#!/bin/bash
# Copyright 2015, Google Inc.
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
#     * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
#     * Redistributions in binary form must reproduce the above
# copyright notice, this list of conditions and the following disclaimer
# in the documentation and/or other materials provided with the
# distribution.
#     * Neither the name of Google Inc. nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#
# Contains funcs that help maintain GRPC's Docker images.
#
# Most funcs rely on the special-purpose GCE instance to build the docker
# instances and store them in a GCS-backed docker repository.
#
# The GCE instance
# - should be based on the container-optimized GCE instance
# [https://cloud.google.com/compute/docs/containers].
# - should be running google/docker-registry image
# [https://registry.hub.docker.com/u/google/docker-registry/], so that images
# can be saved to GCS
# - should have the GCE support scripts from this directory install on it.
#
# The expected workflow is
# - start a grpc docker GCE instance
#  * on startup, some of the docker images will be regenerated automatically
# - used grpc_update_image to update images via that instance


# Creates the ssh key file expect by 'gcloud compute ssh' if it does not exist.
#
# Allows gcloud ssh commands to run on freshly started docker instances.
_grpc_ensure_gcloud_ssh() {
  local default_key_file="$HOME/.ssh/google_compute_engine"
  if [ "$HOME" == "/" ]
  then
    default_key_file="/root/.ssh/google_compute_engine"
  fi
  [ -f $default_key_file ] || {
    ssh-keygen -f $default_key_file -N '' > /dev/null || {
      echo "could not precreate $default_key_file" 1>&2
      return 1
    }
  }
}

# Pushes a dockerfile dir to cloud storage.
#
# dockerfile is expected to the parent directory to a nunber of directoies each
# of which specifies a Dockerfiles.
#
# grpc_push_dockerfiles path/to/docker_parent_dir gs://bucket/path/to/gcs/parent
grpc_push_dockerfiles() {
  local docker_dir=$1
  [[ -n $docker_dir ]] || {
    echo "$FUNCNAME: missing arg: docker_dir" 1>&2
    return 1
  }

  local gs_root_uri=$2
  [[ -n $gs_root_uri ]] || {
    echo "$FUNCNAME: missing arg: gs_root_uri" 1>&2
    return 1
  }

  find $docker_dir -name '*~' -o -name '#*#' -exec rm -fv {} \; || {
    echo "$FUNCNAME: failed: cleanup of tmp files in $docker_dir" 1>&2
    return 1
  }
  gsutil cp -R $docker_dir $gs_root_uri || {
    echo "$FUNCNAME: failed: cp $docker_dir -> $gs_root_uri" 1>&2
    return 1
  }
}

# Adds the user to docker group on a GCE instance, and restarts the docker
# daemon
grpc_add_docker_user() {
  _grpc_ensure_gcloud_ssh || return 1;
  local host=$1
  [[ -n $host ]] || {
    echo "$FUNCNAME: missing arg: host" 1>&2
    return 1
  }

  local project=$2
  local project_opt=''
  [[ -n $project ]] && project_opt=" --project $project"

  local zone=$3
  local zone_opt=''
  [[ -n $zone ]] && zone_opt=" --zone $zone"


  local func_lib="/var/local/startup_scripts/shared_startup_funcs.sh"
  local ssh_cmd="source $func_lib && grpc_docker_add_docker_group"
  gcloud compute $project_opt ssh $zone_opt $host --command "$ssh_cmd"
}

_grpc_update_image_args() {
  echo "image_args $@"
  # default the host, root storage uri and docker file root
  grpc_gs_root='gs://tmp-grpc-dev/admin/'
  grpc_dockerfile_root='tools/dockerfile'
  grpc_gce_script_root='tools/gce_setup'
  host='grpc-docker-builder'

  # see if -p or -z is used to override the the project or zone
  local OPTIND
  local OPTARG
  while getopts :r:d:h: name
  do
    case $name in
      d)  grpc_dockerfile_root=$OPTARG ;;
      r)  grpc_gs_root=$OPTARG ;;
      s)  grpc_gce_script_root=$OPTARG ;;
      h)  host=$OPTARG ;;
      :)  continue ;; # ignore -r or -d without args, just use the defaults
      \?)  echo "-$OPTARG: unknown flag; it's ignored" 1>&2;  continue ;;
    esac
  done
  shift $((OPTIND-1))

  [[ -d $grpc_dockerfile_root ]] || {
    echo "Could not locate dockerfile root dir: $grpc_dockerfile_root" 1>&2
    return 1
  }

  [[ -d $grpc_gce_script_root ]] || {
    echo "Could not locate gce script dir: $grpc_gce_script_root" 1>&2
    return 1
  }

  # the suffix is required and can't be defaulted
  # the suffix has two roles:
  # - images are labelled grpc/<label_suffix>
  # - the dockerfile is for an image is dockerfile_root/grpc_<label_suffix>
  [[ -n $1 ]] && {
    label_suffix=$1
    shift
  } || {
    echo "$FUNCNAME: missing arg: label_suffix (e.g cxx,base,ruby,java_base)" 1>&2
    return 1
  }
}

# Updates a docker image specified in a local dockerfile via the docker
# container GCE instance.
#
# the docker container GCE instance
# - should have been setup using ./new_grpc_docker_instance
#
# There are options for
#
# call-seq:
#   grpc_update_image php_base
#   grpc_update_image cxx  # rebuilds the cxx image
#
grpc_update_image() {
  _grpc_ensure_gcloud_ssh || return 1;

  # set up by _grpc_update_args
  local host grpc_gs_root grpc_gce_script_root grpc_dockerfile_root label_suffix
  local grpc_zone grpc_project dry_run  # set by _grpc_set_project_and_zone
  _grpc_set_project_and_zone -f _grpc_update_image_args "$@" || return 1
  local project_opt="--project $grpc_project"
  local zone_opt="--zone $grpc_zone"
  local image_label="grpc/$label_suffix"
  local docker_dir_basename="grpc_$label_suffix"
  local gce_docker_dir="/var/local/dockerfile/${docker_dir_basename}"

  # Set up and run the SSH command that builds the image
  local func_lib="shared_startup_funcs.sh"
  local gce_func_lib="/var/local/startup_scripts/$func_lib"
  local ssh_cmd="source $gce_func_lib"
  local ssh_cmd+=" && grpc_dockerfile_refresh $image_label $gce_docker_dir"
  echo "will run:"
  echo "  $ssh_cmd"
  echo "on $host"
  [[ $dry_run == 1 ]] && return 0  # don't run the command on a dry run

  # Update the remote copy of the GCE func library.
  local src_func_lib="$grpc_gce_script_root/$func_lib"
  local rmt_func_lib="$host:$gce_func_lib"
  gcloud compute copy-files $src_func_lib $rmt_func_lib $project_opt $zone_opt || return 1

