| blob | a074fcfadf1cc2cb3d354df62eab0691537e91e1 |
1 # -*- encoding: binary -*-
3 require 'socket'
4 require 'logger'
6 module Unicorn
8 # Implements a simple DSL for configuring a Unicorn server.
9 #
10 # Example (when used with the unicorn config file):
11 # worker_processes 4
12 # listen '/tmp/my_app.sock', :backlog => 1
13 # listen 9292, :tcp_nopush => true
14 # timeout 10
15 # pid "/tmp/my_app.pid"
16 #
17 # # combine REE with "preload_app true" for memory savings
18 # # http://rubyenterpriseedition.com/faq.html#adapt_apps_for_cow
19 # preload_app true
20 # GC.respond_to?(:copy_on_write_friendly=) and
21 # GC.copy_on_write_friendly = true
22 #
23 # before_fork do |server, worker|
24 # # the following is recomended for Rails + "preload_app true"
25 # # as there's no need for the master process to hold a connection
26 # defined?(ActiveRecord::Base) and
27 # ActiveRecord::Base.connection.disconnect!
28 #
29 # # the following allows a new master process to incrementally
30 # # phase out the old master process with SIGTTOU to avoid a
31 # # thundering herd (especially in the "preload_app false" case)
32 # # when doing a transparent upgrade. The last worker spawned
33 # # will then kill off the old master process with a SIGQUIT.
34 # old_pid = "#{server.config[:pid]}.oldbin"
35 # if old_pid != server.pid
36 # begin
37 # sig = (worker.nr + 1) >= server.worker_processes ? :QUIT : :TTOU
38 # Process.kill(sig, File.read(old_pid).to_i)
39 # rescue Errno::ENOENT, Errno::ESRCH
40 # end
41 # end
42 #
43 # # optionally throttle the master from forking too quickly by sleeping
44 # sleep 1
45 # end
46 #
47 # after_fork do |server, worker|
48 # # per-process listener ports for debugging/admin/migrations
49 # addr = "127.0.0.1:#{9293 + worker.nr}"
50 # server.listen(addr, :tries => -1, :delay => 5, :tcp_nopush => true)
51 #
52 # # the following is required for Rails + "preload_app true",
53 # defined?(ActiveRecord::Base) and
54 # ActiveRecord::Base.establish_connection
55 #
56 # # if preload_app is true, then you may also want to check and
57 # # restart any other shared sockets/descriptors such as Memcached,
58 # # and Redis. TokyoCabinet file handles are safe to reuse
59 # # between any number of forked children (assuming your kernel
60 # # correctly implements pread()/pwrite() system calls)
61 # end
62 class Configurator < Struct.new(:set, :config_file)
64 # Default settings for Unicorn
65 DEFAULTS = {
66 :timeout => 60,
67 :logger => Logger.new($stderr),
68 :worker_processes => 1,
69 :after_fork => lambda { |server, worker|
70 server.logger.info("worker=#{worker.nr} spawned pid=#{$$}")
71 },
72 :before_fork => lambda { |server, worker|
73 server.logger.info("worker=#{worker.nr} spawning...")
74 },
75 :before_exec => lambda { |server|
76 server.logger.info("forked child re-executing...")
