In Function Compute, you can use a function to call the Lindorm API to perform operations such as insert and query on a Lindorm instance. In normal cases, states cannot be shared among different execution environments in Function Compute. You can persist structured data in a database so that states can be shared. This topic describes how to use Funcraft to deploy a function to access a Lindorm database.

Prerequisites

  1. You have created a virtual private cloud (VPC) and a VSwitch.

    The VSwitch must belong to a zone supported by Function Compute. For more information about the zones supported by Function Compute, see VPC access.

  2. A Lindorm instance that meets your business needs has been created.

    You have created a database instance in same VPC as Function Compute. You do not need to create the VSwitch in the same zone as Function Compute. VSwitches under the same VPC can communicate with each other even when they are in different zones.

  3. Configure a whitelist for an ApsaraDB RDS for PostgreSQL instance.

    If you need to control access to databases by using an IP address whitelist, ensure that you have entered the internal Classless Inter-Domain Routing (CIDR) blocks of the target VPCs in the IP field. To find the CIDR block of a VPC, log on to the VPC console and view the VPC Details page.

  4. Create a security group

    You have configured the security group to allow outbound traffic from the internal CIDR block and port of the database.

Write a function

The following section describes how to use Funcraft to write a function that accesses a database. The sample code is written in Python 3.

  1. On the local machine, create a directory to store code and dependent modules. In the directory, create the template.yml file. In this example, the /tmp/code/template.yml file is created and contains the following content:
    ROSTemplateFormatVersion: '2015-09-01'
    Transform: 'Aliyun::Serverless-2018-04-03'
    Resources:
      service:
        Type: 'Aliyun::Serverless::Service'
        Properties:
          Description: This is Lindorm service
          Policies:
            - AliyunECSNetworkInterfaceManagementAccess
          VpcConfig:
            VpcId: vpc-XXXX
            VSwitchIds:
              - vsw-XXX
            SecurityGroupId: sg-XXXX
          InternetAccess: true
        function:
          Type: 'Aliyun::Serverless::Function'
          Properties:
            Handler: 'index.handler'
            Runtime: python3
            Timeout: 100
            MemorySize: 1024
            CodeUri: '. /'

    The following list describes the main parameters:

    • A service named service is declared.
      • Policies: grants Function Compute permission to manage elastic network interfaces (ENIs) attached to Elastic Compute Service (ECS) instances. Function Compute can then access resources in the VPC.
      • VpcConfig: binds the VPC to the service. You must replace the following values with the information for your VPC.
        • VpcId: the ID of the VPC.
        • VSwitchId: the ID of the VSwitch.
        • SecurityGroupId: the ID of the security group.
    • A function named function is declared.
      • Initializer: the initializer function. For more information, see Initializer function.
      • Handler: the function handler. For more information, see Function entry point.
      • Runtime: the runtime environment of the function.
      • CodeUri: the directory where the code package is located.

        During function deployment, Funcraft packages and uploads the items in the directory specified by the CodeUri parameter.

  2. In the directory that contains the template.yml file, create the Funfile file. In this example, the new file contains the following sample content:
    RUNTIME python3
    RUN fun-install pip install cassandra-driver
  3. Run the fun install command to install dependencies.
    fun install
    When the code editor shows the following content, the dependencies have been installed.
    Install Success
  4. In the directory that contains the template.yml file, create a Python file. In this example, the /tmp/code/index.py file is created and contains the following sample content:
    Note You can log on to the Lindorm console, find the destination instance, and obtain the endpoint, username, and password on the Wide Table Engine tab of the Database Connection page.
    # -*- coding: utf-8 -*-
    import logging
    import sys
    from cassandra.cluster import Cluster
    from cassandra.auth import PlainTextAuthProvider
    
    logger = logging.getLogger()
    
    def handler(event, context):
        logger.info("start to test Lindorm ")
        cluster = Cluster(
            # Configure the endpoint.
            contact_points=["ld-bp10ljb1mxae5****-proxy-lindorm.lindorm.rds.aliyuncs.com"],
            # Configure the username and password.
            auth_provider=PlainTextAuthProvider("XXX", "XXX"))
        session = cluster.connect()
        session.execute("CREATE KEYSPACE IF NOT EXISTS testKeyspace WITH replication = {'class':'SimpleStrategy', 'replication_factor':1};");
        session.execute("CREATE TABLE IF NOT EXISTS testKeyspace.testTable (id int PRIMARY KEY, name text,age int,address text);");
        session.execute("INSERT INTO testKeyspace.testTable (id, name, age, address) VALUES ( 1, 'testname', 11, 'hangzhou');");
        rows = session.execute( "SELECT * FROM testKeyspace.testTable ;");
        for row in rows:
            logger.info("# row: {}".format(row))
    
        session.shutdown()
        cluster.shutdown()
  5. Run the following command to deploy the function to Function Compute by using Funcraft:
    fun deploy 
    When the code editor shows the following content, the function has been deployed.
            function <function-name> deploy success
    service <service-name> deploy success

    After the deployment is complete, log on to the and click Service/Function. On the page that appears, you can see the newly deployed service and function.

Debug a function

After the function is deployed, you can debug it in the Function Compute console.

  1. Log on to the Function Compute console.
  2. In the top navigation bar, select a region.
  3. In the left-side navigation pane, click Service/Function.
  4. Find the required function in the required service and click the name of the function.
  5. On the Code tab, click Invoke.
    After the execution is complete, you can view the execution results and logs.lindorm-result