  # Update the remote version of the docker func.
  local src_docker_dir="$grpc_dockerfile_root/$docker_dir_basename"
  local rmt_docker_root="$host:/var/local/dockerfile"
  gcloud compute copy-files $src_docker_dir $rmt_docker_root $project_opt $zone_opt || return 1

  gcloud compute $project_opt ssh $zone_opt $host --command "$ssh_cmd"
}

# gce_has_instance checks if a project contains a named instance
#
# call-seq:
#   gce_has_instance <project> <instance_name>
gce_has_instance() {
  local project=$1
  [[ -n $project ]] || { echo "$FUNCNAME: missing arg: project" 1>&2; return 1; }
  local checked_instance=$2
  [[ -n $checked_instance ]] || {
    echo "$FUNCNAME: missing arg: checked_instance" 1>&2
    return 1
  }

  instances=$(gcloud --project $project compute instances list \
    | sed -e 's/ \+/ /g' | cut -d' ' -f 1)
  for i in $instances
  do
    if [[ $i == $checked_instance ]]
    then
      return 0
    fi
  done

  echo "instance '$checked_instance' not found in compute project $project" 1>&2
  return 1
}

# gce_find_internal_ip finds the ip address of a instance if it is present in
# the project.
#
# gce_find_internal_ip <project> <instance_name>
gce_find_internal_ip() {
  local project=$1
  [[ -n $project ]] || { echo "$FUNCNAME: missing arg: project" 1>&2; return 1; }
  local checked_instance=$2
  [[ -n $checked_instance ]] || {
    echo "$FUNCNAME: missing arg: checked_instance" 1>&2
    return 1
  }

  gce_has_instance $project $checked_instance || return 1
  gcloud --project $project compute instances list \
    | grep -e "$checked_instance\s" \
    | sed -e 's/ \+/ /g' | cut -d' ' -f 4
}

# sets the vars grpc_zone and grpc_project
#
# to be used in funcs that want to set the zone and project and potential
# override them with
#
# grpc_zone
# - is set to the value gcloud config value for compute/zone if that's present
# - it defaults to asia-east1-a
# - it can be overridden by passing -z <other value>
#
# grpc_project
# - is set to the value gcloud config value for project if that's present
# - it defaults to stoked-keyword-656 (the grpc cloud testing project)
# - it can be overridden by passing -p <other value>
_grpc_set_project_and_zone() {
  # can be set to 1 by passing -n in the args
  dry_run=0

  # by default; grpc_zone == gcloud config value || asia-east1-a
  # - can be assigned via -p<project> in the args
  grpc_zone=$(gcloud config list compute/zone --format text \
    | sed -e 's/ \+/ /g' | cut -d' ' -f 2)
  # pick a known zone as a default
  [[ $grpc_zone == 'None' ]] && grpc_zone='asia-east1-a'

  # grpc_project == gcloud config value || stoked-keyword-656
  # - can be assigned via -z<zone> in the args
  grpc_project=$(gcloud config list project --format text \
    | sed -e 's/ \+/ /g' | cut -d' ' -f 2)
  # pick an known zone as a default
  [[ $grpc_project == 'None' ]] && grpc_project='stoked-keyword-656'

  # see if -p or -z is used to override the the project or zone
  local OPTIND
  local OPTARG
  local arg_func
  while getopts :np:z:f: name
  do
    case $name in
      f)   declare -F $OPTARG >> /dev/null && {
          arg_func=$OPTARG;
        } || {
          echo "-f: arg_func value: $OPTARG is not defined"
          return 2
        }
        ;;
      n)   dry_run=1 ;;
      p)   grpc_project=$OPTARG ;;
      z)   grpc_zone=$OPTARG ;;
      :)   [[ $OPT_ARG == 'f' ]] && {
          echo "-f: arg_func provided" 1>&2
          return 2
        } || {
          # ignore -p or -z without args, just use the defaults
          continue
        }
        ;;
      \?)  echo "-$OPTARG: unknown flag; it's ignored" 1>&2;  continue ;;
    esac
  done
  shift $((OPTIND-1))
  [[ -n $arg_func ]] && $arg_func "$@"
}

# construct the flags to be passed to the binary running the test client
#
# call-seq:
#   flags=$(grpc_interop_test_flags <server_ip> <server_port> <test_case>)
#   [[ -n flags ]] || return 1
grpc_interop_test_flags() {
  [[ -n $1 ]] && {  # server_ip
    local server_ip=$1
    shift
  } || {
    echo "$FUNCNAME: missing arg: server_ip" 1>&2
    return 1
  }
  [[ -n $1 ]] && {  # port
    local port=$1
    shift
  } || {
    echo "$FUNCNAME: missing arg: port" 1>&2
    return 1
  }
  [[ -n $1 ]] && {  # test_case
    local test_case=$1
    shift
  } || {
    echo "$FUNCNAME: missing arg: test_case" 1>&2
    return 1
  }
  echo "--server_host_override=foo.test.google.fr --server_host=$server_ip --server_port=$port --test_case=$test_case"
}

# checks the positional args and assigns them to variables visible in the caller
#
# these are the positional args passed to grpc_interop_test after option flags
# are removed
#
# five args are expected, in order
# - test_case
# - host <the gce docker instance on which to run the test>
# - client to run
# - server_host <the gce docker instance on which the test server is running>
# - server type
grpc_interop_test_args() {
  [[ -n $1 ]] && {  # test_case
    test_case=$1
    shift
  } || {
    echo "$FUNCNAME: missing arg: test_case" 1>&2
    return 1
  }

  [[ -n $1 ]] && {  # host
    host=$1
    shift
  } || {
    echo "$FUNCNAME: missing arg: host" 1>&2
    return 1
  }

  [[ -n $1 ]] && {  # client_type
    case $1 in
      cxx|go|java|node|php|python|ruby|csharp_mono)
        grpc_gen_test_cmd="grpc_interop_gen_$1_cmd"
        declare -F $grpc_gen_test_cmd >> /dev/null || {
          echo "-f: test_func for $1 => $grpc_gen_test_cmd is not defined" 1>&2
          return 2
        }
        shift
        ;;
      *)
        echo "bad client_type: $1" 1>&2
        return 1
        ;;
    esac
  } || {
    echo "$FUNCNAME: missing arg: client_type" 1>&2
    return 1
  }

  [[ -n $1 ]] && {  # grpc_server
    grpc_server=$1
    shift
  } || {
    echo "$FUNCNAME: missing arg: grpc_server" 1>&2
    return 1
  }

