Access an ApsaraDB for Redis database

Write code for 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 Redis service
         Policies:
           - AliyunECSNetworkInterfaceManagementAccess
         VpcConfig:
           VpcId: vpc-xxxx
           VSwitchIds:
             - vsw-xxxx
           SecurityGroupId: sg-xxxx
         InternetAccess: true
       function:
         Type: 'Aliyun::Serverless::Function'
         Properties:
           Initializer: 'index.initializer'
           Handler: 'index.handler'
           Runtime: python3
           CodeUri: '. /'
           EnvironmentVariables:
             REDIS_HOST: r-xxxx.redis.rds.aliyuncs.com
             REDIS_PASSWORD: Txd1xxxx
             REDIS_PORT: '6379'

   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.

     • EnvironmentVariables: the environment variables of the function.
       • REDIS_HOST: the internal endpoint of the ApsaraDB for Redis instance.

         To find the internal endpoint, log on to the ApsaraDB for Redis console and open the Instance Information page for the target instance. In the Connection Information section, check the value of Internal Endpoint (Host).

       • REDIS_PASSWORD: the password for logging on to the ApsaraDB for Redis database.
       • REDIS_PORT: the port used to connect to the ApsaraDB for Redis database.

   For more information about configuration rules, see Serverless Application Model.

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 redis                        

3. Run the fun install command to install dependencies.

   fun install

   using template: template.yml
   start installing function dependencies without docker
   
   building service/function
   Funfile exist, Fun will use container to build forcely
   Step 1/2 : FROM registry.cn-beijing.aliyuncs.com/aliyunfc/runtime-python3.6:build-1.7.7
   ---> 373f5819463b
   Step 2/2 : RUN fun-install pip install redis
   ---> Running in f26aef48f9e5
   Task => PipTask
        => PYTHONUSERBASE=/code/.fun/python pip install --user redis
   Removing intermediate container f26aef48f9e5
   ---> 809c6655f9e9
   sha256:809c6655f9e93d137840b1446f46572fbab7548c5c36b6ae66599dfc2e27555b
   Successfully built 809c6655f9e9
   Successfully tagged fun-cache-78c74899-5497-4205-a670-24e4daf88284:latest
   copying function artifact to /Users/txd123/Desktop/Redis/Python
   
   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:

   # -*- coding: utf-8 -*-
   import os,sys
   import redis
   def initializer(context):
       global conn_pool
       conn_pool=redis.ConnectionPool(host=os.environ['REDIS_HOST'],password=os.environ['REDIS_PASSWORD'],port=os.environ['REDIS_PORT'],db=1,decode_responses=True)
   
   def handler(event, context):
       r = redis.Redis(connection_pool=conn_pool)
       r.set('test','89898')
       r.set('zyh_info','{"name":"Tanya","password":"123456","account":11234}')
       print(r.get('test'))
       return r.get('zyh_info')                       

5. Run the following command to deploy the function to Function Compute by using Funcraft:

   fun deploy

   using template: template.yml
   using region: cn-hangzhou
   using accountId: ***********3743
   using accessKeyId: ***********Ptgk
   using timeout: 60
   
   Waiting for service service to be deployed...
           Waiting for function function to be deployed...
                   Waiting for packaging function function code...
                   The function function has been packaged. A total of 25 files files were compressed and the final size was 138.78 KB
           function function deploy success
   service service deploy success                       

Debug the function

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 Services and Functions.
4. In the Services pane, click the service that you require. On the Functions tab, click the name of the function that you require.
   
5. On the page that appears, click the Code tab. On the Code tab, click Invoke.
   After the execution is complete, you can view the execution results and logs.