Запуск HTTP Traffic Replayer на AWS Elastic Beanstalk

Gor — отличная утилита для репликации (подмножества) рабочего трафика в промежуточную / тестовую среду. Запуск его в AWS Elastic Beanstalk (EB) сопряжен с некоторыми трудностями, в основном из-за того, что он не поддерживает запуск в качестве демона и что для этого нет документации / примеров. Ну, вот решение:

# File: .ebextensions/10gor.config
# Config Gor to copy a sample of Prod http traffice to staging
files:
  # Utility for daemonizing binaries such as gor; see http://libslack.org/daemon
  /opt/daemon.rpm:
    source: "https://s3-eu-west-1.amazonaws.com/elasticbeanstalk-eu-west-1-<our>/our_fileserver/daemon-0.6.4-1.x86_64.rpm"
    authentication: S3Access # See AWS::CloudFormation::Authentication below
    owner: root
    group: root

  # daemon config so that we don't need to repeat these command line options and
  # can just use the service's name ("gor")
  # We need to intercept the port 8080, not 80 (that iptables redirect to 8080)
  /etc/daemon.conf:
    # Troubleshooting tips:
    # 1) Send stderr/out output of both daemon and the service to a file - see the commented-out line
    #    (it should be also possible to send it to syslog but that did not work for me)
    # 2) Add "foreground" to the options and start the service manually on the server
    content: |
      gor  respawn,command=/opt/gor --input-raw :8080 --output-http 'https://our-staging.example.com|1'
      #gor  output=/var/log/gor.log,respawn,command=/opt/gor --stats --output-http-stats --input-raw :8080 --output-http 'https://our-staging.example.com|1'
      #gor  errlog=/var/log/daemonapp.log,dbglog=/var/log/daemonapp.log,output=/var/log/gor.log,verbose,debug,respawn,command=/opt/gor --verbose --stats --output-http-stats --input-raw :8080 --output-http 'https://our-staging.example.com|1'
    # Use the commented-out line to enable stats logging to syslog (/var/log/messages) every 5s for troubleshooting
    content: |
      gor  respawn,command=/opt/gor --input-raw :8080 --output-http 'https://our-staging.example.com|1'
      #gor  respawn,output=gor.info,command=/opt/gor --stats --output-http-stats --input-raw :8080 --output-http 'https://our-staging.example.com|1'
  # HTTP traffic replicator; see https://github.com/buger/gor
  /opt/gor:
    source: "https://s3-eu-west-1.amazonaws.com/elasticbeanstalk-eu-west-1-<our>/our_fileserver/gor"
    authentication: S3Access
    mode: "000755"
    owner: root
    group: root

  # System V service that supports chkconfig
  /etc/init.d/gor:
    mode: "000755"
    owner: root
    group: root
    content: |
      ## The chkconfig <levels> <startup order> <stop order> + descr. needed to
      ## support ensureRunning
      # chkconfig: 345 92 08
      # description: Gor copies traffic to staging
      ### BEGIN INIT INFO
      # Provides: gor
      # Short-Description: Start Gor to copy traffic to staging
      ### END INIT INFO
      # See how we were called.
      case "$1" in
        start)
              /usr/local/bin/daemon --name gor
              ;;
        stop)
              /usr/local/bin/daemon --name gor --stop
              ;;
        status)
              if ! /usr/local/bin/daemon --name gor --running; then
                  echo "gor is stopped"; exit 3
              fi
              ;;
        restart)
              /usr/local/bin/daemon --name gor --stop
              /usr/local/bin/daemon --name gor
              ;;
        *)
              echo $"Usage: $0 {start|stop|restart}"
              exit 2
      esac
      exit 0
commands:
  "Install daemon":
    command: rpm -i /opt/daemon.rpm
    test: /bin/sh -c "! rpm -q daemon" # It seems 'test: ! rpm -q daemon' ignores the !

services:
  sysvinit:
    gor:
      enabled: true
      ensureRunning: true

  # Allow files: to access our S3 bucket
  # See https://forums.aws.amazon.com/thread.jspa?messageID=557993
  # BEWARE: We have to explicitely allow access to any subdirectory by
  # editing the S3 bucket's policy and adding the subdir to the allowed Resources
  AWSEBAutoScalingGroup:
    Metadata:
      AWS::CloudFormation::Authentication:
        "S3Access": # reference this in the "authentication" property
          type: S3
          roleName: aws-elasticbeanstalk-ec2-role
          buckets: elasticbeanstalk-eu-west-1-<our id>