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Cloud Functions Development

Activation Contract

Use this first when

• The task is to create, update, deploy, inspect, or debug a CloudBase Event Function or HTTP Function.

Read before writing code if

• The request mentions runtime, HTTP function, scf_bootstrap, function logs, or function deployment.

Then also read

• Auth setup or provider-related backend work -> ../auth-tool/SKILL.md
• AI in functions -> ../ai-model-nodejs/SKILL.md

Do NOT use for

• CloudRun container services or Web authentication UI implementation.

Common mistakes / gotchas

• Picking the wrong function type and trying to compensate later.
• Mixing Event Function code shape (exports.main(event, context)) with HTTP Function code shape (req / res on port 9000).
• Treating HTTP Access as the implementation model for HTTP Functions. HTTP Access is a gateway configuration for Event Functions, not the HTTP Function runtime model.
• Forgetting that runtime cannot be changed after creation.
• Using cloud functions as the first solution for Web login.
• Forgetting that HTTP Functions do NOT auto-install dependencies — always include node_modules.
• Forgetting to add app.use(express.json()) or equivalent body parsing middleware for POST/PUT requests.
• Leaving HTTP handlers without sending a response (causes request timeout).
• Not returning proper HTTP status codes (400, 401, 405) for error cases.

Minimal checklist

• Read Cloud Functions Execution Checklist before deployment or runtime changes.

Overview

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

Writing mode at a glance

• If the request is for a normal CloudBase function triggered by SDK calls, timers, or other events, write an Event Function with exports.main = async (event, context) => {}.
• If the request is for an HTTP endpoint, REST API, SSE, or WebSocket service, write an HTTP Function that listens on port 9000 and handles req / res.
• If the user mentions HTTP access for an existing Event Function, keep the Event Function code shape and add gateway access separately.

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
   • If the prompt says "HTTP 云函数", use the HTTP Function model first; if it says "触发器云函数" or omits HTTP, default to the Event Function model.

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. Write code AND deploy — do not stop after writing files

   • CRITICAL : After writing function code, you MUST also deploy it using manageFunctions. Creating files locally without deploying is incomplete.
   • Use manageFunctions(action="createFunction") to create AND deploy in one step
   • Provide functionRootPath as the parent directory of the function folder (e.g., /project/cloudfunctions/ not )

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:

• UseNodejs18.15 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

Event Function Deployment

Creating New Functions:

Use manageFunctions(action="createFunction") (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
• Legacy compatibility : If an older prompt says createFunction, keep the same payload but send it through manageFunctions

Updating Function Code:

Use manageFunctions(action="updateFunctionCode"):

• ⚠️ Note : Only updates code, cannot change runtime
• If runtime needs to change, delete and recreate function
• Legacy compatibility : If an older prompt says updateFunctionCode, map it to this manageFunctions action

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.

HTTP Function coding model

• Use a web-server style handler with req / res
• Parse query, headers, and body from the HTTP request directly
• Return HTTP status codes and response bodies explicitly
• Do not use exports.main(event, context) as the primary HTTP Function shape

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 requirescf_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 Request & Response Handling

⚠️ CRITICAL: HTTP Functions are standard web servers. They receive full HTTP requests (method, headers, query string, body) and must return complete HTTP responses (status code, headers, body). Unlike Event Functions, there is no CloudBase-specific request envelope.

Dependencies:

• HTTP Functions do NOT auto-install dependencies. You MUST include node_modules in the function directory or use layers.
• Common packages: express, body-parser (built into Express 4.16+), cors, helmet

Handling Different HTTP Methods:

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

// IMPORTANT: Must parse JSON body for POST/PUT requests
app.use(express.json());

// GET - read query parameters from req.query
app.get('/users', (req, res) => {
  const { userId, page = 1, pageSize = 10 } = req.query;

  if (!userId) {
    return res.status(400).json({ error: 'userId is required' });
  }

  res.json({
    method: 'GET',
    params: { userId, page: Number(page), pageSize: Number(pageSize) },
    message: 'Query parameters processed'
  });
});

// POST - read body from req.body, query from req.query
app.post('/users', (req, res) => {
  const { action } = req.query;    // query string: ?action=create
  const { name, email } = req.body; // JSON body

  if (!name || !email) {
    return res.status(400).json({ error: 'name and email are required' });
  }

  res.json({
    method: 'POST',
    action,
    data: { name, email },
    message: 'Body and query parameters processed'
  });
});

// PUT - read custom headers from req.headers
app.put('/users/:id', (req, res) => {
  const userId = req.headers['x-user-id']; // custom header

  if (!userId) {
    return res.status(401).json({ error: 'x-user-id header is required' });
  }

  const { status } = req.body;
  res.json({
    method: 'PUT',
    userId,
    status,
    message: 'Headers and body processed'
  });
});

