unicorn_rails - unicorn launcher for Rails 1.x and 2.x users
unicorn_rails [-c CONFIG_FILE] [-E RAILS_ENV] [-D]
A rackup(1)-like command to launch ancient Rails (2.x and
earlier) applications using Unicorn. Rails 3 (and later)
support Rack natively, so users are encouraged to use
unicorn(1) instead of unicorn_rails(1).
It is expected to be started in your Rails application root
(RAILS_ROOT), but the "working_directory" directive may be used
in the CONFIG_FILE.
The outward interface resembles rackup(1), the internals and
default middleware loading is designed like the script/server
command distributed with Rails.
While Unicorn takes a myriad of command-line options for
compatibility with ruby(1) and rackup(1), it is recommended to
stick to the few command-line options specified in the SYNOPSIS
and use the CONFIG_FILE as much as possible.
-c, --config-file CONFIG_FILE
Path to the Unicorn-specific config file. The config
file is implemented as a Ruby DSL, so Ruby code may
executed. See the RDoc/ri for the Unicorn::Configurator
class for the full list of directives available from the
DSL. Using an absolute path for for CONFIG_FILE is
recommended as it makes multiple instances of Unicorn
easily distinguishable when viewing ps(1) output.
Run daemonized in the background. The process is
detached from the controlling terminal and stdin is
redirected to "/dev/null". Unlike many common UNIX
daemons, we do not chdir to "/" upon daemonization to
allow more control over the startup/upgrade process.
Unless specified in the CONFIG_FILE, stderr and stdout
will also be redirected to "/dev/null". Daemonization
will skip loading of the Rails::Rack::LogTailer
middleware under Rails >= 2.3.x. By default,
unicorn_rails(1) will create a PID file in
"RAILS_ROOT/tmp/pids/unicorn.pid". You may override
this by specifying the "pid" directive to override this
Unicorn config file.
-E, --env RAILS_ENV
Run under the given RAILS_ENV. This sets the RAILS_ENV
environment variable. Acceptable values are exactly
those you expect in your Rails application, typically
"development" or "production".
-l, --listen ADDRESS
Listens on a given ADDRESS. ADDRESS may be in the form
of HOST:PORT or PATH, HOST:PORT is taken to mean a TCP
socket and PATH is meant to be a path to a UNIX domain
socket. Defaults to "0.0.0.0:8080" (all addresses on
TCP port 8080). For production deployments, specifying
the "listen" directive in CONFIG_FILE is recommended as
it allows fine-tuning of socket options.
RACKUP COMPATIBILITY OPTIONS
-o, --host HOST
Listen on a TCP socket belonging to HOST, default is
"0.0.0.0" (all addresses). If specified multiple times
on the command-line, only the last-specified value takes
effect. This option only exists for compatibility with
the rackup(1) command, use of "-l"/"--listen" switch is
-p, --port PORT
Listen on the specified TCP PORT, default is 8080. If
specified multiple times on the command-line, only the
last-specified value takes effect. This option only
exists for compatibility with the rackup(1) command, use
of "-l"/"--listen" switch is recommended instead.
Mounts the Rails application at the given PATH (instead
of "/"). This is equivalent to setting the
RAILS_RELATIVE_URL_ROOT environment variable. This is
only supported under Rails 2.3 or later at the moment.
-e, --eval LINE
Evaluate a LINE of Ruby code. This evaluation happens
immediately as the command-line is being parsed.
Turn on debug mode, the $DEBUG variable is set to true.
For Rails >= 2.3.x, this loads the Rails::Rack::Debugger
Turn on verbose warnings, the $VERBOSE variable is set
-I, --include PATH
specify $LOAD_PATH. PATH will be prepended to
$LOAD_PATH. The ':' character may be used to delimit
multiple directories. This directive may be used more
than once. Modifications to $LOAD_PATH take place
immediately and in the order they were specified on the
-r, --require LIBRARY
require a specified LIBRARY before executing the
application. The "require" statement will be executed
immediately and in the order they were specified on the
This defaults to "config.ru" in RAILS_ROOT. It should be the
same file used by rackup(1) and other Rack launchers, it uses
the Rack::Builder DSL. Unlike many other Rack applications,
RACKUP_FILE is completely optional for Rails, but may be used
to disable some of the default middleware for performance.
Embedded command-line options are mostly parsed for
compatibility with rackup(1) but strongly discouraged.
The RAILS_ENV variable is set by the aforementioned -E switch.
The RAILS_RELATIVE_URL_ROOT is set by the aforementioned --path
switch. Either of these variables may also be set in the shell
or the Unicorn CONFIG_FILE. All application or
library-specific environment variables (e.g. TMPDIR,
RAILS_ASSET_ID) may always be set in the Unicorn CONFIG_FILE in
addition to the spawning shell. When transparently upgrading
Unicorn, all environment variables set in the old master
process are inherited by the new master process. Unicorn only
uses (and will overwrite) the UNICORN_FD environment variable
internally when doing transparent upgrades.
The following UNIX signals may be sent to the master process:
• HUP - reload config file, app, and gracefully restart all
• INT/TERM - quick shutdown, kills all workers immediately
• QUIT - graceful shutdown, waits for workers to finish their
current request before finishing.
• USR1 - reopen all logs owned by the master and all workers
See Unicorn::Util.reopen_logs for what is considered a log.
• USR2 - reexecute the running binary. A separate QUIT should
be sent to the original process once the child is verified to
be up and running.
• WINCH - gracefully stops workers but keep the master running.
This will only work for daemonized processes.
• TTIN - increment the number of worker processes by one
• TTOU - decrement the number of worker processes by one
See the SIGNALS (https://yhbt.net/unicorn/SIGNALS.html)
document for full description of all signals used by Unicorn.
• Rack::Builder ri/RDoc
• Unicorn::Configurator ri/RDoc
• unicorn RDoc ⟨https://yhbt.net/unicorn/⟩
• Rack RDoc ⟨https://www.rubydoc.info/github/rack/rack/⟩
• Rackup HowTo
The Unicorn Community <firstname.lastname@example.org>.
Unicorn User Manual September 17, 2009 UNICORN_RAILS(1)
mail archives: https://yhbt.net/unicorn-public/
source code: git clone https://yhbt.net/unicorn.git
torsocks git clone http://ou63pmih66umazou.onion/unicorn.git