Cloud Functions

Standalone Install Note

If this environment only installed the current skill, start from the CloudBase main entry and use the published cloudbase/references/... paths for sibling skills.

• CloudBase main entry: https://cnb.cool/tencent/cloud/cloudbase/cloudbase-skills/-/git/raw/main/skills/cloudbase/SKILL.md
• Current skill raw source: https://cnb.cool/tencent/cloud/cloudbase/cloudbase-skills/-/git/raw/main/skills/cloudbase/references/cloud-functions/SKILL.md

Keep local references/... paths for files that ship with the current skill directory. When this file points to a sibling skill such as auth-tool or web-development, use the standalone fallback URL shown next to that reference.

Cross-cutting protocols (required for public exposure and code changes):

• Change Safety Protocol: https://cnb.cool/tencent/cloud/cloudbase/cloudbase-skills/-/git/raw/main/skills/cloudbase/references/cloudbase-platform/references/protocols/change-safety-protocol.md
• Deployment Gate: https://cnb.cool/tencent/cloud/cloudbase/cloudbase-skills/-/git/raw/main/skills/cloudbase/references/cloudbase-platform/references/protocols/deployment-gate.md

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 that serves application runtime logic.
• The request mentions function runtime, function logs, scf_bootstrap, function triggers, or function gateway exposure.

Read before writing code if

• You still need to decide between Event Function and HTTP Function.
• The task mentions manageFunctions, queryFunctions, manageGateway, or legacy function-tool names.
• The task might require callCloudApi as a fallback for logs or gateway setup.

Then also read

• Detailed reference routing -> ./references.md
• Auth setup or provider-related backend work -> ../auth-tool/SKILL.md (standalone fallback: https://cnb.cool/tencent/cloud/cloudbase/cloudbase-skills/-/git/raw/main/skills/cloudbase/references/auth-tool/SKILL.md)
• CloudBase Integration Center generated WeChat Pay or Official Account functions -> ../cloudbase-wechat-integration/SKILL.md (standalone fallback: https://cnb.cool/tencent/cloud/cloudbase/cloudbase-skills/-/git/raw/main/skills/cloudbase/references/cloudbase-wechat-integration/SKILL.md; official docs: https://docs.cloudbase.net/integration/introduce/index.md)
• AI in functions -> ../ai-model-nodejs/SKILL.md (standalone fallback: https://cnb.cool/tencent/cloud/cloudbase/cloudbase-skills/-/git/raw/main/skills/cloudbase/references/ai-model-nodejs/SKILL.md)
• Long-lived container services or Agent runtimes -> ../cloudrun-development/SKILL.md (standalone fallback: https://cnb.cool/tencent/cloud/cloudbase/cloudbase-skills/-/git/raw/main/skills/cloudbase/references/cloudrun-development/SKILL.md)
• Calling CloudBase official platform APIs from a client or script -> ../http-api/SKILL.md (standalone fallback: https://cnb.cool/tencent/cloud/cloudbase/cloudbase-skills/-/git/raw/main/skills/cloudbase/references/http-api/SKILL.md)

Do NOT use for

• CloudRun container services.
• Web authentication UI implementation.
• Database-schema design or general data-model work.
• CloudBase official platform API clients or raw HTTP integrations that only consume platform endpoints.
• Creating Integration Center instances through guessed APIs. For WeChat Pay or Official Account generated functions, use cloudbase-wechat-integration for the business contract and this skill only for function operations.
• Tasks that the CloudBase JS SDK can handle directly — simple data reads/writes, leaderboards, file uploads, real-time queries. Reach for the matching SDK surface before writing a function: db.collection(...).get/add/update only for confirmed NoSQL collections, and app.rdb().from(...) for CloudBase PG tables. Functions add deployment complexity, CORS configuration, and HTTP gateway binding that the SDK eliminates entirely.

Common mistakes / gotchas

• Picking the wrong function type and trying to compensate later.
• Confusing official CloudBase API client work with building your own HTTP function.
• 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.
• Assuming db.collection("name").add(...) will create a missing document-database collection automatically. Collection creation is a separate management step.
• Forgetting that runtime cannot be changed after creation.
• Using cloud functions as the first answer for Web login.
• Forgetting that HTTP Functions must ship scf_bootstrap, listen on port 9000, and include dependencies.
• Forgetting to configure function security rules after creating an HTTP Function. Default rules reject anonymous callers with EXCEED_AUTHORITY. Note: anonymous login is disabled by default for new environments — if the function needs public access without authentication, configure the security rule to allow all callers rather than relying on anonymous login.
• Mismatching the scf_bootstrap Node.js binary path with the function runtime (e.g. using /var/lang/node18/bin/node but setting runtime: "Nodejs16.13").
• For Custom Image HTTP Functions: forgetting that TCR, the CloudApp build, and SCF must be in the same region; using :latest instead of a unique tag; or confusing the request-driven port-9000 image model with a long-lived CloudRun container that listens on the injected PORT.
• Assuming MCP covers the whole image pipeline. manageFunctions covers SCF image deploy (Stage B) via runtime: "CustomImage" + imageConfig, but the CloudApp custom build → TCR push (Stage A) is a raw Tencent Cloud API path — confirm action names and parameters from official docs before any callCloudApi fallback.
• Making code or configuration changes without first following the Change Safety Protocol (cloudbase-platform/references/protocols/change-safety-protocol.md).
• Exposing functions publicly or deploying without first completing the checks in cloudbase-platform/references/protocols/deployment-gate.md.

