Add needrestart_info.py to monitore needrestart.

[RomainMou]

Hi,

I've made a small script to retrieve some metrics from needrestart, and perhaps it could be useful for others?

The script runs needrestart -b (batch mode), parses the output, and displays some metrics. It looks like this:

# HELP needrestart_timestamp information about the version and when it was last run
# TYPE needrestart_timestamp gauge
needrestart_timestamp{version="3.5"} 1.702655157e+09
# HELP needrestart_kernel_status information about the kernel status
# TYPE needrestart_kernel_status gauge
needrestart_kernel_status{current="5.10.0-26-amd64",expected="5.10.0-26-amd64"} 1.0
# HELP needrestart_services_count number of services requiring a restart
# TYPE needrestart_services_count gauge
needrestart_services_count 0.0
# HELP needrestart_containers_count number of containers requiring a restart
# TYPE needrestart_containers_count gauge
needrestart_containers_count 0.0
# HELP needrestart_sessions_count number of sessions requiring a restart
# TYPE needrestart_sessions_count gauge
needrestart_sessions_count 0.0

[funkyfuture]

it seems more consistent to name this NeedRestartData. it could also be a dataclass and the parsing would be implemented in a function.

[funkyfuture]

Suggested change

	key, value = line.split(": ")
	key, value = line.split(": ", maxsplit=1)

[funkyfuture]

imo, this doesn't need to be marked as private. per convention. this modules isn't intended to be used as library, so i'd question any marking of functions as private.

[funkyfuture]

Suggested change

	subprocess.run(["needrestart", "-b"], stdout=subprocess.PIPE)
	needrestart_output = subprocess.run(["needrestart", "-b"], capture_output=True, text=True).stdout
	needrestart_data = NeedrestartParser(needrestart_output)

i think that makes it clearer that the process' output is to be used, the text option makes is unnecessary to decode it in the parsing logic.

the extra statement for capturing the output makes it better comprehensible imo.

[funkyfuture]

Suggested change

	from prometheus_client import (
	from prometheus_client import (

per convention, 3rd party module imports are separated w/ an empty line from the ones from stdlib.

[funkyfuture]

Suggested change

	#
	#
	# Description: Expose metrics from needrestart.
	#
	# This script runs needrestart in batch mode. It will never ask for input
	# and will never restart or upgrade anything.
	#
	# Dependencies: python >= 3.5, python3-prometheus-client, needrestart
	#
	# Authors: RomainMou
	"""
	Description: Expose metrics from needrestart.
	This script runs needrestart in batch mode. It will never ask for input
	and will never restart or upgrade anything.
	Dependencies: python >= 3.5, python3-prometheus-client, needrestart
	Authors: RomainMou
	"""

This is considered as module docstring by Python interpreters.