#!/bin/sh
#
# Copyright (c) 2014 David Vossel <dvossel@redhat.com>
#                    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.
#

##
# README.
# 
# This agent only supports being configured as a multistate Master
# resource.
#
# Slave vs Master role:
#
# During the 'Slave' role, galera instances are in read-only mode and
# will not attempt to connect to the cluster. This role exists only as
# a means to determine which galera instance is the most up-to-date. The
# most up-to-date node will be used to bootstrap a galera cluster that
# has no current members.
#
# The galera instances will only begin to be promoted to the Master role
# once all the nodes in the 'wsrep_cluster_address' connection address
# have entered read-only mode. At that point the node containing the
# database that is most current will be promoted to Master. Once the first
# Master instance bootstraps the galera cluster, the other nodes will be
# promoted to Master as well.
#
# Example: Create a galera cluster using nodes rhel7-node1 rhel7-node2 rhel7-node3
#
# pcs resource create db galera enable_creation=true \
# wsrep_cluster_address="gcomm://rhel7-auto1,rhel7-auto2,rhel7-auto3" meta master-max=3 --master
#
# By setting the 'enable_creation' option, the database will be automatically 
# generated at startup. The meta attribute 'master-max=3' means that all 3
# nodes listed in the wsrep_cluster_address list will be allowed to connect
# to the galera cluster and perform replication.
#
# NOTE: If you have more nodes in the pacemaker cluster then you wish
# to have in the galera cluster, make sure to use location contraints to prevent
# pacemaker from attempting to place a galera instance on a node that is
# not in the 'wsrep_cluster_address" list. 
#
##

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

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

# It is common for some galera instances to store
# check user that can be used to query status
# in this file
if [ -f "/etc/sysconfig/clustercheck" ]; then
    . /etc/sysconfig/clustercheck
fi

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

usage() {
  cat <<UEND
usage: $0 (start|stop|validate-all|meta-data|monitor|promote|demote)

$0 manages a galera Database as an HA resource.

The 'start' operation starts the database.
The 'stop' operation stops the database.
The 'status' operation reports whether the database is running
The 'monitor' operation reports whether the database seems to be working
The 'promote' operation makes this mysql server run as master
The 'demote' operation makes this mysql server run as slave
The 'validate-all' operation reports whether the parameters are valid

UEND
}

meta_data() {
   cat <<END
<?xml version="1.0"?>
<!DOCTYPE resource-agent SYSTEM "ra-api-1.dtd">
<resource-agent name="galera">
<version>1.0</version>

<longdesc lang="en">
Resource script for managing galara database.
</longdesc>
<shortdesc lang="en">Manages a galara instance</shortdesc>
<parameters>

<parameter name="binary" unique="0" required="0">
<longdesc lang="en">
Location of the MySQL server binary
</longdesc>
<shortdesc lang="en">MySQL server binary</shortdesc>
<content type="string" default="${OCF_RESKEY_binary_default}" />
</parameter>

<parameter name="client_binary" unique="0" required="0">
<longdesc lang="en">
Location of the MySQL client binary
</longdesc>
<shortdesc lang="en">MySQL client binary</shortdesc>
<content type="string" default="${OCF_RESKEY_client_binary_default}" />
</parameter>

<parameter name="config" unique="0" required="0">
<longdesc lang="en">
Configuration file
</longdesc>
<shortdesc lang="en">MySQL config</shortdesc>
<content type="string" default="${OCF_RESKEY_config_default}" />
</parameter>

<parameter name="datadir" unique="0" required="0">
<longdesc lang="en">
Directory containing databases
</longdesc>
<shortdesc lang="en">MySQL datadir</shortdesc>
<content type="string" default="${OCF_RESKEY_datadir_default}" />
</parameter>

<parameter name="user" unique="0" required="0">
<longdesc lang="en">
User running MySQL daemon
</longdesc>
<shortdesc lang="en">MySQL user</shortdesc>
<content type="string" default="${OCF_RESKEY_user_default}" />
</parameter>