  [[ -n $1 ]] && {  # server_type
    case $1 in
      cxx)          grpc_port=8010 ;;
      go)           grpc_port=8020 ;;
      java)         grpc_port=8030 ;;
      node)         grpc_port=8040 ;;
      python)       grpc_port=8050 ;;
      ruby)         grpc_port=8060 ;;
      csharp_mono)  grpc_port=8070 ;;
      *) echo "bad server_type: $1" 1>&2; return 1 ;;
    esac
    shift
  } || {
    echo "$FUNCNAME: missing arg: server_type" 1>&2
    return 1
  }
}

# checks the positional args and assigns them to variables visible in the caller
#
# these are the positional args passed to grpc_cloud_prod_test after option flags
# are removed
#
# three args are expected, in order
# - test_case
# - host <the gce docker instance on which to run the test>
# - client to run
grpc_cloud_prod_test_args() {
  [[ -n $1 ]] && {  # test_case
    test_case=$1
    shift
  } || {
    echo "$FUNCNAME: missing arg: test_case" 1>&2
    return 1
  }

  [[ -n $1 ]] && {  # host
    host=$1
    shift
  } || {
    echo "$FUNCNAME: missing arg: host" 1>&2
    return 1
  }

  [[ -n $1 ]] && {  # client_type
    case $1 in
      cxx|go|java|node|php|python|ruby|csharp_mono)
        grpc_gen_test_cmd="grpc_cloud_prod_gen_$1_cmd"
        declare -F $grpc_gen_test_cmd >> /dev/null || {
          echo "-f: test_func for $1 => $grpc_gen_test_cmd is not defined" 1>&2
          return 2
        }
        shift
        ;;
      *)
        echo "bad client_type: $1" 1>&2
        return 1
        ;;
    esac
  } || {
    echo "$FUNCNAME: missing arg: client_type" 1>&2
    return 1
  }
}

# checks the positional args and assigns them to variables visible in the caller
#
# these are the positional args passed to grpc_cloud_prod_auth_test after option flags
# are removed
#
# three args are expected, in order
# - test_case
# - host <the gce docker instance on which to run the test>
# - client to run
grpc_cloud_prod_auth_test_args() {
  grpc_gen_test_cmd="grpc_cloud_prod_auth_"
  [[ -n $1 ]] && {  # test_case
    test_case=$1
    grpc_gen_test_cmd+="$1"
    shift
  } || {
    echo "$FUNCNAME: missing arg: test_case" 1>&2
    return 1
  }

  [[ -n $1 ]] && {  # host
    host=$1
    shift
  } || {
    echo "$FUNCNAME: missing arg: host" 1>&2
    return 1
  }

  [[ -n $1 ]] && {  # client_type
    case $1 in
      cxx|go|java|node|php|python|ruby)
        grpc_gen_test_cmd+="_gen_$1_cmd"
        declare -F $grpc_gen_test_cmd >> /dev/null || {
          echo "-f: test_func for $1 => $grpc_gen_test_cmd is not defined" 1>&2
          return 2
        }
        shift
        ;;
      *)
        echo "bad client_type: $1" 1>&2
        return 1
        ;;
    esac
  } || {
    echo "$FUNCNAME: missing arg: client_type" 1>&2
    return 1
  }
}

_grpc_sync_scripts_args() {
  grpc_gce_script_root='tools/gce_setup'

  local OPTIND
  local OPTARG
  while getopts :s: name
  do
    case $name in
      s)  grpc_gce_script_root=$OPTARG ;;
      :)  continue ;; # ignore -s without args, just use the defaults
      \?)  echo "-$OPTARG: unknown flag; it's ignored" 1>&2;  continue ;;
    esac
  done
  shift $((OPTIND-1))

  [[ -d $grpc_gce_script_root ]] || {
    echo "Could not locate gce script dir: $grpc_gce_script_root" 1>&2
    return 1
  }

  [[ $# -lt 1  ]] && {
    echo "$FUNCNAME: missing arg: host1 [host2 ... hostN]" 1>&2
    return 1
  }
  grpc_hosts="$@"
}

# Updates the latest version of the support scripts on some hosts.
#
# call-seq;
#   grpc_sync_scripts <server_name1>, <server_name2> .. <server_name3>
#
# Updates the GCE docker instance <server_name>
grpc_sync_scripts() {
  _grpc_ensure_gcloud_ssh || return 1;

  # declare vars local so that they don't pollute the shell environment
  # where this func is used.
  local grpc_zone grpc_project dry_run  # set by _grpc_set_project_and_zone
  local grpc_hosts grpc_gce_script_root

  # set the project zone and check that all necessary args are provided
  _grpc_set_project_and_zone -f _grpc_sync_scripts_args "$@" || return 1

  local func_lib="shared_startup_funcs.sh"
  local gce_func_lib="/var/local/startup_scripts/$func_lib"
  local project_opt="--project $grpc_project"
  local zone_opt="--zone $grpc_zone"
  local host
  for host in $grpc_hosts
  do
    gce_has_instance $grpc_project $host || return 1;
    # Update the remote copy of the GCE func library.
    local src_func_lib="$grpc_gce_script_root/$func_lib"
    local rmt_func_lib="$host:$gce_func_lib"
    gcloud compute copy-files $src_func_lib $rmt_func_lib $project_opt $zone_opt || return 1
  done
}

grpc_sync_images_args() {
  [[ $# -lt 1  ]] && {
    echo "$FUNCNAME: missing arg: host1 [host2 ... hostN]" 1>&2
    return 1
  }
  grpc_hosts="$@"
}

# Updates all the known docker images on a host..
#
# call-seq;
#   grpc_sync_images <server_name1>, <server_name2> .. <server_name3>
#
# Updates the GCE docker instance <server_name>
grpc_sync_images() {
  _grpc_ensure_gcloud_ssh || return 1;

  # declare vars local so that they don't pollute the shell environment
  # where this func is used.
  local grpc_zone grpc_project dry_run  # set by _grpc_set_project_and_zone
  local grpc_hosts

  # set the project zone and check that all necessary args are provided
  _grpc_set_project_and_zone -f grpc_sync_images_args "$@" || return 1

  local func_lib="/var/local/startup_scripts/shared_startup_funcs.sh"
  local cmd="source $func_lib && grpc_docker_pull_known"
  local project_opt="--project $grpc_project"
  local zone_opt="--zone $grpc_zone"
  local host
  for host in $grpc_hosts
  do
    gce_has_instance $grpc_project $host || return 1;
    local ssh_cmd="bash -l -c \"$cmd\""
    echo "will run:"
    echo "  $ssh_cmd"
    echo "on $host"
    [[ $dry_run == 1 ]] && continue  # don't run the command on a dry run
    gcloud compute $project_opt ssh $zone_opt $host --command "$cmd"
  done
}

