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. If you want to share instance status, you need to store structured data in a database. This topic describes how to deploy a function to access an ApsaraDB RDS for PostgreSQL database by using Serverless Devs. Python 3 is used in this topic


  • Create an ApsaraDB RDS for PostgreSQL instance
    • Make sure that the database instance that you create 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 Function Compute supports. For more information about the message routing feature, see Zones where Function Compute is available.

      If your database instance is not deployed in a zone that is supported by Function Compute, create a vSwitch in your VPC. The vSwitch must be in the same zone as Function Compute. In addition, you must specify the vSwitch ID in the VPC configuration of the specified service in 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 VPCs that reside in other zones. For more information, see How can I resolve the "vSwitch is in unsupported zone" error?.

  • A table named COMPANY is created and the ID, NAME, AGE, ADDRESS, and SALARY columns are inserted into the table.

    In this example, the s init command is used to insert a data entry into the COMPANY table. The schema of the table contains the ID, NAME, AGE, ADDRESS, and SALARY columns. You must create the table and the columns in advance.

Step 1: Configure the IP address whitelist for the database

We recommend that you use an IP address whitelist, instead of a security group, for secure access. Otherwise, the function connection may be unstable, which affects your business.

  1. Go to the Instances page. In the top navigation bar, select the region in which the RDS instance resides. Then, find the RDS instance and click the ID of the instance.
  2. In the left-side navigation pane, click Whitelists and SecGroup.
    On the Whitelist Settings tab, you can view the mode of the IP address whitelist.
    Note Existing RDS instances may run in enhanced whitelist mode. All new RDS instances run in standard whitelist mode.
  3. On the Whitelist Settings tab that appears, find the default whitelist group and click Modify.
  4. In the Edit Whitelist dialog box, configure IP Addresses and click OK.
    Important You must specify an IP address that belongs to the CIDR block of the vSwitch that you add when you configure the network for Function Compute.

Step 2: Deploy and invoke the function

  1. Install Serverless Devs and Docker and add a key.
    For more information, see Install Serverless Devs and Docker and Add a key.
  2. Initialize a project.
    s init start-fc-postgresql-python -d start-fc-postgresql-python
  3. Access the project.
    cd start-fc-postgresql-python
  4. Edit the s.yaml file.

    The following sample code provides a configuration example:

    edition: 1.0.0         
    name: fcDeployApp       
    access: "default"  
        component: devsapp/fc  
          region: cn-hangzhou
            name: fc-db-demo
            description: 'demo for fc visit db'
            internetAccess: true
              vpcId: vpc-bp1hcg467ekqsv0zr**** # The ID of the virtual private cloud (VPC) in which the database instance resides. 
              securityGroupId: sg-bp1j6knvj40yjn0g**** # The ID of the security group. 
                - vsw-bp1lgecrqfslgji9b**** # Make sure that the CIDR block of the vSwitch is added to the whitelist of the database instance. 
            name: postgresql
            description: visit postgresql
            runtime: python3
            codeUri: ./code
            handler: index.handler
            memorySize: 256
            timeout: 30
              DATABASE: post**** # The name of the database. 
              HOST: pgm-bp1n6g63x0xdb7oy16**** # The endpoint of the database. 
              PORT: 19** # The port of the database. 
              USER: ni**** # The username of the database. 
              PASSWORD: Hang**** # The password of the database. 
  5. Run the following command to build the project:
    s build --use-docker
  6. Run the following command to deploy the project:
    s deploy -y
  7. Run the following command to invoke a function:
    s invoke -e "{}"

    Expected command output:

    [2021-09-23T11:03:17.792] [INFO ] [S-CLI] - Start ...
    ========= FC invoke Logs begin =========
    FC Invoke Start RequestId: 7e6657d4-504a-4faa-8f59-5464df73aa65
    FC Invoke End RequestId: 7e6657d4-504a-4faa-8f59-5464df73aa65
    Duration: 101.87 ms, Billed Duration: 102 ms, Memory Size: 256 MB, Max Memory Used: 35.08 MB
    ========= FC invoke Logs end =========
    FC Invoke Result:
    End of method: invoke

Sample code

Access a PostgreSQL database in a Python runtime of Function Compute