Serverless Cloud Function (SCF)

Serverless Cloud Function (SCF) is Tencent Cloud's event-driven serverless compute service. SCF lets you run code without managing servers — the equivalent of AWS Lambda or Alibaba Cloud Function Compute.

---

What is SCF?

SCF allows you to:

• Write functions in supported languages
• Deploy without provisioning or managing servers
• Pay only for the compute time your code consumes
• Scale automatically from zero to thousands of concurrent executions

---

How SCF Works

1. You write a function and define a trigger
2. When an event occurs, SCF provisions the runtime
3. Your code executes and returns a result
4. After execution, the runtime may be reused or released

graph TD
  E["Event (e.g., COS upload, API Gateway request)"] --> SCF["SCF Runtime"]
  SCF --> Code["Your Code"]
  Code --> Resp["Response / Output"]

---

Supported Runtimes

Runtime	Versions
Python	2.7, 3.6, 3.7, 3.9
Node.js	10, 12, 14, 16, 18
Java	8, 11
Go	1.x
PHP	5.6, 7.2, 7.4, 8.0
Custom Runtime	Any language
Custom Image	Docker container images

---

Triggers

Triggers define how a function is invoked:

Trigger	Use Case
API Gateway	HTTP requests (REST APIs, webhooks)
COS	File uploads, deletions in Cloud Object Storage
Timer	Scheduled execution (cron expressions)
CMQ (Message Queue)	Process messages from Cloud Message Queue
CKafka	Process messages from Cloud Kafka
CLS (Log Service)	Process log data in real time
MPS (Media Processing)	Media transcoding completion events

Example: COS Trigger

graph LR
  A["User uploads image"] --> B["COS bucket"]
  B --> C["COS event"]
  C --> D["SCF function"]
  D --> E["Creates thumbnail"]
  E --> F["Saves to COS"]

---

Function Configuration

Setting	Description	Limits
Memory	Allocated memory (64 MB to 3,072 MB)	CPU scales with memory
Timeout	Maximum execution time	Up to 900 seconds (15 minutes)
Environment variables	Configuration key-value pairs	Up to 4 KB
Layers	Shared dependencies	Up to 5 layers
Concurrency	Reserved and provisioned concurrency	Configurable per function