#!@BASH_SHELL@
#
#
# OCF resource agent to move an IP address within a VPC in GCP
#
# License: GNU General Public License (GPL)
# Copyright (c) 2018 Hervé Werner (MFG Labs)
# Based on code from Markus Guertler (aws-vpc-move-ip)
# All Rights Reserved.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of version 2 of the GNU General Public License as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it would be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
#
# Further, this software is distributed without any warranty that it is
# free of the rightful claim of any third person regarding infringement
# or the like.  Any license provided herein, whether implied or
# otherwise, applies only to this software file.  Patent licenses, if
# any, provided herein do not apply to combinations of this program with
# other software, or any other product whatsoever.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write the Free Software Foundation,
# Inc., 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
#


#######################################################################
# Initialization:

: ${OCF_FUNCTIONS_DIR=${OCF_ROOT}/lib/heartbeat}
. ${OCF_FUNCTIONS_DIR}/ocf-shellfuncs

# Defaults
OCF_RESKEY_gcloud_default="/usr/bin/gcloud"
OCF_RESKEY_configuration_default="default"
OCF_RESKEY_vpc_network_default="default"
OCF_RESKEY_interface_default="eth0"
OCF_RESKEY_route_name_default="ra-${__SCRIPT_NAME}"

: ${OCF_RESKEY_gcloud=${OCF_RESKEY_gcloud_default}}
: ${OCF_RESKEY_configuration=${OCF_RESKEY_configuration_default}}
: ${OCF_RESKEY_vpc_network=${OCF_RESKEY_vpc_network_default}}
: ${OCF_RESKEY_interface=${OCF_RESKEY_interface_default}}
: ${OCF_RESKEY_route_name=${OCF_RESKEY_route_name_default}}

gcp_api_url_prefix="https://www.googleapis.com/compute/v1"
gcloud="${OCF_RESKEY_gcloud} --quiet --configuration=${OCF_RESKEY_configuration}"

#######################################################################

USAGE="usage: $0 {start|stop|monitor|status|meta-data|validate-all}";
###############################################################################


###############################################################################
#
# Functions
#
###############################################################################


metadata() {
cat <<END
<?xml version="1.0"?>
<!DOCTYPE resource-agent SYSTEM "ra-api-1.dtd">
<resource-agent name="gcp-vpc-move-ip" version="1.0">
<version>1.0</version>
<longdesc lang="en">
Resource Agent that can move a floating IP addresse within a GCP VPC by changing an 
entry in the routing table. This agent also configures the floating IP locally
on the instance OS.
Requirements :
- IP forwarding must be enabled on all instances in order to be able to 
terminate the route
- The floating IP address must be chosen so that it is outside all existing
subnets in the VPC network
- IAM permissions
(see https://cloud.google.com/compute/docs/access/iam-permissions) : 
1) compute.routes.delete, compute.routes.get and compute.routes.update on the 
route
2) compute.networks.updatePolicy on the network (to add a new route)
3) compute.networks.get on the network (to check the VPC network existence)
4) compute.routes.list on the project (to check conflicting routes)
</longdesc>
<shortdesc lang="en">Move IP within a GCP VPC</shortdesc>

<parameters>
<parameter name="gcloud">
<longdesc lang="en">
Path to command line tools for GCP
</longdesc>
<shortdesc lang="en">Path to the gcloud tool</shortdesc>
<content type="string" default="${OCF_RESKEY_gcloud_default}" />
</parameter>

<parameter name="configuration">
<longdesc lang="en">
Named configuration for gcloud
</longdesc>
<shortdesc lang="en">Named gcloud configuration</shortdesc>
<content type="string" default="${OCF_RESKEY_configuration_default}" />
</parameter>

<parameter name="ip" unique="1" required="1">
<longdesc lang="en">
Floating IP address. Note that this IP must be chosen outside of all existing 
subnet ranges
</longdesc>
<shortdesc lang="en">Floating IP</shortdesc>
<content type="string" />
</parameter>

<parameter name="vpc_network" required="1">
<longdesc lang="en">
Name of the VPC network
</longdesc>
<shortdesc lang="en">VPC network</shortdesc>
<content type="string" default="${OCF_RESKEY_vpc_network_default}" />
</parameter>

<parameter name="interface">
<longdesc lang="en">
Name of the network interface
</longdesc>
<shortdesc lang="en">Network interface name</shortdesc>
<content type="string" default="${OCF_RESKEY_interface_default}" />
</parameter>

<parameter name="route_name" unique="1">
<longdesc lang="en">
Route name
</longdesc>
<shortdesc lang="en">Route name</shortdesc>
<content type="string" default="${OCF_RESKEY_route_name_default}" />
</parameter>
</parameters>

