#!/bin/bash
#
# Copyright (c) 2022 Wind River Systems, Inc.
#
# SPDX-License-Identifier: Apache-2.0
#

#
# This script provides an example in-service patching restart,
# triggering a restart of the patching daemons themselves
#

#
# The patching subsystem provides a patch-functions bash source file
# with useful function and variable definitions.
#
. /etc/patching/patch-functions

#
# We can now check to see what type of node we're on, if it's locked, etc,
# and act accordingly
#

#
# Declare an overall script return code
#
declare -i GLOBAL_RC=$PATCH_STATUS_OK

#
# Declare subset of kubernetes versions we want to patch.
# This is customized for the particular patch.
#
declare -a PATCH_RESTART_VERSIONS=( "v1.21.8" )

# kubelet doesn't run on storage nodes
if is_storage
then
    exit $GLOBAL_RC
fi

if [ ! -f $PATCH_FLAGDIR/kubelet.restarted ]
then
    # Check to see if kubelet is running
    systemctl status kubelet.service|grep -q "Active: active (running)"
    if [ $? -eq 0 ]
    then
        # Obtain current kubelet version
        KVER=$(kubectl version --short=true 2>/dev/null | grep -oP 'Client Version: \K\S+')

        # Check current kubelet version matches any expected restart versions
        FOUND=0
        for val in ${PATCH_RESTART_VERSIONS[@]}; do
            if [ "${val}" == "${KVER}" ]; then
                FOUND=1
                break
            fi
        done
        if [ ${FOUND} -eq 1 ]; then
            loginfo "$0: Current kubelet ${KVER} found in: ${PATCH_RESTART_VERSIONS[@]}"
        else
            # do not restart versions that do not require patching
            loginfo "$0: Current kubelet ${KVER} not found in" \
                "${PATCH_RESTART_VERSIONS[@]}, skipping kubelet restart"
            exit $GLOBAL_RC
        fi

        # issue a systemd daemon-reload once the rpms have been installed
        # and before the processes have been restarted.
        systemctl daemon-reload

        # Ask pmon to stop kubelet and isolcpu_plugin so that it won't raise
        # any alarms as we force a restart
        loginfo "$0: pmond stopping kubelet"
        OLDPID=`pgrep -f /usr/bin/kubelet`
        pmon-stop kubelet
        pmon-stop isolcpu_plugin

        # Wait up to 30 seconds for service stop and enter a systemd
        # auto-restart state
        let -i UNTIL=$SECONDS+30
        while [ $UNTIL -ge $SECONDS ]
        do
            # Check to see if the process has stopped and switched states
            systemctl status kubelet.service | grep -q "Active: activating (auto-restart)"
            if [ $? -eq 0 ]
            then
                # Now that we are waiting on systemd to restart. Tell pmon
                # to start this back up and enter it's delayed monitoring
                # state
                loginfo "$0: pmond starting kubelet"
                pmon-start kubelet
                pmon-start isolcpu_plugin
                break
            fi

            # Check every second to catch this auto-restart state
            sleep 1
        done

        let -i UNTIL=$SECONDS+15
        while [ $UNTIL -ge $SECONDS ]
        do
            # Check to make sure the service is running
            systemctl status kubelet.service | grep -q "Active: active (running)"
            if [ $? -eq 0 ]
            then
                # Verify that it's not still the old process
                NEWPID=`pgrep -f /usr/bin/kubelet`
                if [ $? -eq 0 -a "$OLDPID" != "$NEWPID" ]
                then
                    touch $PATCH_FLAGDIR/kubelet.restarted
                    break
                fi
            fi

            # Still not running? Let's wait 5 seconds and check again
            sleep 5
        done

        systemctl status kubelet.service|grep -q "Active: active (running)"
        STATUS=$?
        NEWPID=`pgrep -f /usr/bin/kubelet`
        if [ $STATUS -ne 0 -o $? -ne 0 -o "$OLDPID" = "$NEWPID" ]
        then
            # Still not running new kubelet! Clear the flag and mark the RC as failed
            loginfo "$0: Failed to restart kubelet"
            rm -f $PATCH_FLAGDIR/kubelet.restarted
            GLOBAL_RC=$PATCH_STATUS_FAILED
        fi
    fi
fi

#
# Exit the script with the overall return code
#
exit $GLOBAL_RC