[DJ Semantic Fingerprint 4] Bulk endpoint for viewing fingerprints + testing fixtures

[philipfweiss]

Fingerprints currently surface only while previewing a deployment, so metadata-file consumers cannot bootstrap a complete file or reconcile committed state after a failed or out-of-band change. A namespace snapshot endpoint makes committed hashes available from the same server-owned evaluator.

Depends on #2483.

This PR:

• adds GET /namespaces/{namespace}/semantic-fingerprints for a namespace and its descendants
• returns each node's name, type, sorted owners, and current versioned fingerprint
• represents uncomputable nodes and their dependents with the unknown sentinel
• rejects unsupported fingerprint versions
• adds a Git-backed lunch fixture that locks version 1 rows and checks impact predictions against post-deployment snapshots

The endpoint is additive and does not change existing namespace or deployment responses.

Lunch snapshot example

Changing the kitchen's grill table changes the burger and taco paths, including the taco-truck subnamespace. The independent milkshake path remains stable.

flowchart LR
    G["grill_orders<br/>source hash changes"]
    B["burger_orders"]
    BM["burger_count"]
    P["picnic_basket"]
    T["taco_truck.taco_orders"]
    TM["taco_truck.taco_count"]
    S["milkshake_orders<br/>unchanged"]
    SM["milkshake_count<br/>unchanged"]

    G --> B --> BM --> P
    G --> T --> TM
    S --> SM

    classDef changed fill:#fff1d6,stroke:#c2410c,color:#431407
    classDef stable fill:#ecfdf5,stroke:#059669,color:#064e3b
    class G,B,BM,P,T,TM changed
    class S,SM stable

Loading

A snapshot of lunch returns all eight sorted rows. The six changed fingerprints predicted by /deployments/impact match the committed snapshot after deployment, while both milkshake rows retain their prior hashes.

---

Verification:

1. Built and started this branch in a fresh Docker slot:

printf '2\n' > .dev-port
./dev.sh up -d
curl http://localhost:8200/health/

Observed:

[{"name":"database","status":"ok"}]

2. Logged in as dj, deployed fingerprint_food.kitchen and fingerprint_food.taco_truck, and configured the root and child namespaces as Git-backed. The kitchen contained the burger and milkshake paths shown above. The taco transform read from fingerprint_food.kitchen.grill_orders.

POST /basic/login/                                           -> 200
POST /deployments (fingerprint_food.kitchen)                 -> 200, success
POST /deployments (fingerprint_food.taco_truck)              -> 200, success
PATCH /namespaces/fingerprint_food/git                       -> 200
PATCH /namespaces/fingerprint_food.kitchen/git               -> 200
PATCH /namespaces/fingerprint_food.taco_truck/git            -> 200
GET /namespaces/fingerprint_food/semantic-fingerprints?version=1 -> 200

The response had namespace=fingerprint_food, version=1, and eight name-sorted nodes with sorted owners. One generated metadata row was:

source::fingerprint_food.kitchen.grill_orders::fa4e66f1924973b8cca8aeb59752e2fe90066bdfc45894d9a31cac5c7b0c4d2c

3. Changed only the grill source table to grill_orders_v2, previewed impact, deployed it, and fetched the committed root snapshot again.

POST /deployments/impact                                     -> 200
POST /deployments                                            -> 200, success
GET /namespaces/fingerprint_food/semantic-fingerprints?version=1 -> 200

Observed:

{
  "changed": [
    "fingerprint_food.kitchen.burger_count",
    "fingerprint_food.kitchen.burger_orders",
    "fingerprint_food.kitchen.grill_orders",
    "fingerprint_food.kitchen.picnic_basket",
    "fingerprint_food.taco_truck.taco_count",
    "fingerprint_food.taco_truck.taco_orders"
  ],
  "impact_matches_committed_snapshot": true,
  "stable": [
    "fingerprint_food.kitchen.milkshake_orders",
    "fingerprint_food.kitchen.milkshake_count"
  ]
}

4. Exercised version and access failures:

GET .../semantic-fingerprints?version=2 without a supported version -> 422
GET .../semantic-fingerprints?version=1 without login               -> 403

The version error body contained Unsupported semantic fingerprint version: 2.

5. Deployed a valid fingerprint_food.mystery chain, then changed the persisted current SQL for mystery_meat to SELECT ( in Postgres to represent a legacy invalid node. The snapshot remained available and propagated the sentinel:

{
  "status": 200,
  "mystery_meat": "unknown",
  "customer": "unknown"
}

---

Semantic fingerprint stack

This is PR 4 of 4:

1. #2482: Add semantic node fingerprints
2. #2488: Evaluate fingerprints across deployment graphs
3. #2483: Add semantic fingerprints to deployment impact
4. #2490: Bulk endpoint for viewing fingerprints and testing fixtures (this PR)