<actions>
<action name="start" timeout="180s" />
<action name="stop" timeout="180s" />
<action name="monitor" depth="0" timeout="30s" interval="60s" />
<action name="validate-all" timeout="5s" />
<action name="meta-data" timeout="5s" />
</actions>
</resource-agent>
END
}

validate() {
  if ! ocf_is_root; then
    ocf_exit_reason "You must run this agent as root"
    exit $OCF_ERR_PERM
  fi

  for cmd in ${OCF_RESKEY_gcloud} ip curl; do
    check_binary "$cmd"
  done

  if [ -z "${OCF_RESKEY_ip}" ]; then
    ocf_exit_reason "Missing mandatory parameter"
    exit $OCF_ERR_CONFIGURED
  fi

  GCE_INSTANCE_NAME=$(curl -s -H "Metadata-Flavor: Google" "http://metadata.google.internal/computeMetadata/v1/instance/name")
  GCE_INSTANCE_ZONE=$(curl -s -H "Metadata-Flavor: Google" "http://metadata.google.internal/computeMetadata/v1/instance/zone" | awk -F '/' '{ print $NF }')
  GCE_INSTANCE_PROJECT=$(curl -s -H "Metadata-Flavor: Google" "http://metadata.google.internal/computeMetadata/v1/project/project-id")

  if [ -z "${GCE_INSTANCE_NAME}" -o -z "${GCE_INSTANCE_ZONE}" -o -z "${GCE_INSTANCE_PROJECT}" ]; then
    ocf_exit_reason "Instance information not found. Is this a GCE instance ?"
    exit $OCF_ERR_GENERIC
  fi

  if ! ${OCF_RESKEY_gcloud} config configurations describe ${OCF_RESKEY_configuration} &>/dev/null; then
    ocf_exit_reason "Gcloud configuration not found"
    exit $OCF_ERR_CONFIGURED
  fi

  if ! ip link show ${OCF_RESKEY_interface} &> /dev/null; then
    ocf_exit_reason "Network interface not found"
    exit $OCF_ERR_CONFIGURED
  fi

  return $OCF_SUCCESS
}

check_conflicting_routes() {
  cmd="${gcloud} compute routes list \
              --filter='destRange:${OCF_RESKEY_ip} AND \
                        network=(${gcp_api_url_prefix}/projects/${GCE_INSTANCE_PROJECT}/global/networks/${OCF_RESKEY_vpc_network}) AND \
                        NOT name=${OCF_RESKEY_route_name}' \
              --format='value[terminator=\" \"](name)'"
  ocf_log debug "Executing command: $(echo $cmd)"
  route_list=$(eval ${cmd})
  if [ $? -ne 0 ]; then
    exit $OCF_ERR_GENERIC
  fi
  if [ -n "${route_list}" ]; then
    ocf_exit_reason "Conflicting unnmanaged routes for destination ${OCF_RESKEY_ip}/32 in VPC ${OCF_RESKEY_vpc_network} found : ${route_list}"
    exit $OCF_ERR_CONFIGURED
  fi
  return $OCF_SUCCESS
}

route_monitor() {
  ocf_log info "GCP route monitor: checking route table"

  # Ensure that there is no route that we are not aware of that is also handling our IP
  check_conflicting_routes

  cmd="${gcloud} compute routes describe ${OCF_RESKEY_route_name} --format='get(nextHopInstance)'"
  ocf_log debug "Executing command: $cmd"
  # Also redirect stderr as we parse the output to use an appropriate exit code
  routed_to_instance=$(eval $cmd 2>&1)
  if [ $? -ne 0 ]; then
    if echo $routed_to_instance | grep -qi "Insufficient Permission" ; then
      ocf_exit_reason "Insufficient permissions to get route information"
      exit $OCF_ERR_PERM 
    elif echo $routed_to_instance | grep -qi "Could not fetch resource"; then
      ocf_log debug "The route ${OCF_RESKEY_route_name} doesn't exist"
      return $OCF_NOT_RUNNING
    else
      ocf_exit_reason "Error : ${routed_to_instance}"
      exit $OCF_ERR_GENERIC
    fi
  fi
  if [ -z "${routed_to_instance}" ]; then
    routed_to_instance="<unknown>"
  fi

  if [ "${routed_to_instance}" != "${gcp_api_url_prefix}/projects/${GCE_INSTANCE_PROJECT}/zones/${GCE_INSTANCE_ZONE}/instances/${GCE_INSTANCE_NAME}" ]; then
    ocf_log warn "The floating IP ${OCF_RESKEY_ip} is not routed to this instance (${GCE_INSTANCE_NAME}) but to instance ${routed_to_instance##*/}"
    return $OCF_NOT_RUNNING
  fi

  ocf_log debug "The floating IP ${OCF_RESKEY_ip} is correctly routed to this instance (${GCE_INSTANCE_NAME})"
  return $OCF_SUCCESS
}

