(feat): Refactor lsblk -J to lsblk -P + LVM Validation Test Cases

[lasith-kg]

I was experimenting with ebs-bootstrap running on RHEL 7.9 and found that lsblk -J, a command that returns a JSON representation of a block device, is only supported on relatively modern operating systems.

After some digging, I found that lsblk -P returns a machine readable format response in the form of key-value pairs. Since this machine readable format is supported on older versions of lsblk, I refactored any invocations of lsblk -J to lsblk -P

# RHEL 9.2
$ lsblk -o NAME,LABEL,FSTYPE,MOUNTPOINT --nodeps -J /dev/nvme9n1
{
   "blockdevices": [
      {
         "name": "nvme9n1",
         "label": "ifmx-var",
         "fstype": "ext4",
         "mountpoint": null
      }
   ]
}

$ lsblk -o NAME,LABEL,FSTYPE,MOUNTPOINT --nodeps -P /dev/nvme9n1
NAME="nvme9n1" LABEL="ifmx-var" FSTYPE="ext4" MOUNTPOINT=""

# RHEL 7.9
$ lsblk -o NAME,LABEL,FSTYPE,MOUNTPOINT --nodeps -J /dev/nvme9n1
lsblk: invalid option -- 'J'
...

$ lsblk -o NAME,LABEL,FSTYPE,MOUNTPOINT --nodeps -P /dev/nvme9n1
NAME="nvme9n1" LABEL="ifmx-var" FSTYPE="ext4" MOUNTPOINT=""

Additionaly, I use this oppurtunity to improve the test cases around LVM validation and error handling. I introduce a performance optimisation for Regex logic by computing the expressions ahead of time and storing them in top-level variables