77 },
78 :pid => nil,
79 :preload_app => false,
80 }
82 def initialize(defaults = {}) #:nodoc:
83 self.set = Hash.new(:unset)
84 use_defaults = defaults.delete(:use_defaults)
85 self.config_file = defaults.delete(:config_file)
86 set.merge!(DEFAULTS) if use_defaults
87 defaults.each { |key, value| self.send(key, value) }
88 Hash === set[:listener_opts] or
89 set[:listener_opts] = Hash.new { |hash,key| hash[key] = {} }
90 Array === set[:listeners] or set[:listeners] = []
91 reload
92 end
94 def reload #:nodoc:
95 instance_eval(File.read(config_file), config_file) if config_file
96 end
98 def commit!(server, options = {}) #:nodoc:
99 skip = options[:skip] || []
100 set.each do |key, value|
101 value == :unset and next
102 skip.include?(key) and next
103 server.__send__("#{key}=", value)
104 end
105 end
107 def [](key) # :nodoc:
108 set[key]
109 end
111 # sets object to the +new+ Logger-like object. The new logger-like
112 # object must respond to the following methods:
113 # +debug+, +info+, +warn+, +error+, +fatal+, +close+
114 def logger(new)
115 %w(debug info warn error fatal close).each do |m|
116 new.respond_to?(m) and next
117 raise ArgumentError, "logger=#{new} does not respond to method=#{m}"
118 end
120 set[:logger] = new
121 end
123 # sets after_fork hook to a given block. This block will be called by
124 # the worker after forking. The following is an example hook which adds
125 # a per-process listener to every worker:
126 #
127 # after_fork do |server,worker|
128 # # per-process listener ports for debugging/admin:
129 # addr = "127.0.0.1:#{9293 + worker.nr}"
130 #
131 # # the negative :tries parameter indicates we will retry forever
132 # # waiting on the existing process to exit with a 5 second :delay
133 # # Existing options for Unicorn::Configurator#listen such as
134 # # :backlog, :rcvbuf, :sndbuf are available here as well.
135 # server.listen(addr, :tries => -1, :delay => 5, :backlog => 128)
136 #
137 # # drop permissions to "www-data" in the worker
138 # # generally there's no reason to start Unicorn as a priviledged user
139 # # as it is not recommended to expose Unicorn to public clients.
140 # uid, gid = Process.euid, Process.egid
141 # user, group = 'www-data', 'www-data'
142 # target_uid = Etc.getpwnam(user).uid
143 # target_gid = Etc.getgrnam(group).gid
144 # worker.tmp.chown(target_uid, target_gid)
145 # if uid != target_uid || gid != target_gid
146 # Process.initgroups(user, target_gid)
147 # Process::GID.change_privilege(target_gid)
148 # Process::UID.change_privilege(target_uid)
149 # end
150 # end
151 def after_fork(*args, &block)
152 set_hook(:after_fork, block_given? ? block : args[0])
153 end
155 # sets before_fork got be a given Proc object. This Proc
156 # object will be called by the master process before forking
157 # each worker.
158 def before_fork(*args, &block)
159 set_hook(:before_fork, block_given? ? block : args[0])
160 end
162 # sets the before_exec hook to a given Proc object. This
163 # Proc object will be called by the master process right
164 # before exec()-ing the new unicorn binary. This is useful
165 # for freeing certain OS resources that you do NOT wish to
166 # share with the reexeced child process.
167 # There is no corresponding after_exec hook (for obvious reasons).
168 def before_exec(*args, &block)
169 set_hook(:before_exec, block_given? ? block : args[0], 1)
170 end
172 # sets the timeout of worker processes to +seconds+. Workers
173 # handling the request/app.call/response cycle taking longer than
174 # this time period will be forcibly killed (via SIGKILL). This
175 # timeout is enforced by the master process itself and not subject
176 # to the scheduling limitations by the worker process. Due the
177 # low-complexity, low-overhead implementation, timeouts of less
178 # than 3.0 seconds can be considered inaccurate and unsafe.
179 #
180 # For running Unicorn behind nginx, it is recommended to set
181 # "fail_timeout=0" for in your nginx configuration like this
182 # to have nginx always retry backends that may have had workers
183 # SIGKILL-ed due to timeouts.
