In Function Compute, you can use a function to call database APIs to insert or query data. In most cases, instance status is not shared among different execution environments in Function Compute. You can persist structured data in a database to share instance status. This topic uses Python 3 as an example to describe how to use Serverless Devs to deploy a function to access an ApsaraDB for Redis database.

Prerequisites

  • Create an ApsaraDB for Redis instance.
    Notice
    • Make sure that the database instance you created is in the same region as the function that needs to access the database instance.

    • We recommend that you create the database instance in a zone that supports Function Compute.

      If your resources are not deployed in the zones shown in the following list, create a vSwitch in your virtual private cloud (VPC). The vSwitch must be in the same zone as Function Compute. Also, you must specify the vSwitch ID when you configure the VPC for Function Compute. vSwitches in the same VPC can communicate with each other over the private network. Therefore, Function Compute can use the vSwitch to access resources in the VPC that reside in other zones. For more information, see How can I resolve the "vSwitch is in unsupported zone" error?.

      Region Region ID Zones supported by Function Compute
      China (Hangzhou) cn-hangzhou cn-hangzhou-f, cn-hangzhou-g, cn-hangzhou-h
      China (Shanghai) cn-shanghai cn-shanghai-b, cn-shanghai-e, cn-shanghai-g, cn-shanghai-f
      China (Qingdao) cn-qingdao cn-qingdao-c
      China (Beijing) cn-beijing cn-beijing-h, cn-beijing-c, cn-beijing-e, cn-beijing-f
      China (Zhangjiakou) cn-zhangjiakou cn-zhangjiakou-b, cn-zhangjiakou-a
      China (Hohhot) cn-huhehaote cn-huhehaote-a, cn-huhehaote-b
      China (Shenzhen) cn-shenzhen cn-shenzhen-e, cn-shenzhen-d
      China (Chengdu) cn-chengdu cn-chengdu-a, cn-chengdu-b
      China (Hong Kong) cn-hongkong cn-hongkong-c
      Singapore (Singapore) ap-southeast-1 ap-southeast-1a, ap-southeast-1b
      Australia (Sydney) ap-southeast-2 ap-southeast-2a, ap-southeast-2b
      Malaysia (Kuala Lumpur) ap-southeast-3 ap-southeast-3a
      Indonesia (Jakarta) ap-southeast-5 ap-southeast-5a, ap-southeast-5b
      Japan (Tokyo) ap-northeast-1 ap-northeast-1b, ap-northeast-1a
      UK (London) eu-west-1 eu-west-1a
      Germany (Frankfurt) eu-central-1 u-central-a, eu-central-1a, eu-central-1b
      US (Silicon Valley) us-west-1 us-west-1a, us-west-1b
      US (Virginia) us-east-1 us-east-1b, us-east-1a
      India (Mumbai) ap-south-1 ap-south-1a, ap-south-1b
  • Install Serverless Devs and Docker.
  • Configure Serverless Devs
  • Create a security group

    Create a default security group in the VPC where the database instance is deployed. If you want to use an existing security group, make sure that the security group allows outbound traffic to the ports and private CIDR blocks of the database instance. By default, the security group allows all outbound traffic.

Configure the whitelist for the database

In ApsaraDB for Redis, you can add IP addresses to the whitelist or specify security groups to access the database. We recommend that you add IP addresses to the whitelist to access the database.

  1. Log on to the ApsaraDB for Redis console.
  2. In the top navigation bar of the page, select the region in which the instance is deployed.
  3. On the Instances page, click the ID of the instance.
  4. In the left-side navigation pane, click Whitelist Settings.
  5. Find the whitelist group that you want to modify and click Modify.
    Notice The IP address that you want to specify must be the CIDR block of the vSwitch that you added in the network configuration of Function Compute.
  6. Click OK.

Deploy and invoke functions

  1. Initialize a project.
    s init start-fc-redis-python -d start-fc-redis-python
  2. Access the project.
    cd start-fc-redis-python
  3. Edit the s.yaml file.

    Example:

    edition: 1.0.0         
    name: fcDeployApp       
    access: "default"  
    
    services:
      fc-db-redis-python: 
        component: devsapp/fc  
        props: 
          region: cn-hangzhou
          service:
            name: fc-db-demo
            description: 'demo for fc visit db'
            internetAccess: true
            vpcConfig:
              vpcId: vpc-bp1hcg467ekqsv0zr**** # The ID of the VPC where the database instance resides. 
              securityGroupId: sg-bp1gg2tyyzuvz8x0**** # The ID of the security group. 
              vswitchIds:
                - vsw-bp1sciqyju9qxocys**** # Make sure that the CIDR block of the vSwitch is added to the whitelist of the database instance. 
          function:
            name: redis
            description: visit redis
            runtime: python3
            codeUri: ./code
            handler: index.handler
            memorySize: 256
            timeout: 30
            initializationTimeout: 60
            initializer: index.initializer
            environmentVariables:
              REDIS_HOST: r-bp1v04cjj0jlr7****.redis.rds.aliyuncs.com # The private IP address of the database instance. 
              REDIS_PASSWORD: Hangzhou**** # The password of the database instance. 
              REDIS_PORT: 63** # The private port of the database instance. 
  4. Run the following command to build the project.
    s build --use-docker
  5. Run the following command to deploy the project.
    s deploy -y
  6. Run the following command to invoke a function.
    s invoke -e "{}"

    The expected command output is as follows:

    [2021-09-14T17:08:50.875] [INFO ] [S-CLI] - Start ...
    ========= FC invoke Logs begin =========
    FC Initialize Start RequestId: ccd73383-048d-4c8d-834e-93da59b86a21
    FC Initialize End RequestId: ccd73383-048d-4c8d-834e-93da59b86a21
    FC Invoke Start RequestId: eccafc0a-493e-4f3e-9afa-45c0b84a2c0f
    counter: 0
    FC Invoke End RequestId: eccafc0a-493e-4f3e-9afa-45c0b84a2c0f
    
    Duration: 27.51 ms, Billed Duration: 28 ms, Memory Size: 256 MB, Max Memory Used: 34.05 MB
    ========= FC invoke Logs end =========
    
    FC Invoke Result:
    0
    
    
    End of method: invoke

What to do next

Collection of cases to access the database instance by using Function Compute