_grpc_show_servers_args() {
  [[ -n $1 ]] && {  # host
    host=$1
    shift
  } || {
    echo "$FUNCNAME: missing arg: host" 1>&2
    return 1
  }
}


# Shows servers on a docker instance.
#
# call-seq;
#   grpc_show_servers <server_name>
#   E.g
#   grpc_show_server grpc-docker-server
#
# Shows the grpc servers on the GCE instance <server_name>
grpc_show_servers() {
  # declare vars local so that they don't pollute the shell environment
  # where this func is used.
  local grpc_zone grpc_project dry_run  # set by _grpc_set_project_and_zone
  # set by _grpc_show_servers
  local host

  # set the project zone and check that all necessary args are provided
  _grpc_set_project_and_zone -f _grpc_show_servers_args "$@" || return 1
  gce_has_instance $grpc_project $host || return 1;

  local cmd="sudo docker ps | grep grpc_"
  local ssh_cmd="bash -l -c \"$cmd\""
  echo "will run:"
  echo "  $ssh_cmd"
  echo "on $host"
  [[ $dry_run == 1 ]] && continue  # don't run the command on a dry run
  gcloud compute $project_opt ssh $zone_opt $host --command "$cmd"
}

_grpc_build_proto_bins_args() {
  [[ -n $1 ]] && {  # host
    host=$1
    shift
  } || {
    host='grpc-docker-builder'
  }
}

# grpc_build_proto_bins
#
# - rebuilds the dist_proto docker image
#   * doing this builds the protoc and the ruby, python and cpp bins statically
#
# - runs a docker command that copies the built protos to the GCE host
# - copies the built protos to the local machine
grpc_build_proto_bins() {
  _grpc_ensure_gcloud_ssh || return 1;

  # declare vars local so that they don't pollute the shell environment
  # where this func is used.
  local grpc_zone grpc_project dry_run  # set by _grpc_set_project_and_zone
  # set by _grpc_build_proto_bins_args
  local host

  # set the project zone and check that all necessary args are provided
  _grpc_set_project_and_zone -f _grpc_build_proto_bins_args "$@" || return 1
  gce_has_instance $grpc_project $host || return 1;
  local project_opt="--project $grpc_project"
  local zone_opt="--zone $grpc_zone"

  # rebuild the dist_proto image
  local label='dist_proto'
  grpc_update_image -- -h $host $label || return 1

  # run a command to copy the generated archive to the docker host
  local docker_prefix='sudo docker run -v /tmp:/tmp/proto_bins_out'
  local tar_name='proto-bins*.tar.gz'
  local cp_cmd="/bin/bash -c 'cp -v /tmp/$tar_name /tmp/proto_bins_out'"
  local cmd="$docker_prefix grpc/$label $cp_cmd"
  local ssh_cmd="bash -l -c \"$cmd\""
  echo "will run:"
  echo "  $ssh_cmd"
  echo "on $host"
  gcloud compute $project_opt ssh $zone_opt $host --command "$cmd" || return 1

  # copy the tar.gz locally
  local rmt_tar="$host:/tmp/$tar_name"
  local local_copy="$(pwd)"
  gcloud compute copy-files $rmt_tar $local_copy $project_opt $zone_opt || return 1
}

_grpc_build_debs_args() {
  [[ -n $1 ]] && {  # host
    host=$1
    shift
  } || {
    host='grpc-docker-builder'
  }
}

# grpc_build_debs
#
# - rebuilds the build_debs
#   * doing this builds a deb package for release debs
#
# - runs a docker command that copies the debs from the docker instance to its
#   host
# - copies the debs from the host to the local machine
grpc_build_debs() {
  _grpc_ensure_gcloud_ssh || return 1;

  # declare vars local so that they don't pollute the shell environment
  # where this func is used.
  local grpc_zone grpc_project dry_run  # set by _grpc_set_project_and_zone
  # set by _grpc_build_debs_args
  local host

  # set the project zone and check that all necessary args are provided
  _grpc_set_project_and_zone -f _grpc_build_debs_args "$@" || return 1
  gce_has_instance $grpc_project $host || return 1;
  local project_opt="--project $grpc_project"
  local zone_opt="--zone $grpc_zone"

  # Update the remote distpackages_dir
  local src_dist_dir='tools/distpackages'
  local rmt_dist_dir="$host:~"
  gcloud compute copy-files $src_dist_dir $rmt_dist_dir $project_opt $zone_opt || return 1

  # rebuild the build_deb image
  local label='build_deb'
  grpc_update_image -- -h $host $label || return 1

  # run a command to copy the debs from the docker instance to the host.
  local docker_prefix='sudo docker run -v /tmp:/tmp/host_deb_out'
  local cp_cmd="/bin/bash -c 'cp -v /tmp/deb_out/*.deb /tmp/host_deb_out'"
  local cmd="$docker_prefix grpc/$label $cp_cmd"
  local ssh_cmd="bash -l -c \"$cmd\""
  echo "will run:"
  echo "  $ssh_cmd"
  echo "on $host"
  gcloud compute $project_opt ssh $zone_opt $host --command "$cmd" || return 1

  # copy the debs from host machine to the local one.
  local rmt_debs="$host:/tmp/*.deb"
  local local_copy="$(pwd)"
  gcloud compute copy-files $rmt_debs $local_copy $project_opt $zone_opt || return 1
}

_grpc_launch_servers_args() {
  [[ -n $1 ]] && {  # host
    host=$1
    shift
  } || {
    echo "$FUNCNAME: missing arg: host" 1>&2
    return 1
  }
  [[ -n $1 ]] && {
    servers="$@"
  } || {
    servers="cxx java go node ruby python csharp_mono"
    echo "$FUNCNAME: no servers specified, will launch defaults '$servers'"
  }
}

# Launches servers on a docker instance.
#
# call-seq;
#   grpc_launch_servers <server_name> [server1 server2 ...]
#   E.g
#   grpc_launch_server grpc-docker-server ruby node
#
# Restarts all the specified servers on the GCE instance <server_name>
# If no servers are specified, it launches all known servers
grpc_launch_servers() {
  # declare vars local so that they don't pollute the shell environment
  # where this func is used.
  local grpc_zone grpc_project dry_run  # set by _grpc_set_project_and_zone
  # set by _grpc_launch_servers_args
  local host servers

  # set the project zone and check that all necessary args are provided
  _grpc_set_project_and_zone -f _grpc_launch_servers_args "$@" || return 1
  gce_has_instance $grpc_project $host || return 1;

