rwadurian/backend/mpc-system/PARTY_ROLE_VERIFICATION_REPORT.md

# Party Role Labels Implementation - Verification Report

**Date**: 2025-12-05
**Commit**: e975e9d - "feat(mpc-system): implement party role labels with strict persistent-only default"
**Environment**: Docker Compose (Local Development)

---

## 1. Implementation Summary

### 1.1 Overview
Implemented Party Role Labels (Solution 1) to differentiate between three types of server parties:
- **Persistent**: Stores key shares in database permanently
- **Delegate**: Generates user shares and returns them to caller (doesn't store)
- **Temporary**: For ad-hoc operations

### 1.2 Core Changes

#### Files Modified
1. `services/session-coordinator/application/ports/output/party_pool_port.go`
   - Added `PartyRole` enum (persistent, delegate, temporary)
   - Added `PartyEndpoint.Role` field
   - Added `PartySelectionFilter` struct with role filtering
   - Added `SelectPartiesWithFilter()` and `GetAvailablePartiesByRole()` methods

2. `services/session-coordinator/infrastructure/k8s/party_discovery.go`
   - Implemented role extraction from K8s pod labels (`party-role`)
   - Implemented `GetAvailablePartiesByRole()` for role-based filtering
   - Implemented `SelectPartiesWithFilter()` with role and count requirements
   - Default role: `persistent` if label not found

3. `services/session-coordinator/application/ports/input/session_management_port.go`
   - Added `PartyComposition` struct with role-based party counts
   - Added optional `PartyComposition` field to `CreateSessionInput`

4. `services/session-coordinator/application/use_cases/create_session.go`
   - Implemented strict persistent-only default policy (lines 102-114)
   - Implemented `selectPartiesByComposition()` method with empty composition validation (lines 224-284)
   - Added clear error messages for insufficient parties

5. `k8s/server-party-deployment.yaml`
   - Added label: `party-role: persistent` (line 25)

6. `k8s/server-party-api-deployment.yaml` (NEW FILE)
   - New deployment for delegate parties
   - Added label: `party-role: delegate` (line 25)
   - Replicas: 2 (for generating user shares)

---

## 2. Security Policy Implementation

### 2.1 Strict Persistent-Only Default
When `PartyComposition` is **nil** (not specified):
- System MUST select only `persistent` parties
- If insufficient persistent parties available → **Fail immediately with clear error**
- NO automatic fallback to delegate/temporary parties
- Error message: "insufficient persistent parties: need N persistent parties but not enough available. Use PartyComposition to specify custom party requirements"

**Code Reference**: [create_session.go:102-114](c:\Users\dong\Desktop\rwadurian\backend\mpc-system\services\session-coordinator\application\use_cases\create_session.go#L102-L114)

### 2.2 Empty PartyComposition Validation
When `PartyComposition` is specified but all counts are 0:
- System returns error: "PartyComposition specified but no parties selected: all counts are zero and no custom filters provided"
- Prevents accidental bypass of persistent-only requirement

**Code Reference**: [create_session.go:279-281](c:\Users\dong\Desktop\rwadurian\backend\mpc-system\services\session-coordinator\application\use_cases\create_session.go#L279-L281)

### 2.3 Threshold Security Guarantee
- Default policy ensures MPC threshold security by using only persistent parties
- Persistent parties store shares in database, ensuring T-of-N shares are always available for future sign operations
- Delegate parties (which don't store shares) are only used when explicitly specified via `PartyComposition`

---

## 3. Docker Compose Deployment Verification

### 3.1 Build Status
**Command**: `./deploy.sh build`
**Status**: ✅ SUCCESS
**Images Built**:
1. mpc-system-postgres (postgres:15-alpine)
2. mpc-system-rabbitmq (rabbitmq:3-management-alpine)
3. mpc-system-redis (redis:7-alpine)
4. mpc-system-session-coordinator
5. mpc-system-message-router
6. mpc-system-server-party-1/2/3
7. mpc-system-server-party-api
8. mpc-system-account-service

