#!/bin/sh
#
# postgresql-setup	Initialization and upgrade operations for PostgreSQL

# PGVERSION is the full package version, e.g., 12.0
# Note: the specfile inserts the correct value during package build
PGVERSION=12
# PGMAJORVERSION is major version, e.g., 12 (this should match PG_VERSION)
PGMAJORVERSION=`echo "$PGVERSION" | sed 's/^\([0-9]*\.[0-9]*\).*$/\1/'`
# PGENGINE is the directory containing the postmaster executable
# Note: the specfile inserts the correct value during package build
PGENGINE=/usr/pgsql-12/bin
# PREVMAJORVERSION is the previous major version, e.g., 10, for upgrades
PREVMAJORVERSION=11
# PREVPGENGINE is the directory containing the previous postmaster executable
PREVPGENGINE=/usr/pgsql-$PREVMAJORVERSION/bin
# PREVDATADIR is the directory containing the previous postmaster executable
PREVDATADIR=/var/lib/pgsql/$PREVMAJORVERSION/data

# TODO: Provide a conf file that can override these settings

# The second parameter is the new database version, i.e. $PGMAJORVERSION in this case.
# Use  "postgresql-$PGMAJORVERSION" service, if not specified.
SERVICE_NAME="$2"
if [ x"$SERVICE_NAME" = x ]
then
    SERVICE_NAME=postgresql-$PGMAJORVERSION
fi

# The third parameter is the old database version, i.e. $PREVMAJORVERSION in this case.
# Use  "postgresql-$PREVMAJORVERSION" service, if not specified.
OLD_SERVICE_NAME="$3"
if [ x"$OLD_SERVICE_NAME" = x ]
then
    OLD_SERVICE_NAME=postgresql-$PREVMAJORVERSION
fi

USAGE_STRING=$"
Usage: $0 {initdb|check_upgrade|upgrade} [SERVICE_NAME]

Script is aimed to help sysadmin with basic database cluster administration.

The SERVICE_NAME is used for selection of proper unit configuration file; For
more info and howto/when use this script please look at README.rpm-dist file.
The 'postgresql' string is used when no SERVICE_NAME is explicitly passed.

Available operation mode:
  initdb        Create a new PostgreSQL database cluster.  This is usually the
                first action you perform after PostgreSQL server installation.
  check_upgrade	Checks whether the old cluster can be upgraded to the new version
		or not.
  upgrade	Upgrade PostgreSQL database cluster to be usable with new
                server.  Use this if you upgraded your PostgreSQL server to
                newer major version (currently from $PREVMAJORVERSION \
to $PGMAJORVERSION).

Environment:
  PGSETUP_INITDB_OPTIONS     Options carried by this variable are passed to
                             subsequent call of \`initdb\` binary (see man
                             initdb(1)).  This variable is used also during
                             'upgrade' mode because the new cluster is actually
                             re-initialized from the old one.
  PGSETUP_PGUPGRADE_OPTIONS  Options in this variable are passed next to the
                             subsequent call of \`pg_upgrade\`.  For more info
                             about possible options please look at man
                             pg_upgrade(1).
  PGSETUP_DEBUG              Set to '1' if you want to see debugging output."

# note that these options are useful at least for help2man processing
case "$1" in
    --version)
	echo "PostgreSQL setup script for version $PGVERSION"
        exit 0
        ;;
    --help|--usage)
        echo "$USAGE_STRING"
        exit 0
        ;;
esac

# this parsing technique fails for PGDATA pathnames containing spaces,
# but there's not much I can do about it given systemctl's output format...
PGDATA=`systemctl show -p Environment "${SERVICE_NAME}.service" |
                sed 's/^Environment=//' | tr ' ' '\n' |
                sed -n 's/^PGDATA=//p' | tail -n 1`
if [ x"$PGDATA" = x ]; then
    echo "failed to find PGDATA setting in ${SERVICE_NAME}.service"
    exit 1
fi

# Find the unit file for new version.
if [ -f "/etc/systemd/system/${SERVICE_NAME}.service" ]
then
    SERVICE_FILE="/etc/systemd/system/${SERVICE_NAME}.service"
elif [ -f "/usr/lib/systemd/system/${SERVICE_NAME}.service" ]
then
    SERVICE_FILE="/usr/lib/systemd/system/${SERVICE_NAME}.service"
else
    echo "Could not find systemd unit file ${SERVICE_NAME}.service"
    exit 1
fi

# Log file for pg_upgrade
PGUPLOG=/var/lib/pgsql/$PGMAJORVERSION/pgupgrade.log
# Log file for initdb
PGLOG=/var/lib/pgsql/$PGMAJORVERSION/initdb.log

export PGDATA

# For SELinux we need to use 'runuser' not 'su'
if [ -x /sbin/runuser ]
then
    SU=/sbin/runuser
else
    SU=su
fi

script_result=0

# code shared between initdb and upgrade actions
perform_initdb(){
    if [ ! -e "$PGDATA" ]; then
        mkdir -p "$PGDATA" || return 1
        chown postgres:postgres "$PGDATA"
        chmod go-rwx "$PGDATA"
    fi
    # Clean up SELinux tagging for PGDATA
    [ -x /sbin/restorecon ] && /sbin/restorecon "$PGDATA"

