op mode: T6498: move uptime helpers to vyos.utils.system

[dmbaturin]

Change Summary

Move the functions for getting system uptime and load averages from uptime.py to vyos.utils.system, mainly to be able to call them from the new tech-support script, but that's not all.

There's also a "while we are at it" change that makes the performance of those functions better.

1. get_uptime_seconds() no longer reads the uptime file twice.
2. get_load_averages() now reads /proc/loadavg directly instead of spawning uptime as a subprocess.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, renaming)
• Refactoring (no functional changes)
• Migration from an old Vyatta component to vyos-1x, please link to related PR inside obsoleted component
• Other (please describe):

Related Task(s)

Related PR(s)

Component(s) name

Op mode.

Proposed changes

How to test

run show system uptime should work as before.

Smoketest result

Checklist:

• I have read the CONTRIBUTING document
• I have linked this PR to one or more Phabricator Task(s)
• I have run the components SMOKETESTS if applicable
• My commit headlines contain a valid Task id
• My change requires a change to the documentation
• I have updated the documentation accordingly

[github-actions]

❌
PR title 'op mode: T6498: move uptime helpers to vyos.utils.system' does not match the required format!. Valid title example: T99999: make IPsec secure

[jestabro]

One minor point: pylint complains about '\s' and '\.' if the regex is not a raw string; annoyingly, it can produce a vague warning message when pylint called on an unrelated file:
<unknown>:108: SyntaxWarning: invalid escape sequence '\.'

To make pylint happy:

diff --git a/python/vyos/utils/system.py b/python/vyos/utils/system.py
index dc8c9aa89..b3b1dbb7f 100644
--- a/python/vyos/utils/system.py
+++ b/python/vyos/utils/system.py
@@ -105,7 +105,7 @@ def get_uptime_seconds():
     from vyos.utils.file import read_file
 
     data = read_file("/proc/uptime")
-    seconds = search("([0-9\.]+)\s", data).group(1)
+    seconds = search(r'([0-9\.]+)\s', data).group(1)
     res  = int(float(seconds))
 
     return res

I have encountered this recently and have in a working repo (part of a larger PR):

diff --git a/python/vyos/utils/dict.py b/python/vyos/utils/dict.py
index 062ab9c81..1eb6abcd5 100644
--- a/python/vyos/utils/dict.py
+++ b/python/vyos/utils/dict.py
@@ -34,7 +34,7 @@ def colon_separated_to_dict(data_string, uniquekeys=False):
         otherwise they are always lists of strings.
     """
     import re
-    key_value_re = re.compile('([^:]+)\s*\:\s*(.*)')
+    key_value_re = re.compile(r'([^:]+)\s*\:\s*(.*)')
 
     data_raw = re.split('\n', data_string)