Implementation of grpc-server command

grpc-server command - servicex.rb

#!/usr/bin/env ruby

# Print logs immediately
$stdout.sync = true

# Load Ruby on Rails
APP_PATH = File.expand_path('./config/application', Dir.pwd)
require './config/boot'
require 'rails'
require './config/environment'

# Load Servicex::Grpc::Server
require 'servicex/grpc/server'

server = Servicex::Grpc::Server.new(ARGV)
Dir.glob(File.expand_path("#{Rails.root}/app/#{Servicex::Grpc::Config.grpc_dir}/*")) do |f|
  klassname = File.basename(f, ".rb").classify
  klass = klassname.constantize
  server.set_handler(klass.new)
end
server.run

Servicex::Grpc::Server - servicex.rb

require 'optparse'
require 'grpc/health/checker'

# NOTE: We must inject module-level logger.
# cf. https://github.com/grpc/grpc/blob/de893acb6aef88484a427e64b96727e4926fdcfd/src/ruby/lib/grpc/logconfig.rb#L43
# cf. https://github.com/grpc/grpc/blob/49be7a6667ee27be7be44c6307428ace9dbe373b/src/ruby/spec/spec_helper.rb#L42-L44
module GRPC
  class << self
    def logger
      @logger ||= Servicex.logger
    end
  end
end

module Servicex::Grpc
  class Server
    attr_reader :port

    # @param argv [<String>]
    def initialize(argv = [])
      options = parse(argv)

      @server = GRPC::RpcServer.new(
        interceptors: Servicex::Grpc.server_interceptors
      )
      @port = options.fetch(:port)
      @server.add_http2_port("0.0.0.0:#{@port}", :this_port_is_insecure)

      set_handler(health_checker)
    end

    def set_handler(service)
      @server.handle(service)
    end

    def run
      GRPC.logger.info("gRPC server starting...")
      GRPC.logger.info("* Listening on tcp://0.0.0.0:#{@port}")
      GRPC.logger.info("* Environment: #{Servicex.app_env}")
      GRPC.logger.info("Use Ctrl-C to stop")
      @server.run_till_terminated_or_interrupted(['SIGHUP', 'SIGINT', 'SIGQUIT'])
      GRPC.logger.info("Exiting")
    end

  private

    # @return [Grpc::Health::Checker]
    def health_checker
      checker = Grpc::Health::Checker.new
      checker.add_status("", Grpc::Health::V1::HealthCheckResponse::ServingStatus::SERVING)
      checker
    end

    def parse(argv)
      options = {
        port: ENV.fetch('APP_PORT') { Servicex::Grpc::Config.default_port },
      }

      OptionParser.new do |parser|
        parser.banner = "Usage: bundle exec grpc-server [options]"

        parser.on("-p", "--port [PORT]", "Runs gRPC server on the specified port - defaults to #{Servicex::Grpc::Config.default_port}") do |v|
          options[:port] = v.to_i
        end
      end.parse(argv)

      options
    end
  end
end