Building Application

Last updated: 2021-01-18 14:07:54

    Overview

    After Serverless Framework is installed, you can initialize a project template and build a multiple-component application as instructed in this document.

    Prerequisites

    You have installed Serverless Framework.

    Directions

    Initializing project template

    You can quickly initialize a demo project by running the following command and modify it for further development:

    sls init scf-demo

    This command can quickly build a basic function application locally with the following directory structure:

    .
    ├── serverless.yml  # Configuration file
    └── src
       └── index.js # Entry function

    You can enter this directory and develop your project based on the demo template.

    Note:

    sls init can quickly initialize multiple project templates. You can run the sls registry command to view all supported project templates.

    Building multiple-component application

    Serverless Framework provides multiple basic resource components, which you can mix and use to quickly create and deploy resources in the cloud, thus eliminating the need for manual operations in the console.

    This document uses deploying a function project triggered by a COS trigger as an example to describe how to import multiple components into your project and quickly complete the deployment. The steps are as follows:

    1. Adjust the structure of the project directory, create a COS folder, and write the configuration file serverless.yml for the COS component in this directory. The adjusted structure of the directory is as follows:
      .
      ├── src
      │   ├── serverless.yml # Function configuration file
      │   └── index.js # Entry function
      ├── cos
      │   └── serverless.yml # COS bucket configuration file
      └── .env # Environment variable file

    A sample .yml file for the COS component is provided below. For more information on all configuration items, please see COS Component Configuration.

    app: appDemo
    stage: dev
    component: cos
    name: cosdemo
    inputs:
      bucket: my-bucket
      region: ap-guangzhou
    1. Modify the .yml configuration file for the SCF project and impot the deployment result of the COS component according to the following syntax in the trigger configuration part:

      app: appDemo
      stage: dev
      component: scf
      name: scfdemo
      inputs:
      ...
      events:
      - cos: # COS trigger
           parameters:
             bucket: ${output:${stage}:${app}:cosdemo.bucket}

      Note:

      When deploying multiple component instances in the same project, you need to make sure that the app and stage parameters of each project are the same; otherwise, they cannot be successfully imported.

    2. In the project root directory, run sls deploy to complete COS bucket creation and use the output of the COS component as the input of the SCF component to configure the trigger.

    Variable import description

    serverless.yml supports multiple ways to import variables:

    • Import top-level parameters
      In the inputs field, you can directly import top-level configuration information through the ${org} and ${app} syntax.

    • Import environment variables
      In serverless.yml, you can directly import the environment variable configuration (including the environment variable configuration in the .env file and variable parameters manually configured in the environment) through the ${env} syntax.
      For example, you can import the environment variable REGION through ${env:REGION}.

    • Import the output results of other components
      If you want to import the output information of other component instances into the current component configuration file, you can configure it by using the following syntax: ${output:[app]:[stage]:[instance name].[output]}

    Sample .yml file:

    org: xxx
    app: demo
    component: scf
    name: rest-api
    stage: dev
    inputs:
      name: ${org}-${stage}-${app}-${name} # The final name is "acme-prod-ecommerce-rest-api"
      region: ${env:REGION} # `REGION=` information specified in the environment variable
      vpcName: ${output:prod:my-app:vpc.name} # Get the output information of other components
      vpcName: ${output:${stage}:${app}:vpc.name} # The above methods can also be used in combination

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