// For unsupported methods, return 405
app.all('*', (req, res) => {
  res.status(405).json({ error: 'Method Not Allowed' });
});

app.listen(9000); // Must be port 9000

Key Rules:

• req.query - URL query string parameters (e.g., ?userId=123&page=1)
• req.body - Parsed request body (requires app.use(express.json()) or equivalent middleware)
• req.headers - All HTTP headers (lowercased, e.g., req.headers['x-user-id'])
• req.params - URL path parameters (e.g., /users/:id)
• Always return proper HTTP status codes: 200 (success), 400 (bad request), 401 (unauthorized), 405 (method not allowed)
• Always call res.json(), res.send(), or to send a response

HTTP Function Structure & Example

my-http-function/
├── scf_bootstrap      # Required: startup script
├── package.json       # Dependencies
├── node_modules/      # Required for HTTP Functions (no auto-install)
└── index.js           # Application code

Minimal Node.js Example (Express):

const express = require('express');
const app = express();
app.use(express.json());

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

HTTP Function Deployment

MCP Tool:

manageFunctions({
  action: "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 includewebfn=true parameter

Method 2: HTTP Access Service (Custom Domain)

Use manageGateway(action="createAccess") to configure HTTP access:

manageGateway({
  action: "createAccess",
  targetType: "function",
  targetName: "myHttpFunction",
  type: "HTTP",           // "HTTP" for HTTP Function
  path: "/api/hello",     // Trigger path
  // auth: false            // Optional: only set this when you intentionally need anonymous/public access
})

Notes:

• manageFunctions(action="createFunction") 只创建 HTTP 云函数本身，不会默认替你创建 HTTP 访问路径。

• 如果用户明确说“不需要配置 HTTP 访问服务”，不要额外调用 manageGateway(action="createAccess")。

• 评测、浏览器或其他外部调用方可能会以匿名身份访问，而且失败后不一定会把 EXCEED_AUTHORITY 再反馈给 AI。只要场景涉及匿名 URL 访问，就要主动确认两件事：访问路径是否已创建，以及函数安全规则是否允许该访问方式。

• 若外部请求已经报 EXCEED_AUTHORITY，先调用 readSecurityRule(resourceType="function") 查看当前规则，再根据实际需求决定是否用 writeSecurityRule(resourceType="function", aclTag="CUSTOM", rule="true") 或更细粒度规则放开权限。

  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 manageFunctions(action="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 queryFunctions(action="listFunctionLogs") and queryFunctions(action="getFunctionLogDetail") (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
• Important : This section applies to Event Functions only. It does not change an HTTP Function into an Event Function or vice versa.

Creating HTTP Access:

Primary Method: Use manageGateway(action="createAccess") (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 queryFunctions(action="getFunctionDetail") 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 queryFunctions({
  action: "getFunctionDetail",
  functionName: "functionName"
});

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

// 3. Update with merged variables
await manageFunctions({
  action: "updateFunctionConfig",
  functionName: "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:

• queryFunctions(action="listFunctions"|"getFunctionDetail") - Preferred read entrance for function inventory and detail
• manageFunctions(action="createFunction") - Create cloud function (supports both Event and HTTP types via func.type)
  • func.type: "Event" - Event Function (default)
  • func.type: "HTTP" - HTTP Function
  • func.protocolType: "WS" - Enable WebSocket for HTTP Function
• manageFunctions(action="updateFunctionCode") - Update function code (runtime cannot change)
• manageFunctions(action="updateFunctionConfig") - Update function configuration (⚠️ when updating envVariables, must first query and merge with existing values to avoid overwriting)

Logging:

• queryFunctions(action="listFunctionLogs") - Get function log list (basic info)
• queryFunctions(action="getFunctionLogDetail") - Get detailed log content by RequestId
• callCloudApi (Plan B) - Use GetFunctionLogs and GetFunctionLogDetail actions if direct tools unavailable
• Legacy aliases still seen in historical prompts: getFunctionLogs, getFunctionLogDetail

HTTP Access:

• queryGateway(action="getAccess") - Query current function gateway exposure
• manageGateway(action="createAccess") - Create HTTP access for function
• callCloudApi (Plan B) - Use CreateCloudBaseGWAPI action if direct tool unavailable
• Legacy alias still seen in historical prompts: createFunctionHTTPAccess

Triggers:

• queryFunctions(action="listFunctionTriggers") - Inspect triggers
• manageFunctions(action="createFunctionTrigger"|"deleteFunctionTrigger") - Create or delete function triggers
• Legacy alias still seen in historical prompts: manageFunctionTriggers

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

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Repository

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