Class: Foreman::Engine

Inherits:
Object
  • Object
show all
Defined in:
lib/foreman/engine.rb

Direct Known Subclasses

CLI

Defined Under Namespace

Classes: CLI

Constant Summary collapse

HANDLED_SIGNALS =

The signals that the engine cares about.

[ :TERM, :INT, :HUP, :USR1, :USR2 ]

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ Engine

Create an Engine for running processes

Parameters:

  • options (Hash) (defaults to: {})

Options Hash (options):

  • :formation (String) — default: all=1 —

    The process formation to use

  • :port (Fixnum) — default: 5000 —

    The base port to assign to processes

  • :root (String) — default: Dir.pwd —

    The root directory from which to run processes



27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
 
# File 'lib/foreman/engine.rb', line 27

def initialize(options={})
  @options = options.dup

  @options[:formation] ||= "all=1"
  @options[:timeout] ||= 5

  @env       = {}
  @mutex     = Mutex.new
  @names     = {}
  @processes = []
  @running   = {}
  @readers   = {}
  @shutdown  = false

  # Self-pipe for deferred signal-handling (ala djb: http://cr.yp.to/docs/selfpipe.html)
  reader, writer       = create_pipe
  reader.close_on_exec = true if reader.respond_to?(:close_on_exec)
  writer.close_on_exec = true if writer.respond_to?(:close_on_exec)
  @selfpipe            = { :reader => reader, :writer => writer }

  # Set up a global signal queue
  # http://blog.rubybestpractices.com/posts/ewong/016-Implementing-Signal-Handlers.html
  Thread.main[:signal_queue] = []
end

Instance Attribute Details

#env ⇒ Object (readonly)

Returns the value of attribute env.



15
16
17
 
# File 'lib/foreman/engine.rb', line 15

def env
  @env
end

#options ⇒ Object (readonly)

Returns the value of attribute options.



16
17
18
 
# File 'lib/foreman/engine.rb', line 16

def options
  @options
end

#processes ⇒ Object (readonly)

Returns the value of attribute processes.



17
18
19
 
# File 'lib/foreman/engine.rb', line 17

def processes
  @processes
end

Instance Method Details

#base_port ⇒ Object

Get the base port for this foreman instance



282
283
284
 
# File 'lib/foreman/engine.rb', line 282

def base_port
  (options[:port] || env["PORT"] || ENV["PORT"] || 5000).to_i
end

#clear ⇒ Object

Clear the processes registered to this Engine



158
159
160
161
 
# File 'lib/foreman/engine.rb', line 158

def clear
  @names     = {}
  @processes = []
end

#each_process ⇒ Object

Yield each Process in order



249
250
251
252
253
 
# File 'lib/foreman/engine.rb', line 249

def each_process
  process_names.each do |name|
    yield name, process(name)
  end
end

#environment ⇒ Object

deprecated



287
288
289
 
# File 'lib/foreman/engine.rb', line 287

def environment
  env
end

#formation ⇒ Object

Get the process formation



225
226
227
 
# File 'lib/foreman/engine.rb', line 225

def formation
  @formation ||= parse_formation(options[:formation])
end

#handle_hangup ⇒ Object

Handle a HUP signal



130
131
132
133
 
# File 'lib/foreman/engine.rb', line 130

def handle_hangup
  system "SIGHUP received, starting shutdown"
  @shutdown = true
end

#handle_interrupt ⇒ Object

Handle an INT signal



123
124
125
126
 
# File 'lib/foreman/engine.rb', line 123

def handle_interrupt
  system "SIGINT received, starting shutdown"
  @shutdown = true
end

#handle_signal(sig) ⇒ Object

Invoke the real handler for signal sig. This shouldn’t be called directly by signal handlers, as it might invoke code which isn’t re-entrant.

Parameters:

  • sig (Symbol) —

    the name of the signal to be handled



99
100
101
102
103
104
105
106
107
108
109
110
111
112
 
# File 'lib/foreman/engine.rb', line 99

def handle_signal(sig)
  case sig
  when :TERM
    handle_term_signal
  when :INT
    handle_interrupt
  when :HUP
    handle_hangup
  when *HANDLED_SIGNALS
    handle_signal_forward(sig)
  else
    system "unhandled signal #{sig}"
  end
end

#handle_signal_forward(signal) ⇒ Object 



135
136
137
138
 
# File 'lib/foreman/engine.rb', line 135

def handle_signal_forward(signal)
  system "#{signal} received, forwarding it to children"
  kill_children signal
end

#handle_term_signal ⇒ Object

Handle a TERM signal



116
117
118
119
 
# File 'lib/foreman/engine.rb', line 116

def handle_term_signal
  system "SIGTERM received, starting shutdown"
  @shutdown = true
end

#kill_children(signal = "SIGTERM") ⇒ Object

Send a signal to all processes started by this Engine

Parameters:

  • signal (String) (defaults to: "SIGTERM") —

    The signal to send to each process



189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
 
# File 'lib/foreman/engine.rb', line 189

def kill_children(signal="SIGTERM")
  if Foreman.windows?
    @running.each do |pid, (process, index)|
      system "sending #{signal} to #{name_for(pid)} at pid #{pid}"
      begin
        Process.kill(signal, pid)
      rescue Errno::ESRCH, Errno::EPERM
      end
    end
  else
    begin
      Process.kill signal, *@running.keys unless @running.empty?
    rescue Errno::ESRCH, Errno::EPERM
    end
  end
end

#killall(signal = "SIGTERM") ⇒ Object

Send a signal to the whole process group.

