feat(volcengine): Phase 2 - veFaaS Function Service Support

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Phase 2: veFaaS Function Service Support

Parent Epic: #179
Depends on: Phase 1 (#PHASE1)

Overview

Implement full CRUD support for Volcengine's Function Service (veFaaS), enabling deploy, update, and destroy of serverless functions.

Service Information

Property	Value
Service Name	函数服务 (veFaaS)
Documentation	https://www.volcengine.com/docs/6662
SDK Package	@volcengine/vefaas
API Version	2024-06-06

Supported Runtimes

python/3.10, python/3.9, python/3.8
nodejs/18, nodejs/16, nodejs/14
golang/1
java/11, java/8

Tasks

1. Type Definitions (vefaasTypes.ts)

// src/stack/volcengineStack/vefaasTypes.ts

export type VefaasFunctionConfig = {
  functionName: string;
  runtime: string;
  handler: string;
  memoryMb: number;
  requestTimeout: number;
  environmentVariables?: Record<string, string>;
  description?: string;
  vpcConfig?: {
    vpcId: string;
    subnetIds: string[];
    securityGroupIds: string[];
  };
  tosMountConfig?: {
    bucketName: string;
    mountPath: string;
  };
};

export type VefaasFunctionInfo = {
  functionId: string;
  functionName: string;
  runtime: string;
  handler: string;
  memoryMb: number;
  requestTimeout: number;
  environmentVariables?: Record<string, string>;
  status: string;
  createdTime: string;
  lastModifiedTime: string;
};

2. Client Operations (vefaasOperations.ts)

// src/common/volcengineClient/vefaasOperations.ts

export const createVefaasOperations = (client: VefaasClient) => ({
  createFunction: async (config: VefaasFunctionConfig, codePath: string): Promise<void> => {
    const code = fs.readFileSync(codePath);
    const command = new CreateFunctionCommand({
      Name: config.functionName,
      Runtime: config.runtime,
      Handler: config.handler,
      MemoryMb: config.memoryMb,
      RequestTimeout: config.requestTimeout,
      Code: { ZipFile: code.toString('base64') },
      Envs: config.environmentVariables,
    });
    await client.send(command);
  },
  
  getFunction: async (functionName: string): Promise<VefaasFunctionInfo | null> => {
    // Implement with error handling for NotFound
  },
  
  updateFunctionConfiguration: async (config: VefaasFunctionConfig): Promise<void> => { ... },
  updateFunctionCode: async (functionName: string, codePath: string): Promise<void> => { ... },
  deleteFunction: async (functionName: string): Promise<void> => { ... },
  listFunctions: async (): Promise<VefaasFunctionInfo[]> => { ... },
});

3. Resource Implementation (vefaasResource.ts)

Implement four lifecycle functions:

export const createResource = async (
  context: Context,
  fn: FunctionDomain,
  state: StateFile,
): Promise<StateFile> => {
  // 1. Create dependent resources (IAM role if needed)
  // 2. Upload code to TOS if large
  // 3. Create function
  // 4. Update state
};

export const readResource = async (
  context: Context, 
  functionName: string
): Promise<VefaasFunctionInfo | null> => { ... };

export const updateResource = async (
  context: Context,
  fn: FunctionDomain,
  state: StateFile,
): Promise<StateFile> => { ... };

export const deleteResource = async (
  context: Context,
  functionName: string,
  logicalId: string,
  state: StateFile,
): Promise<StateFile> => { ... };

4. Planner (vefaasPlanner.ts)

• Implement generateVefaasPlan() function
• Compare desired state vs current state
• Generate CREATE/UPDATE/DELETE actions
• Handle code hash comparison for code changes

5. Executor (vefaasExecutor.ts)

• Implement executeVefaasPlan() function
• Execute plans in order
• Handle partial failures
• Update state after each operation

6. Integration

• Update volcengineStack/planner.ts to include vefaas planner
• Update volcengineStack/deployer.ts to execute vefaas plan
• Update volcengineStack/destroyer.ts to delete functions

Function Configuration Mapping

YAML Field	veFaaS API Field	Notes
name	Name	Required
code.runtime	Runtime	e.g., "nodejs/18"
code.handler	Handler	e.g., "index.handler"
code.path	Code.ZipFile	Base64 encoded
memory	MemoryMb	Default: 128
timeout	RequestTimeout	Default: 30
environment	Envs	Key-value pairs
network.vpc_id	VpcConfig.VpcId	Optional
network.subnet_ids	VpcConfig.SubnetIds	Optional

Sample Configuration

# samples/volcengine-poc-function.yml
version: 0.1.0
provider:
  name: volcengine
  region: cn-beijing

app: insight-poc
service: insight-poc-vefaas

functions:
  hello_function:
    name: insight-poc-hello
    code:
      runtime: nodejs/18
      handler: index.handler
      path: ./artifacts/function.zip
    memory: 256
    timeout: 30
    environment:
      NODE_ENV: production

Acceptance Criteria

Must Have

• si deploy -f samples/volcengine-poc-function.yml creates function in Volcengine
• si deploy (second run) detects no changes
• si deploy with code changes updates function code
• si deploy with config changes updates function configuration
• si destroy removes function and cleans up state
• State file correctly stores function metadata
• Error messages are i18n formatted
• npm test passes for vefaas-related tests

Should Have

• VPC configuration support
• Environment variable updates work correctly
• Code hash used for change detection
• Partial failure recovery works

Nice to Have

• TOS mount configuration
• NAS storage mounting
• GPU function support

Test Cases

describe('vefaasResource', () => {
  it('should create a function with minimal config', async () => { ... });
  it('should create a function with environment variables', async () => { ... });
  it('should update function configuration', async () => { ... });
  it('should update function code', async () => { ... });
  it('should delete a function', async () => { ... });
  it('should handle function not found on delete', async () => { ... });
  it('should handle partial failure and save state', async () => { ... });
});

References

• veFaaS API Reference
• FC3 Resource Implementation - Reference
• SCF Resource Implementation - Reference
• Terraform vefaas_function

Estimated Effort

Large (5-7 days)