# GPU Implementation Summary

## Overview
Implemented dedicated GPU instance tables and code infrastructure for Linode GPU instances in the cloud-server project.

## Files Modified

### 1. Database Schema (`schema.sql`)
Added two new tables with full indexing and triggers:

#### `gpu_instances` Table
- **Purpose**: GPU-specific instance types separate from regular instances
- **Key Fields**:
  - Standard fields: id, provider_id, instance_id, instance_name, vcpu, memory_mb, storage_gb, transfer_tb, network_speed_gbps
  - GPU-specific: gpu_count (NOT NULL, CHECK > 0), gpu_type (NOT NULL), gpu_memory_gb
  - Metadata: JSON string for provider-specific additional data
- **Indexes**:
  - `idx_gpu_instances_provider_id` - Provider lookups
  - `idx_gpu_instances_gpu_type` - GPU type filtering
  - `idx_gpu_instances_gpu_count` - GPU count filtering
  - `idx_gpu_instances_provider_type` - Composite index for provider + GPU type queries
- **Triggers**: `update_gpu_instances_updated_at` - Auto-update timestamp

#### `gpu_pricing` Table
- **Purpose**: Region-specific pricing for GPU instances
- **Key Fields**: gpu_instance_id, region_id, hourly_price, monthly_price, currency, available
- **Indexes**:
  - `idx_gpu_pricing_instance_id` - Instance lookups
  - `idx_gpu_pricing_region_id` - Region lookups
  - `idx_gpu_pricing_hourly_price` - Price sorting
  - `idx_gpu_pricing_monthly_price` - Price sorting
  - `idx_gpu_pricing_available` - Availability filtering
- **Triggers**: `update_gpu_pricing_updated_at` - Auto-update timestamp

### 2. Type Definitions (`src/types.ts`)
Added new types following existing patterns:

```typescript
export interface GpuInstance {
  id: number;
  provider_id: number;
  instance_id: string;
  instance_name: string;
  vcpu: number;
  memory_mb: number;
  storage_gb: number;
  transfer_tb: number | null;
  network_speed_gbps: number | null;
  gpu_count: number;
  gpu_type: string;
  gpu_memory_gb: number | null;
  metadata: string | null;
  created_at: string;
  updated_at: string;
}

export interface GpuPricing {
  id: number;
  gpu_instance_id: number;
  region_id: number;
  hourly_price: number;
  monthly_price: number;
  currency: string;
  available: number;
  created_at: string;
  updated_at: string;
}

export type GpuInstanceInput = Omit<GpuInstance, 'id' | 'created_at' | 'updated_at'>;
export type GpuPricingInput = Omit<GpuPricing, 'id' | 'created_at' | 'updated_at'>;
```

### 3. Repositories

#### `src/repositories/gpu-instances.ts` - GpuInstancesRepository
Extends `BaseRepository<GpuInstance>` with specialized methods:

**Methods**:
- `findByProvider(providerId: number)` - Find all GPU instances for a provider
- `findByGpuType(gpuType: string)` - Find instances by GPU type
- `findByInstanceId(providerId: number, instanceId: string)` - Find specific instance
- `upsertMany(providerId: number, instances: GpuInstanceInput[])` - Bulk upsert with conflict resolution
- `search(criteria)` - Advanced search with filters for vCPU, memory, GPU count, GPU type, GPU memory
- `getAvailableGpuTypes()` - Get distinct GPU types in database

**Features**:
- Follows BaseRepository pattern
- Uses `createLogger('[GpuInstancesRepository]')`
- Batch operations for efficiency
- Comprehensive error handling with RepositoryError
- Proper parameter binding for SQL injection prevention

#### `src/repositories/gpu-pricing.ts` - GpuPricingRepository
Extends `BaseRepository<GpuPricing>` for pricing operations:

**Methods**:
- `findByGpuInstance(gpuInstanceId: number)` - Get all pricing for GPU instance
- `findByRegion(regionId: number)` - Get all GPU pricing in region
- `findByGpuInstanceAndRegion(gpuInstanceId, regionId)` - Get specific pricing record
- `upsertMany(pricingData: GpuPricingInput[])` - Bulk upsert pricing data
- `searchByPriceRange(minHourly?, maxHourly?, minMonthly?, maxMonthly?)` - Search by price

**Features**:
- Follows BaseRepository pattern
- Uses `createLogger('[GpuPricingRepository]')`
- Batch operations with conflict resolution
- Price range filtering

### 4. Repository Factory (`src/repositories/index.ts`)
Extended RepositoryFactory with GPU repositories:

```typescript
export class RepositoryFactory {
  private _gpuInstances?: GpuInstancesRepository;
  private _gpuPricing?: GpuPricingRepository;

  get gpuInstances(): GpuInstancesRepository {
    return this._gpuInstances ??= new GpuInstancesRepository(this.db);
  }

  get gpuPricing(): GpuPricingRepository {
    return this._gpuPricing ??= new GpuPricingRepository(this.db);
  }
}
```

### 5. Linode Connector (`src/connectors/linode.ts`)
Added GPU normalization methods:

**New Methods**:
- `normalizeGpuInstance(raw: LinodeInstanceType, providerId: number): GpuInstanceInput`
  - Normalizes Linode GPU instance data for database storage
  - Extracts GPU-specific information
  - Converts units (MB to GB, GB to TB, Mbps to Gbps)
  - Stores pricing in metadata

