Class: DigitalFabric::Service

Inherits:
Object
  • Object
show all
Defined in:
lib/tipi/digital_fabric/service.rb

Constant Summary collapse

INVALID_HOST = 
'INVALID_HOST'

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(token:) ⇒ Service

Returns a new instance of Service.



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# File 'lib/tipi/digital_fabric/service.rb', line 12

def initialize(token: )
  @token = token
  @agents = {}
  @routes = {}
  @counters = {
    connections: 0,
    http_requests: 0,
    errors: 0
  }
  @connection_count = 0
  @current_request_count = 0
  @http_latency_accumulator = 0
  @http_latency_counter = 0
  @http_latency_max = 0
  @last_counters = @counters.merge(stamp: Time.now.to_f - 1)
  @fiber = Fiber.current
  # @timer = Polyphony::Timer.new('service_timer', resolution: 5)
end

Instance Attribute Details

#stats ⇒ Object (readonly)

Returns the value of attribute stats.



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# File 'lib/tipi/digital_fabric/service.rb', line 106

def stats
  @stats
end

#timer ⇒ Object (readonly)

Returns the value of attribute timer.



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# File 'lib/tipi/digital_fabric/service.rb', line 10

def timer
  @timer
end

#token ⇒ Object (readonly)

Returns the value of attribute token.



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# File 'lib/tipi/digital_fabric/service.rb', line 9

def token
  @token
end

Instance Method Details

#calculate_stats ⇒ Object 



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# File 'lib/tipi/digital_fabric/service.rb', line 31

def calculate_stats
  now = Time.now.to_f
  elapsed = now - @last_counters[:stamp]
  connections = @counters[:connections] - @last_counters[:connections]
  http_requests = @counters[:http_requests] - @last_counters[:http_requests]
  errors = @counters[:errors] - @last_counters[:errors]
  @last_counters = @counters.merge(stamp: now)

  average_latency = @http_latency_counter == 0 ? 0 :
                    @http_latency_accumulator / @http_latency_counter
  @http_latency_accumulator = 0
  @http_latency_counter = 0
  max_latency = @http_latency_max
  @http_latency_max = 0

  cpu, rss = pid_cpu_and_rss(Process.pid)

  backend_stats = Thread.backend.stats
  op_rate = backend_stats[:op_count] / elapsed
  switch_rate = backend_stats[:switch_count] / elapsed
  poll_rate = backend_stats[:poll_count] / elapsed

  object_space_stats = ObjectSpace.count_objects

  {
    service: {
      agent_count: @agents.size,
      connection_count: @connection_count,
      connection_rate: connections / elapsed,
      error_rate: errors / elapsed,
      http_request_rate: http_requests / elapsed,
      latency_avg: average_latency,
      latency_max: max_latency,
      pending_requests: @current_request_count,
      },
    backend: {
      op_rate: op_rate,
      pending_ops: backend_stats[:pending_ops],
      poll_rate: poll_rate,
      runqueue_size: backend_stats[:runqueue_size],
      runqueue_high_watermark: backend_stats[:runqueue_max_length],
      switch_rate: switch_rate,

    },
    process: {
      cpu_usage: cpu,
      rss: rss.to_f / 1024,
      objects_total: object_space_stats[:TOTAL],
      objects_free:  object_space_stats[:FREE]
    }
  }
end

#compile_agent_routes ⇒ Object 



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# File 'lib/tipi/digital_fabric/service.rb', line 229

def compile_agent_routes
  @routing_changed = false

  @routes.clear
  @agents.keys.reverse.each do |agent|
    route = @agents[agent]
    @routes[route] ||= agent
  end
  @route_keys = @routes.keys
end

#decr_connection_count ⇒ Object 



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# File 'lib/tipi/digital_fabric/service.rb', line 102

def decr_connection_count
  @connection_count -= 1
end

#df_upgrade(req) ⇒ Object 



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# File 'lib/tipi/digital_fabric/service.rb', line 182

def df_upgrade(req)
  # we don't want to count connected agents
  @current_request_count -= 1
  if req.headers['df-token'] != @token
    return req.respond(nil, ':status' => Qeweney::Status::FORBIDDEN)
  end

  req.adapter.conn << Protocol.df_upgrade_response
  AgentProxy.new(self, req)
ensure
  @current_request_count += 1
end

#find_agent(req) ⇒ Object 



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# File 'lib/tipi/digital_fabric/service.rb', line 215

def find_agent(req)
  compile_agent_routes if @routing_changed

  host = req.headers[':authority'] || req.headers['host'] || INVALID_HOST
  path = req.headers[':path']

  route = @route_keys.find do |route|
    (host == route[:host]) || (path =~ route[:path_regexp])
  end
  return @routes[route] if route

  nil
end

#get_stats ⇒ Object 



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# File 'lib/tipi/digital_fabric/service.rb', line 94

def get_stats
  calculate_stats
end

#graceful_shutdown ⇒ Object 



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# File 'lib/tipi/digital_fabric/service.rb', line 244

def graceful_shutdown
  @shutdown = true
  @agents.keys.each do |agent|
    if agent.respond_to?(:send_shutdown)
      agent.send_shutdown
    else
      @agents.delete(agent)
    end
  end
  move_on_after(60) do
    while !@agents.empty?
      sleep 0.25
    end
  end
end