<parameter name="group" unique="0" required="0">
<longdesc lang="en">
Group running MySQL daemon (for logfile and directory permissions)
</longdesc>
<shortdesc lang="en">MySQL group</shortdesc>
<content type="string" default="${OCF_RESKEY_group_default}"/>
</parameter>

<parameter name="log" unique="0" required="0">
<longdesc lang="en">
The logfile to be used for mysqld.
</longdesc>
<shortdesc lang="en">MySQL log file</shortdesc>
<content type="string" default="${OCF_RESKEY_log_default}"/>
</parameter>

<parameter name="pid" unique="0" required="0">
<longdesc lang="en">
The pidfile to be used for mysqld.
</longdesc>
<shortdesc lang="en">MySQL pid file</shortdesc>
<content type="string" default="${OCF_RESKEY_pid_default}"/>
</parameter>

<parameter name="socket" unique="0" required="0">
<longdesc lang="en">
The socket to be used for mysqld.
</longdesc>
<shortdesc lang="en">MySQL socket</shortdesc>
<content type="string" default="${OCF_RESKEY_socket_default}"/>
</parameter>

<parameter name="enable_creation" unique="0" required="0">
<longdesc lang="en">
If the MySQL database does not exist, it will be created
</longdesc>
<shortdesc lang="en">Create the database if it does not exist</shortdesc>
<content type="boolean" default="${OCF_RESKEY_enable_creation_default}"/>
</parameter>

<parameter name="additional_parameters" unique="0" required="0">
<longdesc lang="en">
Additional parameters which are passed to the mysqld on startup.
(e.g. --skip-external-locking or --skip-grant-tables)
</longdesc>
<shortdesc lang="en">Additional parameters to pass to mysqld</shortdesc>
<content type="string" default="${OCF_RESKEY_additional_parameters_default}"/>
</parameter>


<parameter name="wsrep_cluster_address" unique="0" required="1">
<longdesc lang="en">
The galera cluster address. This takes the form of:
gcomm://node,node,node

Only nodes present in this node list will be allowed to start a galera instance.
It is expected that the galera node names listed in this address match valid
pacemaker node names.
</longdesc>
<shortdesc lang="en">Galera cluster address</shortdesc>
<content type="string" default=""/>
</parameter>

<parameter name="check_user" unique="0" required="0">
<longdesc lang="en">
Cluster check user.
</longdesc>
<shortdesc lang="en">MySQL test user</shortdesc>
<content type="string" default="root" />
</parameter>

<parameter name="check_passwd" unique="0" required="0">
<longdesc lang="en">
Cluster check user password
</longdesc>
<shortdesc lang="en">check password</shortdesc>
<content type="string" default="" />
</parameter>

</parameters>

<actions>
<action name="start" timeout="120" />
<action name="stop" timeout="120" />
<action name="status" timeout="60" />
<action name="monitor" depth="0" timeout="30" interval="20" />
<action name="monitor" role="Master" depth="0" timeout="30" interval="10" />
<action name="monitor" role="Slave" depth="0" timeout="30" interval="30" />
<action name="promote" timeout="300" />
<action name="demote" timeout="120" />
<action name="validate-all" timeout="5" />
<action name="meta-data" timeout="5" />
</actions>
</resource-agent>
END
}

get_option_variable()
{
    local key=$1

    $MYSQL $MYSQL_OPTIONS_CHECK  -e "SHOW VARIABLES like '$key';" | tail -1
}

get_status_variable()
{
    local key=$1

    $MYSQL $MYSQL_OPTIONS_CHECK -e "show status like '$key';" | tail -1
}

set_bootstrap_node()
{
    local node=$1

    ${HA_SBIN_DIR}/crm_attribute -N $node -l reboot --name "${INSTANCE_ATTR_NAME}-bootstrap" -v "true"
}

clear_bootstrap_node()
{
    ${HA_SBIN_DIR}/crm_attribute -N $NODENAME -l reboot --name "${INSTANCE_ATTR_NAME}-bootstrap" -D
}

is_bootstrap()
{
    ${HA_SBIN_DIR}/crm_attribute -N $NODENAME -l reboot --name "${INSTANCE_ATTR_NAME}-bootstrap" -Q 2>/dev/null

