#author("2018-09-09T15:06:54+00:00","","")
[[AWSメモ]] >
* PythonでAWS DynamoDBのCRUDを書いてみる [#w8a52561]
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#contents
-- 関連
--- [[AWS Java SDKでDynamoDBのCRUDを書いてみる]]

** 概要 [#xd911e47]
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Python で DynamoDB へのCRUDを書いてみる。

尚、今回は GET、POST、PUT、DELETE ハンドラーをそれぞれ別々に作成する。
https://github.com/awslabs/serverless-application-model/tree/master/examples/2016-10-31/api_backend

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** 参考 [#h78b1d6b]
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http://docs.aws.amazon.com/ja_jp/amazondynamodb/latest/developerguide/GettingStarted.Python.03.html
http://boto3.readthedocs.io/en/latest/reference/services/dynamodb.html
http://boto3.readthedocs.io/en/latest/guide/dynamodb.html
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** テーブル作成 [#z86e5b6a]

*** テーブル定義の作成 [#ka94cfa2]
ddl/books.json
#mycode2(){{
{
    "TableName": "Books",
    "AttributeDefinitions": [
        { "AttributeName": "id", "AttributeType": "S" },
        { "AttributeName": "isbn", "AttributeType": "S" },
        { "AttributeName": "title", "AttributeType": "S" }
    ],  
    "KeySchema": [
        { "AttributeName": "id", "KeyType": "HASH" }
    ],  
    "ProvisionedThroughput": { "WriteCapacityUnits": 1, "ReadCapacityUnits": 1 },
    "GlobalSecondaryIndexes": [
        {
            "IndexName": "isbn-index",
            "KeySchema": [
                { "AttributeName":"isbn", "KeyType":"HASH" }
            ],
            "Projection": {"ProjectionType": "KEYS_ONLY" },
            "ProvisionedThroughput": {"ReadCapacityUnits": 1,"WriteCapacityUnits": 1 } 
        },
        {
            "IndexName": "title-index",
            "KeySchema": [
                { "AttributeName":"title", "KeyType":"HASH" }
            ],
            "Projection": {"ProjectionType": "KEYS_ONLY" },
            "ProvisionedThroughput": {"ReadCapacityUnits": 1,"WriteCapacityUnits": 1 } 
        }
    ]   
}
}}

*** テーブル作成 [#efb826d2]

#myterm2(){{
aws dynamodb create-table  --endpoint-url http://localhost:8000  --cli-input-json file://ddl/books.json
}}
※ローカルのDynamoDBでない場合は --endpoint-url は不要。

** Lambda関数の作成 [#z5c813af]
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book.js
#mycode2(){{
import os
import boto3
import json
import decimal

dynamodb = None
if os.environ and os.environ["DYNAMO_REGION"] and os.environ["DYNAMO_END_POINT"]:
    dynamodb = boto3.resource('dynamodb', region_name=os.environ["DYNAMO_REGION"], endpoint_url=os.environ["DYNAMO_END_POINT"])
else:
    dynamodb = boto3.resource('dynamodb', dynamo_opt)
dynamo_opt = {}
if os.environ and os.environ["DYNAMO_REGION"] and os.environ["DYNAMO_ENDPOINT"]:
    dynamo_opt['region_name'] = os.environ['DYNAMO_REGION']
    dynamo_opt['endpoint_url'] = os.environ['DYNAMO_ENDPOINT']
dynamodb = boto3.resource('dynamodb', **dynamo_opt)

# テーブル名
TABLE_NAME = "Books"

# 一覧
def list(event, context):
    res = dynamodb.Table(TABLE_NAME).scan()
    return { 'body' : str(res) }

# 一意検索
def get(event, context):
    res = dynamodb.Table(TABLE_NAME).get_item(
        Key={
            "id" : event["pathParameters"]["id"]
        }   
    )   
    return { 'body' : str(res) }

# 登録
def create(event, context):
    req = json.loads(event["body"]) if type(event["body"]) == str else event["body"]
    res = dynamodb.Table(TABLE_NAME).put_item(
        Item={
            "id": req["id"],
            "isbn": req["isbn"],
            "title": req["title"],
            "price": decimal.Decimal(req["price"])
        }   
    )
    return { 'body' : str(res) }