ip_monitor() {
  ocf_log info "IP monitor: checking local network configuration"

  cmd="ip address show dev ${OCF_RESKEY_interface} to ${OCF_RESKEY_ip}/32"
  ocf_log debug "Executing command: $cmd"
  if [ -z "$($cmd)" ]; then
    ocf_log warn "The floating IP ${OCF_RESKEY_ip} is not locally configured on this instance (${GCE_INSTANCE_NAME})"
    return $OCF_NOT_RUNNING
  fi

  ocf_log debug "The floating IP ${OCF_RESKEY_ip} is correctly configured on this instance (${GCE_INSTANCE_NAME})"
  return $OCF_SUCCESS
}

ip_release() {
  cmd="ip address delete ${OCF_RESKEY_ip}/32 dev ${OCF_RESKEY_interface}"
  ocf_log debug "Executing command: $cmd"
  ocf_run $cmd || return $OCF_ERR_GENERIC
  return $OCF_SUCCESS
}

route_release() {
  cmd="${gcloud} compute routes delete ${OCF_RESKEY_route_name}"
  ocf_log debug "Executing command: $cmd"
  ocf_run $cmd || return $OCF_ERR_GENERIC
  return $OCF_SUCCESS
}

ip_and_route_start() {
  ocf_log info "Bringing up the floating IP ${OCF_RESKEY_ip}"

  # Add a new entry in the routing table
  # If the route entry exists and is pointing to another instance, take it over

  # Ensure that there is no route that we are not aware of that is also handling our IP
  check_conflicting_routes

  # There is no replace API, We need to first delete the existing route if any
  if ${gcloud} compute routes describe ${OCF_RESKEY_route_name} &>/dev/null; then
    route_release
  fi

  cmd="${gcloud} compute routes create ${OCF_RESKEY_route_name} \
    --network=${OCF_RESKEY_vpc_network}  --destination-range=${OCF_RESKEY_ip}/32 \
    --next-hop-instance-zone=${GCE_INSTANCE_ZONE}  --next-hop-instance=${GCE_INSTANCE_NAME}"
  ocf_log debug "Executing command: $(echo $cmd)"
  ocf_run $cmd

  if [ $? -ne $OCF_SUCCESS ]; then
    if ! ${gcloud} compute networks describe ${OCF_RESKEY_vpc_network} &>/dev/null; then
      ocf_exit_reason "VPC network not found"
      exit $OCF_ERR_CONFIGURED
    else
      return $OCF_ERR_GENERIC
    fi
  fi

  # Configure the IP address locally
  # We need to release the IP first
  ip_monitor &>/dev/null
  if [ $? -eq $OCF_SUCCESS ]; then
    ip_release
  fi

  cmd="ip address add ${OCF_RESKEY_ip}/32 dev ${OCF_RESKEY_interface}"
  ocf_log debug "Executing command: $cmd"
  ocf_run $cmd || return $OCF_ERR_GENERIC

  cmd="ip link set ${OCF_RESKEY_interface} up"
  ocf_log debug "Executing command: $cmd"
  ocf_run $cmd || return $OCF_ERR_GENERIC

  ocf_log info "Successfully brought up the floating IP ${OCF_RESKEY_ip}"
  return $OCF_SUCCESS
}

ip_and_route_stop() {
  ocf_log info "Bringing down the floating IP ${OCF_RESKEY_ip}"

  # Delete the route entry
  # If the route entry exists and is pointing to another instance, don't touch it
  route_monitor &>/dev/null
  if [ $? -eq $OCF_NOT_RUNNING ]; then
    ocf_log info "The floating IP ${OCF_RESKEY_ip} is already not routed to this instance (${GCE_INSTANCE_NAME})"
  else
    route_release
  fi

  # Delete the local IP address
  ip_monitor &>/dev/null
  if [ $? -eq $OCF_NOT_RUNNING ]; then
    ocf_log info "The floating IP ${OCF_RESKEY_ip} is already down"
  else
    ip_release
  fi

  ocf_log info "Successfully brought down the floating IP ${OCF_RESKEY_ip}"
  return $OCF_SUCCESS
}


###############################################################################
#
# MAIN
#
###############################################################################

ocf_log warn "gcp-vpc-move-ip is deprecated, prefer to use gcp-vpc-move-route instead"

case $__OCF_ACTION in
  meta-data)  metadata
              exit $OCF_SUCCESS
              ;;
  usage|help) echo $USAGE
              exit $OCF_SUCCESS
              ;;
esac

validate || exit $?

case $__OCF_ACTION in
  start)          ip_and_route_start;;
  stop)           ip_and_route_stop;;
  monitor|status) route_monitor || exit $?
                  ip_monitor || exit $?
                  ;;
  validate-all)   ;;
  *)              echo $USAGE
                  exit $OCF_ERR_UNIMPLEMENTED
                  ;;
esac