Minimal checklist

• Read [Cloud Functions Execution Checklist](checklist.md) before deployment or runtime changes.
• Decide whether the task is Event Function, HTTP Function, or actually CloudRun.
• Pick the detailed reference file in [references.md](references.md) before writing implementation code.

Overview

Use this skill when developing, deploying, and operating CloudBase cloud functions. CloudBase has two different programming models:

• Event Functions: serverless handlers driven by SDK calls, timers, and other events.
• HTTP Functions: standard web services for HTTP endpoints, SSE, or WebSocket workloads. By default they run on a managed runtime (scf_bootstrap + zip); when they need custom system libraries or an arbitrary runtime they can instead run from a container image (Runtime: CustomImage, deployed from TCR — see ./references/http-functions-custom-image.md).

Writing mode at a glance

• If the request is for SDK calls, timers, or event-driven workflows, write an Event Function with exports.main = async (event, context) => {}.
• If the request is for REST APIs, browser-facing endpoints, SSE, or WebSocket, write an HTTP Function with req / res on port 9000.
• For Node.js HTTP Functions, default to the native http module unless the user explicitly asks for Express, Koa, NestJS, or another framework.
• If the HTTP Function needs custom system libraries or an arbitrary runtime but should still be SCF request-driven and scale to zero, deploy it as a Custom Image HTTP Function (Runtime: CustomImage) from a TCR image. The container still listens on the fixed port 9000. See ./references/http-functions-custom-image.md. This is distinct from a CloudRun container, which listens on the injected PORT and runs long-lived.
• If the user mentions HTTP access for an existing Event Function, keep the Event Function code shape and add gateway access separately.

HTTP Function authoring contract

Use these rules whenever you are writing the function code itself:

• Do not write an HTTP Function as exports.main(event, context). That is the Event Function contract.
• Treat the function as a standard web server process that must listen on port 9000.
• With Node.js, prefer http.createServer((req, res) => { ... }) by default so the runtime contract stays explicit.
• With the Node.js native http module, do not assume Express-style helpers exist. req.body, req.query, and req.params are not provided for you.
• For Node.js HTTP Functions, choose one module system up front and keep it consistent. Default to CommonJS for simple functions (require(...), no "type": "module" in package.json) unless you explicitly want ES Modules.
• If you do choose ES Modules ("type": "module" + import ...), do not mix in CommonJS-only globals or APIs such as require(...), module.exports, or bare __dirname. In ESM, derive file paths from import.meta.url with fileURLToPath(...) only when needed.
• With the native http module, parse req.url yourself with new URL(...), collect the request body from the stream, and only then call JSON.parse. Empty bodies should be handled explicitly instead of assuming JSON is always present.
• Return responses explicitly with res.writeHead(...) and res.end(...), including Content-Type such as application/json; charset=utf-8 for JSON APIs.
• Handle CORS headers. Browsers block cross-origin requests without proper CORS headers. Default to allowing all origins for simple APIs:
• Respond to OPTIONS preflight with 200 and CORS headers
• Include Access-Control-Allow-Origin: * (or specific origin) on all responses
• Include Access-Control-Allow-Methods: GET, POST, OPTIONS as needed
• Include Access-Control-Allow-Headers: Content-Type for JSON requests
• Keep routing and method handling explicit. Unknown paths should return 404, and known paths with unsupported methods should normally return 405.
• Keep gateway setup and security-rule changes separate from the runtime code. They affect access, not the HTTP Function programming model.
• Do not add HTTP access service configuration when the task is only to create an HTTP Function itself. Gateway paths or custom domains are separate access-layer work; public invocation requirements should be handled through the function security rule workflow (note: anonymous login is disabled by default).