### 3.2 Deployment Status
**Command**: `./deploy.sh up`
**Status**: ✅ SUCCESS
**Services Running** (10 containers):

| Service | Status | Ports | Notes |
|---------|--------|-------|-------|
| mpc-postgres | Healthy | 5432 (internal) | PostgreSQL 15 |
| mpc-rabbitmq | Healthy | 5672, 15672 (internal) | Message broker |
| mpc-redis | Healthy | 6379 (internal) | Cache store |
| mpc-session-coordinator | Healthy | 8081:8080 | Core orchestration |
| mpc-message-router | Healthy | 8082:8080 | Message routing |
| mpc-server-party-1 | Healthy | 50051, 8080 (internal) | Persistent party |
| mpc-server-party-2 | Healthy | 50051, 8080 (internal) | Persistent party |
| mpc-server-party-3 | Healthy | 50051, 8080 (internal) | Persistent party |
| mpc-server-party-api | Healthy | 8083:8080 | Delegate party |
| mpc-account-service | Healthy | 4000:8080 | Application service |

### 3.3 Health Check Results
```bash
# Session Coordinator
$ curl http://localhost:8081/health
{"service":"session-coordinator","status":"healthy"}

# Account Service
$ curl http://localhost:4000/health
{"service":"account","status":"healthy"}
```

**Status**: ✅ All services responding to health checks

---

## 4. Known Limitations in Docker Compose Environment

### 4.1 K8s Party Discovery Not Available
**Log Message**:
```
{"level":"warn","message":"K8s party discovery not available, will use dynamic join mode",
 "error":"failed to create k8s config: stat /home/mpc/.kube/config: no such file or directory"}
```

**Impact**:
- Party role labels (`party-role`) from K8s deployments are not accessible in Docker Compose
- System falls back to dynamic join mode (universal join tokens)
- `PartyPoolPort` is not available, so `selectPartiesByComposition()` logic is not exercised

**Why This Happens**:
- Docker Compose doesn't provide K8s API access
- Party discovery requires K8s Service Discovery and pod label queries
- This is expected behavior for non-K8s environments

### 4.2 Party Role Labels Not Testable in Docker Compose
The following features cannot be tested in Docker Compose:
1. Role-based party filtering (`SelectPartiesWithFilter`)
2. `PartyComposition`-based party selection
3. Strict persistent-only default policy
4. K8s pod label reading (`party-role`)

**These features require actual Kubernetes deployment to test.**

---

## 5. What Was Verified

### 5.1 Code Compilation ✅
- All modified Go files compile successfully
- No syntax errors or type errors
- Build completes on both Windows (local) and WSL (Docker)

### 5.2 Service Deployment ✅
- All 10 services start successfully
- All health checks pass
- Services can connect to each other (gRPC connectivity verified in logs)
- Database connections established
- Message broker connections established

### 5.3 Code Logic Review ✅
- Strict persistent-only default policy correctly implemented
- Empty `PartyComposition` validation prevents loophole
- Clear error messages for insufficient parties
- Role extraction from K8s pod labels correctly implemented
- Role-based filtering logic correct

---

## 6. What Cannot Be Verified Without K8s

### 6.1 Runtime Behavior
1. **Party Discovery**: K8s pod label queries
2. **Role Filtering**: Actual filtering by `party-role` label values
3. **Persistent-Only Policy**: Enforcement when persistent parties insufficient
4. **Error Messages**: Actual error messages when party selection fails
5. **PartyComposition**: Custom party mix selection

### 6.2 Integration Testing
1. Creating a session with default (nil) `PartyComposition` → should select only persistent parties
2. Creating a session with insufficient persistent parties → should return clear error
3. Creating a session with empty `PartyComposition` → should return validation error
4. Creating a session with custom `PartyComposition` → should select correct party mix

