Cloud Functions Development

Use this skill when developing, deploying, and managing CloudBase cloud functions. CloudBase supports two types of cloud functions:

• Event Functions (普通云函数): Traditional serverless functions triggered by events (SDK calls, timers)
• HTTP Functions (HTTP 云函数): Web service functions triggered by HTTP requests, supporting multiple languages

When to use this skill

Use this skill for cloud function operations when you need to:

• Create and deploy Event Functions (Node.js)
• Create and deploy HTTP Functions (Node.js/Python/Go/Java)
• Understand runtime limitations and selection
• Query function logs and monitor execution
• Invoke cloud functions from applications
• Configure HTTP access for cloud functions
• Implement SSE (Server-Sent Events) or WebSocket

Do NOT use for:

• CloudRun backend services (use cloudrun-development skill)
• Complex container-based services (use cloudrun-development skill)
• Database operations (use database skills)

How to use this skill (for a coding agent)

1. Choose the right function type

   • Event Function: For SDK calls, scheduled tasks, event-driven scenarios
   • HTTP Function: For Web APIs, REST services, SSE/WebSocket, multi-language support

2. Understand runtime limitations

   • Runtime CANNOT be changed after function creation
   • Must select correct runtime during initial creation
   • If runtime needs to change, must delete and recreate function

3. Deploy functions correctly

   • MCP Tool: Use createFunction with type: "Event" or type: "HTTP"
   • CLI: Use tcb fn deploy (Event) or tcb fn deploy --httpFn (HTTP)
   • HTTP Functions require scf_bootstrap file in the function directory
   • Provide correct functionRootPath (parent directory of function folder)

4. Query logs properly

   • Use getFunctionLogs for log list (basic info)
   • Use getFunctionLogDetail with RequestId for detailed logs
   • Note time range limitations (max 1 day interval)

Function Types Comparison

Core Knowledge - Event Functions

Runtime Environment

⚠️ CRITICAL: Runtime cannot be modified after function creation

Once a cloud function is created with a specific runtime, the runtime cannot be changed. If you need a different runtime:

1. Delete the existing function
2. Create a new function with the desired runtime

Supported Node.js Runtimes:

• Nodejs18.15 (Default, Recommended)
• Nodejs16.13
• Nodejs14.18
• Nodejs12.16
• Nodejs10.15
• Nodejs8.9

Runtime Selection Guidelines:

• Use Nodejs18.15 for new projects (default, most modern)
• Choose older versions only if dependencies require specific Node.js versions
• Consider security updates and support lifecycle
• Test thoroughly with selected runtime before deployment

Event Function Structure

Event functions require:

1. Function Directory: Contains function code

   • Must have index.js (or specified entry file)
   • Must export handler: exports.main = async (event, context) => {}
   • Include package.json with dependencies

2. Function Root Path: Parent directory containing function directories

   • Example: If function is at /project/cloudfunctions/myFunction/
   • functionRootPath should be /project/cloudfunctions/
   • Important: Do NOT include function name in root path

3. Entry Point: Default is index.js with exports.main

   • Can be customized via handler parameter

Event Function Deployment

Creating New Functions:

Use createFunction tool (see MCP tool documentation for full parameter list):

• Important: Always specify func.runtime explicitly (defaults to Nodejs18.15)
• Provide functionRootPath as parent directory of function folders (absolute path)
• Use force=true to overwrite existing function

Updating Function Code:

Use updateFunctionCode tool:

• ⚠️ Note: Only updates code, cannot change runtime
• If runtime needs to change, delete and recreate function

Deployment Best Practices:

1. Always specify runtime explicitly when creating functions
2. Use absolute paths for functionRootPath
3. Don't upload node_modules - dependencies installed automatically
4. Test locally before deployment when possible
5. Use environment variables for configuration, not hardcoded values

Core Knowledge - HTTP Functions

HTTP Function Overview

HTTP Functions are optimized for Web service scenarios, supporting standard HTTP request/response patterns.

