class Unicorn::Configurator
Implements a simple DSL for configuring a Unicorn
server.
See unicorn.bogomips.org/examples/unicorn.conf.rb for an example config file.
Constants
- DEFAULTS
Default settings for
Unicorn
Public Instance Methods
sets after_fork
hook to a given block. This block will be called by the worker after forking. The following is an example hook which adds a per-process listener to every worker:
after_fork do |server,worker| # per-process listener ports for debugging/admin: addr = "127.0.0.1:#{9293 + worker.nr}" # the negative :tries parameter indicates we will retry forever # waiting on the existing process to exit with a 5 second :delay # Existing options for Unicorn::Configurator#listen such as # :backlog, :rcvbuf, :sndbuf are available here as well. server.listen(addr, :tries => -1, :delay => 5, :backlog => 128) # drop permissions to "www-data" in the worker # generally there's no reason to start Unicorn as a priviledged user # as it is not recommended to expose Unicorn to public clients. worker.user('www-data', 'www-data') if Process.euid == 0 end
# File lib/unicorn/configurator.rb, line 107 def after_fork(*args, &block) set_hook(:after_fork, block_given? ? block : args[0]) end
# File lib/unicorn/configurator.rb, line 118 def app(&block) set_hook(:app, block, 0) end
sets the before_exec
hook to a given Proc object. This Proc object will be called by the master process right before exec()-ing the new unicorn binary. This is useful for freeing certain OS resources that you do NOT wish to share with the reexeced child process. There is no corresponding after_exec hook (for obvious reasons).
# File lib/unicorn/configurator.rb, line 128 def before_exec(*args, &block) set_hook(:before_exec, block_given? ? block : args[0], 1) end
sets before_fork
got be a given Proc object. This Proc object will be called by the master process before forking each worker.
# File lib/unicorn/configurator.rb, line 114 def before_fork(*args, &block) set_hook(:before_fork, block_given? ? block : args[0]) end
expands “unix:path/to/foo” to a socket relative to the current path expands pathnames of sockets if relative to “~” or “~username” expands “*:port and ”:port“ to ”0.0.0.0:port“
# File lib/unicorn/configurator.rb, line 338 def expand_addr(address) #:nodoc return "0.0.0.0:#{address}" if Integer === address return address unless String === address case address when %r{\Aunix:(.*)\z} File.expand_path($1) when %r{\A~} File.expand_path(address) when %r{\A(?:\*:)?(\d+)\z} "0.0.0.0:#$1" when %r{\A(.*):(\d+)\z} # canonicalize the name packed = Socket.pack_sockaddr_in($2.to_i, $1) Socket.unpack_sockaddr_in(packed).reverse!.join(':') else address end end
adds an address
to the existing listener set.
The following options may be specified (but are generally not needed):
:backlog
: this is the backlog of the listen() syscall.
Some operating systems allow negative values here to specify the maximum allowable value. In most cases, this number is only recommendation and there are other OS-specific tunables and variables that can affect this number. See the listen(2) syscall documentation of your OS for the exact semantics of this.
If you are running unicorn on multiple machines, lowering this number can help your load balancer detect when a machine is overloaded and give requests to a different machine.
Default: 1024
:rcvbuf
, :sndbuf
: maximum receive and send buffer sizes of sockets
These correspond to the SO_RCVBUF and SO_SNDBUF settings which can be set via the setsockopt(2) syscall. Some kernels (e.g. Linux 2.4+) have intelligent auto-tuning mechanisms and there is no need (and it is sometimes detrimental) to specify them.
See the socket API documentation of your operating system to determine the exact semantics of these settings and other operating system-specific knobs where they can be specified.
Defaults: operating system defaults
:tcp_nodelay
: disables Nagle's algorithm on TCP sockets
This has no effect on UNIX sockets.
Default: operating system defaults (usually Nagle's algorithm enabled)
:tcp_nopush
: enables TCP_CORK in Linux or TCP_NOPUSH in FreeBSD
This will prevent partial TCP frames from being sent out. Enabling tcp_nopush
is generally not needed or recommended as controlling tcp_nodelay
already provides sufficient latency reduction whereas Unicorn
does not know when the best times are for flushing corked sockets.
This has no effect on UNIX sockets.
:tries
: times to retry binding a socket if it is already in use
A negative number indicates we will retry indefinitely, this is useful for migrations and upgrades when individual workers are binding to different ports.
Default: 5
:delay
: seconds to wait between successive tries
Default: 0.5 seconds
:umask
: sets the file mode creation mask for UNIX sockets
Typically UNIX domain sockets are created with more liberal file permissions than the rest of the application. By default, we create UNIX domain sockets to be readable and writable by all local users to give them the same accessibility as locally-bound TCP listeners.
This has no effect on TCP listeners.
