Setting up Auto-Restart (Linux)

Ways to setup auto restart for your bot on Linux hosts.

PM2

PM2 is a process manager originally intended for Node.js but can also be used with Python applications, such as our Modmail bot and Logviewer. To use `pm2`, we will need to install Node Package Manager (`npm`).

Installing pm2 Using apt (Ubuntu, Debian, etc):

sudo apt install npm -y && sudo npm i pm2 -g

Installing pm2 using dnf (Fedora, Alma Linux, etc):

sudo dnf -y install npm && sudo npm i pm2 -g

Then, in the Modmail folder, start the Modmail process in the background with:

pm2 start modmail.sh --name "modmail"

You can see the logs of your Modmail process with:

pm2 logs modmail

And then, to make sure that pm2 stays active and persistent between machine restarts, run the following commands:

pm2 save && pm2 startup

Here's some of the other PM2 commands for future reference:

pm2 restart modmail
pm2 reload modmail
pm2 stop modmail
pm2 delete modmail
pm2 list
``` </div>

<div data-gb-custom-block data-tag="tab" data-title='systemd (Setting up Modmail as a Linux Service)'> `systemd` is a built-in service manager for most Linux systems. It's primary used to manage background applications and services and to make applications auto-restart on crash and run on system startup.

We will be using `systemd` for Modmail by making a service file for our bot.

In order to create the service file, you will first need to know three things, your Linux `username`, your Modmail folder location as `modmail_path` and your Pipenv location as `pipenv_path`.

First, your Linux `username` can be fetched with the following command:

```bash
whoami

You can get your pipenv_path with:

whereis pipenv

Now, using nano, create a service file for systemd with:

sudo nano /etc/systemd/system/modmail.service

and paste in the contents below, replacing username, modmail_path and pipenv_path with yours respectively. Ctrl+O and Enter to save. Ctrl+X to exit the nano editor.

modmail.service

[Unit]
Description=Modmail bot
After=network.target

[Service]
User=username # replace this
Group=username # replace this
Restart=always
RestartSec=10
Type=simple
WorkingDirectory=modmail_path # replace this
ExecStart=pipenv_path run python bot.py # replace pipenv_path only

[Install]
WantedBy=multi-user.target

Now, start your Modmail bot with:

sudo systemctl start modmail

If everything goes correctly, you should see your bot online. You can also view the logs of your systemd process with:

sudo journalctl -eu modmail

With that said, go ahead and enable your Modmail service to auto-restart after crash and reboot with:

sudo systemctl enable modmail

If in the future you need to stop and disable your Modmail service, you can do so with:

sudo systemctl stop modmail
sudo systemctl disable modmail
``` </div>

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