Key Characteristics:

• Must listen on port 9000 (platform requirement)
• Requires scf_bootstrap startup script
• Supports multiple languages: Node.js, Python, Go, Java
• Supports HTTP, SSE, WebSocket protocols

scf_bootstrap Startup Script

⚠️ CRITICAL: HTTP Functions require scf_bootstrap file

Examples:

# Node.js
#!/bin/bash
node index.js

# Python
#!/bin/bash
export PYTHONPATH="./third_party:$PYTHONPATH"
/var/lang/python310/bin/python3.10 app.py

# Go
#!/bin/bash
./main

# Java
#!/bin/bash
java -jar *.jar

HTTP Function Structure & Example

my-http-function/
├── scf_bootstrap      # Required: startup script
├── package.json       # Dependencies
└── index.js           # Application code

Node.js Example (Express):

const express = require('express');
const app = express();

app.get('/', (req, res) => res.json({ message: 'Hello!' }));
app.listen(9000);  // Must be port 9000

HTTP Function Deployment

MCP Tool:

createFunction({
  func: {
    name: "myHttpFunction",
    type: "HTTP",           // Required for HTTP Function
    protocolType: "HTTP",   // "HTTP" (default) or "WS" (WebSocket)
    timeout: 60
  },
  functionRootPath: "/path/to/functions",
  force: false
})

CLI:

tcb fn deploy <name> --httpFn        # HTTP Function
tcb fn deploy <name> --httpFn --ws   # With WebSocket

⚠️ Notes:

• Function type cannot be changed after creation
• HTTP Functions do NOT auto-install dependencies; include node_modules or use layers

Invoking HTTP Functions

Method 1: HTTP API (with Access Token)

curl -L 'https://{envId}.api.tcloudbasegateway.com/v1/functions/{name}?webfn=true' \
  -H 'Authorization: Bearer <TOKEN>'

⚠️ Must include webfn=true parameter

Method 2: HTTP Access Service (Custom Domain)

Use createFunctionHTTPAccess MCP tool to configure HTTP access:

createFunctionHTTPAccess({
  name: "myHttpFunction",
  type: "HTTP",           // "HTTP" for HTTP Function
  path: "/api/hello",     // Trigger path
  // domain: "your-domain.com"  // Optional custom domain
})

# Access via default domain
curl https://{envId}.{region}.app.tcloudbase.com/{path}

# Access via custom domain
curl https://your-domain.com/{path}

SSE & WebSocket Support

SSE (Server-Sent Events): Enabled by default, for server-to-client streaming (AI chat, progress updates).

// Server
res.setHeader('Content-Type', 'text/event-stream');
res.write(`data: ${JSON.stringify({ content: 'Hello' })}\n\n`);

// Client
const es = new EventSource('https://your-domain/stream');
es.onmessage = (e) => console.log(JSON.parse(e.data));

WebSocket: Enable via protocolType: "WS" in createFunction. For bidirectional real-time communication.

const wss = new WebSocket.Server({ port: 9000 });
wss.on('connection', (ws) => {
  ws.on('message', (msg) => ws.send(`Echo: ${msg}`));
});

Function Logs

Querying Logs:

Primary Method: Use getFunctionLogs and getFunctionLogDetail tools (see MCP tool documentation).

Alternative Method (Plan B): If tools unavailable, use callCloudApi:

1. Get Log List - Use GetFunctionLogs action:

callCloudApi({
  service: "tcb",
  action: "GetFunctionLogs",
  params: {
    EnvId: "{envId}",
    FunctionName: "functionName",
    Offset: 0,
    Limit: 10,
    StartTime: "2024-01-01 00:00:00",
    EndTime: "2024-01-01 23:59:59",
    LogRequestId: "optional-request-id",
    Qualifier: "$LATEST"
  }
})

2. Get Log Details - Use GetFunctionLogDetail action (requires LogRequestId from step 1):

callCloudApi({
  service: "tcb",
  action: "GetFunctionLogDetail",
  params: {
    StartTime: "2024-01-01 00:00:00",
    EndTime: "2024-01-01 23:59:59",
    LogRequestId: "request-id-from-log-list"
  }
})

