feat: Python example for api-sqs-lambda

python/api-sqs-lambda/README.md

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+
+# API Gateway + SQS + Lambda
+
+Creates an API Gateway API with a POST Method, a SQS queue, and a Lambda function. Requests to the API are enqueued into the SQS queue, which triggers the Lambda function.
+
+![Architecture](architecture.png)
+
+The `cdk.json` file tells the CDK Toolkit how to execute your app.
+
+This project is set up like a standard Python project. The initialization process also creates a virtualenv within this
+project, stored under the `.env` directory. To create the virtualenv it assumes that there is a `python3` (or `python`
+for Windows) executable in your path with access to the `venv` package. If for any reason the automatic creation of the
+virtualenv fails, you can create the virtualenv manually.
+
+To manually create a virtualenv on MacOS and Linux:
+
+```
+$ python3 -m venv .env
+```
+
+After the init process completes and the virtualenv is created, you can use the following
+step to activate your virtualenv.
+
+```
+$ source .env/bin/activate
+```
+
+If you are a Windows platform, you would activate the virtualenv like this:
+
+```
+% .env\Scripts\activate.bat
+```
+
+Once the virtualenv is activated, you can install the required dependencies.
+
+```
+$ pip install -r requirements.txt
+```
+
+At this point you can now synthesize the CloudFormation template for this code.
+
+```
+$ cdk synth
+```
+
+Upon successful deployment, you should see an API Gateway REST API in your account. It can be tested from the console or the CLI:
+
+```
+$ aws apigateway test-invoke-method --rest-api-id <API ID> --resource-id <RESOURCE ID> --http-method POST --body {"key":"value"}
+```
+
+This request should complete with a 200 OK. The Lambda function should print the API Gateway request body in its CloudWatch logs. (https://docs.aws.amazon.com/lambda/latest/dg/monitoring-cloudwatchlogs.html)
+
+```
+2020-05-27T11:50:44.755-05:00           Received Message Body from API GW: {key:value}
+```
+
+This message will also be visible in the SQS Queue metrics in CloudWatch. (https://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/sqs-access-metrics.html)

python/api-sqs-lambda/api_sqs_lambda/api_sqs_lambda_stack.py

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+from aws_cdk import (
+    aws_sqs as sqs,
+    aws_iam as iam,
+    aws_apigateway as apigw,
+    aws_lambda as _lambda,
+    aws_lambda_event_sources as lambda_event_source,
+    core
+)
+
+class ApiSqsLambdaStack(core.Stack):
+
+    def __init__(self, scope: core.Construct, id: str, **kwargs) -> None:
+        super().__init__(scope, id, **kwargs)
+
+        #Create the SQS queue
+        queue = sqs.Queue(self, "SQSQueue")
+
+        #Create the API GW service role with permissions to call SQS
+        rest_api_role = iam.Role(
+            self,
+            "RestAPIRole",
+            assumed_by=iam.ServicePrincipal("apigateway.amazonaws.com"),
+            managed_policies=[iam.ManagedPolicy.from_aws_managed_policy_name("AmazonSQSFullAccess")]
+        )
+
+        #Create an API GW Rest API
+        base_api = apigw.RestApi(self, 'ApiGW',rest_api_name='TestAPI')
+
+        #Create a resource named "example" on the base API
+        api_resource = base_api.root.add_resource('example')
+
+
+        #Create API Integration Response object: https://docs.aws.amazon.com/cdk/api/latest/python/aws_cdk.aws_apigateway/IntegrationResponse.html
+        integration_response = apigw.IntegrationResponse(
+            status_code="200",
+            response_templates={"application/json": ""},
+
+        )
+
+        #Create API Integration Options object: https://docs.aws.amazon.com/cdk/api/latest/python/aws_cdk.aws_apigateway/IntegrationOptions.html
+        api_integration_options = apigw.IntegrationOptions(
+            credentials_role=rest_api_role,
+            integration_responses=[integration_response],
+            request_templates={"application/json": "Action=SendMessage&MessageBody=$input.body"},
+            passthrough_behavior=apigw.PassthroughBehavior.NEVER,
+            request_parameters={"integration.request.header.Content-Type": "'application/x-www-form-urlencoded'"},
+        )
+
+        #Create AWS Integration Object for SQS: https://docs.aws.amazon.com/cdk/api/latest/python/aws_cdk.aws_apigateway/AwsIntegration.html
+        api_resource_sqs_integration = apigw.AwsIntegration(
+            service="sqs",
+            integration_http_method="POST",
+            path="{}/{}".format(core.Aws.ACCOUNT_ID, queue.queue_name),
+            options=api_integration_options
+        )
+
+        #Create a Method Response Object: https://docs.aws.amazon.com/cdk/api/latest/python/aws_cdk.aws_apigateway/MethodResponse.html
+        method_response = apigw.MethodResponse(status_code="200")
+
+        #Add the API GW Integration to the "example" API GW Resource
+        api_resource.add_method(
+            "POST",
+            api_resource_sqs_integration,
+            method_responses=[method_response]
+        )
+
+        #Creating Lambda function that will be triggered by the SQS Queue
+        sqs_lambda = _lambda.Function(self,'SQSTriggerLambda',
+            handler='lambda-handler.handler',
+            runtime=_lambda.Runtime.PYTHON_3_7,
+            code=_lambda.Code.asset('lambda'),
+        )
+
+        #Create an SQS event source for Lambda
+        sqs_event_source = lambda_event_source.SqsEventSource(queue)
+
+        #Add SQS event source to the Lambda function
+        sqs_lambda.add_event_source(sqs_event_source)