}

clear_last_commit()
{
    ${HA_SBIN_DIR}/crm_attribute -N $NODENAME -l reboot --name "${INSTANCE_ATTR_NAME}-last-committed" -D
}

set_last_commit()
{
    ${HA_SBIN_DIR}/crm_attribute -N $NODENAME -l reboot --name "${INSTANCE_ATTR_NAME}-last-committed" -v $1
}

get_last_commit()
{
    local node=$1

    if [ -z "$node" ]; then
       ${HA_SBIN_DIR}/crm_attribute -N $NODENAME -l reboot --name "${INSTANCE_ATTR_NAME}-last-committed" -Q 2>/dev/null
    else 
       ${HA_SBIN_DIR}/crm_attribute -N $node -l reboot --name "${INSTANCE_ATTR_NAME}-last-committed" -Q 2>/dev/null
    fi
}

wait_for_sync()
{
    local state=$(get_status_variable "wsrep_local_state")

    ocf_log info "Waiting for database to sync with the cluster. "
    while [ "$state" != "4" ]; do
        sleep 1
        state=$(get_status_variable "wsrep_local_state")
    done
    ocf_log info "Database synced."
}

is_primary()
{
    cluster_status=$(get_status_variable "wsrep_cluster_status")
    if [ "$cluster_status" = "Primary" ]; then
        return 0
    fi

    if [ -z "$cluster_status" ]; then
        ocf_exit_reason "Unable to retrieve wsrep_cluster_status, verify check_user '$OCF_RESKEY_check_user' has permissions to view status"
    else
        ocf_log info "Galera instance wsrep_cluster_status=${cluster_status}"
    fi
    return 1
}

is_readonly()
{
    local res=$(get_option_variable "read_only")

    if ! ocf_is_true "$res"; then
        return 1
    fi

    cluster_status=$(get_status_variable "wsrep_cluster_status")
    if ! [ "$cluster_status" = "Disconnected" ]; then
        return 1
    fi

    return 0
}

master_exists()
{
    # determine if a master instance is already up and is healthy
    crm_mon --as-xml | grep "resource.*id=\"${OCF_RESOURCE_INSTANCE}\".*role=\"Master\".*active=\"true\".*orphaned=\"false\".*failed=\"false\"" > /dev/null 2>&1
    return $?
}

clear_master_score()
{
    local node=$1
    if [ -z "$node" ]; then
        $CRM_MASTER -D
    else 
        $CRM_MASTER -D -N $node
    fi
}

set_master_score()
{
    local node=$1

    if [ -z "$node" ]; then
        $CRM_MASTER -v 100
    else 
        $CRM_MASTER -N $node -v 100
    fi
}

promote_everyone()
{

    for node in $(echo "$OCF_RESKEY_wsrep_cluster_address" | sed 's/gcomm:\/\///g' | tr -d ' ' | tr -s ',' ' '); do

        set_master_score $node
    done
}

greater_than_equal_long()
{
    # there are values we need to compare in this script
    # that are too large for shell -gt to process
    echo | awk -v n1="$1" -v n2="$2"  '{if (n1>=n2) printf ("true"); else printf ("false");}' |  grep -q "true"
}

detect_first_master()
{
    local best_commit=0
    local best_node="$NODENAME"
    local last_commit=0
    local missing_nodes=0

    for node in $(echo "$OCF_RESKEY_wsrep_cluster_address" | sed 's/gcomm:\/\///g' | tr -d ' ' | tr -s ',' ' '); do
        last_commit=$(get_last_commit $node)

        if [ -z "$last_commit" ]; then
            ocf_log info "Waiting on node <${node}> to report database status before Master instances can start."
            missing_nodes=1
            continue
        fi

        # this means -1, or that no commit has occured yet.
        if [ "$last_commit" = "18446744073709551615" ]; then
            last_commit="0"
        fi

        greater_than_equal_long "$last_commit" "$best_commit"
        if [ $? -eq 0 ]; then
            best_node=$node
            best_commit=$last_commit
        fi

    done

    if [ $missing_nodes -eq 1 ]; then
        return
    fi

    ocf_log info "Promoting $best_node to be our bootstrap node"
    set_master_score $best_node
    set_bootstrap_node $best_node
}

