Serverless - Triển khai ứng dụng với SAM > Thiết Lập APIs Và Lambda Function

Thiết Lập APIs Và Lambda Function

Thêm đoạn code sau vào của tệp template.yaml trong sam project. Đoạn code mô tả một bảng DynamoDB với Partition key là id của user và Sort keylà tên tệp.

  # Create a table to storage document informations
  DocsTable:
    Type: AWS::DynamoDB::Table
    Properties:
      TableName: Documents
      BillingMode: PAY_PER_REQUEST
      AttributeDefinitions:
        - AttributeName: user_id
          AttributeType: S
        - AttributeName: file
          AttributeType: S
      KeySchema:
        - AttributeName: user_id
          KeyType: HASH
        - AttributeName: file
          KeyType: RANGE
      StreamSpecification:
        StreamViewType: NEW_IMAGE

  # Create a table to storage general informations
  GeneralTable:
    Type: AWS::DynamoDB::Table
    Properties:
      TableName: General
      BillingMode: PAY_PER_REQUEST
      AttributeDefinitions:
        - AttributeName: id
          AttributeType: S
      KeySchema:
        - AttributeName: id
          KeyType: HASH

CreateLambda

Sao chép đoạn code sau vào tệp template.yaml để thiết lập 5 Lambda function là:
- upload_doc
- list_docs
- delete_doc
- upload_general_infor
- get_general_infor

  # Lambda function to scan all document by user id
  DocsList:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: lambda/list_docs
      Handler: list_docs.lambda_handler
      Runtime: python3.9
      FunctionName: list_docs
      Architectures:
        - x86_64
      Policies:
        - Statement:
            - Sid: ReadDynamoDB
              Effect: Allow
              Action:
                - dynamodb:Scan
                - dynamodb:Query
              Resource:
                - !GetAtt DocsTable.Arn
      Events:
        ListDocs:
          Type: Api
          Properties:
            Path: /docs/{id}
            Method: get
            RestApiId: !Ref DocApi
      Environment:
        Variables:
          TABLE_NAME: !Ref DocsTable

  # Lambda function to upload documents
  DocsUpload:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: lambda/upload_doc
      Handler: upload_doc.lambda_handler
      Runtime: python3.9
      FunctionName: upload_doc
      Architectures:
        - x86_64
      Policies:
        - Statement:
            - Sid: WriteToDynamoDB
              Effect: Allow
              Action:
                - dynamodb:PutItem
              Resource:
                - !GetAtt DocsTable.Arn
      Events:
        UpoadDocs:
          Type: Api
          Properties:
            Path: /docs
            Method: post
            RestApiId: !Ref DocApi
      Environment:
        Variables:
          TZ: Asia/Jakarta
          TABLE_NAME: !Ref DocsTable

  # Lambda function to delete documents by user id
  DocsDelete:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: lambda/delete_doc
      Handler: delete_doc.lambda_handler
      Runtime: python3.9
      FunctionName: delete_doc
      Architectures:
        - x86_64
      Policies:
        - Statement:
          - Sid: DeleteItems
            Effect: Allow
            Action:
              - dynamodb:DeleteItem
              - dynamodb:GetItem
              - dynamodb:Query
            Resource:
              - !GetAtt DocsTable.Arn
      Events:
        DeleteDoc:
          Type: Api
          Properties:
            Path: /docs/{id}
            Method: delete
            RestApiId: !Ref DocApi
      Environment:
        Variables:
          TABLE_NAME: !Ref DocsTable

  GeneralInforUpload:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: lambda/upload_general_infor
      Handler: upload_general_infor.lambda_handler
      Runtime: python3.9
      FunctionName: upload_general_infor
      Architectures:
        - x86_64
      Policies:
        - Statement:
          - Sid: DeleteItems
            Effect: Allow
            Action:
              - dynamodb:PutItem
            Resource:
              - !GetAtt GeneralTable.Arn
      Events:
        DeleteDoc:
          Type: Api
          Properties:
            Path: /docs/{id}/gen/
            Method: post
            RestApiId: !Ref DocApi
      Environment:
        Variables:
          TABLE_NAME: !Ref GeneralTable