Quick decision table

| Question | Choose | | --- | --- | | Triggered by SDK calls or timers? | Event Function | | Needs browser-facing HTTP endpoint? | HTTP Function | | Needs SSE or WebSocket service? | HTTP Function | | Needs custom system libraries / arbitrary runtime, but still SCF request-driven + scale-to-zero? | HTTP Function with Runtime: CustomImage (deploy from a TCR image) | | Needs long-lived container runtime or custom system environment? | CloudRun | | Only needs HTTP access for an existing Event Function? | Event Function + gateway access |

How to use this skill (for a coding agent)

1. Choose the correct runtime model first

• Event Function -> exports.main(event, context)
• HTTP Function -> web server on port 9000
• If the requirement is really a container service, reroute to CloudRun early

1. Use the converged MCP entrances

• Reads -> queryFunctions, queryGateway
• Writes -> manageFunctions, manageGateway
• Translate legacy names before acting rather than copying them literally

1. Write code and deploy, do not stop at local files

• Use manageFunctions(action="createFunction") for creation
• Use manageFunctions(action="updateFunctionCode") for code updates
• Use manageFunctions(action="updateFunctionConfig") for config updates (timeout, memorySize, envVariables)
• For a Custom Image HTTP Function, call manageFunctions(action="createFunction") with func.runtime="CustomImage" and imageConfig (imageUri with tag; registryId for enterprise TCR); iterate later with manageFunctions(action="updateFunctionCode") + imageConfig. No functionRootPath is needed because the code lives in the image. See ./references/http-functions-custom-image.md.
• Keep functionRootPath as the directory that directly contains function folders (e.g., cloudfunctions/ or functions/), NOT the project root and NOT the function subdirectory itself
• Prefer MCP tools over CLI — when MCP tools are available, use manageFunctions and queryFunctions instead of CLI commands
• Do NOT assume CLI is available from task wording alone — if the available capabilities only include MCP tools, use MCP tools exclusively
• For batch updates (multiple functions), call manageFunctions(action="updateFunctionConfig") individually for each function — MCP does not have a --all batch parameter like CLI

1. Prefer doc-first fallbacks

• If a task falls back to callCloudApi, first check the official docs or knowledge-base entry for that action
• Confirm the exact action name and parameter contract before calling it
• Do not guess raw cloud API payloads from memory

1. Read the right detailed reference

• Event Function details -> ./references/event-functions.md
• HTTP Function details -> ./references/http-functions.md
• HTTP Function from a container image (Runtime: CustomImage, TCR image pipeline) -> ./references/http-functions-custom-image.md
• Logs, gateway, env vars, and legacy mappings -> ./references/operations-and-config.md

Database write reminder

• If a function will write to CloudBase document database, create the target collection first through console or management tooling.
• db.collection("feedback").add(...) only inserts into an existing collection; it does not auto-create feedback when absent.
• If the product requirement says "create when missing", implement that as an explicit collection-management step before the first write instead of assuming the runtime write call will provision it.

Function types comparison

| Feature | Event Function | HTTP Function | | --- | --- | --- | | Primary trigger | SDK call, timer, event | HTTP request | | Entry shape | exports.main(event, context) | web server with req / res | | Port | No port | Must listen on 9000 | | scf_bootstrap | Not required | Required | | Dependencies | Auto-installed from package.json | Must be packaged with function code | | Best for | serverless handlers, scheduled jobs | APIs, SSE, WebSocket, browser-facing services |

Minimal code skeletons

Event Function hello world

cloudfunctions/hello-event/index.js

exports.main = async (event, context) => {
  return {
    ok: true,
    message: "hello from event function",
    event,
  };
};

cloudfunctions/hello-event/package.json

{
  "name": "hello-event",
  "version": "1.0.0"
}

HTTP Function hello world

cloudfunctions/hello-http/index.js

const http = require("http");
const { URL } = require("url");

// CORS headers — default to * for simple cross-origin APIs
const CORS_HEADERS = {
  "Access-Control-Allow-Origin": "*",
  "Access-Control-Allow-Methods": "GET, POST, OPTIONS",
  "Access-Control-Allow-Headers": "Content-Type",
};

function sendJson(res, statusCode, data) {
  res.writeHead(statusCode, {
    "Content-Type": "application/json; charset=utf-8",
    ...CORS_HEADERS,
  });
  res.end(JSON.stringify(data));
}

function sendOptions(res) {
  res.writeHead(204, CORS_HEADERS);
  res.end();
}

function readJsonBody(req) {
  return new Promise((resolve, reject) => {
    let raw = "";
    req.on("data", (chunk) =>

…

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [TencentCloudBase](https://github.com/TencentCloudBase)
- **Source:** [TencentCloudBase/cloudbase-skills](https://github.com/TencentCloudBase/cloudbase-skills)
- **License:** MIT

Install and usage instructions live in the source repository linked above.