  # launch each of the servers in turn
  for server in $servers
  do
    local grpc_port
    case $server in
      cxx)    grpc_port=8010 ;;
      go)     grpc_port=8020 ;;
      java)   grpc_port=8030 ;;
      node)   grpc_port=8040 ;;
      python) grpc_port=8050 ;;
      ruby)   grpc_port=8060 ;;
      csharp_mono)   grpc_port=8070 ;;
      *) echo "bad server_type: $1" 1>&2; return 1 ;;
    esac
    local docker_label="grpc/$server"
    local docker_name="grpc_interop_$server"

    cmd="sudo docker kill $docker_name > /dev/null 2>&1; "
    cmd+="sudo docker rm $docker_name > /dev/null 2>&1; "
    cmd+="sudo docker run -d --name $docker_name"
    cmd+=" -p $grpc_port:$grpc_port $docker_label"
    local project_opt="--project $grpc_project"
    local zone_opt="--zone $grpc_zone"
    local ssh_cmd="bash -l -c \"$cmd\""
    echo "will run:"
    echo "  $ssh_cmd"
    echo "on $host"
    [[ $dry_run == 1 ]] && return 0  # don't run the command on a dry run
    gcloud compute $project_opt ssh $zone_opt $host --command "$cmd"
  done
}

# Runs a test command on a docker instance
#
# The test command is issued via gcloud compute
#
# There are 3 possible results:
# 1. successful return code and finished within 60 seconds
# 2. failure return code and finished within 60 seconds
# 3. command does not return within 60 seconds, in which case it will be killed.
test_runner() {
  local project_opt="--project $grpc_project"
  local zone_opt="--zone $grpc_zone"
  local ssh_cmd="bash -l -c \"$cmd\""
  echo "will run:"
  echo "  $ssh_cmd"
  echo "on $host"
  [[ $dry_run == 1 ]] && return 0  # don't run the command on a dry run
  gcloud compute $project_opt ssh $zone_opt $host --command "$cmd" &
  PID=$!
  echo "pid is $PID"
  for x in {0..5}
  do
    if ps -p $PID
    then
      # test command has not returned and 60 seconds timeout has not reached
      sleep 10
    else
      # test command has returned, return the return code from the test command
      wait $PID
      local ret=$?
      echo " test runner return $ret before timeout"
      return $ret
    fi
  done
  kill $PID
  echo "test got killed by timeout return as failure"
  return 1
}

# Runs a test command on a docker instance.
#
# call-seq:
#   grpc_interop_test <test_name> <host> <client_type> \
#                     <server_host> <server_type>
#
# N.B:  server_name defaults to 'grpc-docker-server'
#
# requirements:
#   host is a GCE instance running docker with access to the gRPC docker images
#   server_name is a GCE docker instance running the gRPC server in docker
#   test_name is one of the named gRPC tests [http://go/grpc_interop_tests]
#   client_type is one of [cxx,go,java,php,python,ruby]
#   server_type is one of [cxx,go,java,python,ruby]
#
# it assumes:
#   that each grpc-imp has a docker image named grpc/<imp>, e.g, grpc/java
#   a test is run using $ docker run 'path/to/interop_test_bin --flags'
#   the required images are available on <host>
#
#   server_name [default:grpc-docker-server] is an instance that runs the
#   <server_type> server on the standard test port for the <server_type>
#
# each server_type runs it tests on a standard test port as follows:
#   cxx:    8010
#   go:     8020
#   java:   8030
#   node:   8040
#   python: 8050
#   ruby:   8060
#
# each client_type should have an associated bash func:
#   grpc_interop_gen_<client_type>_cmd
# the func provides the dockerized commmand for running client_type's test.
# If no such func is available, tests for that client type cannot be run.
#
# the flags for running a test are the same:
#
# --server_host=<svr_addr>  --server_port=<svr_port> --test_case=<...>
grpc_interop_test() {
  _grpc_ensure_gcloud_ssh || return 1;
  # declare vars local so that they don't pollute the shell environment
  # where this func is used.

  local grpc_zone grpc_project dry_run  # set by _grpc_set_project_and_zone
  #  grpc_interop_test_args
  local test_case host grpc_gen_test_cmd grpc_server grpc_port

  # set the project zone and check that all necessary args are provided
  _grpc_set_project_and_zone -f grpc_interop_test_args "$@" || return 1
  gce_has_instance $grpc_project $host || return 1;

  local addr=$(gce_find_internal_ip $grpc_project $grpc_server)
  [[ -n $addr ]] || return 1
  local flags=$(grpc_interop_test_flags $addr $grpc_port $test_case)
  [[ -n $flags ]] || return 1
  cmd=$($grpc_gen_test_cmd $flags)
  [[ -n $cmd ]] || return 1

  test_runner
}

# Runs a test command on a docker instance.
#
# call-seq:
#   grpc_cloud_prod_test <test_name> <host> <client_type>
#
# requirements:
#   host is a GCE instance running docker with access to the gRPC docker images
#   test_name is one of the named gRPC tests [http://go/grpc_interop_tests]
#   client_type is one of [cxx,go,java,php,python,ruby]
#
# it assumes:
#   that each grpc-imp has a docker image named grpc/<imp>, e.g, grpc/java
#   a test is run using $ docker run 'path/to/interop_test_bin --flags'
#   the required images are available on <host>
#
# each client_type should have an associated bash func:
#   grpc_cloud_prod_gen_<client_type>_cmd
# the func provides the dockerized commmand for running client_type's test.
# If no such func is available, tests for that client type cannot be run.
grpc_cloud_prod_test() {
  _grpc_ensure_gcloud_ssh || return 1;
  # declare vars local so that they don't pollute the shell environment
  # where this func is used.

  local grpc_zone grpc_project dry_run  # set by _grpc_set_project_and_zone
  #  grpc_cloud_prod_test_args
  local test_case host grpc_gen_test_cmd

  # set the project zone and check that all necessary args are provided
  _grpc_set_project_and_zone -f grpc_cloud_prod_test_args "$@" || return 1
  gce_has_instance $grpc_project $host || return 1;

  local test_case_flag=" --test_case=$test_case"
  cmd=$($grpc_gen_test_cmd $test_case_flag)
  [[ -n $cmd ]] || return 1

  test_runner
}

# Runs a test command on a docker instance.
#
# call-seq:
#   grpc_cloud_prod_auth_test <test_name> <host> <client_type>
#
# requirements:
#   host is a GCE instance running docker with access to the gRPC docker images
#   test_name is one of the named gRPC tests [http://go/grpc_interop_tests]
#   client_type is one of [cxx,go,java,php,python,ruby]
#
# it assumes:
#   that each grpc-imp has a docker image named grpc/<imp>, e.g, grpc/java
#   a test is run using $ docker run 'path/to/interop_test_bin --flags'
#   the required images are available on <host>
#
# each client_type should have an associated bash func:
#   grpc_cloud_prod_auth_<test_case>_gen_<client_type>_cmd
# the func provides the dockerized commmand for running client_type's test.
# If no such func is available, tests for that client type cannot be run.
grpc_cloud_prod_auth_test() {
  _grpc_ensure_gcloud_ssh || return 1;
  # declare vars local so that they don't pollute the shell environment
  # where this func is used.

