Establish Postgres database format upgrade rockstor#2780

Adds a shell script, to be run by rpm during update,
to ensure any Postgres 10 (or later) formated DBs are
updated to our current Postgres target version:
established by rpm dependencies and 'alternatives'.

src/rockstor/scripts/db_upgrade.sh

@@ -0,0 +1,124 @@
+#!/bin/bash
+# exit on error
+set -o errexit
+#
+# Upgrade the database format from 10 to 13.
+# Testing RPM version 5.0.6-0 updated to Django LTS 4.2 & psycopg3.
+# These are no longer compatibility with databases created
+# with Postgres version 10, i.e. installs originally created from:
+# Rockstor-Leap15.3-generic.x86_64-4.1.0-0.install.iso Jan 14 2022
+# or earlier.
+# - RPM version 4.5.0-0 added a Postgresql V13 dependency.
+# - RPM version 5.0.2-0 enforced Postgresql alternative to V13.
+#
+# Uses pg_upgrade https://www.postgresql.org/docs/13/pgupgrade.html
+# Informed by:
+# - https://en.opensuse.org/SDB:PostgreSQL#Upgrading_major_PostgreSQL_version
+# - https://progress.opensuse.org/news/113
+# ps aufx | grep '^postgres.* -D'
+# V10: /usr/lib/postgresql10/bin/postgres -D /var/lib/pgsql/data
+#
+FROM_VERSION="$1"
+TO_VERSION="$2"
+
+if [ $# -ne 2 ]; then
+    echo "This script upgrades the Rockstor Postgres database format."
+    echo "It requires two integer numbers: the 'current' and 'target' DB formats."
+    echo "Example: 10 13"
+    exit 1
+fi
+# OpenSUSE postgres user home (~) is: /var/lib/pgsql/
+# By default databases are created in the "data" subdirectory.
+DATA_BASEDIR="/var/lib/pgsql"
+# Get current database format version via PG_VERSION file.
+if test -r $DATA_BASEDIR/data/PG_VERSION ; then
+    CURRENT_DATA_VERSION=$(cat $DATA_BASEDIR/data/PG_VERSION)
+else
+  echo "No DB PG_VERSION file found."
+  exit 0
+fi
+
+# Filter input parameter.
+if [ "${CURRENT_DATA_VERSION}" -lt 10 ] ; then
+  echo "DB format found is less than 10, this is not an official Rockstor DB format."
+  exit 0
+fi
+if [ "${FROM_VERSION}" -lt 10 ] ; then
+  echo "This script can only upgrade DB formats >=10."
+  exit 0
+fi
+if [ "${CURRENT_DATA_VERSION}" == "${TO_VERSION}" ] ; then
+  echo "Current DB format is already $TO_VERSION."
+  exit 0
+fi
+if [ "${CURRENT_DATA_VERSION}" != "${FROM_VERSION}" ] ; then
+  echo "Current DB format is $CURRENT_DATA_VERSION, This differs from expected format $FROM_VERSION entered."
+  exit 0
+fi
+
+# Postgres binary directory paths, e.g.:
+# 10: /usr/lib/postgresql10/bin/
+# 13: /usr/lib/postgresql13/bin/
+BIN_BASEDIR="/usr/lib/postgresql"
+
+# Check for expected postgres server bin dir locations.
+if ! test -e "${BIN_BASEDIR}${CURRENT_DATA_VERSION}/bin"; then
+  echo "No Current postgresql${CURRENT_DATA_VERSION}-server install found: exiting."
+  exit 0
+fi
+if ! test -e "${BIN_BASEDIR}${TO_VERSION}/bin"; then
+  echo "No Target postgresql${TO_VERSION}-server install found: exiting."
+  exit 0
+fi
+if ! test -e "${BIN_BASEDIR}${TO_VERSION}/bin/pg_upgrade"; then
+  echo "No Target postgresql${TO_VERSION}-contrib install found: exiting."
+  echo "Try 'zypper install --no-recommends postgresql${TO_VERSION}-contrib'"
+  exit 0
+fi
+
+echo "Updating DB format from ${CURRENT_DATA_VERSION} to ${TO_VERSION} via pg_upgrade."
+
+# Push onto dir stack our pwd and change to postgres user's home dir.
+# (required as pg_upgrade creates files in pwd)
+pushd /var/lib/pgsql
+
+# Initialise TO_VERSION database in "${DATA_BASEDIR}/data${TO_VERSION}" directory.
+# install -d -m 0700 -o postgres -g postgres "${DATA_BASEDIR}/data${TO_VERSION}"
+# initdb creates the --pgdata directory with its preferred rights if it does not exist.
+sudo -u postgres "${BIN_BASEDIR}${TO_VERSION}/bin/initdb" --pgdata="${DATA_BASEDIR}/data${TO_VERSION}"
+
+# Stop Postgres - may fail from within another systemd service.
+systemctl stop postgresql.service
+
+# Move default 'data' dir DB to version-specific dir:
+mv ${DATA_BASEDIR}/data ${DATA_BASEDIR}/data"${CURRENT_DATA_VERSION}"
+
+sudo -u postgres pg_upgrade \
+     --old-bindir="${BIN_BASEDIR}${CURRENT_DATA_VERSION}/bin"     \
+     --new-bindir="${BIN_BASEDIR}${TO_VERSION}/bin"       \
+     --old-datadir="${DATA_BASEDIR}/data${CURRENT_DATA_VERSION}/" \
+     --new-datadir="${DATA_BASEDIR}/data${TO_VERSION}/"
+
+# Restore default 'data' dir as symlink to the /data${TO_VERSION}
+# e.g. lrwxrwxrwx 1 postgres postgres ... data -> data13
+sudo -u postgres ln --force --symbolic data"${TO_VERSION}" data
+
+# Remove old database (approximately 80-100MB)
+# rm -rf "${DATA_BASEDIR}/data${CURRENT_DATA_VERSION}/"
+
+# Start Postgres to enable vacuumdb & reindexdb operations.
+systemctl start postgresql.service
+
+# Vacuum & reindex new DB as per pg_upgrade recommendation:
+sudo -u postgres ${BIN_BASEDIR}"${TO_VERSION}"/bin/vacuumdb --all --analyze-in-stages
+sudo -u postgres ${BIN_BASEDIR}"${TO_VERSION}"/bin/reindexdb --all --concurrently
+
+# Restore our prior pwd.
+popd
+
+echo "All Rockstor services, if running, will have been stopped."
+echo "Restart via 'systemctl start rockstor-bootstrap.service'"
+
+# ps aufx | grep '^postgres.* -D'
+# V13: /usr/lib/postgresql13/bin/postgres -D /var/lib/pgsql/data
+