ntfy/docs/examples.md

# Examples

There are a million ways to use ntfy, but here are some inspirations. I try to collect
<a href="https://github.com/binwiederhier/ntfy/tree/main/examples">examples on GitHub</a>, so be sure to check
those out, too.

## A long process is done: backups, copying data, pipelines, ...
I started adding notifications pretty much all of my scripts. Typically, I just chain the <tt>curl</tt> call
directly to the command I'm running. The following example will either send <i>Laptop backup succeeded</i>
or ⚠️ <i>Laptop backup failed</i> directly to my phone:

```
rsync -a root@laptop /backups/laptop \
  && zfs snapshot ... \
  && curl -H prio:low -d "Laptop backup succeeded" ntfy.sh/backups \
  || curl -H tags:warning -H prio:high -d "Laptop backup failed" ntfy.sh/backups
```

## Low disk space alerts
Here's a simple cronjob that I use to alert me when the disk space on the root disk is running low. It's simple, but 
effective. 

``` bash 
#!/bin/bash

mingigs=10
avail=$(df | awk '$6 == "/" && $4 < '$mingigs' * 1024*1024 { print $4/1024/1024 }')
topicurl=https://ntfy.sh/mytopic

if [ -n "$avail" ]; then
  curl \
    -d "Only $avail GB available on the root disk. Better clean that up." \
    -H "Title: Low disk space alert on $(hostname)" \
    -H "Priority: high" \
    -H "Tags: warning,cd" \
    $topicurl
fi
```

## Server-sent messages in your web app
Just as you can [subscribe to topics in the Web UI](subscribe/web.md), you can use ntfy in your own
web application. Check out the <a href="/example.html">live example</a> or just look the source of this page.

## Notify on SSH login
Years ago my home server was broken into. That shook me hard, so every time someone logs into any machine that I
own, I now message myself. Here's an example of how to use <a href="https://en.wikipedia.org/wiki/Linux_PAM">PAM</a>
to notify yourself on SSH login.

=== "/etc/pam.d/sshd"
    ```
    # at the end of the file
    session optional pam_exec.so /usr/bin/ntfy-ssh-login.sh
    ```

=== "/usr/bin/ntfy-ssh-login.sh"
    ```bash
    #!/bin/bash
    if [ "${PAM_TYPE}" = "open_session" ]; then
      curl \
        -H prio:high \
        -H tags:warning \
        -d "SSH login: ${PAM_USER} from ${PAM_RHOST}" \
        ntfy.sh/alerts
    fi
    ```

## Collect data from multiple machines
The other day I was running tasks on 20 servers, and I wanted to collect the interim results
as a CSV in one place. Each of the servers was publishing to a topic as the results completed (`publish-result.sh`), 
and I had one central collector to grab the results as they came in (`collect-results.sh`).

It looked something like this:

=== "collect-results.sh"
    ```bash
    while read result; do
      [ -n "$result" ] && echo "$result" >> results.csv
    done < <(stdbuf -i0 -o0 curl -s ntfy.sh/results/raw)
    ```
=== "publish-result.sh" 
    ```bash
    // This script was run on each of the 20 servers. It was doing heavy processing ...
    
    // Publish script results
    curl -d "$(hostname),$count,$time" ntfy.sh/results
    ```

## Ansible, Salt and Puppet
You can easily integrate ntfy into Ansible, Salt, or Puppet to notify you when runs are done or are highstated.
One of my co-workers uses the following Ansible task to let him know when things are done:

```yml
- name: Send ntfy.sh update
  uri:
    url: "https://ntfy.sh/{{ ntfy_channel }}"
    method: POST
    body: "{{ inventory_hostname }} reseeding complete"
```

## Watchtower notifications (shoutrrr)
You can use `shoutrrr` generic webhook support to send watchtower notifications to your ntfy topic.

Example docker-compose.yml:
```yml
services:
  watchtower:
    image: containrrr/watchtower
    environment:
      - WATCHTOWER_NOTIFICATIONS=shoutrrr
      - WATCHTOWER_NOTIFICATION_URL=generic+https://ntfy.sh/my_watchtower_topic?title=WatchtowerUpdates
```

Or, if you only want to send notifications using shoutrrr:
```
shoutrrr send -u "generic+https://ntfy.sh/my_watchtower_topic?title=WatchtowerUpdates" -m "testMessage"
```

## Random cronjobs
Alright, here's one for the history books. I desperately want the `github.com/ntfy` organization, but all my tickets with
GitHub have been hopeless. In case it ever becomes available, I want to know immediately.

``` cron
# Check github/ntfy user
*/6 * * * * if curl -s https://api.github.com/users/ntfy | grep "Not Found"; then curl -d "github.com/ntfy is available" -H "Tags: tada" -H "Prio: high" ntfy.sh/my-alerts; fi
~           
```