# 更新
def update(event, context):
    req = json.loads(event["body"]) if type(event["body"]) == str else event["body"]
    res = dynamodb.Table(TABLE_NAME).update_item(
        Key={
            'id': event["pathParameters"]["id"]
        },  
        UpdateExpression="set isbn=:i, title=:t, price=:p",
        ExpressionAttributeValues={
            ':i': req["isbn"],
            ':t': req["title"],
            ':p': decimal.Decimal(req["price"])
        },  
        ReturnValues="UPDATED_NEW"
    )
    return { 'body' : str(res) }

# 削除
def delete(event, context):
    res = dynamodb.Table(TABLE_NAME).delete_item(
        Key={
            'id': event["pathParameters"]["id"]
        }
    )
    return { 'body' : str(res) }

}}
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** template.yml の作成 [#fa6a8b2f]
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template-local.yml 
#mycode2(){{

AWSTemplateFormatVersion : '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: Test serverless application.

Resources:

  BookListFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: book.list
      Policies: AmazonDynamoDBFullAccess
      Runtime: python3.6
      MemorySize: 128 
      Timeout: 5
      Environment:
        Variables:
          DYNAMO_END_POINT: http://10.20.30.40:8000
          DYNAMO_ENDPOINT: http://10.20.30.40:8000
          DYNAMO_REGION: localhost
      Events:
        List:
          Type: Api 
          Properties:
            Path: /book
            Method: get 

  BookGetFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: book.get
      Policies: AmazonDynamoDBFullAccess
      Runtime: python3.6
      MemorySize: 128 
      Timeout: 5
      Environment:
        Variables:
          DYNAMO_END_POINT: http://10.20.30.40:8000
          DYNAMO_ENDPOINT: http://10.20.30.40:8000
          DYNAMO_REGION: localhost
      Events:
        Get:
          Type: Api 
          Properties:
            Path: /book/{id}
            Method: get 

  BookCreateFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: book.create
      Policies: AmazonDynamoDBFullAccess
      Runtime: python3.6
      MemorySize: 128 
      Timeout: 5
      Environment:
        Variables:
          DYNAMO_END_POINT: http://10.20.30.40:8000
          DYNAMO_ENDPOINT: http://10.20.30.40:8000
          DYNAMO_REGION: localhost
      Events:
        Create:
          Type: Api 
          Properties:
            Path: /book
            Method: post

  BookUpdateFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: book.update
      Policies: AmazonDynamoDBFullAccess
      Runtime: python3.6
      MemorySize: 128
      Timeout: 5
      Environment:
        Variables:
          DYNAMO_END_POINT: http://10.20.30.40:8000
          DYNAMO_ENDPOINT: http://10.20.30.40:8000
          DYNAMO_REGION: localhost
      Events:
        Update:
          Type: Api
          Properties:
            Path: /book/{id}
            Method: put

  BookDeleteFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: book.delete
      Policies: AmazonDynamoDBFullAccess
      Runtime: python3.6
      MemorySize: 128
      Timeout: 5
      Environment:
        Variables:
          DYNAMO_END_POINT: http://10.20.30.40:8000
          DYNAMO_ENDPOINT: http://10.20.30.40:8000
          DYNAMO_REGION: localhost
      Events:
        Delete:
          Type: Api
          Properties:
            Path: /book/{id}
            Method: delete
}}
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** sam local 上で api を起動 [#h62ee7e2]
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[[AWS Lambda のローカル開発手順]] も参照
#myterm2(){{
sam local start-api --template template-local.yml 
}}

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** 動作確認 [#w02ea84b]
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*** 一覧 [#kbd7d608]
#myterm2(){{
curl http://localhost:3000/book
}}

*** 登録 [#v74ca8c9]
#myterm2(){{
curl -XPOST -H 'Content-type: application/json' --data '{ "id" : "A01", "isbn" : "ABC001", "title" : "テスト001", "price": 1008 }' http://localhost:3000/book
curl -XPOST -H 'Content-type: application/json' --data '{ "id" : "A02", "isbn" : "ABC002", "title" : "テスト002", "price": 2016 }' http://localhost:3000/book
}}

*** 更新 [#l6c32025]
#myterm2(){{
curl -XPUT -H 'Content-type: application/json' --data '{ "isbn" : "XXXXX1", "title" : "テストXX1", "price": 108 }' http://localhost:3000/book/A01
}}

*** 削除 [#badccae6]
#myterm2(){{
curl -XDELETE http://localhost:3000/book/A01
}}

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