Switch to HTTP APIs by default for Python examples

Author: mnapoli

aws-python-http-api-with-dynamodb/.gitignore

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+.serverless
+*.pyc
+*.pyo

aws-python-http-api-with-dynamodb/README.md

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+<!--
+title: 'AWS Serverless HTTP API with DynamoDB store example in Python'
+description: 'This example demonstrates how to setup an HTTP API allowing you to create, list, get, update and delete Todos. DynamoDB is used to store the data.'
+layout: Doc
+framework: v1
+platform: AWS
+language: Python
+authorLink: 'https://github.com/godfreyhobbs'
+authorName: 'Godfrey Hobbs'
+authorAvatar: 'https://avatars1.githubusercontent.com/u/8434141?v=4&s=140'
+-->
+# Serverless HTTP API
+
+This example demonstrates how to setup an HTTP API allowing you to create, list, get, update and delete Todos. DynamoDB is used to store the data. This is just an example and of course you could use any data storage as a backend.
+
+## Structure
+
+This service has a separate directory for all the todo operations. For each operation exactly one file exists e.g. `todos/delete.py`. In each of these files there is exactly one function defined.
+
+The idea behind the `todos` directory is that in case you want to create a service containing multiple resources e.g. users, notes, comments you could do so in the same service. While this is certainly possible you might consider creating a separate service for each resource. It depends on the use-case and your preference.
+
+## Use-cases
+
+- API for a Web Application
+- API for a Mobile Application
+
+## Setup
+
+```bash
+npm install -g serverless
+```
+
+## Deploy
+
+In order to deploy the endpoint simply run
+
+```bash
+serverless deploy
+```
+
+The expected result should be similar to:
+
+```bash
+Serverless: Packaging service…
+Serverless: Uploading CloudFormation file to S3…
+Serverless: Uploading service .zip file to S3…
+Serverless: Updating Stack…
+Serverless: Checking Stack update progress…
+Serverless: Stack update finished…
+
+Service Information
+service: serverless-http-api-dynamodb
+stage: dev
+region: us-east-1
+api keys:
+  None
+endpoints:
+  POST - https://45wf34z5yf.execute-api.us-east-1.amazonaws.com/todos
+  GET - https://45wf34z5yf.execute-api.us-east-1.amazonaws.com/todos
+  GET - https://45wf34z5yf.execute-api.us-east-1.amazonaws.com/todos/{id}
+  PUT - https://45wf34z5yf.execute-api.us-east-1.amazonaws.com/todos/{id}
+  DELETE - https://45wf34z5yf.execute-api.us-east-1.amazonaws.com/todos/{id}
+functions:
+  update: serverless-http-api-dynamodb-dev-update
+  get: serverless-http-api-dynamodb-dev-get
+  list: serverless-http-api-dynamodb-dev-list
+  create: serverless-http-api-dynamodb-dev-create
+  delete: serverless-http-api-dynamodb-dev-delete
+```
+
+## Usage
+
+You can create, retrieve, update, or delete todos with the following commands:
+
+### Create a Todo
+
+```bash
+curl -X POST https://XXXXXXX.execute-api.us-east-1.amazonaws.com/todos --data '{ "text": "Learn Serverless" }' -H "Content-Type: application/json"
+```
+
+No output
+
+### List all Todos
+
+```bash
+curl https://XXXXXXX.execute-api.us-east-1.amazonaws.com/todos
+```
+
+Example output:
+```bash
+[{"text":"Deploy my first service","id":"ac90feaa11e6-9ede-afdfa051af86","checked":true,"updatedAt":1479139961304},{"text":"Learn Serverless","id":"206793aa11e6-9ede-afdfa051af86","createdAt":1479139943241,"checked":false,"updatedAt":1479139943241}]%
+```
+
+### Get one Todo
+
+```bash
+# Replace the <id> part with a real id from your todos table
+curl https://XXXXXXX.execute-api.us-east-1.amazonaws.com/todos/<id>
+```
+
+Example Result:
+```bash
+{"text":"Learn Serverless","id":"ee6490d0-aa11e6-9ede-afdfa051af86","createdAt":1479138570824,"checked":false,"updatedAt":1479138570824}%
+```
+
+### Update a Todo
+
+```bash
+# Replace the <id> part with a real id from your todos table
+curl -X PUT https://XXXXXXX.execute-api.us-east-1.amazonaws.com/todos/<id> --data '{ "text": "Learn Serverless", "checked": true }' -H "Content-Type: application/json"
+```
+
+Example Result:
+```bash
+{"text":"Learn Serverless","id":"ee6490d0-aa11e6-9ede-afdfa051af86","createdAt":1479138570824,"checked":true,"updatedAt":1479138570824}%
+```
+
+### Delete a Todo
+
+```bash
+# Replace the <id> part with a real id from your todos table
+curl -X DELETE https://XXXXXXX.execute-api.us-east-1.amazonaws.com/todos/<id>
+```
+
+No output
+
+## Scaling
+
+### AWS Lambda
+
+By default, AWS Lambda limits the total concurrent executions across all functions within a given region to 1000. The default limit is a safety limit that protects you from costs due to potential runaway or recursive functions during initial development and testing. To increase this limit above the default, follow the steps in [To request a limit increase for concurrent executions](http://docs.aws.amazon.com/lambda/latest/dg/concurrent-executions.html#increase-concurrent-executions-limit).
+
+### DynamoDB
+
+When you create a table, you specify how much provisioned throughput capacity you want to reserve for reads and writes. DynamoDB will reserve the necessary resources to meet your throughput needs while ensuring consistent, low-latency performance. You can change the provisioned throughput and increasing or decreasing capacity as needed.
+
+This is can be done via settings in the `serverless.yml`.
+
+```yaml
+  ProvisionedThroughput:
+    ReadCapacityUnits: 1
+    WriteCapacityUnits: 1
+```
+
+In case you expect a lot of traffic fluctuation we recommend to checkout this guide on how to auto scale DynamoDB [https://aws.amazon.com/blogs/aws/auto-scale-dynamodb-with-dynamic-dynamodb/](https://aws.amazon.com/blogs/aws/auto-scale-dynamodb-with-dynamic-dynamodb/)

