[argszero]

Summary

P0-B backend implementation (rant 2026-08-18T09:55:57 — 网关转发 + 路由故障转移 + 计量账本闭环). Completes the core loop: request in → route to key → forward upstream → meter points → write ledger per architecture v0.2 §4.1/4.2/4.3/4.4. Non-streaming only (SSE deferred to P0-C).

Changes

• Gateway endpoints (src/gateway.rs):
  • POST /v1/chat/completions (OpenAI-compatible, Bearer atk_ API key auth)
  • POST /anthropic/v1/messages (Anthropic-compatible)
  • GET /api/models (marketplace list with key availability, auth required)
  • Upstream response passthrough (status + body); usage parsed per protocol (prompt/completion_tokens vs input/output_tokens)
• Routing & failover (src/router.rs, §4.2.1): initial random pick from healthy keys (status='on', not in 5s cooldown), sticky reuse per user+model (in-memory HashMap), unhealthy marking on 401/403/429/5xx/network error, max 3 switches → 503 {"error":{"message":"该模型暂无可用 key"}}; other 4xx passthrough without switching
• Metering & ledger (src/billing.rs, §4.3/4.4): cost = tokens × per-M price (currency converted to points.anchor_currency), points = cost × points_per_unit; consumer balance deducted (pre-check → 402 when ≤0), sharer earns 90% (10% platform cut); transactions consume+earn pair, usage_records, keys.used += tokens; settle is transactional — rolls back on failure (phantom key refused)
• Models seeding (src/db.rs): startup upsert from data/models.example.json + config.price_overrides
• axum macros feature enabled (debug_handler)

Tests

• 33 tests pass: router (random/sticky/cooldown/3-switch limit), billing (points math, 90/10 split, 402, rollback), gateway (401 no bearer / 400 missing model / 402 insufficient balance / 503 dead-upstream failover / e2e fake-upstream success + ledger + sticky / models endpoint)
• cargo build + cargo clippy --all-targets -- -D warnings + cargo fmt --check clean
• Live smoke: no token → 401; demo key + placeholder upstream → 503 (failover path); GET /api/models returns list

Notes

• Version bumped to v0.2.1
• Upstream keys still plaintext placeholders (encryption deferred to P0-C with SSE streaming)

Closes rant 2026-08-18T09:55:57.804810 (P0-B).