Add option to create database dump from sql script

Loosely copied from the domjudge-scripts repo.

configure.ac

@@ -156,6 +156,7 @@ if test "x$FHS_ENABLED" = xyes ; then
 	AC_SUBST(domserver_rundir,        $localstatedir/run/${PACKAGE_TARNAME})
 	AC_SUBST(domserver_tmpdir,        /tmp)
 	AC_SUBST(domserver_exampleprobdir,$datadir/${PACKAGE_TARNAME}/example_problems)
+	AC_SUBST(domserver_databasedumpdir,$datadir/${PACKAGE_TARNAME}/db-dumps)
 
 	AC_SUBST(judgehost_root,          '')
 	AC_SUBST(judgehost_bindir,        $bindir)
@@ -200,6 +201,7 @@ AX_PATH(domserver_logdir,       [$domserver_root/log])
 AX_PATH(domserver_rundir,       [$domserver_root/run])
 AX_PATH(domserver_tmpdir,       [$domserver_root/tmp])
 AX_PATH(domserver_exampleprobdir, [$domserver_root/example_problems])
+AX_PATH(domserver_databasedumpdir, [$domserver_root/db-dumps])
 AX_WITH_COMMENT(6,[     ])
 AX_PATH(judgehost_bindir,       [$judgehost_root/bin])
 AX_PATH(judgehost_etcdir,       [$judgehost_root/etc])
@@ -348,6 +350,7 @@ echo "    - sql..............: AX_VAR_EXPAND($domserver_sqldir)"
 echo "    - tmp..............: AX_VAR_EXPAND($domserver_tmpdir)"
 echo "    - webapp...........: AX_VAR_EXPAND($domserver_webappdir)"
 echo "    - example_problems.: AX_VAR_EXPAND($domserver_exampleprobdir)"
+echo "    - database_dumps...: AX_VAR_EXPAND($domserver_databasedumpdir)"
 echo ""
 echo " * judgehost...........: AX_VAR_EXPAND($judgehost_root)"
 echo "    - bin..............: AX_VAR_EXPAND($judgehost_bindir)"

paths.mk.in

@@ -85,6 +85,7 @@ domserver_logdir       = @domserver_logdir@
 domserver_rundir       = @domserver_rundir@
 domserver_tmpdir       = @domserver_tmpdir@
 domserver_exampleprobdir = @domserver_exampleprobdir@
+domserver_databasedumpdir = @domserver_databasedumpdir@
 PHPVERSION             = @PHPVERSION@
 
 judgehost_bindir       = @judgehost_bindir@

sql/dj_setup_database.in

@@ -10,6 +10,7 @@ BINDIR="@domserver_bindir@"
 ETCDIR="@domserver_etcdir@"
 WEBAPPDIR="@domserver_webappdir@"
 EXAMPLEPROBDIR="@domserver_exampleprobdir@"
+DATABASEDUMPDIR="@domserver_databasedumpdir@"
 
 PASSWDFILE="$ETCDIR/dbpasswords.secret"
 
@@ -34,6 +35,8 @@ Commands:
   install-examples install examples only
   install-loadtest configure for load testing. WARNING: CREATES A LOT OF EXTRA ITEMS!
   upgrade          upgrade MySQL database schema to current version
+  snapshot-dump    backup the current database to file (without .tar.gz)
+  snapshot-load    load a backup from file (without.tar.gz)
 
 Options:
   -u <user>  connect to MySQL with DB admin <user>
@@ -234,10 +237,14 @@ install_examples()
 	( cd "$EXAMPLEPROBDIR" && yes y | "$BINDIR"/import-contest )
 }
 
+create_database_dump () {
+	sudo mysqldump --opt --skip-lock-tables domjudge | pv | gzip > "$DATABASEDUMPDIR/${1}.sql.gz"
+}
+
 ### Script starts here ###
 
 # Parse command-line options:
-while getopts ':u:p:qrs' OPT ; do
+while getopts ':u:p:d:qrs' OPT ; do
 	case "$OPT" in
 		u)
 			DBA_USER=$OPTARG
@@ -254,6 +261,9 @@ while getopts ':u:p:qrs' OPT ; do
 		s)
 			USE_SOCKET=1
 			;;
+		d)
+			DUMPNAME=$OPTARG
+			;;
 		:)
 			echo "Error: option '$OPTARG' requires an argument."
 			usage
@@ -354,6 +364,33 @@ upgrade)
 	verbose "DOMjudge database upgrade completed."
 	;;
 
+snapshot-dump)
+	echo $@
+	echo $DUMPNAME
+	if [ -z "$DUMPNAME" ]; then
+		usage
+		exit 1
+	fi
+
+	if [ -f "${DATABASEDUMPDIR}/${DUMPNAME}.sql.gz" ]; then
+		while true; do
+			read -p "Overwrite existing database dump (y/N)? " yn
+			case $yn in
+				[Yy]* ) create_database_dump $DUMPNAME; exit 0;
+				''|[Nn]* ) break;;
+			esac
+		done
+	else
+		create_database_dump $DUMPNAME
+	fi
+
+	read -p "Provide prefix or say 'no' to abort. Format: [prefix]-$1 " prefix
+	case $prefix in
+		''|[Nn]o|[Nn] ) exit 2; break;;
+		* ) create_database_dump ${prefix}-${DUMPNAME}; break;;
+	esac
+	;;
+
 *)
 	echo "Error: Unknown subcommand '$1'"
 	usage