debug(coordinator): add detailed logging to track concurrent update issue

Add comprehensive debug logs to:
1. report_completion.go - log all participant statuses at key points
2. session_postgres_repo.go - log before/after each participant update

This will help identify why server-party-1 status remains 'invited'
despite successfully reporting completion.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

backend/.claude/settings.local.json

@@ -19,7 +19,12 @@
       "Bash(git commit:*)",
       "Bash(git push:*)",
       "Bash(git pull:*)",
-      "Bash(del \"api\\proto\\session_coordinator.pb.go\" \"api\\proto\\session_coordinator_grpc.pb.go\" \"api\\proto\\message_router.pb.go\" \"api\\proto\\message_router_grpc.pb.go\")"
+      "Bash(del \"api\\proto\\session_coordinator.pb.go\" \"api\\proto\\session_coordinator_grpc.pb.go\" \"api\\proto\\message_router.pb.go\" \"api\\proto\\message_router_grpc.pb.go\")",
+      "Bash(grep:*)",
+      "Bash(cat:*)",
+      "Bash(dir:*)",
+      "Bash(copy /Y \"api\\proto\\session_coordinator.pb.go\" \"api\\grpc\\coordinator\\v1\"\" && copy /Y \"apiprotosession_coordinator_grpc.pb.go\" \"apigrpccoordinatorv1\"\")",
+      "Bash(timeout /t 10 /nobreak)"
     ],
     "deny": [],
     "ask": []

backend/mpc-system/services/session-coordinator/adapters/output/postgres/session_postgres_repo.go

@@ -8,9 +8,11 @@ import (
 
 	"github.com/google/uuid"
 	"github.com/lib/pq"
+	"github.com/rwadurian/mpc-system/pkg/logger"
 	"github.com/rwadurian/mpc-system/services/session-coordinator/domain/entities"
 	"github.com/rwadurian/mpc-system/services/session-coordinator/domain/repositories"
 	"github.com/rwadurian/mpc-system/services/session-coordinator/domain/value_objects"
+	"go.uber.org/zap"
 )
 
 // SessionPostgresRepo implements SessionRepository for PostgreSQL
@@ -283,8 +285,23 @@ func (r *SessionPostgresRepo) Update(ctx context.Context, session *entities.MPCS
 		return err
 	}
 
+	// DEBUG: Log all participant statuses before update
+	var participantStatuses []string
+	for _, p := range session.Participants {
+		participantStatuses = append(participantStatuses, p.PartyID.String()+":"+p.Status.String())
+	}
+	logger.Debug("repo.Update: updating participants",
+		zap.String("session_id", session.ID.UUID().String()),
+		zap.Strings("participant_statuses", participantStatuses))
+
 	// Update each participant individually
 	for _, p := range session.Participants {
+		// DEBUG: Log before updating each participant
+		logger.Debug("repo.Update: updating individual participant",
+			zap.String("session_id", session.ID.UUID().String()),
+			zap.String("party_id", p.PartyID.String()),
+			zap.String("new_status", p.Status.String()))
+
 		// Try UPDATE first
 		result, err := tx.ExecContext(ctx, `
 			UPDATE participants SET
@@ -317,8 +334,18 @@ func (r *SessionPostgresRepo) Update(ctx context.Context, session *entities.MPCS
 			return err
 		}
 
+		// DEBUG: Log rows affected
+		logger.Debug("repo.Update: participant update result",
+			zap.String("session_id", session.ID.UUID().String()),
+			zap.String("party_id", p.PartyID.String()),
+			zap.Int64("rows_affected", rowsAffected))
+
 		if rowsAffected == 0 {
 			// Participant doesn't exist, INSERT it
+			logger.Debug("repo.Update: inserting new participant",
+				zap.String("session_id", session.ID.UUID().String()),
+				zap.String("party_id", p.PartyID.String()))
+
 			_, err = tx.ExecContext(ctx, `
 				INSERT INTO participants (
 					id, session_id, party_id, party_index, status,
@@ -344,6 +371,9 @@ func (r *SessionPostgresRepo) Update(ctx context.Context, session *entities.MPCS
 		}
 	}
 
+	logger.Debug("repo.Update: committing transaction",
+		zap.String("session_id", session.ID.UUID().String()))
+
 	return tx.Commit()
 }
 

backend/mpc-system/services/session-coordinator/application/use_cases/report_completion.go

@@ -42,12 +42,26 @@ func (uc *ReportCompletionUseCase) Execute(
 	ctx context.Context,
 	inputData input.ReportCompletionInput,
 ) (*input.ReportCompletionOutput, error) {
+	logger.Debug("ReportCompletion.Execute: START",
+		zap.String("session_id", inputData.SessionID.String()),
+		zap.String("party_id", inputData.PartyID))
+
 	// 1. Load session
 	session, err := uc.sessionRepo.FindByUUID(ctx, inputData.SessionID)
 	if err != nil {
 		return nil, err
 	}
 
