chore: eliminate calls at import time #5889
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It is not best practice, and it often adds unnecessary overhead.
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One big inline comment/concern about the regex compiles, but otherwise LGTM.
While namedtuple() and tuple() aren't truly harmful, there are ways to define similar types statically rather than generating them at runtime, so I modified those in a few places too.
Big +1 to changing to new-style named tuples with typing, but is there actually a runtime difference? They both will be evaluated at import time, correct?
cloudinit/config/cc_mounts.py
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| @@ -57,7 +55,7 @@ def is_meta_device_name(name): | |||
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| def is_network_device(name): | |||
| # return true if this is a network device | |||
| if NETWORK_NAME_RE.match(name): | |||
| if re.compile(NETWORK_NAME_FILTER).match(name): | |||
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This can just be an re.match() because compiling a regex is to pay the time cost once so each subsequent match can be faster.
If the time cost of not being compiled is significant, it may be better to move the compilation into a memoized initialization function. Same comment for the rest of the regexes in this PR.
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This can just be an
re.match()because compiling a regex is to pay the time cost once so each subsequent match can be faster.
+1
If the time cost of not being compiled is significant, it may be better to move the compilation into a memoized initialization function. Same comment for the rest of the regexes in this PR.
Every call to re.match() fetches previously-compiled expressions under the covers, so I think this memoization is probably handled for us.
Correct - I don't think that there will be much runtime difference - just the benefit of added typing. |
It is not best practice, and it often adds unnecessary overhead.
Proposed Commit Message
Additional Context
The important part of this is regex compile - that can be done when/if the function is called rather than at import time which will save some cycles.
While
namedtuple()andtuple()aren't truly harmful, there are ways to define similar types statically rather than generating them at runtime, so I modified those in a few places too.Fixes #5344