gitlab-org--gitlab-foss/config/unicorn.rb.example
Stan Hu e9d4b08dc2 Clean up stale Prometheus metrics in before_exec unicorn hook
Issuing a SIGUSR2 to a unicorn involves a dance where new workers are
spun up before the old ones are shut down. To ensure Prometheus
.db files aren't deleted after the new workers are shut down, we
need to clean these files up before the unicorn process is run.

Relates to https://gitlab.com/gitlab-org/omnibus-gitlab/merge_requests/2582
2018-06-11 21:50:32 -07:00

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# Sample verbose configuration file for Unicorn (not Rack)
#
# This configuration file documents many features of Unicorn
# that may not be needed for some applications. See
# http://unicorn.bogomips.org/examples/unicorn.conf.minimal.rb
# for a much simpler configuration file.
#
# See http://unicorn.bogomips.org/Unicorn/Configurator.html for complete
# documentation.
# Note: If you change this file in a Merge Request, please also create a
# Merge Request on https://gitlab.com/gitlab-org/omnibus-gitlab/merge_requests
# Relative URL support
# WARNING: We recommend using an FQDN to host GitLab in a root path instead
# of using a relative URL.
# Documentation: http://doc.gitlab.com/ce/install/relative_url.html
# Uncomment and customize the following line to run in a non-root path
#
# ENV['RAILS_RELATIVE_URL_ROOT'] = "/gitlab"
# Read about unicorn workers here:
# http://doc.gitlab.com/ee/install/requirements.html#unicorn-workers
#
worker_processes 3
# Since Unicorn is never exposed to outside clients, it does not need to
# run on the standard HTTP port (80), there is no reason to start Unicorn
# as root unless it's from system init scripts.
# If running the master process as root and the workers as an unprivileged
# user, do this to switch euid/egid in the workers (also chowns logs):
# user "unprivileged_user", "unprivileged_group"
# Help ensure your application will always spawn in the symlinked
# "current" directory that Capistrano sets up.
working_directory "/home/git/gitlab" # available in 0.94.0+
# Listen on both a Unix domain socket and a TCP port.
# If you are load-balancing multiple Unicorn masters, lower the backlog
# setting to e.g. 64 for faster failover.
listen "/home/git/gitlab/tmp/sockets/gitlab.socket", :backlog => 1024
listen "127.0.0.1:8080", :tcp_nopush => true
# nuke workers after 30 seconds instead of 60 seconds (the default)
#
# NOTICE: git push over http depends on this value.
# If you want to be able to push huge amount of data to git repository over http
# you will have to increase this value too.
#
# Example of output if you try to push 1GB repo to GitLab over http.
# -> git push http://gitlab.... master
#
# error: RPC failed; result=18, HTTP code = 200
# fatal: The remote end hung up unexpectedly
# fatal: The remote end hung up unexpectedly
#
# For more information see http://stackoverflow.com/a/21682112/752049
#
timeout 60
# feel free to point this anywhere accessible on the filesystem
pid "/home/git/gitlab/tmp/pids/unicorn.pid"
# By default, the Unicorn logger will write to stderr.
# Additionally, some applications/frameworks log to stderr or stdout,
# so prevent them from going to /dev/null when daemonized here:
stderr_path "/home/git/gitlab/log/unicorn.stderr.log"
stdout_path "/home/git/gitlab/log/unicorn.stdout.log"
# combine Ruby 2.0.0dev or REE with "preload_app true" for memory savings
# http://rubyenterpriseedition.com/faq.html#adapt_apps_for_cow
preload_app true
GC.respond_to?(:copy_on_write_friendly=) and
GC.copy_on_write_friendly = true
# Enable this flag to have unicorn test client connections by writing the
# beginning of the HTTP headers before calling the application. This
# prevents calling the application for connections that have disconnected
# while queued. This is only guaranteed to detect clients on the same
# host unicorn runs on, and unlikely to detect disconnects even on a
# fast LAN.
check_client_connection false
before_exec do |server|
# The following is necessary to ensure stale Prometheus metrics don't
# accumulate over time. It needs to be done in this hook as opposed to
# inside an init script to ensure metrics files aren't deleted after new
# unicorn workers start after a SIGUSR2 is received.
if ENV['prometheus_multiproc_dir']
old_metrics = Dir[File.join(ENV['prometheus_multiproc_dir'], '*.db')]
FileUtils.rm_rf(old_metrics)
end
end
before_fork do |server, worker|
# the following is highly recommended for Rails + "preload_app true"
# as there's no need for the master process to hold a connection
defined?(ActiveRecord::Base) and
ActiveRecord::Base.connection.disconnect!
# The following is only recommended for memory/DB-constrained
# installations. It is not needed if your system can house
# twice as many worker_processes as you have configured.
#
# This allows a new master process to incrementally
# phase out the old master process with SIGTTOU to avoid a
# thundering herd (especially in the "preload_app false" case)
# when doing a transparent upgrade. The last worker spawned
# will then kill off the old master process with a SIGQUIT.
old_pid = "#{server.config[:pid]}.oldbin"
if old_pid != server.pid
begin
sig = (worker.nr + 1) >= server.worker_processes ? :QUIT : :TTOU
Process.kill(sig, File.read(old_pid).to_i)
rescue Errno::ENOENT, Errno::ESRCH
end
end
#
# Throttle the master from forking too quickly by sleeping. Due
# to the implementation of standard Unix signal handlers, this
# helps (but does not completely) prevent identical, repeated signals
# from being lost when the receiving process is busy.
# sleep 1
end
after_fork do |server, worker|
# per-process listener ports for debugging/admin/migrations
# addr = "127.0.0.1:#{9293 + worker.nr}"
# server.listen(addr, :tries => -1, :delay => 5, :tcp_nopush => true)
# the following is *required* for Rails + "preload_app true",
defined?(ActiveRecord::Base) and
ActiveRecord::Base.establish_connection
# reset prometheus client, this will cause any opened metrics files to be closed
defined?(::Prometheus::Client.reinitialize_on_pid_change) &&
Prometheus::Client.reinitialize_on_pid_change
# if preload_app is true, then you may also want to check and
# restart any other shared sockets/descriptors such as Memcached,
# and Redis. TokyoCabinet file handles are safe to reuse
# between any number of forked children (assuming your kernel
# correctly implements pread()/pwrite() system calls)
end