# For galera, promote is really start
galera_promote()
{
    local rc
    local extra_opts
    local bootstrap
    
    master_exists
    if [ $? -eq 0 ]; then
        # join without bootstrapping
        extra_opts="--wsrep-cluster-address=${OCF_RESKEY_wsrep_cluster_address}"
    else
        bootstrap=$(is_bootstrap)

        if ocf_is_true $bootstrap; then
            ocf_log info "Node <${NODENAME}> is bootstrapping the cluster"
            extra_opts="--wsrep-cluster-address=gcomm://"
        else
            ocf_exit_reason "Failure, Attempted to promote Master instance of $OCF_RESOURCE_INSTANCE before bootstrap node has been detected."
            return $OCF_ERR_GENERIC
        fi

    fi

    # make sure the read only instance is stopped
    mysql_common_stop
    rc=$?
    if [ $rc -ne $OCF_SUCCESS ] && [ $rc -ne $OCF_NOT_RUNNING ]; then
        ocf_exit_reason "Failed to stop read-only galera instance during promotion to Master"
        return $rc
    fi

    sleep 4

    mysql_common_prepare_dirs
    mysql_common_start "$extra_opts"
    rc=$?
    if [ $rc != $OCF_SUCCESS ]; then
        return $rc
    fi

    galera_monitor
    rc=$?
    if [ $rc != $OCF_SUCCESS -a $rc != $OCF_RUNNING_MASTER ]; then
        ocf_exit_reason "Failed initial monitor action"
        return $rc
    fi

    is_readonly
    if [ $? -eq 0 ]; then
        ocf_exit_reason "Failure. Master instance started in read-only mode, check configuration."
        return $OCF_ERR_GENERIC
    fi

    is_primary
    if [ $? -ne 0 ]; then
        ocf_exit_reason "Failure. Master instance started, but is not in Primary mode."
        return $OCF_ERR_GENERIC
    fi

    if ocf_is_true $bootstrap; then
        promote_everyone
        clear_bootstrap_node
        ocf_log info "Bootstrap complete, promoting the rest of the galera instances."
    else
        # if this is not the bootstrap node, make sure this instance
        # syncs with the rest of the cluster before promotion returns.
        wait_for_sync
    fi

    # last commit is no longer relevant once promoted
    clear_last_commit

    ocf_log info "Galera started"
    return $OCF_SUCCESS
}

galera_demote()
{
    mysql_common_stop
    rc=$?
    if [ $rc -ne $OCF_SUCCESS ] && [ $rc -ne $OCF_NOT_RUNNING ]; then
        ocf_exit_reason "Failed to stop Master galera instance during demotion to Master"
        return $rc
    fi

    # if this node was previously a bootstrap node, that is no longer the case.
    clear_bootstrap_node

    # start again in slave mode so the new last commit is recorded
    galera_start
}

galera_start()
{
    local extra_opts='--read-only=true'
    local last_commit

    echo $OCF_RESKEY_wsrep_cluster_address | grep -q $NODENAME
    if [ $? -ne 0 ]; then
        ocf_exit_reason "local node <${NODENAME}> must be a member of the wsrep_cluster_address <${OCF_RESKEY_wsrep_cluster_address}>to start this galera instance"
        return $OCF_ERR_CONFIGURED
    fi

    mysql_common_prepare_dirs
    mysql_common_start "$extra_opts"

    is_readonly
    if [ $? -ne 0 ]; then
        ocf_exit_reason "Slave instance did not start correctly in read-only mode, Make sure local galera.cnf does not have wsrep_cluster_address set."
        return $OCF_ERR_GENERIC
    fi

    ocf_log info "attempting to detect last commit version"
    while [ -z "$last_commit" ]; do
        last_commit=$(get_status_variable "wsrep_last_committed")
        if [ -z "$last_commit" ]; then
            sleep 1
        fi
    done
    ocf_log info "Last commit version found:  $last_commit"

    set_last_commit $last_commit

    master_exists
    if [ $? -eq 0 ]; then
        ocf_log info "Master instances are already up, setting master score so this instance will join galera cluster."
        set_master_score $NODENAME
    else
        clear_master_score
        detect_first_master
    fi

    return $OCF_SUCCESS
}

galera_monitor()
{
    local rc
    local status_loglevel="err"

    # Set loglevel to info during probe
    if ocf_is_probe; then
        status_loglevel="info"
    fi
 
    mysql_common_status $status_loglevel
    rc=$?