  local grpc_zone grpc_project dry_run  # set by _grpc_set_project_and_zone
  #  grpc_cloud_prod_test_args
  local test_case host grpc_gen_test_cmd

  # set the project zone and check that all necessary args are provided
  _grpc_set_project_and_zone -f grpc_cloud_prod_auth_test_args "$@" || return 1
  gce_has_instance $grpc_project $host || return 1;

  local test_case_flag=" --test_case=$test_case"
  cmd=$($grpc_gen_test_cmd $test_case_flag)
  [[ -n $cmd ]] || return 1

  test_runner
}

# constructs the full dockerized ruby interop test cmd.
#
# call-seq:
#   flags= .... # generic flags to include the command
#   cmd=$($grpc_gen_test_cmd $flags)
grpc_interop_gen_ruby_cmd() {
  local cmd_prefix="sudo docker run grpc/ruby bin/bash -l -c"
  local test_script="/var/local/git/grpc/src/ruby/bin/interop/interop_client.rb"
  local the_cmd="$cmd_prefix 'ruby $test_script --use_test_ca --use_tls $@'"
  echo $the_cmd
}

# constructs the full dockerized python interop test cmd.
#
# call-seq:
#   flags= .... # generic flags to include the command
#   cmd=$($grpc_gen_test_cmd $flags)
grpc_interop_gen_python_cmd() {
  local cmd_prefix="sudo docker run grpc/python bin/bash -l -c"
  local the_cmd="$cmd_prefix 'python -B -m interop.client --use_test_ca --use_tls $@'"
  echo $the_cmd
}

# constructs the full dockerized python interop test cmd.
#
# call-seq:
#   flags= .... # generic flags to include the command
#   cmd=$($grpc_gen_test_cmd $flags)
grpc_cloud_prod_gen_python_cmd() {
  local cmd_prefix="sudo docker run grpc/python bin/bash -l -c"
  local gfe_flags=$(_grpc_prod_gfe_flags)
  local env_prefix="SSL_CERT_FILE=/cacerts/roots.pem"
  local the_cmd="$cmd_prefix '$env_prefix python -B -m interop.client --use_tls $gfe_flags $@'"
  echo $the_cmd
}

# constructs the full dockerized python service_account auth interop test cmd.
#
# call-seq:
#   flags= .... # generic flags to include the command
#   cmd=$($grpc_gen_test_cmd $flags)
grpc_cloud_prod_auth_service_account_creds_gen_python_cmd() {
  local cmd_prefix="sudo docker run grpc/python bin/bash -l -c";
  local gfe_flags=$(_grpc_prod_gfe_flags)
  local added_gfe_flags=$(_grpc_default_creds_test_flags)
  local env_prefix="SSL_CERT_FILE=/cacerts/roots.pem"
  env_prefix+=" GOOGLE_APPLICATION_CREDENTIALS=/service_account/stubbyCloudTestingTest-7dd63462c60c.json"
  local the_cmd="$cmd_prefix '$env_prefix python -B -m interop.client --use_tls $gfe_flags $added_gfe_flags $@'"
  echo $the_cmd
}

# constructs the full dockerized python gce auth interop test cmd.
#
# call-seq:
#   flags= .... # generic flags to include the command
#   cmd=$($grpc_gen_test_cmd $flags)
grpc_cloud_prod_auth_compute_engine_creds_gen_python_cmd() {
  local cmd_prefix="sudo docker run grpc/python bin/bash -l -c";
  local gfe_flags=$(_grpc_prod_gfe_flags)
  local added_gfe_flags=$(_grpc_gce_test_flags)
  local env_prefix="SSL_CERT_FILE=/cacerts/roots.pem"
  local the_cmd="$cmd_prefix '$env_prefix python -B -m interop.client --use_tls $gfe_flags $added_gfe_flags $@'"
  echo $the_cmd
}

# constructs the full dockerized ruby interop test cmd.
#
# call-seq:
#   flags= .... # generic flags to include the command
#   cmd=$($grpc_gen_test_cmd $flags)
grpc_cloud_prod_gen_ruby_cmd() {
  local cmd_prefix="sudo docker run grpc/ruby bin/bash -l -c"
  local test_script="/var/local/git/grpc/src/ruby/bin/interop/interop_client.rb"
  local test_script+=" --use_tls"
  local gfe_flags=$(_grpc_prod_gfe_flags)
  local env_prefix="SSL_CERT_FILE=/cacerts/roots.pem"
  local the_cmd="$cmd_prefix '$env_prefix ruby $test_script $gfe_flags $@'"
  echo $the_cmd
}

# constructs the full dockerized Go interop test cmd.
#
# call-seq:
#   flags= .... # generic flags to include the command
#   cmd=$($grpc_gen_test_cmd $flags)
grpc_cloud_prod_auth_service_account_creds_gen_go_cmd() {
  local cmd_prefix="sudo docker run grpc/go /bin/bash -c"
  local test_script="cd src/google.golang.org/grpc/interop/client"
  local test_script+=" && go run client.go --use_tls=true"
  local gfe_flags=$(_grpc_prod_gfe_flags)
  local gfe_flags+="  --tls_ca_file=\"\""
  local added_gfe_flags=$(_grpc_svc_acc_test_flags)
  local the_cmd="$cmd_prefix '$test_script $gfe_flags $added_gfe_flags $@'"
  echo $the_cmd
}

# constructs the full dockerized Go interop test cmd.
#
# call-seq:
#   flags= .... # generic flags to include the command
#   cmd=$($grpc_gen_test_cmd $flags)
grpc_cloud_prod_auth_compute_engine_creds_gen_go_cmd() {
  local cmd_prefix="sudo docker run grpc/go /bin/bash -c"
  local test_script="cd src/google.golang.org/grpc/interop/client"
  local test_script+=" && go run client.go --use_tls=true"
  local gfe_flags=$(_grpc_prod_gfe_flags)
  local gfe_flags+="  --tls_ca_file=\"\""
  local added_gfe_flags=$(_grpc_gce_test_flags)
  local the_cmd="$cmd_prefix '$test_script $gfe_flags $added_gfe_flags $@'"
  echo $the_cmd
}

