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陈杨
陈杨

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HarmonyOS5-Cloud-Function-Guide-EN

Hello everyone! Today, let's explore how to create and configure functions in Huawei's HarmonyOS AGC Cloud Function service. This is a step-by-step guide to mastering cloud functions with HTTP triggers. Whether you're a beginner or looking to optimize existing features, this guide will provide clear instructions. Let's get straight to it! 👇

🌟 1. What Can Cloud Functions Do?

Cloud functions are like your "cloud assistants," allowing you to run code without managing servers. They are perfect for handling real-time tasks (like sending an email automatically after a user submits a form), data cleaning, or integrating with third-party APIs. The HarmonyOS AGC platform offers flexible configurations, supporting multiple languages like Node.js, Python, and Java, and even allows for custom runtime environments!

🛠️ 2. Step-by-Step: Create Your First Cloud Function

Step 1: Access the Cloud Function Console

  1. Log in to the AGC console and select your project.
  2. In the left navigation bar, find Cloud Development > Cloud Functions and click Create Function.

Step 2: Configure Basic Information

  • Function Name: Pick a cool name! Note that it can only contain lowercase letters, numbers, and hyphens, for example, my-first-function.
  • Trigger Method: Select Event Invocation to use an HTTP trigger (it will be linked during later configuration).
  • Memory Size: Choose from 500MB to 4GB as needed. For processing images or videos, a larger memory size is recommended.
  • Runtime Environment: Supports Node.js 14/18, Python 3, and Java 1.8. Choose the language you are familiar with.

Step 3: Write the Function Code

  • Online Editor (for simple code): Write code directly in the WebIDE, which supports syntax highlighting and autocompletion. 
// Node.js example: returns "Hello World!"
exports.handler = async (event) => {
  return { statusCode: 200, body: "Hello World!" };
};
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  • Upload ZIP Package (for complex projects): Java and custom environments require a ZIP file. Remember to place the entry file in the root directory.

Step 4: Set the Function Handler

  • The format is filename.methodName, for example, index.handler for Node.js.
  • Note for Java users: The handler format is packageName.className::methodName, for example, com.example.Hello::handleRequest.

⚙️ 3. Advanced Configuration: Make Your Function More Powerful

1. Environment Variables: Securely Store Sensitive Information

  • Add database passwords, API keys, etc., in Configuration > Environment Variables.
  • Two editing modes are supported:
    • Form Mode: Directly fill in Key-Value pairs, e.g., DB_PASSWORD=123456.
    • JSON Mode: Bulk import with a JSON object, e.g., { "KEY1": "value1", "KEY2": "value2" }.

2. Traffic Governance: Prevent Service Crashes

  • Load Balancing: Select Response Time Weight to prioritize instances with the fastest response times for handling requests.
  • Retry Strategy: When encountering network fluctuations, enable the jittered strategy for automatic retries with exponential backoff (up to 9 retries).
  • Circuit Breaker: Configure it to pause requests for 1 minute if the error rate exceeds 50% within 10 seconds to prevent a cascading failure.

3. Version Management: One-Click Rollback Without Issues

  • The system automatically creates a snapshot each time you publish a new version.
  • Need to roll back? Simply switch to a previous version from the Versions list. It's that stable!

🚀 4. Hands-on: Calling a Function with an HTTP Trigger

  1. After creating the function, bind an HTTP trigger on the Triggers page.
  2. Get the system-generated URL and send a GET/POST request using Postman or your frontend code.
  3. Test the response. If you encounter a timeout (default is 55 seconds), remember to increase the timeout period in the Basic Configuration settings.

💡 5. Troubleshooting Guide

  • ZIP Package Upload Failure: Check your file structure! For Node.js/Python, the entry file must be in the root directory. For Java, the package path must match the code.
  • Insufficient Memory Error: When the function processes large files, selecting 4GB of memory is a safer bet.
  • Environment Variables Not Taking Effect: After making changes, remember to click "Save" and wait about 10 seconds for the configuration to apply.

I hope this guide helps you master HarmonyOS Cloud Functions with ease! If you run into any issues, feel free to leave a comment to discuss. Don't forget to share this with your fellow developers to unlock more serverless secrets together! 🎉

Give it a try! Your first cloud function is waiting to be summoned! 🚀

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