---

## 7. Next Steps for Full Verification

### 7.1 Deploy to Kubernetes Cluster
To fully test Party Role Labels, deploy to actual K8s cluster:
```bash
# Apply K8s manifests
kubectl apply -f k8s/namespace.yaml
kubectl apply -f k8s/configmap.yaml
kubectl apply -f k8s/secrets.yaml
kubectl apply -f k8s/postgres-deployment.yaml
kubectl apply -f k8s/rabbitmq-deployment.yaml
kubectl apply -f k8s/redis-deployment.yaml
kubectl apply -f k8s/server-party-deployment.yaml
kubectl apply -f k8s/server-party-api-deployment.yaml
kubectl apply -f k8s/session-coordinator-deployment.yaml
kubectl apply -f k8s/message-router-deployment.yaml
kubectl apply -f k8s/account-service-deployment.yaml

# Verify party discovery works
kubectl logs -n mpc-system -l app=mpc-session-coordinator | grep -i "party\|role\|discovery"

# Verify pod labels are set
kubectl get pods -n mpc-system -l app=mpc-server-party -o jsonpath='{range .items[*]}{.metadata.name}{"\t"}{.metadata.labels.party-role}{"\n"}{end}'
kubectl get pods -n mpc-system -l app=mpc-server-party-api -o jsonpath='{range .items[*]}{.metadata.name}{"\t"}{.metadata.labels.party-role}{"\n"}{end}'
```

### 7.2 Integration Testing in K8s
1. **Test Default Persistent-Only Selection**:
   ```bash
   curl -X POST http://<account-service>/api/v1/accounts \
     -H "Content-Type: application/json" \
     -d '{"user_id": "test-user-1"}'

   # Expected: Session created with 3 persistent parties
   # Check logs: kubectl logs -n mpc-system -l app=mpc-session-coordinator | grep "selected persistent parties by default"
   ```

2. **Test Insufficient Persistent Parties Error**:
   ```bash
   # Scale down persistent parties to 2
   kubectl scale deployment mpc-server-party -n mpc-system --replicas=2

   # Try creating session requiring 3 parties
   curl -X POST http://<account-service>/api/v1/accounts \
     -H "Content-Type: application/json" \
     -d '{"user_id": "test-user-2"}'

   # Expected: HTTP 500 error with message "insufficient persistent parties: need 3 persistent parties but not enough available"
   ```

3. **Test Empty PartyComposition Validation**:
   - Requires API endpoint that accepts `PartyComposition` parameter
   - Send request with `PartyComposition: {PersistentCount: 0, DelegateCount: 0, TemporaryCount: 0}`
   - Expected: HTTP 400 error with message "PartyComposition specified but no parties selected"

4. **Test Custom PartyComposition**:
   - Send request with `PartyComposition: {PersistentCount: 2, DelegateCount: 1}`
   - Expected: Session created with 2 persistent + 1 delegate party
   - Verify party roles in session data

---

## 8. Conclusion

### 8.1 Implementation Status: ✅ COMPLETE
- All code changes implemented correctly
- Strict persistent-only default policy enforced
- Empty `PartyComposition` validation prevents loophole
- Clear error messages for insufficient parties
- Backward compatibility maintained (optional `PartyComposition`)

### 8.2 Deployment Status: ✅ SUCCESS (Docker Compose)
- All services build successfully
- All services deploy successfully
- All services healthy and responding
- Inter-service connectivity verified

### 8.3 Verification Status: ⚠️ PARTIAL
- ✅ Code compilation and logic review
- ✅ Docker Compose deployment
- ✅ Service health checks
- ❌ Party role filtering runtime behavior (requires K8s)
- ❌ Persistent-only policy enforcement (requires K8s)
- ❌ Integration testing (requires K8s)

### 8.4 Readiness for Production
**Code Readiness**: ✅ READY
**Testing Readiness**: ⚠️ REQUIRES K8S DEPLOYMENT FOR FULL TESTING
**Deployment Readiness**: ✅ READY (K8s manifests prepared)

---

## 9. User Confirmation Required

The Party Role Labels implementation is complete and successfully deployed in Docker Compose. However, full runtime verification requires deploying to an actual Kubernetes cluster.

**Options**:
1. Proceed with K8s deployment for full verification
2. Accept partial verification (code review + Docker Compose deployment)
3. Create integration tests that mock K8s party discovery

Awaiting user instruction on next steps.