pacemaker/extra/resources/attribute

#!/bin/sh
#
# ocf:pacemaker:attribute resource agent
#
# Copyright (C) 2016 Andrew Beekhof <andrew@beekhof.net>
#
# This source code is licensed under GNU General Public License version 2 or
# later (GPLv2+) WITHOUT ANY WARRANTY.
#

USAGE="Usage: $0 {start|stop|monitor|migrate_to|migrate_from|validate-all|meta-data}

Expects to have a fully populated OCF RA-compliant environment set."

# Load OCF helper functions
: ${OCF_FUNCTIONS=${OCF_ROOT}/resource.d/heartbeat/.ocf-shellfuncs}
. ${OCF_FUNCTIONS}
: ${__OCF_ACTION=$1}

# Ensure certain variables are set and not empty
: ${HA_VARRUN:="/var/run"}
: ${OCF_RESKEY_CRM_meta_globally_unique:="false"}
: ${OCF_RESOURCE_INSTANCE:="undef"}

DEFAULT_STATE_FILE="${HA_VARRUN%%/}/opa-${OCF_RESOURCE_INSTANCE}.state"
if [ ${OCF_RESKEY_CRM_meta_globally_unique} = "false" ]; then
    # Strip off any trailing clone marker (note + is not portable in sed)
    DEFAULT_STATE_FILE=$(echo "$DEFAULT_STATE_FILE" | sed s/:[0-9][0-9]*\.state/.state/)
fi

DEFAULT_ATTR_NAME="opa-${OCF_RESOURCE_INSTANCE}"
DEFAULT_ACTIVE_VALUE="1"
DEFAULT_INACTIVE_VALUE="0"

: ${OCF_RESKEY_state:="$DEFAULT_STATE_FILE"}
: ${OCF_RESKEY_name:="$DEFAULT_ATTR_NAME"}

# Values may be empty string
if [ -z ${OCF_RESKEY_active_value+x} ]; then
    OCF_RESKEY_active_value="$DEFAULT_ACTIVE_VALUE"
fi
if [ -z ${OCF_RESKEY_inactive_value+x} ]; then
    OCF_RESKEY_inactive_value="$DEFAULT_INACTIVE_VALUE"
fi

usage() {
    USAGE_RC=$1
    cat <<END
$USAGE
END
    return $USAGE_RC
}

meta_data() {
    cat <<END
<?xml version="1.0"?>
<!DOCTYPE resource-agent SYSTEM "ra-api-1.dtd">
<resource-agent name="attribute" version="1.0">
  <version>1.0</version>
  <shortdesc lang="en">Manages a node attribute</shortdesc>
  <longdesc lang="en">
This resource agent controls a node attribute for the node it's running on.
It sets the attribute one way when started, and another way when stopped,
according to the configuration parameters.
  </longdesc>
  <parameters>

    <parameter name="state" unique="1">
      <longdesc lang="en">
Full path of a temporary file to store the resource state in
      </longdesc>
      <shortdesc lang="en">State file</shortdesc>
      <content type="string" default="${DEFAULT_STATE_FILE}" />
    </parameter>

    <parameter name="name" unique="0">
      <longdesc lang="en">
Name of node attribute to manage
      </longdesc>
      <shortdesc lang="en">Attribute name</shortdesc>
      <content type="string" default="${DEFAULT_ATTR_NAME}" />
    </parameter>

    <parameter name="active_value" unique="0">
      <longdesc lang="en">
Value to use for node attribute when resource becomes active (empty string is
discouraged, because monitor cannot distinguish it from a query error)
      </longdesc>
      <shortdesc lang="en">Attribute value when active</shortdesc>
      <content type="string" default="$DEFAULT_ACTIVE_VALUE" />
    </parameter>

    <parameter name="inactive_value" unique="0">
      <longdesc lang="en">
Value to use for node attribute when resource becomes inactive
      </longdesc>
      <shortdesc lang="en">Attribute value when inactive</shortdesc>
      <content type="string" default="$DEFAULT_INACTIVE_VALUE" />
    </parameter>

  </parameters>
  <actions>
    <action name="start"        timeout="20" />
    <action name="stop"         timeout="20" />
    <action name="monitor"      timeout="20" interval="10" depth="0"/>
    <action name="reload"       timeout="20" />
    <action name="migrate_to"   timeout="20" />
    <action name="migrate_from" timeout="20" />
    <action name="validate-all" timeout="20" />
    <action name="meta-data"    timeout="5" />
  </actions>
</resource-agent>
END
    return $OCF_SUCCESS
}

validate() {
    if [ "$OCF_RESKEY_active_value" = "$OCF_RESKEY_inactive_value" ]; then
        ocf_exit_reason "active value '%s' must be different from inactive value '%s'" \
            "$OCF_RESKEY_active_value" "$OCF_RESKEY_inactive_value"
        return $OCF_ERR_CONFIGURED
    fi