+	// DEBUG: Log all participant statuses after loading session
+	var allParticipantStatuses []string
+	for _, p := range session.Participants {
+		allParticipantStatuses = append(allParticipantStatuses, p.PartyID.String()+":"+p.Status.String())
+	}
+	logger.Debug("ReportCompletion.Execute: loaded session",
+		zap.String("session_id", session.ID.String()),
+		zap.String("party_id", inputData.PartyID),
+		zap.Strings("all_participant_statuses", allParticipantStatuses))
+
 	// 2. Create party ID value object
 	partyID, err := value_objects.NewPartyID(inputData.PartyID)
 	if err != nil {
@@ -60,6 +74,11 @@ func (uc *ReportCompletionUseCase) Execute(
 		return nil, err
 	}
 
+	logger.Debug("ReportCompletion.Execute: current participant status",
+		zap.String("session_id", session.ID.String()),
+		zap.String("party_id", inputData.PartyID),
+		zap.String("current_status", participant.Status.String()))
+
 	// 3.1 Ensure participant is in Ready state before marking as Completed
 	// The status flow is: Invited -> Joined -> Ready -> Completed
 	// Handle all possible states to reach Ready
@@ -139,10 +158,24 @@ func (uc *ReportCompletionUseCase) Execute(
 	}
 
 	// 6. Save updated session
+	// DEBUG: Log all participant statuses before calling Update
+	var beforeUpdateStatuses []string
+	for _, p := range session.Participants {
+		beforeUpdateStatuses = append(beforeUpdateStatuses, p.PartyID.String()+":"+p.Status.String())
+	}
+	logger.Debug("ReportCompletion.Execute: BEFORE sessionRepo.Update",
+		zap.String("session_id", session.ID.String()),
+		zap.String("party_id", inputData.PartyID),
+		zap.Strings("all_participant_statuses", beforeUpdateStatuses))
+
 	if err := uc.sessionRepo.Update(ctx, session); err != nil {
 		return nil, err
 	}
 
+	logger.Debug("ReportCompletion.Execute: AFTER sessionRepo.Update",
+		zap.String("session_id", session.ID.String()),
+		zap.String("party_id", inputData.PartyID))
+
 	// 7. Publish participant completed event
 	event := output.ParticipantCompletedEvent{
 		SessionID:   session.ID.String(),

backend/mpc-system/test_create_session.go

@@ -0,0 +1,111 @@
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"time"
+
+	"github.com/golang-jwt/jwt/v5"
+	"github.com/google/uuid"
+)
+
+type Claims struct {
+	SessionID string `json:"session_id"`
+	PartyID   string `json:"party_id"`
+	TokenType string `json:"token_type"`
+	jwt.RegisteredClaims
+}
+
+func generateAccessToken(secretKey, userID, username string) (string, error) {
+	now := time.Now()
+	claims := Claims{
+		PartyID:   username,
+		TokenType: "access",
+		RegisteredClaims: jwt.RegisteredClaims{
+			ID:        uuid.New().String(),
+			Issuer:    "mpc-system",
+			Subject:   userID,
+			IssuedAt:  jwt.NewNumericDate(now),
+			NotBefore: jwt.NewNumericDate(now),
+			ExpiresAt: jwt.NewNumericDate(now.Add(24 * time.Hour)),
+		},
+	}
+
+	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
+	return token.SignedString([]byte(secretKey))
+}
+
+func main() {
+	// Get JWT secret from environment or use test value
+	jwtSecret := os.Getenv("JWT_SECRET_KEY")
+	if jwtSecret == "" {
+		jwtSecret = "test-jwt-secret-key-please-change-in-production"
+	}
+
+	// Generate access token
+	token, err := generateAccessToken(jwtSecret, "admin", "admin")
+	if err != nil {
+		fmt.Printf("Failed to generate token: %v\n", err)
+		os.Exit(1)
+	}
+
+	fmt.Printf("Generated JWT token: %s\n\n", token)
+
+	// Create keygen session via account-service
+	sessionData := map[string]interface{}{
+		"threshold_n": 3,
+		"threshold_t": 2,
+	}
+
+	jsonData, err := json.Marshal(sessionData)
+	if err != nil {
+		fmt.Printf("Failed to marshal JSON: %v\n", err)
+		os.Exit(1)
+	}
+
+	// Get API key from environment or use test value
+	apiKey := os.Getenv("MPC_API_KEY")
+	if apiKey == "" {
+		apiKey = "test-api-key"
+	}
+
+	// Call account-service API
+	req, err := http.NewRequest("POST", "http://localhost:4000/api/v1/mpc/keygen", bytes.NewBuffer(jsonData))
+	if err != nil {
+		fmt.Printf("Failed to create request: %v\n", err)
+		os.Exit(1)
+	}
+
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("X-API-Key", apiKey)
+
+	client := &http.Client{Timeout: 10 * time.Second}
+	resp, err := client.Do(req)
+	if err != nil {
+		fmt.Printf("Failed to send request: %v\n", err)
+		os.Exit(1)
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		fmt.Printf("Failed to read response: %v\n", err)
+		os.Exit(1)
+	}
+
+	fmt.Printf("Response status: %s\n", resp.Status)
+	fmt.Printf("Response body: %s\n", string(body))
+
+	if resp.StatusCode == 200 || resp.StatusCode == 201 {
+		var result map[string]interface{}
+		if err := json.Unmarshal(body, &result); err == nil {
+			if sessionID, ok := result["session_id"].(string); ok {
+				fmt.Printf("\n✓ Session created successfully: %s\n", sessionID)
+			}
+		}
+	}
+}