#http_request(req, allow_df_upgrade = false) ⇒ Object 



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# File 'lib/tipi/digital_fabric/service.rb', line 127

def http_request(req, allow_df_upgrade = false)
  @current_request_count += 1
  @counters[:http_requests] += 1
  @counters[:connections] += 1 if req.headers[':first']

  return upgrade_request(req, allow_df_upgrade) if req.upgrade_protocol

  inject_request_headers(req)
  agent = find_agent(req)
  unless agent
    @counters[:errors] += 1
    return req.respond(nil, ':status' => Qeweney::Status::SERVICE_UNAVAILABLE)
  end

  agent.http_request(req)
rescue IOError, SystemCallError, HTTP2::Error::StreamClosed
  @counters[:errors] += 1
rescue => e
  @counters[:errors] += 1
  puts '*' * 40
  p req
  p e
  puts e.backtrace.join("\n")
  req.respond(e.inspect, ':status' => Qeweney::Status::INTERNAL_SERVER_ERROR)
ensure
  @current_request_count -= 1
  req.adapter.conn.close if @shutdown
end

#incr_connection_count ⇒ Object 



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# File 'lib/tipi/digital_fabric/service.rb', line 98

def incr_connection_count
  @connection_count += 1
end

#inject_request_headers(req) ⇒ Object 



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# File 'lib/tipi/digital_fabric/service.rb', line 156

def inject_request_headers(req)
  req.headers['x-request-id'] = SecureRandom.uuid
  conn = req.adapter.conn
  req.headers['x-forwarded-for'] = conn.peeraddr(false)[2]
  req.headers['x-forwarded-proto'] ||= conn.is_a?(OpenSSL::SSL::SSLSocket) ? 'https' : 'http'
end

#mount(route, agent) ⇒ Object 



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# File 'lib/tipi/digital_fabric/service.rb', line 195

def mount(route, agent)
  if route[:path]
    route[:path_regexp] = path_regexp(route[:path])
  end
  @executive = agent if route[:executive]
  @agents[agent] = route
  @routing_changed = true
end

#path_regexp(path) ⇒ Object 



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# File 'lib/tipi/digital_fabric/service.rb', line 240

def path_regexp(path)
  /^#{path}/
end

#pid_cpu_and_rss(pid) ⇒ Object 



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# File 'lib/tipi/digital_fabric/service.rb', line 84

def pid_cpu_and_rss(pid)
  s = `ps -p #{pid} -o %cpu,rss`
  cpu, rss = s.lines[1].chomp.strip.split(' ')
  [cpu.to_f, rss.to_i]
rescue Polyphony::BaseException
  raise
rescue Exception
  [nil, nil]
end

#record_latency_measurement(latency, req) ⇒ Object 



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# File 'lib/tipi/digital_fabric/service.rb', line 118

def record_latency_measurement(latency, req)
  @http_latency_accumulator += latency
  @http_latency_counter += 1
  @http_latency_max = latency if latency > @http_latency_max
  return if latency < 1.0

  puts format('slow request (%.1f): %p', latency, req.headers)
end

#total_request_count ⇒ Object 



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# File 'lib/tipi/digital_fabric/service.rb', line 108

def total_request_count
  count = 0
  @agents.keys.each do |agent|
    if agent.respond_to?(:current_request_count)
      count += agent.current_request_count
    end
  end
  count
end

#unmount(agent) ⇒ Object 



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# File 'lib/tipi/digital_fabric/service.rb', line 204

def unmount(agent)
  route = @agents[agent]
  return unless route

  @executive = nil if route[:executive]
  @agents.delete(agent)
  @routing_changed = true
end

#upgrade_request(req, allow_df_upgrade) ⇒ Object 



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# File 'lib/tipi/digital_fabric/service.rb', line 163

def upgrade_request(req, allow_df_upgrade)
  case (protocol = req.upgrade_protocol)
  when 'df'
    if allow_df_upgrade
      df_upgrade(req)
    else
      req.respond(nil, ':status' => Qeweney::Status::SERVICE_UNAVAILABLE)
    end
  else
    agent = find_agent(req)
    unless agent
      @counters[:errors] += 1
      return req.respond(nil, ':status' => Qeweney::Status::SERVICE_UNAVAILABLE)
    end

    agent.http_upgrade(req, protocol)
  end
end