184 #
185 # # See http://wiki.nginx.org/NginxHttpUpstreamModule for more details
186 # # on nginx upstream configuration:
187 # upstream unicorn_backend {
188 # # for UNIX domain socket setups:
189 # server unix:/path/to/unicorn.sock fail_timeout=0;
190 #
191 # # for TCP setups
192 # server 192.168.0.7:8080 fail_timeout=0;
193 # server 192.168.0.8:8080 fail_timeout=0;
194 # server 192.168.0.9:8080 fail_timeout=0;
195 # }
196 def timeout(seconds)
197 Numeric === seconds or raise ArgumentError,
198 "not numeric: timeout=#{seconds.inspect}"
199 seconds >= 3 or raise ArgumentError,
200 "too low: timeout=#{seconds.inspect}"
201 set[:timeout] = seconds
202 end
204 # sets the current number of worker_processes to +nr+. Each worker
205 # process will serve exactly one client at a time.
206 def worker_processes(nr)
207 Integer === nr or raise ArgumentError,
208 "not an integer: worker_processes=#{nr.inspect}"
209 nr >= 0 or raise ArgumentError,
210 "not non-negative: worker_processes=#{nr.inspect}"
211 set[:worker_processes] = nr
212 end
214 # sets listeners to the given +addresses+, replacing or augmenting the
215 # current set. This is for the global listener pool shared by all
216 # worker processes. For per-worker listeners, see the after_fork example
217 # This is for internal API use only, do not use it in your Unicorn
218 # config file. Use listen instead.
219 def listeners(addresses) # :nodoc:
220 Array === addresses or addresses = Array(addresses)
221 addresses.map! { |addr| expand_addr(addr) }
222 set[:listeners] = addresses
223 end
225 # adds an +address+ to the existing listener set.
226 #
227 # The following options may be specified (but are generally not needed):
228 #
229 # +:backlog+: this is the backlog of the listen() syscall.
230 #
231 # Some operating systems allow negative values here to specify the
232 # maximum allowable value. In most cases, this number is only
233 # recommendation and there are other OS-specific tunables and
234 # variables that can affect this number. See the listen(2)
235 # syscall documentation of your OS for the exact semantics of
236 # this.
237 #
238 # If you are running unicorn on multiple machines, lowering this number
239 # can help your load balancer detect when a machine is overloaded
240 # and give requests to a different machine.
241 #
242 # Default: 1024
243 #
244 # +:rcvbuf+, +:sndbuf+: maximum receive and send buffer sizes of sockets
245 #
246 # These correspond to the SO_RCVBUF and SO_SNDBUF settings which
247 # can be set via the setsockopt(2) syscall. Some kernels
248 # (e.g. Linux 2.4+) have intelligent auto-tuning mechanisms and
249 # there is no need (and it is sometimes detrimental) to specify them.
250 #
251 # See the socket API documentation of your operating system
252 # to determine the exact semantics of these settings and
253 # other operating system-specific knobs where they can be
254 # specified.
255 #
256 # Defaults: operating system defaults
257 #
258 # +:tcp_nodelay+: disables Nagle's algorithm on TCP sockets
259 #
260 # This has no effect on UNIX sockets.
261 #
262 # Default: operating system defaults (usually Nagle's algorithm enabled)
263 #
264 # +:tcp_nopush+: enables TCP_CORK in Linux or TCP_NOPUSH in FreeBSD
265 #
266 # This will prevent partial TCP frames from being sent out.
267 # Enabling +tcp_nopush+ is generally not needed or recommended as
268 # controlling +tcp_nodelay+ already provides sufficient latency
269 # reduction whereas Unicorn does not know when the best times are
270 # for flushing corked sockets.
271 #
272 # This has no effect on UNIX sockets.
273 #
274 # +:tries+: times to retry binding a socket if it is already in use
275 #
276 # A negative number indicates we will retry indefinitely, this is
277 # useful for migrations and upgrades when individual workers
278 # are binding to different ports.
279 #
280 # Default: 5
281 #
282 # +:delay+: seconds to wait between successive +tries+
283 #
284 # Default: 0.5 seconds
285 def listen(address, opt = {})
286 address = expand_addr(address)
287 if String === address
288 [ :backlog, :sndbuf, :rcvbuf, :tries ].each do |key|
289 value = opt[key] or next
290 Integer === value or
291 raise ArgumentError, "not an integer: #{key}=#{value.inspect}"
292 end
293 [ :tcp_nodelay, :tcp_nopush ].each do |key|
294 (value = opt[key]).nil? and next
295 TrueClass === value || FalseClass === value or
296 raise ArgumentError, "not boolean: #{key}=#{value.inspect}"
297 end
298 unless (value = opt[:delay]).nil?
