Create Explanation.md

migrations/sqlite/2024-07-09-Exemple of script for database Export/Explanation.md

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+# Database Export Script
+
+## Exporting the Database with a Script
+
+On the machine that will receive the database, create an SSH connection using SSH keys. Then, create a script file that will:
+- Copy the database
+- Create a log file of the execution of this command
+- Delete old log files
+- Send a summary email to one or more email addresses.
+
+You need to configure a mail server on your receiving machine and install the "crontab" tool if it is not already installed.
+
+We obtain the following script:
+
+**The script**
+
+
+## Explanation of the script
+
+### Prerequisites:
+
+- *Install crontab service if it is not running yet*
+- *Install the ackage for sending mail, which can be done easily with mailutils*
+
+**Variables**
+
+```bash
+# Variables
+SRC="user@ip of database source:/your/file/for/data/base" #EDITTHIS
+DEST="/destinyourmachine" #EDITTHIS
+INCLUDE="db*"
+SSH_KEY="/file/ssh/key" #EDITTHIS
+LOG_DIR="/file/log/" #EDITTHIS
+LOG_FILE="$LOG_DIR/rsync_db_$(date +'%Y-%m-%d_%H-%M').log" #Name your log
+EMAIL="Your Email" #EDITTHIS
+```
+
+We declare all our variables:
+
+```bash
+SRC: The source, the machine from which we will retrieve our databases.
+DEST: The destination, the location where we copy the databases on the receiving machine (the machine that runs the script).
+INCLUDE / EXCLUDE: I only want the files that start with "db".
+SSH_KEY: Our SSH key to avoid having to enter a password for the connection.
+LOG_DIR: The location where I want my log files.
+LOG_FILE: Its name with the current date.
+EMAIL: The email that will receive the logs.
+```
+
+*Execute the rsync command*
+
+```bash
+if rsync -avz --include="$INCLUDE" --exclude='*' -e "ssh -i $SSH_KEY" "$SRC" "$DEST" >> "$LOG_FILE" 2>&1; then
+    RSYNC_STATUS="OK"
+    echo "Rsync synchronization completed successfully." >> "$LOG_FILE"
+else
+    RSYNC_STATUS="KO"
+    echo "Rsync synchronization failed." >> "$LOG_FILE"
+fi
+```
+
+The rsync command for copying the databases, with logging to a file if the command result is OK or KO.
+
+Delete log files older than 7 days
+
+```bash
+if find "$LOG_DIR" -type f -name "rsync_db_*.log" -mtime +7 -exec rm {} \; >> "$LOG_FILE" 2>&1; then
+    FIND_STATUS="OK"
+    echo "Old log files deleted." >> "$LOG_FILE"
+else
+    FIND_STATUS="KO"
+    echo "Failed to delete old log files." >> "$LOG_FILE"
+fi
+
+# Display a message after deleting old logs
+echo "End of old log files deletion" >> "$LOG_FILE"
+Delete log files older than 7 days with logging to a file.
+```
+
+Email body
+
+```bash
+Copier le code
+MAIL_BODY="Summary of the rsync script execution on $EXEC_DATE:
+
+- Rsync synchronization: $RSYNC_STATUS
+- Deletion of old logs: $FIND_STATUS
+- Log file created: $LOG_FILE
+
+Execution details:
+$(cat "$LOG_FILE")"
+
+# Send the email
+echo "$MAIL_BODY" | mail -s "Database Synchronization" "$EMAIL
+```
+
+Send a summary email to the addresses entered in the variables.
+
+The script is executed every day at 2:00 AM. The execution is managed by crontab with the command **crontab -e** using this line:
+
+```bash
+0 2 * * * /usr/local/bin/rsync_db.sh
+```