From 1e6869e7730389e64fd70b8aa30034758a4fe392 Mon Sep 17 00:00:00 2001
From: root <root@vps-18a7a2b7.vps.ovh.ca>
Date: Sat, 20 Jan 2024 12:46:56 -0500
Subject: path fixes

---
 src/mariadb-push-replica.sh | 221 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 221 insertions(+)
 create mode 100755 src/mariadb-push-replica.sh

(limited to 'src')

diff --git a/src/mariadb-push-replica.sh b/src/mariadb-push-replica.sh
new file mode 100755
index 0000000..c8e1e0a
--- /dev/null
+++ b/src/mariadb-push-replica.sh
@@ -0,0 +1,221 @@
+#!/bin/bash
+set -e
+PATH=$(dirname "$0"):$PATH
+source rpc.bash
+
+datadir=data
+default_replica_host_file=$datadir/default-replica-host
+replication_password_file=$datadir/replication-password
+
+if [ -r "$default_replica_host_file" ]
+then
+	read default_replica_host < "$default_replica_host_file"
+fi
+
+gen_password()
+{
+	generated_password_length=32
+	generated_password=$(tr -cd a-zA-Z0-9 < /dev/urandom |
+		head -c "$generated_password_length")
+	[ "${#generated_password}" -eq "$generated_password_length" ]
+	printf '%s\n' "$generated_password"
+}
+
+if ! [ -e "$replication_password_file" ]
+then
+	gen_password > "$replication_password_file"
+fi
+
+if [ -r "$replication_password_file" ]
+then
+	read replication_password < "$replication_password_file" 
+	[ "${#replication_password}" -ge 30 ]
+fi
+
+primary_host=$(hostname --fqdn)
+replica_host=${1:-$default_replica_host}
+replication_user=replication
+
+[ "$primary_host" ]
+[ "$replica_host" ]
+[ "$replication_password" ]
+
+run_primary()
+{
+	(set -x
+	: primary : $1 $2 ${3:+ ...})
+	BASH_RPC_REMOTE_DEST=$primary_host remote_run_function "$@"
+}
+
+run_replica()
+{
+	(set -x
+	: replica : $1 $2 ${3:+ ...})
+	BASH_RPC_REMOTE_DEST=$replica_host remote_run_function "$@"
+}
+
+show_hostnames()
+{
+	printf \
+		"==> %s %s <==\n    %s\n" \
+		"$(hostname -A)" \
+		"$(hostname -I)" \
+		"$(uptime)"
+}
+
+check_db()
+{
+	show_hostnames
+	mariadb --skip-reconnect -t <<END
+select @@hostname, @@server_id, @@gtid_slave_pos, @@sql_log_bin;
+END
+}
+
+create_backup()
+{
+	set -e
+	mariabackup_target_dir=/var/mariadb/backup
+	binlog_info_file=$mariabackup_target_dir/xtrabackup_binlog_info 
+	[ -e "$binlog_info_file" ] && return
+	mkdir -p "$mariabackup_target_dir"
+	marialog=$(mktemp)
+	e=0
+	(set -- \
+		-u root \
+		--target-dir="$mariabackup_target_dir"
+	exec >"$marialog" 2>&1
+	set -x
+	mariabackup --backup --rsync "$@"
+	mariabackup --prepare "$@") || e=$?
+	if [ "$e" = 0 -a -e "$binlog_info_file" ]
+	then
+		tail -v -n2 "$marialog" >&2
+		rm "$marialog"
+	else
+		cat "$marialog" >&2
+		false
+	fi
+}
+
+delete_backup()
+{
+	set -x
+	rm -r /var/mariadb/backup
+}
+
+send_backup()
+{
+	mariabackup_target_dir=/var/mariadb/backup
+	set -x
+	rsync -zaR -- /./"${mariabackup_target_dir#/}" "$1":/
+}
+
+stop_database_server_and_remove_database_files()
+{
+	livedb=/var/lib/mysql
+	set -e
+	if [ -e "$livedb" ]
+	then
+		if [ "$(systemctl is-active mariadb)" = active ]
+		then
+			systemctl stop mariadb
+		fi
+		livedb_backup=$livedb~$(date -Ins)
+		mv -v -T -- "$livedb" "$livedb_backup"
+		mkdir "$livedb"
+		chown --reference="$livedb_backup" "$livedb"
+		chmod --reference="$livedb_backup" "$livedb"
+	fi
+}
+
+restore_from_backup()
+{
+	mariabackup_target_dir=/var/mariadb/backup
+	set -e
+
+	stop_database_server_and_remove_database_files
+
+	marialog=$(mktemp)
+	exec >"$marialog" 2>&1
+	set -- \
+		-u root \
+		--target-dir="$mariabackup_target_dir"
+	if mariabackup --move-back "$@"
+	then
+		tail -v -n2 "$marialog" >&2
+		# Can't believe mariabackup
+		# is so primitive as to
+		# recommend this chown in its
+		# documentation
+		chown -R mysql:mysql /var/lib/mysql
+		systemctl start mariadb
+	else
+		cat "$marialog" >&2
+	fi
+
+}
+
+enable_replication()
+{
+	primary_host=$1
+	replication_user=$2
+	replication_password=$3
+	mariabackup_target_dir=/var/mariadb/backup
+	binlog_info_file=$mariabackup_target_dir/xtrabackup_binlog_info 
+	set -e
+	read master_log_file master_log_pos gtid_slave_pos < $binlog_info_file
+	tee /dev/stderr <<END | mariadb --skip-reconnect -t
+STOP SLAVE;
+SET GLOBAL gtid_slave_pos = "$gtid_slave_pos";
+CHANGE MASTER TO
+  MASTER_HOST='$primary_host',
+  MASTER_USER='$replication_user',
+  MASTER_PASSWORD='$replication_password',
+  MASTER_USE_GTID=slave_pos;
+START SLAVE;
+SHOW SLAVE STATUS\G
+END
+	set -x
+	rm -r /var/mariadb/backup
+}
+
+create_replication_user()
+{
+	mariadb --skip-reconnect -t <<END
+CREATE OR REPLACE USER '$2'@'$1' IDENTIFIED BY '$3';
+GRANT REPLICATION SLAVE ON *.*  TO '$2'@'$1';
+END
+}
+
+showvars()
+{
+	for h in "$@"
+	do
+		run_$h mariadb --skip-reconnect -t <<END
+select VARIABLE_NAME,SESSION_VALUE,GLOBAL_VALUE 
+from INFORMATION_SCHEMA.SYSTEM_VARIABLES
+where VARIABLE_NAME LIKE '%SLAVE%' \G
+END
+	done
+}
+
+set -e
+run_primary check_db
+run_replica check_db
+: showvars replica
+: exit
+
+run_primary create_replication_user \
+	"$replica_host" \
+	"$replication_user" \
+	"$replication_password"
+run_primary create_backup
+run_primary send_backup "$replica_host"
+run_replica restore_from_backup
+run_replica enable_replication \
+	"$primary_host" \
+	"$replication_user" \
+	"$replication_password"
+run_replica check_db
+run_primary delete_backup
+run_primary check_db
-- 
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