[hack/verify-file-sizes.sh] Support Mac OS X

[bells17]

What type of PR is this?

/kind bug
/sig testing

What this PR does / why we need it:

Enable the hack/verify-file-sizes.sh script to run successfully on Mac OS X.

Which issue(s) this PR fixes:

Fixes #124155

Ref: #121549

Special notes for your reviewer:

Does this PR introduce a user-facing change?

NONE

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

[k8s-ci-robot]

Please note that we're already in Test Freeze for the release-1.30 branch. This means every merged PR will be automatically fast-forwarded via the periodic ci-fast-forward job to the release branch of the upcoming v1.30.0 release.

Fast forwards are scheduled to happen every 6 hours, whereas the most recent run was: Tue Apr 2 14:19:09 UTC 2024.

[bells17]

/sig testing

[bells17]

/cc @pohly

[carlory]

If this line works well on Linux, why not use it directly in Line 61?

[bells17]

@carlory Thank you for your review.
Regarding the options for the stat command, I tried it on Linux, and here's what I found:

$ touch samplefile

$ stat -f %z samplefile | tr -d '\n'
stat: cannot read file system information for '%z': No such file or directory
  File: "samplefile"    ID: 0        Namelen: 255     Type: fuseblkBlock size: 1048576    Fundamental block size: 4096Blocks: Total: 59840624   Free: 18538697   Available: 18538697Inodes: Total: 744080125  Free: 741547880

$ stat --printf %z ./samplefile | tr -d '\n'
2024-04-03 03:25:17.374582976 +0000

$ stat --printf %s ./samplefile
0

As shown above, an error occurred with stat -f %z, so I am switching options and such depending on whether the environment is Linux or Mac OS X.

[BenTheElder]

this sort of thing tends to cause problems because even on darwin you may have gnu coreutils installed, check e.g. when we require gnu-sed.

wc -c < "$file" would work portably

[bells17]

@BenTheElder Thank you for your comment.
I have changed the implementation to use wc -c < "$file". Please review it when you have time.

Just to be safe, I've attached the test results below after verifying the operation on both Mac OS X and Linux:

Mac OS X

echo "abc" > samplefile
size=$(wc -c < samplefile)
echo "size: $size"
for i in 3 4
do
  maxsize=$i
  if [ "${size}" -gt "$maxsize" ]; then
    echo "size is greater than maxsize"
  else
    echo "size is less than or equal to maxsize"
  fi
done
size:        4
size is greater than maxsize
size is less than or equal to maxsize

Linux

echo "abc" > samplefile
size=$(wc -c < samplefile)
echo "size: $size"
for i in 3 4
do
  maxsize=$i
  if [ "${size}" -gt "$maxsize" ]; then
    echo "size is greater than maxsize"
  else
    echo "size is less than or equal to maxsize"
  fi
done
size: 4
size is greater than maxsize
size is less than or equal to maxsize

[BenTheElder]

also confirming:

this test took
this pr: 3s: https://prow.k8s.io/view/gs/kubernetes-jenkins/pr-logs/pull/124156/pull-kubernetes-verify/1781407536046411776
random PR without this change: 6s: https://prow.k8s.io/view/gs/kubernetes-jenkins/pr-logs/pull/119589/pull-kubernetes-verify/1781378276028059648

so no performance issues

[bells17]

/triage accepted

[bells17]

/priority backlog

[BenTheElder]

/lgtm
/approve

thanks!

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: d1ec4431fac282a9a5dd5fc3269ca41f077e39a4

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: bells17, BenTheElder

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