Backend API Debugging

Starting the Backend Server

CRITICAL: Always run from ecommerce-backend/ directory:

powershell

cd ecommerce-backend

# Ensure database is running
docker compose ps  # Check if PostgreSQL is running

# Run migrations first (if not done)
make migrate-up

# Start server
make run
# OR
go run cmd/api/main.go

Server runs on: http://localhost:8080

Quick Health Checks

powershell

# 1. Health endpoint
curl http://localhost:8080/health

# 2. Check if server is listening
netstat -an | findstr "8080"

Testing API Endpoints

Register New User

powershell

curl -X POST http://localhost:8080/api/v1/auth/register `
  -H "Content-Type: application/json" `
  -d '{
    "email": "test@example.com",
    "password": "SecurePass123!",
    "full_name": "Test User"
  }'

Login

powershell

curl -X POST http://localhost:8080/api/v1/auth/login `
  -H "Content-Type: application/json" `
  -d '{
    "email": "test@example.com",
    "password": "SecurePass123!"
  }'

Test Protected Endpoint

powershell

# Save access token from login response
$token = "your_access_token_here"

curl http://localhost:8080/api/v1/auth/me `
  -H "Authorization: Bearer $token"

Common API Issues

"relation does not exist"

Cause: Database tables not created Solution:

powershell

cd ecommerce-backend
make migrate-up

"dial tcp: connection refused"

Cause: PostgreSQL not running or wrong DATABASE_URL Solution:

powershell

# Check PostgreSQL
docker compose ps  # If using Docker
# OR check Windows service

# Verify DATABASE_URL in .env
cat .env | Select-String "DATABASE_URL"

# Test connection
$env:Path += ";D:\Program Files\PostgreSQL\18\bin"
$env:PGPASSWORD = "postgres"
psql -U postgres -d ecommerce -c "\dt"

"invalid or expired JWT"

Cause: Token expired or invalid JWT_SECRET Solutions:

•Get new token by logging in again
•Check JWT_SECRET in .env matches what was used to create token
•Verify token format: Authorization: Bearer <token>

"password hash mismatch"

Cause: Password stored incorrectly or bcrypt issue Solution: Check password hashing in pkg/crypto/password.go

Port 8080 already in use

powershell

# Find process using port 8080
netstat -ano | findstr ":8080"

# Kill process (replace PID)
taskkill /PID <PID> /F

# Or change port in config

Debugging with Logs

The API uses structured logging. Check console output for:

•Request IDs (for tracing)
•Error messages with stack traces
•Database query errors
•Validation errors

Swagger Documentation

Access API docs at: http://localhost:8080/swagger/index.html

Regenerate if needed:

powershell

cd ecommerce-backend
make swagger
# OR
swag init -g cmd/api/main.go -o docs

Testing Suite

powershell

cd ecommerce-backend

# Run all tests
make test

# Run with coverage
make test-coverage

# Test specific package
go test -v ./internal/service/...

Database Inspection

powershell

# Set up PostgreSQL access
$env:Path += ";D:\Program Files\PostgreSQL\18\bin"
$env:PGPASSWORD = "postgres"

# Connect to database
psql -U postgres -d ecommerce

# Common queries
\dt                    # List tables
\d users              # Describe users table
SELECT * FROM users;  # View users
\q                    # Quit

Request Validation Issues

The API uses go-playground/validator. Common validation errors:

•Email format: must be valid email
•Password: minimum 8 characters
•Required fields: cannot be empty

Check validation tags in internal/api/dto/ files.