    # If status returned an error, return that immediately
    if [ $rc -ne $OCF_SUCCESS ]; then
        return $rc
    fi

    echo $OCF_RESKEY_wsrep_cluster_address | grep -q $NODENAME
    if [ $? -ne 0 ]; then
        ocf_exit_reason "local node <${NODENAME}> is started, but is not a member of the wsrep_cluster_address <${OCF_RESKEY_wsrep_cluster_address}>"
        return $OCF_ERR_GENERIC
    fi

    is_readonly
    if [ $? -ne 0 ]; then
        is_primary
        if [ $? -ne 0 ]; then
            ocf_exit_reason "local node <${NODENAME}> is neither in primary mode nor in read_only mode. Unknown state."
            return $OCF_ERR_GENERIC
        fi

        if ocf_is_probe; then
            # restore master score during probe
            # if we detect this is a master instance
            set_master_score
        fi
        rc=$OCF_RUNNING_MASTER
    else 
        master_exists
        if [ $? -ne 0 ]; then
            detect_first_master
        else
            # a master instance exists and is healthy, promote this
            # local read only instance
            # so it can join the master galera cluster.
            set_master_score
        fi
    fi
    # TODO look at what is done in the wait script

    return $rc
}

galera_stop()
{
    local rc
    # make sure the process is stopped
    mysql_common_stop
    rc=$1

    clear_last_commit
    clear_master_score
    clear_bootstrap_node
    return $rc
}

galera_validate()
{
    if ! ocf_is_ms; then
        ocf_exit_reason "Galera must be configured as a multistate Master/Slave resource."
        return $OCF_ERR_CONFIGURED
    fi

    if [ -z "$OCF_RESKEY_wsrep_cluster_address" ]; then
        ocf_exit_reason "Galera must be configured with a wsrep_cluster_address value."
        return $OCF_ERR_CONFIGURED
    fi

    mysql_common_validate
}

case "$1" in
  meta-data)    meta_data
        exit $OCF_SUCCESS;;
  usage|help)   usage
        exit $OCF_SUCCESS;;
esac

galera_validate
rc=$?
LSB_STATUS_STOPPED=3
if [ $rc -ne 0 ]; then
    case "$1" in
        stop) exit $OCF_SUCCESS;;
        monitor) exit $OCF_NOT_RUNNING;;
        status) exit $LSB_STATUS_STOPPED;;
        *) exit $rc;;
    esac
fi

if [ -z "${OCF_RESKEY_check_passwd}" ]; then
    # This value is automatically sourced from /etc/sysconfig/checkcluster if available
    OCF_RESKEY_check_passwd=${MYSQL_PASSWORD}
fi
if [ -z "${OCF_RESKEY_check_user}" ]; then
    # This value is automatically sourced from /etc/sysconfig/checkcluster if available
    OCF_RESKEY_check_user=${MYSQL_USERNAME}
fi
: ${OCF_RESKEY_check_user="root"}

MYSQL_OPTIONS_CHECK="-nNE --user=${OCF_RESKEY_check_user}"
if [ -n "${OCF_RESKEY_check_passwd}" ]; then
    MYSQL_OPTIONS_CHECK="$MYSQL_OPTIONS_CHECK --password=${OCF_RESKEY_check_passwd}"
fi

# What kind of method was invoked?
case "$1" in
  start)    galera_start;;
  stop)     galera_stop;;
  status)   mysql_common_status err;;
  monitor)  galera_monitor;;
  promote)  galera_promote;;
  demote)   galera_demote;;
  validate-all) exit $OCF_SUCCESS;;

 *)     usage
        exit $OCF_ERR_UNIMPLEMENTED;;
esac

# vi:sw=4:ts=4:et:
