- Fix gofmt: align struct field comments in UsageCache, trim trailing
whitespace on const comments
- Fix errcheck: use comma-ok on type assertion for singleflight result
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Prevents 429 rate-limit retry storms and reduces upstream correlation risk
for Anthropic usage API queries.
Three changes:
1. Negative caching (1 min TTL) — 429/error responses are now cached,
preventing every subsequent page load from re-triggering failed API calls.
2. singleflight dedup — concurrent requests for the same account are
collapsed into a single upstream call, preventing cache stampede.
3. Random jitter (0–800 ms) — staggers multi-account cache-miss bursts so
requests from different accounts don't hit upstream simultaneously with
identical TLS fingerprints, reducing anti-abuse correlation risk.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Previously the /v1/usage endpoint aggregated usage stats (today/total
tokens, cost, RPM/TPM) across all API Keys belonging to the user.
This made it impossible to distinguish usage from different API Keys
(e.g. balance vs subscription keys).
Now the usage stats are filtered by the current request's API Key ID,
so each key only sees its own usage data. The balance/remaining fields
are unaffected and still reflect the user-level wallet balance.
Changes:
- Add GetAPIKeyDashboardStats to repository interface and implementation
- Add getPerformanceStatsByAPIKey helper (also fixes TPM to include
cache_creation_tokens and cache_read_tokens)
- Add GetAPIKeyDashboardStats to UsageService
- Update Usage handler to call GetAPIKeyDashboardStats(apiKey.ID)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
