Error wrapping in t3c

[ocket8888]

This makes errors constructed in from other errors in t3c (everything under cache-config/) use error-wrapping formatting so that the identity of the underlying error is not destroyed. It also ensures that:

• Error strings do not start with a capital letter
• Error strings do not end with punctuation
• Error identity is checked with errors.Is
• Error type is checked with errors.As

Originally, I was going to do that for everything in the repo at once, but I drastically underestimated how large that changeset would be. So I just started with the first component alphabetically. Partially because I did originally want this to encompass the whole repo, there's also a change in here that that removes a newline from an error string in traffic_vault_migrate and some changes to the db/admin program - I left those in because I figured it was harmless to do so, but I can take them out at a reviewer's request.

---

Which Traffic Control components are affected by this PR?

• Traffic Control Cache Config (T3C, formerly ORT)

What is the best way to verify this PR?

Make sure all the tests still pass. To check for non-wrapping errors, I grepped with the regular expression:

(fmt\.Errorf|errors\.New)(.+(\.Error\b|%v.+ \w*[eE]r\w*[,)]|\\n|[!\.?]")|\("[A-Z])

which does output some false positives where an error is passed to fmt.Errorf that just so happens to use %v to format something that isn't an error. I also used errorlint, which is available through golangci-lint, to catch cases where errors.Is and errors.As should be used (but that won't catch all the things the regexp does, it'll miss things like errors.New(err.Error())). Finally, I checked for matches to

errors\.New\(fmt\.Sprintf\(

but that yielded no results, so no changes were necessary.

PR submission checklist

• This PR DOES NOT FIX A SERIOUS SECURITY VULNERABILITY

[rob05c]

See my comment on #6159 (comment) about performance.

t3c isn't nearly as performance-critical as Grove, but we're trying to reduce the runtime of cache config deployment. As we get down from minutes to seconds, it'd be good if we didn't add things that make the whole run take say, 5 seconds instead of 2.

Again, I support the idea of this. And I can't say how much an impact this has without testing. But it'd be really good if, before merging something potentially performance-impacting like this, if someone benchmarked t3c-apply runs for every concievable ordinary configuration on a large CDN, and confirmed it doesn't significantly impact performance.

[codecov]

Codecov Report

Attention: 275 lines in your changes are missing coverage. Please review.

Comparison is base (61865fb) 31.91% compared to head (5092d88) 31.92%.

Files	Patch %	Lines
cache-config/t3cutil/toreq/clientfuncs.go	0.00%	51 Missing ⚠️
cache-config/t3cutil/toreq/toreqold/clientfuncs.go	0.00%	46 Missing ⚠️
cache-config/t3c-apply/torequest/cmd.go	0.00%	38 Missing ⚠️
cache-config/t3c-apply/torequest/torequest.go	0.00%	33 Missing ⚠️
cache-config/t3c-apply/util/gitutil.go	0.00%	23 Missing ⚠️
cache-config/t3cutil/getdata.go	0.00%	19 Missing ⚠️
cache-config/t3cutil/getdatacfg.go	0.00%	18 Missing ⚠️
cache-config/t3c-apply/util/util.go	0.00%	11 Missing ⚠️
cache-config/t3cutil/toreq/client.go	0.00%	8 Missing ⚠️
cache-config/t3c-apply/config/config.go	0.00%	5 Missing ⚠️
... and 12 more

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #6157      +/-   ##
============================================
+ Coverage     31.91%   31.92%   +0.01%     
  Complexity       98       98              
============================================
  Files           719      719              
  Lines         82788    82774      -14     
  Branches        970      970              
============================================
+ Hits          26423    26428       +5     
+ Misses        54202    54184      -18     
+ Partials       2163     2162       -1     

Flag	Coverage Δ
golib_unit	53.86% <ø> (+<0.01%)	⬆️
grove_unit	12.02% <ø> (ø)
t3c_unit	5.91% <0.36%> (+0.10%)	⬆️
traffic_monitor_unit	26.44% <ø> (ø)
traffic_ops_unit	21.68% <ø> (ø)
traffic_portal_v2	74.35% <ø> (+0.01%)	⬆️
traffic_stats_unit	10.78% <ø> (ø)
unit_tests	29.25% <0.36%> (+0.01%)	⬆️

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