299 Numeric === value or
300 raise ArgumentError, "not numeric: delay=#{value.inspect}"
301 end
302 set[:listener_opts][address].merge!(opt)
303 end
305 set[:listeners] << address
306 end
308 # sets the +path+ for the PID file of the unicorn master process
309 def pid(path); set_path(:pid, path); end
311 # Enabling this preloads an application before forking worker
312 # processes. This allows memory savings when using a
313 # copy-on-write-friendly GC but can cause bad things to happen when
314 # resources like sockets are opened at load time by the master
315 # process and shared by multiple children. People enabling this are
316 # highly encouraged to look at the before_fork/after_fork hooks to
317 # properly close/reopen sockets. Files opened for logging do not
318 # have to be reopened as (unbuffered-in-userspace) files opened with
319 # the File::APPEND flag are written to atomically on UNIX.
320 #
321 # In addition to reloading the unicorn-specific config settings,
322 # SIGHUP will reload application code in the working
323 # directory/symlink when workers are gracefully restarted.
324 def preload_app(bool)
325 case bool
326 when TrueClass, FalseClass
327 set[:preload_app] = bool
328 else
329 raise ArgumentError, "preload_app=#{bool.inspect} not a boolean"
330 end
331 end
333 # Allow redirecting $stderr to a given path. Unlike doing this from
334 # the shell, this allows the unicorn process to know the path its
335 # writing to and rotate the file if it is used for logging. The
336 # file will be opened with the File::APPEND flag and writes
337 # synchronized to the kernel (but not necessarily to _disk_) so
338 # multiple processes can safely append to it.
339 def stderr_path(path)
340 set_path(:stderr_path, path)
341 end
343 # Same as stderr_path, except for $stdout
344 def stdout_path(path)
345 set_path(:stdout_path, path)
346 end
348 # expands "unix:path/to/foo" to a socket relative to the current path
349 # expands pathnames of sockets if relative to "~" or "~username"
350 # expands "*:port and ":port" to "0.0.0.0:port"
351 def expand_addr(address) #:nodoc
352 return "0.0.0.0:#{address}" if Integer === address
353 return address unless String === address
355 case address
356 when %r{\Aunix:(.*)\z}
357 File.expand_path($1)
358 when %r{\A~}
359 File.expand_path(address)
360 when %r{\A(?:\*:)?(\d+)\z}
361 "0.0.0.0:#$1"
362 when %r{\A(.*):(\d+)\z}
363 # canonicalize the name
364 packed = Socket.pack_sockaddr_in($2.to_i, $1)
365 Socket.unpack_sockaddr_in(packed).reverse!.join(':')
366 else
367 address
368 end
369 end
371 private
373 def set_path(var, path) #:nodoc:
374 case path
375 when NilClass
376 when String
377 path = File.expand_path(path)
378 File.writable?(File.dirname(path)) or \
379 raise ArgumentError, "directory for #{var}=#{path} not writable"
380 else
381 raise ArgumentError
382 end
383 set[var] = path
384 end
386 def set_hook(var, my_proc, req_arity = 2) #:nodoc:
387 case my_proc
388 when Proc
389 arity = my_proc.arity
390 (arity == req_arity) or \
391 raise ArgumentError,
392 "#{var}=#{my_proc.inspect} has invalid arity: " \
393 "#{arity} (need #{req_arity})"
394 when NilClass
395 my_proc = DEFAULTS[var]
396 else
397 raise ArgumentError, "invalid type: #{var}=#{my_proc.inspect}"
398 end
399 set[var] = my_proc
400 end
402 end
403 end