Class: Raptor::Cluster

Inherits:
Object
  • Object
show all
Defined in:
lib/raptor/cluster.rb,
sig/generated/raptor/cluster.rbs

Overview

Multi-process web server cluster with advanced concurrency architecture.

Cluster manages multiple worker processes, each running a complete server stack including a reactor thread, server thread, ractor pool for HTTP parsing, and thread pool for application processing. It handles process forking, signal management, graceful shutdown, and automatic worker restart when a worker process unexpectedly exits.

The architecture provides horizontal scaling through processes while maintaining efficient I/O and CPU utilization within each process through the combination of NIO reactors, ractor-based parsing, and thread pools.

Flow per worker process:

  1. Server continuously accepts connections but skips acceptance when backlog is high
  2. Reactor manages I/O multiplexing and provides backlog metrics for load control
  3. Ractor pool handles CPU-intensive HTTP parsing in parallel
  4. Thread pool processes Rack applications and handles response writing
  5. Natural load balancing occurs through backpressure-based acceptance control

Examples:

Basic usage

options = {
  threads: 8, ractors: 2, workers: 4,
  binds: ["tcp://0.0.0.0:3000"],
  rackup: "config.ru",
  client: { first_data_timeout: 30, chunk_data_timeout: 10 }
}
Cluster.run(options)

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options) ⇒ Cluster

Creates a new Cluster with the specified configuration.

Initializes the cluster with thread, ractor, and worker counts, sets up network binding, loads the Rack application, and prepares for multi-process operation.

Parameters:

  • options (Hash) —

    cluster configuration options

Options Hash (options):

  • :threads (Integer) —

    number of threads per worker process

  • :ractors (Integer) —

    number of ractors per worker process

  • :workers (Integer) —

    number of worker processes

  • :binds (Array<String>) —

    array of bind URIs

  • :app (#call) —

    pre-built Rack application

  • :rackup (String) —

    path to Rack configuration file

  • :client (Hash) —

    client timeout configuration



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# File 'lib/raptor/cluster.rb', line 86

def initialize(options)
  @thread_count = options[:threads]
  @ractor_count = options[:ractors]
  @worker_count = options[:workers]
  @client_options = options[:client]

  @binder = Binder.new(options[:binds])
  @server_port = @binder.server_port
  @app = options[:app] || Rack::Builder.parse_file(options[:rackup])
  log_initialization

  @shutdown = false
  @workers = {}
  @stats = Stats.new(@worker_count)
  @stats_file = options[:stats_file]
end

Class Method Details

.run(options) ⇒ void

This method returns an undefined value.

Convenience method to create and run a cluster with the given options.

Parameters:

  • options (Hash) —

    cluster configuration options



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# File 'lib/raptor/cluster.rb', line 53

def self.run(options)
  new(options).run
end

Instance Method Details

#exit_description(status) ⇒ String

Returns a human-readable description of how a process exited.

Parameters:

  • status (Process::Status) —

    the exit status of the process

Returns:

  • (String) —

    a description of the exit reason



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# File 'lib/raptor/cluster.rb', line 282

def exit_description(status)
  if status.exited?
    "exited with code #{status.exitstatus}"
  elsif status.signaled?
    "killed by SIG#{Signal.signame(status.termsig)}"
  else
    "exited"
  end
end

#log_initialization ⇒ void

This method returns an undefined value.

Logs cluster initialization details including architecture and bind addresses.

Outputs a hierarchical view of the cluster configuration showing the master process, worker processes, and per-process thread/ractor allocation along with listening addresses.



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# File 'lib/raptor/cluster.rb', line 312

def log_initialization
  puts "Raptor Cluster initializing:"
  puts "├─ Version: #{VERSION}"
  puts "├─ Ruby Version: #{RUBY_DESCRIPTION}"
  puts "├─ Master PID: #{Process.pid}"
  puts "│  └─ #{@worker_count} worker process#{"es" if @worker_count > 1}"
  puts "│     ├─ 1 server thread"
  puts "│     ├─ 1 reactor thread"
  puts "│     ├─ #{@ractor_count} pipeline ractor#{"s" if @ractor_count > 1}"
  puts "│     ├─ 1 pipeline collector thread"
  puts "│     ├─ #{@thread_count} worker thread#{"s" if @thread_count > 1}"
  puts "│     └─ 1 stats thread"
  puts "└─ Listening on #{@binder.addresses.join(", ")}"
end

#log_stats ⇒ void

This method returns an undefined value.

Logs current stats for all workers to stdout.

Triggered by SIGUSR1 in the master process.



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# File 'lib/raptor/cluster.rb', line 334

def log_stats
  @stats.all.each_with_index do |stat, index|
    status = stat[:booted] ? "booted" : "starting"
    puts "Worker #{index}: pid=#{stat[:pid]}, requests=#{stat[:requests]}, " \
         "backlog=#{stat[:backlog]}, #{status}, " \
         "last_checkin=#{Time.at(stat[:last_checkin]).strftime("%H:%M:%S")}"
  end
end

#run ⇒ void

This method returns an undefined value.

Starts the multi-process cluster and manages worker processes.

Forks the configured number of worker processes and monitors them, automatically restarting any that exit unexpectedly. Handles graceful shutdown via INT or TERM signals, and stats logging via USR1.

