Bootstrap File Description

In HTTP Cloud Functions, scf_bootstrap is a required startup file that serves as the entry point for the Web Server. It is responsible for starting your web service, configuring the runtime environment, loading dependencies, and ensuring the service properly listens for requests.

Purpose of the Bootstrap File

The scf_bootstrap file is automatically executed when a cloud function instance starts, primarily performing the following tasks:

Responsibility	Description
Start Web Service	Ensures your web service starts properly and listens for requests (default port is 9000)
Environment Configuration	Sets paths for runtime dependency libraries, environment variables, etc.
Dependency Loading	Loads library files and extensions for custom languages and versions For real-time dependency pulling, it's recommended to download to the /tmp directory
Global Initialization	Performs global operations required before function invocation (such as HTTP Client initialization, database connection pool creation, etc.) for reuse during invocation
Plugin Loading	Starts security, monitoring, and other plugins

Prerequisites

To ensure the bootstrap file can be executed correctly, the following conditions must be met:

Requirement	Description
Fixed Filename	Must be named scf_bootstrap, other names are not supported
Execute Permission	File must have execute permission (recommended 777 or 755)
System Environment	Must be able to run in SCF system environment (CentOS 7.6)
Shebang Declaration	If it's a Shell script, the first line must include #!/bin/bash
Absolute Path	Startup commands must use absolute paths (see "Standard Language Environment Absolute Paths" below)
Listen Address	It's recommended to use 0.0.0.0, do not use internal loopback address 127.0.0.1
File Format	File must end with LF line ending (not CRLF)
Write Permission Restrictions	In Tencent Cloud standard environment, only the /tmp directory is readable/writable; please note the path when outputting files

⚠️ Important Note: On Linux/macOS systems, use the chmod +x scf_bootstrap or chmod 777 scf_bootstrap command to set execute permissions.

Standard Language Environment Absolute Paths

When writing startup commands, you must use the absolute path corresponding to the language. Here are common version path references:

Language Version	Absolute Path
Node.js 18.15	/var/lang/node18/bin/node
Node.js 16.13	/var/lang/node16/bin/node
Node.js 14.18	/var/lang/node14/bin/node
Node.js 12.16	/var/lang/node12/bin/node
Python 3.10	/var/lang/python310/bin/python3.10
Python 3.9	/var/lang/python39/bin/python3.9
Python 3.7	/var/lang/python37/bin/python3.7
Python 3.6	/var/lang/python3/bin/python3.6
PHP 8.0	/var/lang/php80/bin/php
PHP 7.4	/var/lang/php74/bin/php
PHP 7.2	/var/lang/php7/bin/php
Java 11	/var/lang/java11/bin/java
Java 8	/var/lang/java8/bin/java

Startup Command Templates

Node.js

Functions Framework (Recommended)

#!/bin/bash
node node_modules/@cloudbase/functions-framework/bin/tcb-ff.js --port=9000 --logDirname=/tmp/logs --interceptOutput=false --extendedContextKey=X-Cloudbase-Context

Parameter Description:

Parameter	Description	Default Value
--port	Function listening port	9000
--logDirname	Log storage directory	/tmp/logs
--interceptOutput	Whether to intercept standard output	false
--extendedContextKey	Extended context request header key	X-Cloudbase-Context

💡 Tip: You need to install the @cloudbase/functions-framework dependency in package.json.

Express Framework

#!/bin/bash
export PORT=9000
/var/lang/node18/bin/node app.js

📝 Note: Please change app.js to your actual startup filename.

Next.js Framework

#!/bin/bash
export PORT=9000
/var/lang/node18/bin/node node_modules/next/dist/bin/next start

Python

Flask Framework

#!/bin/bash
export PORT=9000
/var/lang/python3/bin/python3 app.py

📝 Note: Please change app.py to your actual startup filename.

Django Framework

#!/bin/bash
export PORT=9000
/var/lang/python3/bin/python3 manage.py runserver 0.0.0.0:9000

FastAPI Framework

#!/bin/bash
export PORT=9000
/var/lang/python3/bin/python3 -m uvicorn main:app --host 0.0.0.0 --port 9000

📝 Note: Please change main in main:app to your application filename, and app to your application instance name.

PHP

Built-in Web Server

#!/bin/bash
/var/lang/php7/bin/php -c /var/runtime/php7 -S 0.0.0.0:9000 hello.php

📝 Note: Please change hello.php to your entry filename.

Laravel Framework

#!/bin/bash
/var/lang/php7/bin/php artisan serve --host=0.0.0.0 --port=9000

Java

Spring Boot

#!/bin/bash
export PORT=9000
/var/lang/java8/bin/java -Dserver.port=${PORT} -jar target/my-app.jar

📝 Note: Please change my-app.jar to your actual JAR filename.

Go

Standard HTTP Server

#!/bin/bash
export PORT=9000
./main

📝 Note: Please ensure the executable file main has been compiled.

Gin Framework

#!/bin/bash
export PORT=9000
./app

📝 Note: Please change app to your actual executable filename.

Related Documentation

• Writing HTTP Cloud Functions
• Cloud Function Type Selection
• Node.js HTTP Cloud Function Quick Start
• Python HTTP Cloud Function Quick Start
• Go HTTP Cloud Function Quick Start
• Java HTTP Cloud Function Quick Start
• Functions Framework Quick Start