# constructs the full dockerized ruby service_account auth interop test cmd.
#
# call-seq:
#   flags= .... # generic flags to include the command
#   cmd=$($grpc_gen_test_cmd $flags)
grpc_cloud_prod_auth_service_account_creds_gen_ruby_cmd() {
  local cmd_prefix="sudo docker run grpc/ruby bin/bash -l -c";
  local test_script="/var/local/git/grpc/src/ruby/bin/interop/interop_client.rb"
  local test_script+=" --use_tls"
  local gfe_flags=$(_grpc_prod_gfe_flags)
  local added_gfe_flags=$(_grpc_default_creds_test_flags)
  local env_prefix="SSL_CERT_FILE=/cacerts/roots.pem"
  env_prefix+=" GOOGLE_APPLICATION_CREDENTIALS=/service_account/stubbyCloudTestingTest-7dd63462c60c.json"
  local the_cmd="$cmd_prefix '$env_prefix ruby $test_script $gfe_flags $added_gfe_flags $@'"
  echo $the_cmd
}

# constructs the full dockerized ruby gce auth interop test cmd.
#
# call-seq:
#   flags= .... # generic flags to include the command
#   cmd=$($grpc_gen_test_cmd $flags)
grpc_cloud_prod_auth_compute_engine_creds_gen_ruby_cmd() {
  local cmd_prefix="sudo docker run grpc/ruby bin/bash -l -c";
  local test_script="/var/local/git/grpc/src/ruby/bin/interop/interop_client.rb"
  local test_script+=" --use_tls"
  local gfe_flags=$(_grpc_prod_gfe_flags)
  local added_gfe_flags=$(_grpc_gce_test_flags)
  local env_prefix="SSL_CERT_FILE=/cacerts/roots.pem"
  local the_cmd="$cmd_prefix '$env_prefix ruby $test_script $gfe_flags $added_gfe_flags $@'"
  echo $the_cmd
}

# constructs the full dockerized Go interop test cmd.
#
# call-seq:
#   flags= .... # generic flags to include the command
#   cmd=$($grpc_gen_test_cmd $flags)
grpc_interop_gen_go_cmd() {
  local cmd_prefix="sudo docker run grpc/go /bin/bash -c"
  local test_script="cd src/google.golang.org/grpc/interop/client"
  local test_script+=" && go run client.go --use_tls=true"
  local the_cmd="$cmd_prefix '$test_script $@'"
  echo $the_cmd
}

# constructs the full dockerized Go interop test cmd.
#
# call-seq:
#   flags= .... # generic flags to include the command
#   cmd=$($grpc_gen_test_cmd $flags)
grpc_cloud_prod_gen_go_cmd() {
  local cmd_prefix="sudo docker run grpc/go /bin/bash -c"
  local test_script="cd src/google.golang.org/grpc/interop/client"
  local test_script+=" && go run client.go --use_tls=true"
  local gfe_flags=$(_grpc_prod_gfe_flags)
  local gfe_flags+="  --tls_ca_file=\"\""
  local the_cmd="$cmd_prefix '$test_script $gfe_flags $@'"
  echo $the_cmd
}

# constructs the full dockerized java interop test cmd.
#
# call-seq:
#   flags= .... # generic flags to include the command
#   cmd=$($grpc_gen_test_cmd $flags)
grpc_interop_gen_java_cmd() {
    local cmd_prefix="sudo docker run grpc/java";
    local test_script="/var/local/git/grpc-java/run-test-client.sh";
    local test_script+=" --use_test_ca=true --use_tls=true"
    local the_cmd="$cmd_prefix $test_script $@";
    echo $the_cmd
}

# constructs the full dockerized java interop test cmd.
#
# call-seq:
#   flags= .... # generic flags to include the command
#   cmd=$($grpc_gen_test_cmd $flags)
grpc_cloud_prod_gen_java_cmd() {
    local cmd_prefix="sudo docker run grpc/java";
    local test_script="/var/local/git/grpc-java/run-test-client.sh";
    local test_script+=" --use_tls=true"
    local gfe_flags=$(_grpc_prod_gfe_flags)
    local the_cmd="$cmd_prefix $test_script $gfe_flags $@";
    echo $the_cmd
}

# constructs the full dockerized php interop test cmd.
#
# TODO(mlumish): update this to use the script once that's on git
#
# call-seq:
#   flags= .... # generic flags to include the command
#   cmd=$($grpc_gen_test_cmd $flags)
grpc_interop_gen_php_cmd() {
    local cmd_prefix="sudo docker run grpc/php bin/bash -l -c";
    local test_script="cd /var/local/git/grpc/src/php/tests/interop";
    local test_script+=" && php -d extension_dir=../../ext/grpc/modules/";
    local test_script+=" -d extension=grpc.so interop_client.php";
    local the_cmd="$cmd_prefix '$test_script $@ 1>&2'";
    echo $the_cmd
}

# constructs the full dockerized node interop test cmd.
#
# call-seq:
#   flags= .... # generic flags to include the command
#   cmd=$($grpc_gen_test_cmd $flags)
grpc_interop_gen_node_cmd() {
  local cmd_prefix="sudo docker run grpc/node";
  local test_script="/usr/bin/nodejs /var/local/git/grpc/src/node/interop/interop_client.js --use_tls=true --use_test_ca=true";
  local the_cmd="$cmd_prefix $test_script $@";
  echo $the_cmd
}

# constructs the full dockerized node gce=>prod interop test cmd.
#
# call-seq:
#   flags= .... # generic flags to include the command
#   cmd=$($grpc_gen_test_cmd $flags)
grpc_cloud_prod_gen_node_cmd() {
  local env_flag="-e SSL_CERT_FILE=/cacerts/roots.pem "
  local cmd_prefix="sudo docker run $env_flag grpc/node";
  local test_script="/usr/bin/nodejs /var/local/git/grpc/src/node/interop/interop_client.js --use_tls=true";
  local gfe_flags=$(_grpc_prod_gfe_flags);
  local the_cmd="$cmd_prefix $test_script $gfe_flags $@";
  echo $the_cmd
}

# constructs the full dockerized node service_account auth interop test cmd.
#
# call-seq:
#   flags= .... # generic flags to include the command
#   cmd=$($grpc_gen_test_cmd $flags)
grpc_cloud_prod_auth_service_account_creds_gen_node_cmd() {
  local env_flag="-e SSL_CERT_FILE=/cacerts/roots.pem "
  env_flag+="-e GOOGLE_APPLICATION_CREDENTIALS=/service_account/stubbyCloudTestingTest-7dd63462c60c.json "
  local cmd_prefix="sudo docker run $env_flag grpc/node";
  local test_script="/usr/bin/nodejs /var/local/git/grpc/src/node/interop/interop_client.js --use_tls=true";
  local gfe_flags=$(_grpc_prod_gfe_flags);
  local the_cmd="$cmd_prefix $test_script $gfe_flags $@";
  echo $the_cmd
}

