fixed graphing failures for VM deployed on legacy Centos 6.9 virtualization
platforms (script uses the Proxmox entries), in the case of VM domain names
beggining with digits (first field name character must be [a-ZA-Z_])
used "Validate field names" Python stanza from documentation ("How to write
plugins", "Notes on field names") to improve the clean_vm_name function, thus
munin kvm graph creation succeeded for VM with names starting with digits,
like "150-121-Apache", deployed on Centos 6.9 virtualization platforms.
fixed graph failure for VM names starting with digits
used "Validate filednames" Python stanza from docs to improve
clean_vm_name functions, helping graph creations for VM with names
starting with digits, like "150-121-Apache".
remember: each data source in a plugin must be identified by a field
name (in this case VM names). The characters must be [a-zA-Z0-9_],
while the first character must be [a-zA-Z_].
* works on debian bullseye with this modification.
* removed all codestyle issues, checked with "pycodestyle" on debian bullseye, besides two "line too long"
* "config" param must not have newlines to avoid a warning in munin-update.log
On Debian Stretch the cmdline is something like:
qemu-system-x86_64-enable-kvm-nameguest=vmname,debug-threads=on-S-[…]
Without null characters:
qemu-system-x86_64 -enable-kvm -name guest=vmname,debug-threads=on[…]
We need to match only guest=vmname, so the regex
"^.*guest=([a-zA-Z0-9.-_-]*).*$" is simpler and match the VM name.
The precedent regex "^.*-name\x00([a-zA-Z0-9.-_-]*)\x00\-.*$" was not matching it.
BTW, It seems that \x00 does not match correctly null characters so I removed it.
