Create a zip deployment package using Gradle

This section describes a way to create a Java-type SCF function deployment package using Gradle. As long as the created zip package conforms to the following rules, it can be recognized and called by the SCF runtime environment.

• The compiled package, class files and resource files are located in the root directory of the zip package.
• The jar package required by the dependencies is located in the /lib directory.

Environment Preparations

Make sure that you have Java and Gradle installed. For the Java version, please use JDK 8. You can download and install the JDK appropriate for your system using OpenJDK (Linux) or at www.java.com.

Install Gradle

The specific installation instructions can be found at https://gradle.org/install/. The following describes how to manually install it:

1. Download Gradle's binary package or full package with documentation and source code.

2. Unzip the package to a desired directory, such as C:\Gradle (Windows) or /opt/gradle/gradle-4.1 (Linux).

3. Add the path to the bin directory in the unzipped directory to the system PATH environment variable. To do so on Linux, use export PATH=$PATH:/opt/gradle/gradle-4.1/bin; on Windows, right click Computer and select Properties > Advanced system settings > Advanced > Environment Variables, select the Path variable, click Edit, and add ;C:\Gradle\bin; at the end of the variable value.

4. Verify that there is an output similar to the one below by executing gradle -v in the command line to prove that Gradle is properly installed. If you have any questions, please see Gradle's official documentation.

    ------------------------------------------------------------
    Gradle 4.1
    ------------------------------------------------------------
   
    Build time:   2017-08-07 14:38:48 UTC
    Revision:     941559e020f6c357ebb08d5c67acdb858a3defc2
   
    Groovy:       2.4.11
    Ant:          Apache Ant(TM) version 1.9.6 compiled on June 29 2015
    JVM:          1.8.0_144 (Oracle Corporation 25.144-b01)
    OS:           Windows 7 6.1 amd64

Code Preparations

Prepare the code file

Create a project folder in the selected location, such as scf_example. In the root directory of the project folder, create a directory src/main/java/ as the directory where the package is stored. Create the example package directory in the created directory and then create a Hello.java file in the package directory. Finally, the following directory structure is formed:
scf_example/src/main/java/example/Hello.java

Enter the code content in the Hello.java file:

package example;

public class Hello {
    public String mainHandler(String name, Context context) {
        System.out.println("Hello world!");
        return String.format("Hello %s.", name);
    }
}

Prepare the compilation file

Create a build.gradle file in the root directory of the project folder and enter the following content:

apply plugin: 'java'

task buildZip(type: Zip) {
    from compileJava
    from processResources              
    into('lib') {
        from configurations.runtime
    }           
}

build.dependsOn buildZip

Use the Maven Central library to handle package dependencies

If you need to reference the external package of Maven Central, you can add dependencies as needed. The content of the build.gradle file is as follows:

apply plugin: 'java'

repositories {
    mavenCentral()
}

dependencies {
    compile (
        'com.qcloud:qcloud-java-sdk:2.0.1'
    )
}

task buildZip(type: Zip) {
    from compileJava
    from processResources              
    into('lib') {
        from configurations.runtime
    }           
}

build.dependsOn buildZip

After "repositories" is used to indicate that the dependency library source is mavenCentral, Gradle will pull the dependencies from Maven Central during compilation, i.e., the com.qcloud:qcloud-scf-java-events:1.0.0 package specified in "dependencies".

Use a local Jar package library to handle package dependencies

If you have already downloaded the Jar package locally, you can use the local library to handle package dependencies. In this case, create a jars directory in the root directory of the project folder and place the downloaded dependency Jar package in this directory. The content of the build.gradle file is as follows:

apply plugin: 'java'

dependencies {
    compile fileTree(dir: 'jars', include: '*.jar')
}

task buildZip(type: Zip) {
    from compileJava
    from processResources              
    into('lib') {
        from configurations.runtime
    }
}

build.dependsOn buildZip

After "dependencies" is used to indicate that the search directory is the *.jar file in the jars directory, the dependencies will be automatically searched for during compilation.

Compiling and Packaging

Execute the command gradle build in the root directory of the project folder, and the compilation output should be like the example below:

Starting a Gradle Daemon (subsequent builds will be faster)

BUILD SUCCESSFUL in 5s
3 actionable tasks: 3 executed

If a compilation failure is displayed, adjust the code based on the outputted compilation error message.
The compiled zip package is located in the /build/distributions directory of the project folder and named scf_example.zip after the project folder.

Using the Function

After the zip package is generated after compilation and packaging, when creating or modifying a function, you can upload the package (if less than 10 MB) through the page or upload it (if bigger) to a COS bucket and then update it into the function through COS upload.