepill/process.rb', line 202 def run_watches now = Time.now.to_i threads = self.watches.collect do |watch| [watch, Thread.new { Thread.current[:events] = watch.run(self.actual_pid, now) }] end @transitioned = false threads.inject([]) do |events, (watch, thread)| thread.join if thread[:events].size > 0 logger.info "#{watch.name} dispatched: #{thread[:events].join(',')}" thread[:events].each do |event| events << [event, watch.to_s] end end events end.each do |(event, reason)| break if @transitioned self.dispatch!(event, reason) end end |
#signal_process(code) ⇒ Object
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# File 'lib/bluepill/process.rb', line 369 def signal_process(code) ::Process.kill(code, actual_pid) true rescue false end |
#skip_ticks_for(seconds) ⇒ Object
Internal State Methods
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# File 'lib/bluepill/process.rb', line 418 def skip_ticks_for(seconds) # TODO: should this be addative or longest wins? # i.e. if two calls for skip_ticks_for come in for 5 and 10, should it skip for 10 or 15? self.skip_ticks_until = (self.skip_ticks_until || Time.now.to_i) + seconds.to_i end |
#skipping_ticks? ⇒ Boolean
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# File 'lib/bluepill/process.rb', line 424 def skipping_ticks? self.skip_ticks_until && self.skip_ticks_until > Time.now.to_i end |
#start_process ⇒ Object
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# File 'lib/bluepill/process.rb', line 265 def start_process logger.warning "Executing start command: #{start_command}" if self.daemonize? System.daemonize(start_command, self.) else # This is a self-daemonizing process with_timeout(start_grace_time) do result = System.execute_blocking(start_command, self.) unless result[:exit_code].zero? logger.warning "Start command execution returned non-zero exit code:" logger.warning result.inspect end end end self.skip_ticks_for(start_grace_time) end |
#stop_process ⇒ Object
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# File 'lib/bluepill/process.rb', line 286 def stop_process if stop_command cmd = self.prepare_command(stop_command) logger.warning "Executing stop command: #{cmd}" with_timeout(stop_grace_time) do result = System.execute_blocking(cmd, self.) unless result[:exit_code].zero? logger.warning "Stop command execution returned non-zero exit code:" logger.warning result.inspect end end elsif stop_signals # issue stop signals with configurable delay between each logger.warning "Sending stop signals to #{actual_pid}" @threads << Thread.new(self, stop_signals.clone) do |process, stop_signals| signal = stop_signals.shift logger.info "Sending signal #{signal} to #{process.actual_pid}" process.signal_process(signal.upcase) # send first signal until stop_signals.empty? # we already checked to make sure stop_signals had an odd number of items delay = stop_signals.shift signal = stop_signals.shift logger.debug "Sleeping for #{delay} seconds" sleep delay #break unless signal_process(0) #break unless the process can be reached unless process.signal_process(0) logger.debug "Process has terminated." break end logger.info "Sending signal #{signal} to #{process.actual_pid}" process.signal_process(signal.upcase) end end else logger.warning "Executing default stop command. Sending TERM signal to #{actual_pid}" signal_process("TERM") end self.unlink_pid # TODO: we only write the pid file if we daemonize, should we only unlink it if we daemonize? self.skip_ticks_for(stop_grace_time) end |
#system_command_options ⇒ Object
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# File 'lib/bluepill/process.rb', line 453 def { :uid => self.uid, :gid => self.gid, :working_dir => self.working_dir, :environment => self.environment, :pid_file => self.pid_file, :logger => self.logger, :stdin => self.stdin, :stdout => self.stdout, :stderr => self.stderr, :supplementary_groups => self.supplementary_groups } end |
#tick ⇒ Object
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# File 'lib/bluepill/process.rb', line 136 def tick return if self.skipping_ticks? self.skip_ticks_until = nil # clear the memoization per tick @process_running = nil # Deal with thread cleanup here since the stopping state isn't used clean_threads if self.unmonitored? # run state machine transitions super if self.up? self.run_watches if self.monitor_children? refresh_children! children.each {|child| child.tick} end end end |
#unlink_pid ⇒ Object
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# File 'lib/bluepill/process.rb', line 412 def unlink_pid File.unlink(pid_file) if pid_file && File.exists?(pid_file) rescue Errno::ENOENT end |
#with_timeout(secs, &blk) ⇒ Object
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# File 'lib/bluepill/process.rb', line 468 def with_timeout(secs, &blk) Timeout.timeout(secs.to_f, &blk) rescue Timeout::Error logger.err "Execution is taking longer than expected. Unmonitoring." logger.err "Did you forget to tell bluepill to daemonize this process?" self.dispatch!("unmonitor") end |