- `extractGpuType(raw: LinodeInstanceType): string` (private)
  - Intelligent GPU type extraction from instance label
  - Recognizes: RTX6000, A100, V100, generic RTX
  - Defaults to "NVIDIA GPU" for unknown types

**Features**:
- Consistent with existing normalization patterns
- Proper unit conversions
- GPU type detection from instance labels
- Metadata preservation

## Design Decisions

### Why Separate GPU Tables?
1. **Performance**: GPU instances have different query patterns (GPU type, GPU count filters)
2. **Schema Clarity**: GPU-specific fields (gpu_memory_gb) don't belong in general instances
3. **Extensibility**: Easy to add GPU-specific features without affecting general instances
4. **Pricing Separation**: GPU pricing may have different dynamics (spot pricing, regional availability)

### Why Not Reuse Pricing Table?
1. **Foreign Key Clarity**: Separate gpu_instance_id vs instance_type_id prevents confusion
2. **Query Optimization**: Dedicated indexes for GPU pricing queries
3. **Future Features**: GPU pricing may need GPU-specific fields (spot pricing, tensor core hours)
4. **Data Integrity**: Clear separation prevents mixing GPU and regular instance pricing

### GPU Type Detection Strategy
Uses label-based heuristics because:
- Linode API doesn't expose specific GPU model in structured fields
- Label parsing is reliable for current Linode naming conventions
- Extensible: Easy to add new GPU models as they become available
- Fallback: Defaults to "NVIDIA GPU" for unknown types

## Integration Points

### Usage in Sync Service
To integrate with existing sync workflows:

```typescript
// Fetch and separate GPU instances
const allInstances = await linodeConnector.fetchInstanceTypes();
const gpuInstances = allInstances.filter(inst => inst.gpus > 0);
const regularInstances = allInstances.filter(inst => inst.gpus === 0);

// Normalize and store separately
const normalizedGpu = gpuInstances.map(inst =>
  linodeConnector.normalizeGpuInstance(inst, providerId)
);

await repos.gpuInstances.upsertMany(providerId, normalizedGpu);
```

### Querying GPU Instances
```typescript
// Find all NVIDIA A100 instances
const a100s = await repos.gpuInstances.findByGpuType('NVIDIA A100');

// Search with filters
const results = await repos.gpuInstances.search({
  providerId: 1,
  minGpuCount: 2,
  minMemoryMb: 32768,
  gpuType: 'NVIDIA RTX6000'
});

// Get available GPU types
const gpuTypes = await repos.gpuInstances.getAvailableGpuTypes();
```

## Testing Status

✅ **TypeScript Compilation**: Passes without errors
✅ **Type Safety**: All types properly defined and used
✅ **Pattern Consistency**: Follows existing repository and connector patterns
⏳ **Unit Tests**: Existing tests still pass (verification in progress)
📝 **New Tests Needed**: GPU-specific repository and connector tests

## Next Steps

### 1. Sync Service Integration
Update `src/services/sync.ts` to:
- Separate GPU instances during sync
- Store GPU instances in gpu_instances table
- Store GPU pricing in gpu_pricing table

### 2. API Endpoints (Optional)
Add GPU-specific endpoints:
- `GET /gpu-instances` - Query GPU instances
- `GET /gpu-types` - List available GPU types
- `GET /gpu-pricing` - Query GPU pricing

### 3. Testing
Create test files:
- `src/repositories/gpu-instances.test.ts`
- `src/repositories/gpu-pricing.test.ts`
- `src/connectors/linode-gpu.test.ts`

### 4. Database Migration
Run schema update on production:
```bash
npm run db:migrate:remote
```

### 5. Documentation
- Update API documentation with GPU endpoints
- Add GPU query examples to README
- Document GPU type naming conventions

## Files Created

1. `/Users/kaffa/cloud-server/src/repositories/gpu-instances.ts` (279 lines)
2. `/Users/kaffa/cloud-server/src/repositories/gpu-pricing.ts` (201 lines)

## Files Modified

1. `/Users/kaffa/cloud-server/schema.sql` - Added gpu_instances and gpu_pricing tables
2. `/Users/kaffa/cloud-server/src/types.ts` - Added GpuInstance and GpuPricing types
3. `/Users/kaffa/cloud-server/src/repositories/index.ts` - Added GPU repositories to factory
4. `/Users/kaffa/cloud-server/src/connectors/linode.ts` - Added GPU normalization methods

## Verification

```bash
# Type check
npx tsc --noEmit  # ✅ Passes

# Run tests
npm test  # ⏳ In progress

# Check schema
cat schema.sql | grep -A 20 "gpu_instances"  # ✅ Tables defined
```

## Notes

- GPU memory (gpu_memory_gb) is set to null for Linode as API doesn't provide this
- Can be populated manually or from external data sources if needed
- Metadata field stores pricing and other provider-specific data as JSON
- All repositories follow lazy singleton pattern via RepositoryFactory
- Proper error handling with RepositoryError and ErrorCodes
- Comprehensive logging with contextual information