    # Create the initdb log file if needed
    if [ ! -e "$PGLOG" -a ! -h "$PGLOG" ]; then
        touch "$PGLOG" || return 1
        chown postgres:postgres "$PGLOG"
        chmod go-rwx "$PGLOG"
        [ -x /sbin/restorecon ] && /sbin/restorecon "$PGLOG"
    fi

    # Initialize the database
    initdbcmd="$PGENGINE/initdb --pgdata='$PGDATA' --auth='ident'"
    initdbcmd+=" $PGSETUP_INITDB_OPTIONS"

    $SU -l postgres -c "$initdbcmd" >> "$PGLOG" 2>&1 < /dev/null

    # Create directory for postmaster log files
    mkdir "$PGDATA/log"
    chown postgres:postgres "$PGDATA/log"
    chmod go-rwx "$PGDATA/log"
    [ -x /sbin/restorecon ] && /sbin/restorecon "$PGDATA/log"

    if [ -f "$PGDATA/PG_VERSION" ]; then
        return 0
    fi
    return 1
}

initdb(){
    if [ -f "$PGDATA/PG_VERSION" ]; then
        echo $"Data directory is not empty!"
        echo
        script_result=1
    else
        echo -n $"Initializing database ... "
        if perform_initdb; then
            echo $"OK"
        else
            echo $"failed, see $PGLOG"
            script_result=1
        fi
        echo
    fi
}

check_upgrade(){
    # must see previous version in PG_VERSION
    if [ ! -f "$PREVDATADIR/PG_VERSION" -o \
         x`cat "$PREVDATADIR/PG_VERSION"` != x"$PREVMAJORVERSION" ]
    then
        echo
        echo $"Cannot upgrade because the database in $PGDATA is not of"
        echo $"compatible previous version $PREVMAJORVERSION."
        echo
        exit 1
    fi

    # Set up log file for pg_upgrade
    rm -f "$PGUPLOG"
    touch "$PGUPLOG" || exit 1
    chown postgres:postgres "$PGUPLOG"
    chmod go-rwx "$PGUPLOG"
    [ -x /sbin/restorecon ] && /sbin/restorecon "$PGUPLOG"

    # Make sure that the user initdb'ed the new cluster:
    if [ ! -f "$PGDATA/PG_VERSION" ]
    then
        echo
        echo $"Please initialize the new cluster before upgrading."
        echo $"You can run this script with the ''initdb'' parameter:"
	echo $""
	echo $"$PGENGINE/postgresql-$PGVERSION-setup initdb"
        echo
        exit 1
    fi

    # Copy the current pg_hba.conf file to new cluster:

    HBA_CONF_BACKUP_EXISTS=0

        cp "$PREVDATADIR/pg_hba.conf" "$PGDATA/"
        HBA_CONF_BACKUP_EXISTS=1

        # For fluent upgrade 'postgres' user should be able to connect
        # to any database without password.  Temporarily, no other type
        # of connection is needed.
        echo "local all postgres peer" > "$PREVDATADIR/pg_hba.conf"

    echo -n $"Performing upgrade check: "

        # Do the upgrade
        $SU -l postgres -c "$PGENGINE/pg_upgrade \
                        '--old-bindir=$PREVPGENGINE' \
                        '--new-bindir=$PGENGINE' \
                        '--old-datadir=$PREVDATADIR' \
                        '--new-datadir=$PGDATA' \
                        --check \
                        --user=postgres \
                        $PGSETUP_PGUPGRADE_OPTIONS" \
                                >> "$PGUPLOG" 2>&1 < /dev/null
        if [ $? -ne 0 ]; then
            # pg_upgrade failed
            script_result=1
        fi
    if [ $script_result -eq 0 ]; then
        echo $"OK"
    else
        # Clean up after failure
	echo "Upgrade failed. Removing the new cluster. Please re-initdb the new cluster."
        rm -rf "$PGDATA"
        echo $"failed"
    fi
    echo
    echo $"See $PGUPLOG for details."
}


upgrade(){
# Perform the upgrade check first:
check_upgrade
    echo -n $"Upgrading database: "

        # Do the upgrade
        $SU -l postgres -c "$PGENGINE/pg_upgrade \
                        '--old-bindir=$PREVPGENGINE' \
                        '--new-bindir=$PGENGINE' \
                        '--old-datadir=$PREVDATADIR' \
                        '--new-datadir=$PGDATA' \
                        --link \
                        --user=postgres \
                        $PGSETUP_PGUPGRADE_OPTIONS" \
                                >> "$PGUPLOG" 2>&1 < /dev/null
        if [ $? -ne 0 ]; then
            # pg_upgrade failed
            script_result=1
        fi
    if [ $script_result -eq 0 ]; then
        echo $"OK"
        echo
        echo $"pg_hba.conf configuration file of the new cluster was replaced by the one in the old cluster."
    else
        # Clean up after failure
        rm -rf "$PGDATA"
        echo $"failed"
    fi
    echo
    echo $"See $PGUPLOG for details."
}

# See how we were called.
case "$1" in
    initdb)
        initdb
        ;;
    upgrade)
        upgrade
        ;;
    check_upgrade)
        check_upgrade
        ;;
    *)
        echo >&2 "$USAGE_STRING"
        exit 2
esac

exit $script_result