  GeneralInforGet:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: lambda/get_general_infor
      Handler: get_general_infor.lambda_handler
      Runtime: python3.9
      FunctionName: get_general_infor
      Architectures:
        - x86_64
      Policies:
        - Statement:
          - Sid: DeleteItems
            Effect: Allow
            Action:
              - dynamodb:GetItem
              - dynamodb:Query
            Resource:
              - !GetAtt GeneralTable.Arn
      Events:
        DeleteDoc:
          Type: Api
          Properties:
            Path: /docs/{id}/gen/
            Method: get
            RestApiId: !Ref DocApi
      Environment:
        Variables:
          TABLE_NAME: !Ref GeneralTable

CreateLambda

Tải tệp sau về và thêm vào thư mục gốc của sam project. Tệp này mô tả các API mà chúng ta cần.

Swagger

swagger.yaml (6 ko)

CreateLambda

Thêm đoạn code sau vào cuối tệp template.yaml để import tệp swagger.yaml.

  # Create REST Api
  DocApi:
    Type: AWS::Serverless::Api
    Properties:
      StageName: dev
      DefinitionBody:
        'Fn::Transform':
          Name: 'AWS::Include'
          Parameters:
            Location: "./swagger.yaml"

CreateLambda

Tạo thư mục và tệp: lambda/list_docs/list_docs.py
Thêm code sau vào tệp list_docs.py

import json
import boto3
import os
from decimal import *
from boto3.dynamodb.types import TypeDeserializer

dynamodb = boto3.client('dynamodb') 
serializer = TypeDeserializer()

class DecimalEncoder(json.JSONEncoder):
    def default(self, obj):
        if isinstance(obj, Decimal):
            return str(obj)
        return json.JSONEncoder.default(self, obj)

def deserialize(data):
    if isinstance(data, list):
        return [deserialize(v) for v in data]

    if isinstance(data, dict):
        try:
            return serializer.deserialize(data)
        except TypeError:
            return {k: deserialize(v) for k, v in data.items()}
    else:
        return data
        
def lambda_handler(event, context):
    table_name = os.environ['TABLE_NAME']
    user_id = event['pathParameters']['id']
    print(user_id)
    docs = dynamodb.query(
        TableName=table_name,
        KeyConditionExpression="user_id = :id",
        ExpressionAttributeValues={ ":id": { 'S': user_id } }
    )
    
    format_data_docs = deserialize(docs["Items"])
    # TODO implement
    return {
        "statusCode": 200,
        "headers": {
            "Content-Type": "application/json",
            "Access-Control-Allow-Origin": "*",
            "Access-Control-Allow-Methods": "GET,PUT,POST,DELETE, OPTIONS",
            "Access-Control-Allow-Headers": "Access-Control-Allow-Headers, Origin,Accept, X-Requested-With, Content-Type, Access-Control-Request-Method,X-Access-Token,XKey,Authorization"
        },
        "body": json.dumps(format_data_docs, cls=DecimalEncoder)
    }

CreateLambda

Tương tự tạo thư mục và tệp upload_doc/upload_doc.py trong thư mục lambda. Tiếp theo sao chép code dưới đây cho tệp đã tạo.

import json
import boto3
import os
from datetime import datetime, timezone

dynamodb = boto3.resource('dynamodb')
client_cloudwatch = boto3.client('cloudwatch')

def lambda_handler(event, context):
    table_name = os.environ['TABLE_NAME']
    now = datetime.now(tz=timezone.utc)
    dt_string = now.strftime("%d/%m/%Y %H:%M:%S")
    doc_data = json.loads(event["body"])

    path = "protected/{}/{}".format(doc_data['identityId'], doc_data['file'])
    doc_data.update({"path": path, "modified": dt_string})
    table = dynamodb.Table(table_name)
    table.put_item(Item = doc_data)
        
    # TODO implement
    return {
        'statusCode': 200,
        'body': 'successfully upload!',
        'headers': {
            'Content-Type': 'application/json',
            "Access-Control-Allow-Headers": "Access-Control-Allow-Headers, Origin, Accept, X-Requested-With, Content-Type, Access-Control-Request-Method,X-Access-Token, XKey, Authorization",
            "Access-Control-Allow-Origin": "*",
            "Access-Control-Allow-Methods": "GET,PUT,POST,DELETE,OPTIONS"
        }
    }