python/api-sqs-lambda/app.py

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+#!/usr/bin/env python3
+
+from aws_cdk import core
+
+from api_sqs_lambda.api_sqs_lambda_stack import ApiSqsLambdaStack
+
+
+app = core.App()
+ApiSqsLambdaStack(app, "ApiSqsLambdaStack")
+
+app.synth()

python/api-sqs-lambda/cdk.json

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+{
+  "app": "python3 app.py",
+  "context": {
+    "@aws-cdk/core:enableStackNameDuplicates": "true",
+    "aws-cdk:enableDiffNoFail": "true"
+  }
+}

python/api-sqs-lambda/lambda/lambda-handler.py

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+import json
+import boto3
+
+def handler(event, context):
+    response = "Received Message Body from API GW: " + event['Records'][0]['body']
+    print(response)
+    return {
+        'statusCode': 200,
+        'body': response
+    }

python/api-sqs-lambda/requirements.txt

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+aws-cdk.core
+
+aws-cdk.aws_lambda
+aws-cdk.aws_lambda_event_sources
+aws-cdk.aws_sqs
+aws-cdk.aws_iam
+aws-cdk.aws_apigateway

python/api-sqs-lambda/setup.py

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+import setuptools
+
+
+with open("README.md") as fp:
+    long_description = fp.read()
+
+
+setuptools.setup(
+    name="api_sqs_lambda",
+    version="0.0.1",
+
+    description="A CDK Python app to create the API GW + SQS + Lambda integration",
+    long_description=long_description,
+    long_description_content_type="text/markdown",
+
+    author="Akshit Khanna",
+
+    package_dir={"": "api_sqs_lambda"},
+    packages=setuptools.find_packages(where="api_sqs_lambda"),
+
+    install_requires=[
+        "aws-cdk.core==1.41.0",
+    ],
+
+    python_requires=">=3.6",
+
+    classifiers=[
+        "Development Status :: 4 - Beta",
+
+        "Intended Audience :: Developers",
+
+        "License :: OSI Approved :: Apache Software License",
+
+        "Programming Language :: JavaScript",
+        "Programming Language :: Python :: 3 :: Only",
+        "Programming Language :: Python :: 3.6",
+        "Programming Language :: Python :: 3.7",
+        "Programming Language :: Python :: 3.8",
+
+        "Topic :: Software Development :: Code Generators",
+        "Topic :: Utilities",
+
+        "Typing :: Typed",
+    ],
+)