Default: 0 (world read/writable)
# File lib/unicorn/configurator.rb, line 244 def listen(address, opt = {}) address = expand_addr(address) if String === address [ :umask, :backlog, :sndbuf, :rcvbuf, :tries ].each do |key| value = opt[key] or next Integer === value or raise ArgumentError, "not an integer: #{key}=#{value.inspect}" end [ :tcp_nodelay, :tcp_nopush ].each do |key| (value = opt[key]).nil? and next TrueClass === value || FalseClass === value or raise ArgumentError, "not boolean: #{key}=#{value.inspect}" end unless (value = opt[:delay]).nil? Numeric === value or raise ArgumentError, "not numeric: delay=#{value.inspect}" end set[:listener_opts][address].merge!(opt) end set[:listeners] << address end
sets object to the new
Logger-like object. The new logger-like object must respond to the following methods:
+debug+, +info+, +warn+, +error+, +fatal+, +close+
# File lib/unicorn/configurator.rb, line 79 def logger(new) %w(debug info warn error fatal close).each do |m| new.respond_to?(m) and next raise ArgumentError, "logger=#{new} does not respond to method=#{m}" end set[:logger] = new end
sets the path
for the PID file of the unicorn master process
# File lib/unicorn/configurator.rb, line 268 def pid(path); set_path(:pid, path); end
Enabling this preloads an application before forking worker processes. This allows memory savings when using a copy-on-write-friendly GC but can cause bad things to happen when resources like sockets are opened at load time by the master process and shared by multiple children. People enabling this are highly encouraged to look at the before_fork/after_fork hooks to properly close/reopen sockets. Files opened for logging do not have to be reopened as (unbuffered-in-userspace) files opened with the File::APPEND flag are written to atomically on UNIX.
In addition to reloading the unicorn-specific config settings, SIGHUP will reload application code in the working directory/symlink when workers are gracefully restarted.
# File lib/unicorn/configurator.rb, line 283 def preload_app(bool) case bool when TrueClass, FalseClass set[:preload_app] = bool else raise ArgumentError, "preload_app=#{bool.inspect} not a boolean" end end
Allow redirecting $stderr to a given path. Unlike doing this from the shell, this allows the unicorn process to know the path its writing to and rotate the file if it is used for logging. The file will be opened with the File::APPEND flag and writes synchronized to the kernel (but not necessarily to disk) so multiple processes can safely append to it.
# File lib/unicorn/configurator.rb, line 298 def stderr_path(path) set_path(:stderr_path, path) end
Same as stderr_path
, except for $stdout
# File lib/unicorn/configurator.rb, line 303 def stdout_path(path) set_path(:stdout_path, path) end
sets the timeout of worker processes to seconds
. Workers handling the request/app.call/response cycle taking longer than this time period will be forcibly killed (via SIGKILL). This timeout is enforced by the master process itself and not subject to the scheduling limitations by the worker process. Due the low-complexity, low-overhead implementation, timeouts of less than 3.0 seconds can be considered inaccurate and unsafe.
# File lib/unicorn/configurator.rb, line 139 def timeout(seconds) Numeric === seconds or raise ArgumentError, "not numeric: timeout=#{seconds.inspect}" seconds >= 3 or raise ArgumentError, "too low: timeout=#{seconds.inspect}" set[:timeout] = seconds end
Runs worker processes as the specified user
and group
. The master process always stays running as the user who started it. This switch will occur after calling the after_fork
hook, and only if the Worker#user method is not called in the after_fork
hook
# File lib/unicorn/configurator.rb, line 328 def user(user, group = nil) # raises ArgumentError on invalid user/group Etc.getpwnam(user) Etc.getgrnam(group) if group set[:user] = [ user, group ] end
sets the current number of worker_processes
to nr
. Each worker process will serve exactly one client at a time. You can increment or decrement this value at runtime by sending SIGTTIN or SIGTTOU respectively to the master process without reloading the rest of your Unicorn
configuration. See the SIGNALS document for more information.
# File lib/unicorn/configurator.rb, line 153 def worker_processes(nr) Integer === nr or raise ArgumentError, "not an integer: worker_processes=#{nr.inspect}" nr >= 0 or raise ArgumentError, "not non-negative: worker_processes=#{nr.inspect}" set[:worker_processes] = nr end
sets the working directory for Unicorn
. This ensures USR2 will start a new instance of Unicorn
in this directory. This may be a symlink.
# File lib/unicorn/configurator.rb, line 310 def working_directory(path) # just let chdir raise errors path = File.expand_path(path) if config_file && config_file[0] != ?/ && ! test(?r, "#{path}/#{config_file}") raise ArgumentError, "config_file=#{config_file} would not be accessible in" \ " working_directory=#{path}" end Dir.chdir(path) Server::START_CTX[:cwd] = ENV["PWD"] = path end