Add a custom label to external disks

[Flowwwww]

Hello,
Thank you for this project. I'm loving it !

I mainly use it to monitor some external drives and couldn't find a way to modify the disk label in charts.
It is currently showing the devices names (/dev/sdh2 for example). I don't find it very explicit.

Would it be possible to add a configuration that allow end-user to add a custom label for each external drive ?

[henrygd]

I agree we need a solution for this.

I've been thinking about adding an optional config file for the agent, which would be a good place to specify disk options as well.

Something like this, which could be passed to the agent via CONFIG=/path/to/config.yml.

# device information
devices:
  sda1:
    name: Extra Disk One
  pool01:
    name: ZFS Storage Pool
    io: ["sdc", "sdd", "sde"]

# monitor network services / devices
services:
  - name: paperless
    host: 192.168.8.8:8000
    type: http
  - name: security-camera
    host: 192.168.8.14
    type: ping

# define custom charts
charts:
  - name: HTTP Connections
    desc: Current number of HTTP connections to the server
    cmd: example-command | grep xxx | sed 's/xxx/xxx/'
  - name: Another Chart
    desc: Lorem ipsum dolor sit amet consectetur
    file: /path/to/file

There's also a separate issue where device paths can change after reboot on some systems (#294), so we may need to use a different identifier instead, like UUID or mount path.