Puma
Puma 是 Rails 的默认 Web Server，在创建 Rails 项目时已经自动添加了 Puma 的依赖。Puma 是用了多进程加多线程模型，它可以同时在 fork 出来的多个 worker 中创建多个线程来处理请求；不仅如此 Puma 还实现了用于提高并发速度的 Reactor 模块和线程池能够在提升吞吐量的同时，降低内存的消耗。
gem 'puma', '~> 3.7'
创建 config/puma.rb 配置文件，下面是文件内容：
# Puma can serve each request in a thread from an internal thread pool.
# The `threads` method setting takes two numbers: a minimum and maximum.
# Any libraries that use thread pools should be configured to match
# the maximum value specified for Puma. Default is set to 5 threads for minimum
# and maximum; this matches the default thread size of Active Record.
#
threads_count = ENV.fetch("RAILS_MAX_THREADS") { 5 }
threads threads_count, threads_count
# Specifies the `port` that Puma will listen on to receive requests; default is 3000.
#
port ENV.fetch("PORT") { 3000 }
# Specifies the `environment` that Puma will run in.
#
environment ENV.fetch("RAILS_ENV") { "development" }
# Specifies the number of `workers` to boot in clustered mode.
# Workers are forked webserver processes. If using threads and workers together
# the concurrency of the application would be max `threads` * `workers`.
# Workers do not work on JRuby or Windows (both of which do not support
# processes).
#
# workers ENV.fetch("WEB_CONCURRENCY") { 2 }
# Use the `preload_app!` method when specifying a `workers` number.
# This directive tells Puma to first boot the application and load code
# before forking the application. This takes advantage of Copy On Write
# process behavior so workers use less memory. If you use this option
# you need to make sure to reconnect any threads in the `on_worker_boot`
# block.
#
# preload_app!
# If you are preloading your application and using Active Record, it's
# recommended that you close any connections to the database before workers
# are forked to prevent connection leakage.
#
# before_fork do
# ActiveRecord::Base.connection_pool.disconnect! if defined?(ActiveRecord)
# end
# The code in the `on_worker_boot` will be called if you are using
# clustered mode by specifying a number of `workers`. After each worker
# process is booted, this block will be run. If you are using the `preload_app!`
# option, you will want to use this block to reconnect to any threads
# or connections that may have been created at application boot, as Ruby
# cannot share connections between processes.
#
# on_worker_boot do
# ActiveRecord::Base.establish_connection if defined?(ActiveRecord)
# end
#
# Allow puma to be restarted by `rails restart` command.
plugin :tmp_restart
Unicorn
与 Thin 同年发布的 Unicorn 虽然也是 Mongrel 项目的一个 fork，但是使用了完全不同的并发模型，每Unicorn 内部通过多次 fork 创建多个 worker 进程，所有的 worker 进程也都由一个 master 进程管理和控制。由于 master 进程的存在，当 worker 进程被意外杀掉后会被 master 进程重启，能够保证持续对外界提供服务，多个进程的 worker 也能够充分的利用多核 CPU 的性能，尽可能地提高请求的处理速度。
gem 'unicorn', '~> 5.5', '>= 5.5.1'
创建 config/unicorn.rb 配置文件，下面是文件内容。
# 启动 unicorn
# $ unicorn
# 带配置文件的方式启动
# $ unicorn -c config/unicorn.rb
# 启动生产环境
# $ unicorn -c config/unicorn.rb --env production
# 后台运行
# $ unicorn -c config/unicorn.rb --env production --daemonize
# 也可以通过 unicorn_rails 启动. unicorn_rails 命令更适用于 rails 项目，unicorn 命令适用于非 rails 项目。
# $ unicorn_rails -c config/unicorn.rb
module Rails
class < 64
# TODO: listen to port 3000 on all TCP interfaces
listen 3000, :tcp_nopush => true
# 设置 worker processes 的超时时间
# nuke workers after 30 seconds instead of 60 seconds (the default)
timeout 30
# 设置pid文件的位置
# feel free to point this anywhere accessible on the filesystem
pid "#{Rails.root}/tmp/pids/unicorn.pid"
# 设置 Logger 输出的位置
# By default, the Unicorn logger will write to stderr.
# Additionally, ome applications/frameworks log to stderr or stdout,
# so prevent them from going to /dev/null when daemonized here:
# 重定向 stderr 到指定文件
# stderr_path "#{Rails.root}/log/unicorn.stderr.log"
# 重定向 stdout 到指定文件
# stdout_path "#{Rails.root}/log/unicorn.stdout.log"
# 在 forking worker processes 之前预加载程序
# combine Ruby 2.0.0+ with "preload_app true" for memory savings
preload_app true
# 禁止 rewindability，可以提高上传的性能，降低 io 和内存使用
rewindable_input false
# 检查客户端链接是否断开，防止断开的请求调用。
# 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
# local variable to guard against running a hook multiple times
run_once = true
# 在 master fork work之前被调用。
before_fork do |server, worker|
# the following is highly recomended 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!
# Occasionally, it may be necessary to run non-idempotent code in the
# master before forking. Keep in mind the above disconnect! example
# is idempotent and does not need a guard.
if run_once
# do_something_once_here ...
run_once = false # prevent from firing again
end
# 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
# TODO: worker fork 之后被调用。
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
# 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
Thin
Thin 使用 Reactor 模型处理客户端的 HTTP 请求，每一个请求都会交由 EventMachine，通过内部对事件的分发，最终执行相应的回调，这种事件驱动的 IO 模型与 node.js 非常相似，使用单进程单线程的并发模型却能够快速处理 HTTP 请求。
gem 'thin', '~> 1.7', '>= 1.7.2'
Thin 提供了生成配置文件的功能，在项目根目录输入 thin config -C config/thin.yml 可以快速的创建一份配置文件。
---
chdir: "/Users/vincent/"
environment: development
address: 0.0.0.0
port: 3000
timeout: 30
log: "/Users/vincent/log/thin.log"
pid: tmp/pids/thin.pid
max_conns: 1024
max_persistent_conns: 100
require: []
wait: 30
threadpool_size: 20
daemonize: true
参考文献
- http://www.mojidong.com/rails/2013/04/20/rails-nginx-unicorn/
- https://ruby-china.org/topics/4709
- https://bogomips.org/unicorn/
- https://read01.com/zh-hk/zm5B.html#.Xc1XC-u-t0t
- https://ruby-china.org/topics/25276
- https://ruby-china.org/topics/10832
- https://stackoverflow.com/questions/4113299/ruby-on-rails-server-options
- https://draveness.me/ruby-webserver