Python. Automating creation backups of MySQL database.
Tags: python, mysql, devops, database
Published: 2024-05-14 19:15:27

This script automates creating backups of MySQL databases, restoring them, and managing database and user creation on the destination MySQL server.

```
import subprocess
import datetime
import sys
import os

def check_and_create_database(host, port, username, password, database):
    # Command to check if the database exists
    check_database_command = f"mysql -sN --host={host} --port={port} --user={username} --password={password} -e \"SELECT EXISTS(SELECT 1 FROM INFORMATION_SCHEMA.SCHEMATA WHERE SCHEMA_NAME = '{database}')\" 2>/dev/null"
    
    # Execute the command
    output = subprocess.check_output(check_database_command, shell=True)
    
    # If the output contains b'1', the database exists
    if b'1' in output:
        subprocess.run(check_database_command, shell=True, check=True)
        print(f"Database '{database}' already exists.")
        sys.exit(1)
    else:
        # If the command fails, the database does not exist
        print(f"Database '{database}' does not exist. Creating...")

        # Command to create the database
        create_database_command = f"mysql --host={host} --port={port} --user={username} --password={password} -e 'CREATE DATABASE {database}' 2>/dev/null"
        subprocess.run(create_database_command, shell=True)

def check_and_create_user(host, port, username, password, database, new_username, new_password):
    # Command to check if the user exists
    check_user_command = f"mysql -sN --host={host} --port={port} --user={username} --password={password} -e \"SELECT EXISTS(SELECT 1 FROM mysql.user WHERE user = '{new_username}')\" 2>/dev/null"

    # Execute the command
    output = subprocess.check_output(check_user_command, shell=True)
    
    # If the output contains b'1', the user exists
    if b'1' in output:
        print(f"User '{new_username}' already exists.")
        sys.exit(1)
    else:
        # The user does not exist, create it
        print(f"User '{new_username}' does not exist. Creating...")

        # Command to create the user and grant privileges
        create_user_command = f"mysql --host={host} --port={port} --user={username} --password={password} -e \"CREATE USER '{new_username}'@'%' IDENTIFIED BY '{new_password}'; GRANT ALL PRIVILEGES ON {database}.* TO '{new_username}'@'%'; FLUSH PRIVILEGES;\" 2>/dev/null"
        subprocess.run(create_user_command, shell=True)

def backup_mysql_database(host, port, username, password, database, backup_path):
    
    # Check if the backup directory exists
    if not os.path.exists(backup_path):
        print(f"Error: Backup directory '{backup_path}' does not exist.")
        sys.exit(1)
    
    # Create a filename for the backup with the current date and time
    timestamp = datetime.datetime.now().strftime("%Y-%m-%d_%H-%M-%S")
    backup_file = f"{backup_path}/{database}_{timestamp}.sql"

    # Command to create a database backup using mysqldump
    dump_command = f"mysqldump --no-tablespaces --host={host} --port={port} --user={username} --password={password} {database} > {backup_file} 2>/dev/null"
    
    # Execute the mysqldump command
    subprocess.run(dump_command, shell=True)

    return backup_file

def restore_mysql_database(host, port, username, password, database, backup_file):
    # Command to restore a database from a backup using mysql
    restore_command = f"mysql --host={host} --port={port} --user={username} --password={password} {database} < {backup_file} 2>/dev/null"

    # Execute the mysql command
    subprocess.run(restore_command, shell=True)

def main():
    # Connection parameters to the source MySQL database
    source_host = "127.0.0.1"
    source_port = "3309"
    source_username = "my_user"
    source_password = "my_password"
    source_database = "my_database"

    # Connection parameters to the target MySQL database
    target_host = "127.0.0.1"
    target_port = "3309"
    new_username = "new_username"
    new_password = "new_password"
    target_database = "my_database_two"
    
    target_username = "root"
    target_password = "root_password"

    # Path to save the backup locally
    backup_path = "my_dbs_dumps"
    
    # Check if source_database is different from target_database
    if source_database == target_database:
        print("Error: Source database should be different from target database.")
        sys.exit(1)

    # Check and create the target database if it does not exist
    check_and_create_database(target_host, target_port, target_username, target_password, target_database)

    # Check and create the target user if it does not exist
    check_and_create_user(target_host, target_port, target_username, target_password, target_database, new_username, new_password)

    # Create a backup of the MySQL database
    backup_file = backup_mysql_database(source_host, source_port, source_username, source_password, source_database, backup_path)
    print(f"Database backup created: {backup_file}")

    # Restore the database on the target server from the backup
    restore_mysql_database(target_host, target_port, target_username, target_password, target_database, backup_file)
    print("Database backup restored on the target server.")

if __name__ == "__main__":
    main()
```

check_and_create_database:
This function checks if a database exists on a MySQL server. If the database does not exist, it creates it. It takes parameters such as the host, port, username, password, and database name to check or create.

check_and_create_user:
Like the database function, this function checks if a user exists on the MySQL server. If the user does not exist, it creates the user and grants privileges to a specific database. It also takes parameters such as the host, port, username, password, the name of the database, the new username, and the new password.

backup_mysql_database:
This function performs a backup of a MySQL database using mysqldump. It takes parameters such as the host, port, username, password, database name, and the path to save the backup file.

restore_mysql_database:
This function restores a MySQL database from a backup file. It takes parameters such as the host, port, username, password, database name, and the path to the backup file.

main:
This is the main function of the script. It sets up parameters for the source and target MySQL databases, including connection details, database names, and backup paths. It then performs checks to ensure that the source and target databases are different, creates the target database and user if they don’t exist, creates a backup of the source database, and finally restores the backup to the target database.

Additionally, the script uses the subprocess module to execute shell commands for MySQL operations (mysql, mysqldump) and performs error handling and output redirection (2>/dev/null) to suppress unnecessary output.

If you’re working with MySQL databases and want to create automation, this code will help you.

This code represents a good starting template for creating automation scripts for managing MySQL databases.

```
dmi@dmi-laptop:~/my_python$ python3 mysql_backup_restore.py 
Database 'my_database_two' does not exist. Creating...
User 'new_username' does not exist. Creating...
Database backup created: my_dbs_dumps/my_database_2024-05-13_20-05-24.sql
Database backup restored on the target server.
dmi@dmi-laptop:~/my_python$ 
```

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