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python-3.xamazon-dynamodbserverless-application-model

Why is AWS SAM giving me random DynamoDB table names


When i use SAM to create my Lambda,API gateway and DynamoDB table it all works until i get to the actual created table. It is supposed to be called "List" however after the word "list" it gives me a bunch of random numbers and letters. What i want to do is when all 3 of the services are created they should talk to eachother however since i am getting this problem, I have to manually add the name to my function for it to work.

AWSTemplateFormatVersion: '2010-09-09'
Transform: 'AWS::Serverless-2016-10-31'
Resources:
  ClickSam:
    Type: 'AWS::Serverless::Function'
    Properties:
      Handler: app.lambda_handler
      Runtime: python3.8
      CodeUri: Lambda/
      MemorySize: 128
      Timeout: 3
      Environment:
        Variables:
          TABLE_NAME: !Ref List
          REGION_NAME: !Ref AWS::Region
      Events:
        ClickAPI:
          Type: Api
          Properties:
            Path: /visits
            Method: GET
      Policies:
        - DynamoDBCrudPolicy:
            TableName: !Ref List

List:
  Type: AWS::Serverless::SimpleTable
  Properties:
    PrimaryKey:
      Name: url
      Type: String

---------- This is my Lambda Function code to create items for the table.

import boto3
import json
def lambda_handler(event, context):
dynamodb = boto3.client('dynamodb')
response = dynamodb.update_item(
TableName='List', 
Key={
    'url':{'S': "etc.com"}
},
UpdateExpression='ADD visits :inc',
ExpressionAttributeValues={
    ':inc': {'N': '1'}
},
ReturnValues="UPDATED_NEW"
)

response = {
'statusCode': 200,
'headers': {
    "Content-Type" : "application/json",
    "Access-Control-Allow-Origin" : "*",
    "Allow" : "GET, OPTIONS, POST",
    "Access-Control-Allow-Methods" : "GET, OPTIONS, POST",
    "Access-Control-Allow-Headers" : "*"
},
'body': json.dumps(int(response["Attributes"]["visits"]["N"]))
}
return response

Solution

  • Use TableName parameter to fix the table name (cf. AWS::Serverless::SimpleTable).

    Type: AWS::Serverless::SimpleTable
    Properties:
      TableName: MyTable
    

    Documentation of the AWS::DynamoDB::Table resource :

    If you don't specify a name, AWS CloudFormation generates a unique physical ID and uses that ID for the table name.