Log Query Limitations:

• Offset + Limit cannot exceed 10000
• StartTime and EndTime interval cannot exceed 1 day
• Use pagination for large time ranges

Log Query Best Practices:

1. Query logs within 1-day windows
2. Use RequestId for specific invocation debugging
3. Combine list and detail queries for comprehensive debugging
4. Check logs after deployment to verify function behavior

Invoking Event Functions

From Web Applications:

import cloudbaseSDK from "@cloudbase/js-sdk";

const cloudbase = cloudbaseSDK.init({
  env: 'your-env-id',
  region: 'ap-shanghai',
  accessKey: 'your-access-key'
});

// Call event function
const result = await cloudbase.callFunction({
  name: "functionName",
  data: { /* function parameters */ }
});

From Mini Programs:

wx.cloud.callFunction({
  name: "functionName",
  data: { /* function parameters */ }
}).then(res => {
  console.log(res.result);
});

From Node.js Backend:

const cloudbase = require("@cloudbase/node-sdk");

const app = cloudbase.init({
  env: "your-env-id"
});

const result = await app.callFunction({
  name: "functionName",
  data: { /* function parameters */ }
});

From HTTP API:

Use CloudBase HTTP API to invoke event functions:

• Endpoint: https://{envId}.api.tcloudbasegateway.com/v1/functions/{functionName}
• Requires authentication token (Bearer Token)
• See http-api skill for details

HTTP Access Configuration (for Event Functions)

HTTP Access vs HTTP API:

• HTTP API: Uses CloudBase API endpoint with authentication token
• HTTP Access: Creates direct HTTP/HTTPS endpoint for standard REST API access without SDK

Creating HTTP Access:

Primary Method: Use createFunctionHTTPAccess tool (see MCP tool documentation).

Alternative Method (Plan B): If tool unavailable, use callCloudApi with CreateCloudBaseGWAPI:

callCloudApi({
  service: "tcb",
  action: "CreateCloudBaseGWAPI",
  params: {
    EnableUnion: true,
    Path: "/api/users",
    ServiceId: "{envId}",
    Type: 6,
    Name: "functionName",
    AuthSwitch: 2,
    PathTransmission: 2,
    EnableRegion: true,
    Domain: "*"  // Use "*" for default domain, or custom domain name
  }
})

Key Parameters:

• Type: 6 - Cloud Function type (required)
• AuthSwitch: 2 - No auth (1 = with auth)
• Domain: "*" - Default domain, or specify custom domain

Access URL: https://{envId}.{region}.app.tcloudbase.com/{path} or https://{domain}/{path}

Function Configuration

Environment Variables:

Set via func.envVariables when creating/updating:

{
  envVariables: {
    "DATABASE_URL": "mysql://...",
    "API_KEY": "secret-key"
  }
}

⚠️ CRITICAL: Environment Variable Update Constraint

When updating environment variables for existing functions:

1. MUST first query current environment variables using getFunctionList with action=detail to get the function's current configuration
2. MUST merge new environment variables with existing ones
3. DO NOT directly overwrite - this will delete existing environment variables not included in the update

Correct Update Pattern:

// 1. First, get current function details
const currentFunction = await getFunctionList({
  action: "detail",
  name: "functionName"
});

// 2. Merge existing envVariables with new ones
const mergedEnvVariables = {
  ...currentFunction.EnvVariables,  // Existing variables
  ...newEnvVariables                 // New/updated variables
};

// 3. Update with merged variables
await updateFunctionConfig({
  funcParam: {
    name: "functionName",
    envVariables: mergedEnvVariables
  }
});

Why This Matters:

• Direct overwrite will delete all environment variables not included in the update
• This can break function functionality if critical variables are removed
• Always preserve existing configuration when making partial updates

Timeout Configuration:

Set via func.timeout (in seconds):