# constructs the full dockerized node gce auth interop test cmd.
#
# call-seq:
#   flags= .... # generic flags to include the command
#   cmd=$($grpc_gen_test_cmd $flags)
grpc_cloud_prod_auth_compute_engine_creds_gen_node_cmd() {
  local env_flag="-e SSL_CERT_FILE=/cacerts/roots.pem "
  local cmd_prefix="sudo docker run $env_flag grpc/node";
  local test_script="/usr/bin/nodejs /var/local/git/grpc/src/node/interop/interop_client.js --use_tls=true";
  local gfe_flags=$(_grpc_prod_gfe_flags)
  local added_gfe_flags=$(_grpc_gce_test_flags)
  local the_cmd="$cmd_prefix $test_script $gfe_flags $added_gfe_flags $@";
  echo $the_cmd
}

# constructs the full dockerized cpp interop test cmd.
#
# call-seq:
#   flags= .... # generic flags to include the command
#   cmd=$($grpc_gen_test_cmd $flags)
grpc_interop_gen_cxx_cmd() {
    local cmd_prefix="sudo docker run grpc/cxx";
    local test_script="/var/local/git/grpc/bins/opt/interop_client --enable_ssl";
    local the_cmd="$cmd_prefix $test_script $@";
    echo $the_cmd
}

# constructs the full dockerized cpp gce=>prod interop test cmd.
#
# call-seq:
#   flags= .... # generic flags to include the command
#   cmd=$($grpc_gen_test_cmd $flags)
grpc_cloud_prod_gen_cxx_cmd() {
    local cmd_prefix="sudo docker run grpc/cxx";
    local test_script="/var/local/git/grpc/bins/opt/interop_client --enable_ssl --use_prod_roots";
    local gfe_flags=$(_grpc_prod_gfe_flags)
    local the_cmd="$cmd_prefix $test_script $gfe_flags $@";
    echo $the_cmd
}

# constructs the full dockerized cpp service_account auth interop test cmd.
#
# call-seq:
#   flags= .... # generic flags to include the command
#   cmd=$($grpc_gen_test_cmd $flags)
grpc_cloud_prod_auth_service_account_creds_gen_cxx_cmd() {
    local cmd_prefix="sudo docker run grpc/cxx";
    local test_script="/var/local/git/grpc/bins/opt/interop_client --enable_ssl --use_prod_roots";
    local gfe_flags=$(_grpc_prod_gfe_flags)
    local added_gfe_flags=$(_grpc_svc_acc_test_flags)
    local the_cmd="$cmd_prefix $test_script $gfe_flags $added_gfe_flags $@";
    echo $the_cmd
}

# constructs the full dockerized cpp gce auth interop test cmd.
#
# call-seq:
#   flags= .... # generic flags to include the command
#   cmd=$($grpc_gen_test_cmd $flags)
grpc_cloud_prod_auth_compute_engine_creds_gen_cxx_cmd() {
    local cmd_prefix="sudo docker run grpc/cxx";
    local test_script="/var/local/git/grpc/bins/opt/interop_client --enable_ssl --use_prod_roots";
    local gfe_flags=$(_grpc_prod_gfe_flags)
    local added_gfe_flags=$(_grpc_gce_test_flags)
    local the_cmd="$cmd_prefix $test_script $gfe_flags $added_gfe_flags $@";
    echo $the_cmd
}

# constructs the full dockerized cpp jwt_token auth interop test cmd.
#
# call-seq:
#   flags= .... # generic flags to include the command
#   cmd=$($grpc_gen_test_cmd $flags)
grpc_cloud_prod_auth_jwt_token_creds_gen_cxx_cmd() {
    local cmd_prefix="sudo docker run grpc/cxx";
    local test_script="/var/local/git/grpc/bins/opt/interop_client --enable_ssl --use_prod_roots";
    local gfe_flags=$(_grpc_prod_gfe_flags)
    local added_gfe_flags=$(_grpc_jwt_token_test_flags)
    local the_cmd="$cmd_prefix $test_script $gfe_flags $added_gfe_flags $@";
    echo $the_cmd
}

# constructs the full dockerized csharp-mono interop test cmd.
#
# call-seq:
#   flags= .... # generic flags to include the command
#   cmd=$($grpc_gen_test_cmd $flags)
grpc_interop_gen_csharp_mono_cmd() {
  local workdir_flag="-w /var/local/git/grpc/src/csharp/Grpc.IntegrationTesting.Client/bin/Debug"
  local cmd_prefix="sudo docker run $workdir_flag grpc/csharp_mono";
  local test_script="mono Grpc.IntegrationTesting.Client.exe --use_tls=true --use_test_ca=true";
  local the_cmd="$cmd_prefix $test_script $@";
  echo $the_cmd
}

# constructs the full dockerized csharp-mono gce=>prod interop test cmd.
#
# call-seq:
#   flags= .... # generic flags to include the command
#   cmd=$($grpc_gen_test_cmd $flags)
grpc_cloud_prod_gen_csharp_mono_cmd() {
  local env_flag="-e SSL_CERT_FILE=/cacerts/roots.pem "
  local workdir_flag="-w /var/local/git/grpc/src/csharp/Grpc.IntegrationTesting.Client/bin/Debug"
  local cmd_prefix="sudo docker run $env_flag $workdir_flag grpc/csharp_mono";
  local test_script="mono Grpc.IntegrationTesting.Client.exe --use_tls=true";
  local gfe_flags=$(_grpc_prod_gfe_flags);
  local the_cmd="$cmd_prefix $test_script $gfe_flags $@";
  echo $the_cmd
}

# outputs the flags passed to gfe tests
_grpc_prod_gfe_flags() {
  echo " --server_port=443 --server_host=grpc-test.sandbox.google.com --server_host_override=grpc-test.sandbox.google.com"
}

# outputs the flags passed to the service account auth tests
_grpc_svc_acc_test_flags() {
  echo " --service_account_key_file=/service_account/stubbyCloudTestingTest-7dd63462c60c.json --oauth_scope=https://www.googleapis.com/auth/xapi.zoo"
}

# outputs the flags passed to the service account auth tests
_grpc_jwt_token_test_flags() {
  echo " --service_account_key_file=/service_account/stubbyCloudTestingTest-7dd63462c60c.json"
}

# default credentials test flag
_grpc_default_creds_test_flags() {
  echo " --oauth_scope=https://www.googleapis.com/auth/xapi.zoo"
}

# outputs the flags passed to the gcloud auth tests
_grpc_gce_test_flags() {
  echo " --default_service_account=155450119199-r5aaqa2vqoa9g5mv2m6s3m1l293rlmel@developer.gserviceaccount.com --oauth_scope=https://www.googleapis.com/auth/xapi.zoo"
}