# Automatic Database Migrations - Implementation Summary

## What Was Implemented

Database migrations now run **automatically** every time the API server starts. This eliminates the need to manually run migration commands.

## Changes Made

### 1. Created Migration Runner (`apps/api/src/db/migrate.ts`)

A new module that:
- Connects to MySQL using environment variables
- Runs pending migrations from the `drizzle/` folder
- Provides clear console output with emojis
- Handles errors gracefully

```typescript
export async function runMigrations() {
  console.log('🔄 Running database migrations...');
  // ... migration logic ...
  console.log('✅ Database migrations completed successfully');
}
```

### 2. Integrated into Server Startup (`apps/api/src/index.ts`)

Modified the server startup to:
- Run migrations before starting Express
- Exit with error if migrations fail
- Provide clear startup sequence

```typescript
async function startServer() {
  await runMigrations();  // ← Runs automatically
  app.listen(PORT, () => {
    console.log(`API server running on port ${PORT}`);
  });
}
```

## Benefits

### ✅ **No Manual Steps**
- Just run `docker-compose up -d --build`
- Migrations run automatically
- Database is always up-to-date

### ✅ **Idempotent**
- Safe to run multiple times
- Only applies new migrations
- No duplicate data or errors

### ✅ **Developer Friendly**
- Clear console output
- Easy to debug
- Works in development and production

### ✅ **CI/CD Ready**
- No extra deployment steps
- Migrations run on container start
- Automatic rollout of schema changes

## How It Works

### Startup Sequence

```
1. Docker starts API container
2. Node.js starts
3. Environment variables loaded (.env)
4. 🔄 Migrations run automatically
5. ✅ Migrations complete
6. Express server starts
7. API ready to accept requests
```

### Console Output

When you start the API, you'll see:

```bash
[OpenAIClient] Initialized with timeout: 600s, maxRetries: 2
ENV ADMIN_PASSWORD loaded: true
🔄 Running database migrations...
✅ Database migrations completed successfully
API server running on port 3301
```

## Testing

### Verify Automatic Migrations

```bash
# 1. Reset database (deletes all data!)
docker-compose down -v

# 2. Start fresh
docker-compose up -d --build

# 3. Watch the logs
docker-compose logs -f api

# You should see:
# 🔄 Running database migrations...
# ✅ Database migrations completed successfully
```

### Verify Tables Created

```bash
docker exec voxblog-mysql mysql -u voxblog -pvoxblogAppPass123! voxblog -e "SHOW TABLES;"
```

Expected output:
```
Tables_in_voxblog
__drizzle_migrations
audio_clips
posts
settings
```

## Troubleshooting

### Migrations Don't Run

**Check API logs:**
```bash
docker-compose logs api | grep -i migration
```

**Common issues:**
- MySQL not ready yet (wait 30 seconds)
- Wrong database credentials in `.env`
- Migration files missing in `apps/api/drizzle/`

### Migration Fails

**Error in logs:**
```bash
❌ Migration failed: [error details]
```

**Solutions:**
1. Check MySQL is healthy: `docker-compose ps mysql`
2. Verify credentials in `.env`
3. Check migration files exist: `ls apps/api/drizzle/`
4. Run manually: `docker exec voxblog-api sh -c "cd /app/apps/api && pnpm drizzle:migrate"`

### Server Won't Start

If migrations fail, the server exits with error code 1.

**Check logs:**
```bash
docker-compose logs api
```

**Restart after fixing:**
```bash
docker-compose restart api
```

## Manual Migration (Still Available)

You can still run migrations manually if needed:

```bash
# Inside container
docker exec voxblog-api sh -c "cd /app/apps/api && pnpm drizzle:migrate"

# Or using pnpm scripts
docker exec voxblog-api pnpm --filter api drizzle:migrate
```

## Creating New Migrations

When you modify the schema (`apps/api/src/db/schema.ts`):

```bash
# 1. Generate migration file
docker exec voxblog-api sh -c "cd /app/apps/api && pnpm drizzle:generate"

# 2. Restart API (migrations run automatically)
docker-compose restart api

# 3. Verify migration applied
docker-compose logs api | grep migration
```

## Production Deployment

### Zero-Downtime Deployment

1. **Build new image** with schema changes
2. **Deploy new container** - migrations run automatically
3. **Old container** continues serving requests
4. **New container** takes over after migrations complete

### Rollback Strategy

If a migration fails:
1. Container exits with error
2. Old container keeps running
3. Fix migration and redeploy
4. Or rollback to previous version

## Best Practices

### ✅ **DO**
- Test migrations locally first
- Make migrations backward compatible
- Keep migrations small and focused
- Add indexes in separate migrations
- Document breaking changes

### ❌ **DON'T**
- Don't delete migration files
- Don't modify existing migrations
- Don't make breaking schema changes without planning
- Don't skip testing migrations

## Files Modified

1. **`apps/api/src/db/migrate.ts`** (new)
   - Migration runner logic
   - Error handling
   - Console output

2. **`apps/api/src/index.ts`** (modified)
   - Import migration runner
   - Call migrations before server start
   - Async startup function

3. **`DATABASE_SETUP.md`** (updated)
   - Document automatic migrations
   - Update troubleshooting guide
   - Remove manual migration steps

## Migration History

Migrations are tracked in the `__drizzle_migrations` table:

```sql
SELECT * FROM __drizzle_migrations;
```

Shows:
- Migration ID
- Hash
- Created timestamp

## Future Enhancements

Potential improvements:
- Migration rollback command
- Migration status endpoint (`/api/migrations`)
- Dry-run mode
- Migration locking for multi-instance deployments
- Slack/email notifications on migration failures

---

**Status**: ✅ Implemented and Working
**Last Updated**: 2025-10-26
**Author**: Automated Migration System