feat(cogs): objectstore.cogs.usage datadog metric

[matt-codecov]

imitating how relay does compute COGS, except we are using request counts rather than request timings because we're network-bound and CPU-light

every request incrs the counter by 1, except batch requests incr it for each operation in the batch

need to update usage-accountant config to consume the counter but then compute COGS is finished

Ref FS-195

[linear-code]

FS-195

[codecov]

Codecov Report

❌ Patch coverage is 97.93814% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 87.25%. Comparing base (3de99d5) to head (bdefa80).

Files with missing lines	Patch %	Lines
objectstore-server/src/web/middleware.rs	97.18%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #492      +/-   ##
==========================================
+ Coverage   87.17%   87.25%   +0.07%     
==========================================
  Files          83       84       +1     
  Lines       13138    13234      +96     
==========================================
+ Hits        11453    11547      +94     
- Misses       1685     1687       +2     

Components	Coverage Δ
Rust Backend	92.38% <97.93%> (+0.05%)	⬆️
Rust Client	79.70% <ø> (ø)
Python Client	88.51% <ø> (ø)

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[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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[cursor]

Batch COGS skips pre-auth ops

Medium Severity

Per-operation objectstore.cogs.usage is incremented only after rate limiting, authorization, and use-case policy checks, while non-batch routes increment once in middleware before those checks. Batch operations that fail earlier in the pipeline emit no COGS, and batch HTTP requests rejected before the handler also emit none, unlike equivalent single-object requests.

Additional Locations (1)

• objectstore-server/src/web/middleware.rs#L119-L136

 

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