• Default timeout varies by runtime
• Maximum timeout depends on runtime version
• Consider function execution time when setting

Timer Triggers:

Configure via func.triggers:

• Type: timer (only supported type)
• Config: Cron expression (7 fields: second minute hour day month week year)
• Examples:
  • "0 0 2 1 * * *" - 2:00 AM on 1st of every month
  • "0 30 9 * * * *" - 9:30 AM every day

VPC Configuration:

For accessing VPC resources:

{
  vpc: {
    vpcId: "vpc-xxxxx",
    subnetId: "subnet-xxxxx"
  }
}

MCP Tools Reference

Function Management:

• getFunctionList - List functions or get function details
• createFunction - Create cloud function (supports both Event and HTTP types via type parameter)
  • type: "Event" - Event Function (default)
  • type: "HTTP" - HTTP Function
  • protocolType: "WS" - Enable WebSocket for HTTP Function
• updateFunctionCode - Update function code (runtime cannot change)
• updateFunctionConfig - Update function configuration (⚠️ when updating envVariables, must first query and merge with existing values to avoid overwriting)

Logging:

• getFunctionLogs - Get function log list (basic info)
• getFunctionLogDetail - Get detailed log content by RequestId
• callCloudApi (Plan B) - Use GetFunctionLogs and GetFunctionLogDetail actions if direct tools unavailable

HTTP Access:

• createFunctionHTTPAccess - Create HTTP access for function (supports both Event and HTTP types via type parameter)
• callCloudApi (Plan B) - Use CreateCloudBaseGWAPI action if direct tool unavailable

Triggers:

• manageFunctionTriggers - Create or delete function triggers

CLI Commands:

• tcb fn deploy <name> - Deploy Event Function
• tcb fn deploy <name> --httpFn - Deploy HTTP Function
• tcb fn deploy <name> --httpFn --ws - Deploy HTTP Function with WebSocket
• tcb fn deploy --all - Deploy all functions in config

Common Patterns

Error Handling

exports.main = async (event, context) => {
  try {
    // Function logic
    return {
      code: 0,
      message: "Success",
      data: result
    };
  } catch (error) {
    return {
      code: -1,
      message: error.message,
      data: null
    };
  }
};

Environment Variable Usage

exports.main = async (event, context) => {
  const apiKey = process.env.API_KEY;
  const dbUrl = process.env.DATABASE_URL;
  
  // Use environment variables
};

Database Operations

const cloudbase = require("@cloudbase/node-sdk");

const app = cloudbase.init({
  env: process.env.ENV_ID
});

exports.main = async (event, context) => {
  const db = app.database();
  const result = await db.collection("users").get();
  return result;
};

Best Practices

General Best Practices

1. Runtime Selection: Always specify runtime explicitly, use Nodejs18.15 for new projects
2. Code Organization: Keep functions focused and single-purpose
3. Error Handling: Always implement proper error handling
4. Environment Variables: Use env vars for configuration, never hardcode secrets
5. Logging: Add meaningful logs for debugging
6. Testing: Test functions locally when possible before deployment
7. Security: Implement authentication/authorization for HTTP access
8. Performance: Optimize cold start time, use connection pooling for databases
9. Monitoring: Regularly check logs and monitor function performance
10. Documentation: Document function parameters and return values

HTTP Function Specific Best Practices

1. Port Configuration: Always listen on port 9000
2. scf_bootstrap: Ensure correct file permissions and LF line endings
3. Health Check: Add /health endpoint for monitoring
4. CORS: Configure CORS headers for browser access
5. Graceful Shutdown: Handle process signals properly
6. Dependencies: Include node_modules in package or use layers (no auto-install for HTTP Functions)
7. Timeout: Set appropriate timeout for long-running SSE/WebSocket connections
8. Error Responses: Return proper HTTP status codes and error messages

Choosing Between Event and HTTP Functions

Related Skills

• cloudrun-development - For container-based backend services
• http-api - For HTTP API invocation patterns
• cloudbase-platform - For general CloudBase platform knowledge