aws-python-http-api-with-dynamodb/package.json

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+{
+  "name": "aws-http-with-dynamodb",
+  "version": "1.0.0",
+  "description": "Serverless HTTP API",
+  "author": "",
+  "license": "MIT"
+}

aws-python-http-api-with-dynamodb/serverless.yml

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+service: serverless-http-api-dynamodb
+frameworkVersion: '2'
+
+provider:
+  name: aws
+  runtime: python3.8
+  environment:
+    DYNAMODB_TABLE: ${self:service}-${sls:stage}
+  httpApi:
+    cors: true
+  iam:
+    role:
+      statements:
+        - Effect: Allow
+          Action:
+            - dynamodb:Query
+            - dynamodb:Scan
+            - dynamodb:GetItem
+            - dynamodb:PutItem
+            - dynamodb:UpdateItem
+            - dynamodb:DeleteItem
+          Resource: "arn:aws:dynamodb:${aws:region}:*:table/${self:provider.environment.DYNAMODB_TABLE}"
+
+functions:
+  create:
+    handler: todos/create.create
+    events:
+      - httpApi:
+          path: /todos
+          method: post
+
+  list:
+    handler: todos/list.list
+    events:
+      - httpApi:
+          path: /todos
+          method: get
+
+  get:
+    handler: todos/get.get
+    events:
+      - httpApi:
+          path: /todos/{id}
+          method: get
+
+  update:
+    handler: todos/update.update
+    events:
+      - httpApi:
+          path: /todos/{id}
+          method: put
+
+  delete:
+    handler: todos/delete.delete
+    events:
+      - httpApi:
+          path: /todos/{id}
+          method: delete
+
+resources:
+  Resources:
+    TodosDynamoDbTable:
+      Type: 'AWS::DynamoDB::Table'
+      DeletionPolicy: Retain
+      Properties:
+        AttributeDefinitions:
+          -
+            AttributeName: id
+            AttributeType: S
+        KeySchema:
+          -
+            AttributeName: id
+            KeyType: HASH
+        BillingMode: PAY_PER_REQUEST
+        TableName: ${self:provider.environment.DYNAMODB_TABLE}

aws-python-http-api-with-dynamodb/todos/__init__.py

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+import json
+import logging
+import os
+import time
+import uuid
+
+import boto3
+dynamodb = boto3.resource('dynamodb')
+
+
+def create(event, context):
+    data = json.loads(event['body'])
+    if 'text' not in data:
+        logging.error("Validation Failed")
+        raise Exception("Couldn't create the todo item.")
+    
+    timestamp = str(time.time())
+
+    table = dynamodb.Table(os.environ['DYNAMODB_TABLE'])
+
+    item = {
+        'id': str(uuid.uuid1()),
+        'text': data['text'],
+        'checked': False,
+        'createdAt': timestamp,
+        'updatedAt': timestamp,
+    }
+
+    # write the todo to the database
+    table.put_item(Item=item)
+
+    # create a response
+    response = {
+        "statusCode": 200,
+        "body": json.dumps(item)
+    }
+
+    return response

aws-python-http-api-with-dynamodb/todos/create.py

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+import decimal
+import json
+
+
+# This is a workaround for: http://bugs.python.org/issue16535
+class DecimalEncoder(json.JSONEncoder):
+    def default(self, obj):
+        if isinstance(obj, decimal.Decimal):
+            return int(obj)
+        return super(DecimalEncoder, self).default(obj)

aws-python-http-api-with-dynamodb/todos/decimalencoder.py

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+import os
+
+import boto3
+dynamodb = boto3.resource('dynamodb')
+
+
+def delete(event, context):
+    table = dynamodb.Table(os.environ['DYNAMODB_TABLE'])
+
+    # delete the todo from the database
+    table.delete_item(
+        Key={
+            'id': event['pathParameters']['id']
+        }
+    )
+
+    # create a response
+    response = {
+        "statusCode": 200
+    }
+
+    return response

aws-python-http-api-with-dynamodb/todos/delete.py

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+import os
+import json
+
+from todos import decimalencoder
+import boto3
+dynamodb = boto3.resource('dynamodb')
+
+
+def get(event, context):
+    table = dynamodb.Table(os.environ['DYNAMODB_TABLE'])
+
+    # fetch todo from the database
+    result = table.get_item(
+        Key={
+            'id': event['pathParameters']['id']
+        }
+    )
+
+    # create a response
+    response = {
+        "statusCode": 200,
+        "body": json.dumps(result['Item'],
+                           cls=decimalencoder.DecimalEncoder)
+    }
+
+    return response

aws-python-http-api-with-dynamodb/todos/get.py

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+import json
+import os
+
+from todos import decimalencoder
+import boto3
+dynamodb = boto3.resource('dynamodb')
+
+
+def list(event, context):
+    table = dynamodb.Table(os.environ['DYNAMODB_TABLE'])
+
+    # fetch all todos from the database
+    result = table.scan()
+
+    # create a response
+    response = {
+        "statusCode": 200,
+        "body": json.dumps(result['Items'], cls=decimalencoder.DecimalEncoder)
+    }
+
+    return response