Parameters:

  • signal (String) (defaults to: "SIGTERM") —

    The signal to send



210
211
212
213
214
215
216
217
218
219
 
# File 'lib/foreman/engine.rb', line 210

def killall(signal="SIGTERM")
  if Foreman.windows?
    kill_children(signal)
  else
    begin
      Process.kill "-#{signal}", Process.pid
    rescue Errno::ESRCH, Errno::EPERM
    end
  end
end

#load_env(filename) ⇒ Object

Load a .env file into the env for this Engine

Parameters:

  • filename (String) —

    A .env file to load into the environment



179
180
181
182
183
 
# File 'lib/foreman/engine.rb', line 179

def load_env(filename)
  Foreman::Env.new(filename).entries do |name, value|
    @env[name] = value
  end
end

#load_procfile(filename) ⇒ Object

Register processes by reading a Procfile

Parameters:

  • filename (String) —

    A Procfile from which to read processes to register



167
168
169
170
171
172
173
 
# File 'lib/foreman/engine.rb', line 167

def load_procfile(filename)
  options[:root] ||= File.dirname(filename)
  Foreman::Procfile.new(filename).entries do |name, command|
    register name, command, :cwd => options[:root]
  end
  self
end

#notice_signal ⇒ Object

Wake the main thread up via the selfpipe when there’s a signal



85
86
87
88
89
90
91
92
 
# File 'lib/foreman/engine.rb', line 85

def notice_signal
  @selfpipe[:writer].write_nonblock( '.' )
rescue Errno::EAGAIN
  # Ignore writes that would block
rescue Errno::EINTR
  # Retry if another signal arrived while writing
  retry
end

#port_for(process, instance, base = nil) ⇒ Object

Get the port for a given process and offset

Parameters:

  • process (Foreman::Process) —

    A Process associated with this engine

  • instance (Fixnum) —

    The instance of the process



270
271
272
273
274
275
276
 
# File 'lib/foreman/engine.rb', line 270

def port_for(process, instance, base=nil)
  if base
    base + (@processes.index(process.process) * 100) + (instance - 1)
  else
    base_port + (@processes.index(process) * 100) + (instance - 1)
  end
end

#process(name) ⇒ Object

Get the Process for a specifid name

Parameters:

  • name (String) —

    The process name



243
244
245
 
# File 'lib/foreman/engine.rb', line 243

def process(name)
  @names.invert[name]
end

#process_names ⇒ Object

List the available process names



233
234
235
 
# File 'lib/foreman/engine.rb', line 233

def process_names
  @processes.map { |p| @names[p] }
end

#register(name, command, options = {}) ⇒ Object

Register a process to be run by this Engine

Parameters:

  • name (String) —

    A name for this process

  • command (String) —

    The command to run

  • options (Hash) (defaults to: {})

Options Hash (options):

  • :env (Hash) —

    A custom environment for this process



148
149
150
151
152
153
154
 
# File 'lib/foreman/engine.rb', line 148

def register(name, command, options={})
  options[:env] ||= env
  options[:cwd] ||= File.dirname(command.split(" ").first)
  process = Foreman::Process.new(command, options)
  @names[process] = name
  @processes << process
end

#register_signal_handlers ⇒ Object

Set up deferred signal handlers



67
68
69
70
71
72
73
 
# File 'lib/foreman/engine.rb', line 67

def register_signal_handlers
  HANDLED_SIGNALS.each do |sig|
    if ::Signal.list.include? sig.to_s
      trap(sig) { Thread.main[:signal_queue] << sig ; notice_signal }
    end
  end
end

#restore_default_signal_handlers ⇒ Object

Unregister deferred signal handlers



77
78
79
80
81
 
# File 'lib/foreman/engine.rb', line 77

def restore_default_signal_handlers
  HANDLED_SIGNALS.each do |sig|
    trap(sig, :DEFAULT) if ::Signal.list.include? sig.to_s
  end
end

#root ⇒ Object

Get the root directory for this Engine



259
260
261
 
# File 'lib/foreman/engine.rb', line 259

def root
  File.expand_path(options[:root] || Dir.pwd)
end

#start ⇒ Object

Start the processes registered to this Engine



54
55
56
57
58
59
60
61
62
63
 
# File 'lib/foreman/engine.rb', line 54

def start
  register_signal_handlers
  startup
  spawn_processes
  watch_for_output
  sleep 0.1
  wait_for_shutdown_or_child_termination
  shutdown
  exit(@exitstatus) if @exitstatus
end