    VALIDATE_DIR=$(dirname "${OCF_RESKEY_state}")
    if [ ! -d "$VALIDATE_DIR" ]; then
        ocf_exit_reason "state file '$OCF_RESKEY_state' does not have a valid directory"
        return $OCF_ERR_PERM
    fi
    if [ ! -w "$VALIDATE_DIR" -o ! -x "$VALIDATE_DIR" ]; then
        ocf_exit_reason "insufficient privileges on directory of state file '$OCF_RESKEY_state'"
        return $OCF_ERR_PERM
    fi

    return $OCF_SUCCESS
}

get_attribute() {
    GET_LINE=$(attrd_updater -n "$OCF_RESKEY_name" -Q 2>/dev/null)
    if [ $? -ne 0 ]; then
        echo ""
    else
        echo "$GET_LINE" | sed -e "s/.* value=\"\(.*\)\"$/\1/"
    fi
}

set_attribute() {
    attrd_updater -n "$OCF_RESKEY_name" -U "$1" 2>/dev/null
    # TODO if above call is async, loop until get_attribute returns expected value
}

check_attribute() {
    CHECK_VALUE=$(get_attribute)
    CHECK_REASON=""
    if [ ! -f "$OCF_RESKEY_state" ]; then
        if [ "$CHECK_VALUE" != "" -a "$CHECK_VALUE" != "$OCF_RESKEY_inactive_value" ]; then
            CHECK_REASON="Node attribute $OCF_RESKEY_name='$CHECK_VALUE' differs from expected value '$OCF_RESKEY_inactive_value'"
            return $OCF_ERR_GENERIC
        fi
        return $OCF_NOT_RUNNING
    fi
    if [ "$CHECK_VALUE" != "$OCF_RESKEY_active_value" ]; then
        CHECK_REASON="Node attribute $OCF_RESKEY_name='$CHECK_VALUE' differs from expected value '$OCF_RESKEY_active_value'"
        return $OCF_ERR_GENERIC
    fi
    return $OCF_SUCCESS
}

monitor() {
    check_attribute
    MONITOR_RC=$?
    if [ $MONITOR_RC -eq $OCF_ERR_GENERIC ]; then
        ocf_exit_reason "$CHECK_REASON"
    fi
    return $MONITOR_RC
}

start() {
    check_attribute
    if [ $? -eq $OCF_SUCCESS ]; then
        return $OCF_SUCCESS
    fi

    touch "${OCF_RESKEY_state}" 2>/dev/null
    if [ $? -ne 0 ]; then
        ocf_exit_reason "Unable to manage state file $OCF_RESKEY_state"
        return $OCF_ERR_GENERIC
    fi

    set_attribute "${OCF_RESKEY_active_value}"
    if [ $? -ne 0 ]; then
        rm -f "${OCF_RESKEY_state}"
        ocf_exit_reason "Unable to set node attribute $OCF_RESKEY_name='$OCF_RESKEY_active_value'"
        return $OCF_ERR_GENERIC
    fi

    return $OCF_SUCCESS
}

stop() {
    check_attribute
    if [ $? -eq $OCF_NOT_RUNNING ]; then
        return $OCF_SUCCESS
    fi

    rm -f ${OCF_RESKEY_state}

    set_attribute "${OCF_RESKEY_inactive_value}"
    if [ $? -ne 0 ]; then
        ocf_exit_reason "Unable to set node attribute $OCF_RESKEY_name='$OCF_RESKEY_inactive_value'"
        return $OCF_ERR_GENERIC
    fi

    return $OCF_SUCCESS
}

case $__OCF_ACTION in
meta-data)      meta_data ;;
start)          start ;;
stop)           stop ;;
monitor)        monitor ;;
# We don't do anything special for live migration, but we support it so that
# other resources that live migrate can depend on this one.
migrate_to)     stop ;;
migrate_from)   start ;;
reload)         start ;;
validate-all)   validate ;;
usage|help)     usage $OCF_SUCCESS ;;
*)              usage $OCF_ERR_UNIMPLEMENTED ;;
esac

exit $?

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