CreateLambda

Tương tự với tệp lambda/delete_doc/delete_doc.py

import json
import boto3
import os

client = boto3.resource('dynamodb')

def lambda_handler(event, context):
    # TODO implement
    table_name = os.environ['TABLE_NAME']
    error = None
    doc_pk = event['pathParameters']['id']
    print("doc_pk ", doc_pk)
    doc_sk = event['queryStringParameters']['file']
    print("doc_sk ", doc_sk)
    table = client.Table(table_name)
    key = {
        'user_id':doc_pk,
        'file':  doc_sk
    }
    
    try:
        table.delete_item(Key = key)
    except Exception as e:
        error = e
        
        
    except Exception as e:
        error = e
        
    if error is None:
        message = 'successfully document item!'
    else:
        print(error)
        message = 'delete document fail'
    
    return {
            'statusCode': 200,
            'body': message,
            'headers': {
                'Content-Type': 'application/json',
                'Access-Control-Allow-Origin': '*'
            },
        }

CreateLambda

Tương tự với tệp lambda/upload_general_infor/upload_general_infor.py

import json
import boto3
import os

dynamodb = boto3.resource('dynamodb')

def lambda_handler(event, context):
    table_name = os.environ['TABLE_NAME']
    data = json.loads(event["body"])
    table = dynamodb.Table(table_name)
    data.update({"id": event['pathParameters']['id']})
    table.put_item(Item = data)

    # TODO implement
    return {
        'statusCode': 200,
        'body': 'successfully upload!',
        'headers': {
            'Content-Type': 'application/json',
            "Access-Control-Allow-Headers": "Access-Control-Allow-Headers, Origin, Accept, X-Requested-With, Content-Type, Access-Control-Request-Method,X-Access-Token, XKey, Authorization",
            "Access-Control-Allow-Origin": "*",
            "Access-Control-Allow-Methods": "GET,PUT,POST,DELETE,OPTIONS"
        }
    }

CreateLambda

Tương tự với tệp lambda/get_general_infor/get_general_infor.py

import json
import boto3
import os
from decimal import *
from boto3.dynamodb.types import TypeDeserializer

dynamodb = boto3.client('dynamodb') 
serializer = TypeDeserializer()
    
class DecimalEncoder(json.JSONEncoder):
    def default(self, obj):
        if isinstance(obj, Decimal):
            return str(obj)
        return json.JSONEncoder.default(self, obj)
        
def deserialize(data):
    if isinstance(data, list):
        return [deserialize(v) for v in data]

    if isinstance(data, dict):
        try:
            return serializer.deserialize(data)
        except TypeError:
            return {k: deserialize(v) for k, v in data.items()}
    else:
        return data
        
def lambda_handler(event, context):
    # TODO implement
    table_name = os.environ['TABLE_NAME']
    user_id = event['pathParameters']['id']
    print(user_id)
    data = dynamodb.query(
        TableName=table_name,
        KeyConditionExpression="id = :id",
        ExpressionAttributeValues={ ":id": { 'S': user_id } }
    )
    
    format_data = deserialize(data["Items"])

    return {
        "statusCode": 200,
        "headers": {
            "Content-Type": "application/json",
            "Access-Control-Allow-Origin": "*",
            "Access-Control-Allow-Methods": "GET,PUT,POST,DELETE, OPTIONS",
            "Access-Control-Allow-Headers": "Access-Control-Allow-Headers, Origin,Accept, X-Requested-With, Content-Type, Access-Control-Request-Method,X-Access-Token,XKey,Authorization"
        },
        "body": json.dumps(format_data, cls=DecimalEncoder)
        #"body": format_data
    }

CreateLambda

Chạy câu lệnh dưới đây để build và deploy sam project sau khi cập nhật template:

sam build
sam deploy

Trong lúc đợi CloudFormation hoàn thành, bạn có thể tìm hiểu về tệp swagger.yaml. Phần tiếp theo chúng ta sẽ thực hiện các thao tác trên Front-end để kiểm tra hoạt động của các API.