Each worker process includes:

  • 1 server thread (continuously accepts connections with backpressure control)
  • 1 reactor thread (I/O multiplexing, timeout handling, backlog monitoring)
  • N ractor workers (parallel HTTP parsing)
  • 1 ractor collector thread (coordinates parsing results)
  • M worker threads (Rack application processing and response writing)
  • 1 stats thread (writes per-worker metrics to shared memory every second)


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# File 'lib/raptor/cluster.rb', line 120

def run
  trap("INT") { shutdown }
  trap("TERM") { shutdown }
  trap("USR1") { log_stats }

  @worker_count.times { |index| spawn_worker(index) }

  stats_file_thread = if @stats_file
    Thread.new do
      Thread.current.name = "Raptor Stats File"

      write_stats_file_loop
    end
  end

  until @shutdown
    begin
      pid, status = Process.wait2(-1, Process::WNOHANG)
    rescue Errno::ECHILD
      break
    end

    if pid
      index = @workers.key(pid)
      @workers.delete(index)

      unless @shutdown
        warn "[#{Process.pid}] Restarting worker #{index} (#{pid}), #{exit_description(status)}"
        spawn_worker(index)
      end
    else
      sleep 0.1
    end
  end

  @workers.values.each { |pid| Process.kill("TERM", pid) rescue nil }
  @workers.values.each { |pid| Process.wait(pid) rescue nil }
  stats_file_thread&.join
  File.delete(@stats_file) rescue nil if @stats_file
  @stats.unmap
end

#run_worker(index) ⇒ void

This method returns an undefined value.

Runs the full server stack inside a worker process.

Sets up and coordinates the reactor, server, ractor pool, thread pool, and stats thread, running until a shutdown signal is received or a critical component fails.

Parameters:

  • index (Integer) —

    slot index for this worker in the stats region



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# File 'lib/raptor/cluster.rb', line 195

def run_worker(index)
  shutdown_requested = false
  trap("INT") { shutdown_requested = true }
  trap("TERM") { shutdown_requested = true }

  started_at = Process.clock_gettime(Process::CLOCK_REALTIME)
  request_count = 0

  @stats.write(
    index,
    pid: Process.pid,
    requests: 0,
    backlog: 0,
    started_at:,
    last_checkin: started_at,
    booted: false
  )

  reactor = nil

  counting_app = ->(env) {
    request_count += 1
    @app.call(env)
  }
  thread_pool = AtomicThreadPool.new(name: "Raptor Workers", size: @thread_count)
  request = Request.new(counting_app, @server_port)
  http2 = Http2.new(counting_app, @server_port)
  ractor_pool = RactorPool.new(
    name: "Raptor Pipeline Workers",
    size: @ractor_count,
    worker: request.http_parser_worker
  ) do |parsed_result|
    if parsed_result[:protocol] == :http2
      http2.handle_parsed_request(parsed_result, reactor, thread_pool)
    else
      request.handle_parsed_request(parsed_result, reactor, thread_pool)
    end
  end

  reactor = Reactor.new(thread_pool, ractor_pool, client_options: @client_options)
  reactor_thread = reactor.run

  server = Server.new(@binder, reactor, thread_pool, request)
  server_thread = server.run

  puts "[#{Process.pid}] Worker #{index} booted"

  stats_thread = Thread.new do
    Thread.current.name = "Raptor Stats"

    loop do
      @stats.write(
        index,
        pid: Process.pid,
        requests: request_count,
        backlog: reactor.backlog,
        started_at:,
        last_checkin: Process.clock_gettime(Process::CLOCK_REALTIME),
        booted: true
      )
      break if shutdown_requested

      sleep 1
    end
  end

  until shutdown_requested
    break unless server_thread.alive? && reactor_thread.alive?

    sleep 0.5
  end

  server.shutdown
  server_thread.join
  reactor.shutdown
  reactor_thread.join
  ractor_pool.shutdown
  thread_pool.shutdown
  stats_thread.join
end

#shutdown ⇒ void

This method returns an undefined value.

Initiates graceful shutdown of the cluster.



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# File 'lib/raptor/cluster.rb', line 297

def shutdown
  return if @shutdown

  @shutdown = true
end

#spawn_worker(index) ⇒ void

This method returns an undefined value.

Forks a new worker process and registers it at the given index.

Parameters:

  • index (Integer) —

    slot index for this worker in the stats region



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# File 'lib/raptor/cluster.rb', line 180

def spawn_worker(index)
  pid = fork { run_worker(index) }
  @workers[index] = pid
end

#stats ⇒ Array<Hash>

Returns stats for all worker processes.

Returns:

  • (Array<Hash>) —

    array of per-worker stat hashes, each containing :pid, :requests, :backlog, :started_at, :last_checkin, and :booted



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# File 'lib/raptor/cluster.rb', line 168

def stats
  @stats.all
end

#write_stats_file_loop ⇒ void

This method returns an undefined value.

Writes the stats file on a 1-second interval until shutdown.



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# File 'lib/raptor/cluster.rb', line 348

def write_stats_file_loop
  loop do
    File.write(@stats_file, JSON.generate({ master_pid: Process.pid, workers: @stats.all }))
    break if @shutdown

    sleep 1
  end
rescue SystemCallError
end