无法使用 python 将数据插入 dynamodb

Question

I am new to the serverless framework and I am trying to put data into my dynamodb using python. But not able to insert the data. Even I am not getting any error.

I have tried all the setting for.yml file but no progress

.yml

provider:
  name: aws
  runtime: python3.7

  environment:
    DYNAMODB_TABLE: employee
  iamRoleStatements:
    - Effect: Allow
      Action:
        - dynamodb:Query
        - dynamodb:Scan
        - dynamodb:GetItem
        - dynamodb:PutItem
        - dynamodb:UpdateItem
        - dynamodb:DeleteItem
      Resource: "arn:aws:dynamodb:${opt:region, self:provider.region}:*:table/${self:provider.environment.DYNAMODB_TABLE}"

  stage: dev
  region: us-east-1


functions:
   create:
    handler: functions/create.create
    events:
     - http:
         path: employee
         method: post
         cors: true
         authorizer: aws_iam
   get:
    handler: functions/get.get
    events:
     - http:
         path: employee/{id}
         method: get
         cors: true
         authorizer: aws_iam

resources:
  Resources:
    employee:
      Type: 'AWS::DynamoDB::Table'
      DeletionPolicy: Retain
      Properties:
        AttributeDefinitions:
          - AttributeName: employeeId
            AttributeType: S
        KeySchema:
          - AttributeName: employeeId
            KeyType: HASH
        ProvisionedThroughput:
          ReadCapacityUnits: 1
          WriteCapacityUnits: 1
        TableName: ${self:provider.environment.DYNAMODB_TABLE}

.py file

import json
import os
import logging

import boto3
dynamodb = boto3.resource('dynamodb')

logger = logging.getLogger("handler_logger")
logger.setLevel(logging.DEBUG)

def create(event, context):
    data = json.loads(event['body'])

    table = dynamodb.Table(os.environ['DYNAMODB_TABLE'])
    logger.info(table)

    item = {
        'employeeId': "2",
        'employeeName': "Singhs",
    }

    # write the todo to the database
    table.put_item(Item=item)

    # create a response
    response = {
        "statusCode": 200,
        "body": json.dumps(item)
    }

    return response

Answer 1

I'm not sure why the insert isn't working, the code looks correct. You can get more info if you get the response from put_item though. For example:

    # write the todo to the database
    put_response = table.put_item(Item=item)

    # create a response
    response = {
        "statusCode": 200,
        "body": json.dumps(put_response)
    }

Answer 2

I've deployed your project and with just small modifications, it works. Means that basically your code is working but as there might be other problems like your iAM role, it would be better if you can provide the result of your POST request.

Mine is like below:

1. file structure - You're using functions/create.create so it may be different from yours but with given files, but just to make it work, I needed to make it as a simple serverless project.

.
├── serverless.yml
└── handler.py

2. serverless.yml - added 'service' property and removed your authorizer to call it without any authorization.

service: stack1
provider:
  name: aws
  runtime: python3.7

  environment:
    DYNAMODB_TABLE: employee
  iamRoleStatements:
    - Effect: Allow
      Action:
        - dynamodb:Query
        - dynamodb:Scan
        - dynamodb:GetItem
        - dynamodb:PutItem
        - dynamodb:UpdateItem
        - dynamodb:DeleteItem
      Resource: "arn:aws:dynamodb:${opt:region, self:provider.region}:*:table/${self:provider.environment.DYNAMODB_TABLE}"

  stage: dev
  region: us-east-1

functions:
  create:
    handler: handler.create
    events:
      - http:
        path: employee
        method: post
        cors: true
  get:
    handler: functions/get.get
    events:
      - http:
        path: employee/{id}
        method: get
        cors: true

resources:
  Resources:
    employee:
      Type: 'AWS::DynamoDB::Table'
      DeletionPolicy: Retain
        Properties:
          AttributeDefinitions:
            - AttributeName: employeeId
              AttributeType: S
          KeySchema:
            - AttributeName: employeeId
              KeyType: HASH
          ProvisionedThroughput:
            ReadCapacityUnits: 1
            WriteCapacityUnits: 1
          TableName: ${self:provider.environment.DYNAMODB_TABLE}

3. handler.py - same with your.py file.

4. result

~/prj/temp/stack> curl -X POST -H "Content-Type: application/json" -d "{}" https://u85k6*****.execute-api.us-east-1.amazonaws.com/dev/employee
{"employeeId": "2", "employeeName": "Singhs"}%

Suggestion

It seems like your code does not have any critical flaws but there're still bunch of points you can have errors from. These two suggestions might help:

1) Catch any exceptions and print out If you use functions like below, you can easily catch what happens there and hints for debugging.

import sys
import traceback
import os


def printException(exception, writer=None):
    if writer is None:
        writer = print
    top = traceback.extract_tb(sys.exc_info()[2])[-1]
    writer(", ".join([type(exception).__name__, str(sys.exc_info()[1]), os.path.basename(top[0]), str(top[1])]))```


if __name__ == "__main__":
    try:
        1/0 # just to raise an exception and see how this functions works
    except Exception as e:
        printException(e)

The exception will be printed so you can see it in your Cloudwatch logs.

2) Enable access logs and see logs in Cloudwatch - from serverless framework v1.42.0, you can enable access logs in the framework. Just set below properties:

...
provider:
  ...
  logs:
    restApi:
      level: INFO
...

Then you'll be easy to find any api endpoint-related error like authentication, validation or lambda response format errors.