`mail` Command in `backup-tool.sh` Script Must Be Replaced

Description:

The backup-tool.sh script currently uses the mail command to send email notifications. However, if no Mail Transfer Agent (MTA) is installed, the script's execution fails when run via cron, resulting in discarded output. This prevents the crontab from completing successfully.

Syslog Details:

The syslogs show the following messages indicating the issue:

Jun 24 01:30:01 hostname-xxx CRON[2246694]: (root) CMD (bash /data/scripts/backup-tool.sh >/dev/null 2>&1)
Jun 24 01:30:01 hostname-xxx CRON[2246690]: (CRON) info (No MTA installed, discarding output)

Affected Command in Script:

The script fails at the following command due to the missing MTA:

cat $mailtext | mail -s "$mailsubject" $email

Steps to Reproduce:

Ensure no MTA is installed on the system.
Schedule the backup-tool.sh script to run via cron.
Observe the syslogs for the error message related to the missing MTA.

Expected Behavior:

The backup-tool.sh script should complete successfully, sending email notifications without relying on a local MTA.

Additional Context:

This change is critical to ensure that the backup process can run smoothly in environments where an MTA is not available. Proper error handling and notification are essential for maintaining the reliability of the backup process.

The initial idea of the Script was to use the mail command together with postfix which can be installed on debian based system with apt-get install mailutils .

Nevertheless, if there is already an MTA on the system then this could be a challange.

For Mailcow, this could be a way to try it out. :)

To use Mailcow as your MTA with the mail command, you need to ensure that the mail command is properly configured to use Mailcow's Postfix setup. Here’s how you can configure and verify the setup:

Ensure Mailcow is Running: First, make sure that Mailcow and its components are running correctly. You can usually check this with Docker since Mailcow runs inside Docker containers.
```
docker ps
```
This should show you a list of running containers, including those related to Mailcow.
Configure System to Use Mailcow’s Postfix: If you want to use Mailcow’s Postfix setup for system emails, you need to configure your system’s mail command to use it. Here’s a general approach to configure Postfix:
- Edit the Postfix configuration file:
```
sudo nano /etc/postfix/main.cf
```
- Ensure the relayhost parameter points to the Mailcow SMTP server. For example:
```
relayhost = [127.0.0.1]:587
```
  Note: Replace [127.0.0.1]:587 with the appropriate address and port where Mailcow’s Postfix is listening.
- Reload or restart Postfix to apply the changes:
```
sudo systemctl reload postfix
```
Testing the Configuration: After configuration, you can test sending an email using the mail command to verify that it works with Mailcow’s Postfix.
```
echo "This is a test email from the mail command" | mail -s "Test Email" recipient@example.com
```
- Check Mailcow’s logs to see if the email was processed correctly.
Configuring Mailcow Postfix to Accept Local Emails: Ensure that Mailcow’s Postfix is configured to accept emails from your local system. This typically involves editing the main.cf and master.cf files inside the Mailcow Postfix container.
- Access the Postfix container:
```
docker exec -it mailcowdockerized-postfix-mailcow1 /bin/bash
```
- Edit the Postfix configuration as necessary. Ensure that mynetworks includes your local network or the IP of your server.
```
postconf -e 'mynetworks = 127.0.0.0/8 [::1]/128 <your_local_network>'
```
  Reload Postfix inside the container after making changes.
- Exit the container:
```
exit
```

By following these steps, you should be able to configure your system to use Mailcow as the MTA for the mail command. This setup ensures that all outgoing emails from the mail command are handled by Mailcow’s Postfix.

psyadm / backuptools-bash