internal TheScalableWebhookStack(Construct scope, string id, IStackProps props = null) : base(scope, id, props)
{
/*
* DynamoDB Table
* This is standing in for what is RDS on the diagram due to simpler/cheaper setup
*/
_dynamoDbTable = new DynamoDB.Table(this, "Messages", new DynamoDB.TableProps
{
PartitionKey = new DynamoDB.Attribute {
Name = "id", Type = DynamoDB.AttributeType.STRING
}
});
/*
* Queue Setup
*/
_queueRds = new SQS.Queue(this, "RDSPublishQueue", new SQS.QueueProps
{
VisibilityTimeout = Duration.Seconds(300)
});
/*
* Lambdas
* Both publisher and subscriber from pattern
*/
/*
* defines an AWS Lambda resource to publish to our sqs_queue
*/
_functionPublish = new Lambda.Function(this, "SQSPublishLambdaHandler", new Lambda.FunctionProps
{
Runtime = Lambda.Runtime.NODEJS_12_X, // execution environment
Handler = "lambda.handler", // file is "lambda", function is "handler"
Code = Lambda.Code.FromAsset("lambda_fns/publish"), // code loaded from the "lambda_fns/publish" directory
Environment = new Dictionary <string, string>
{
{ "queueURL", _queueRds.QueueUrl }
}
});
_queueRds.GrantSendMessages(_functionPublish);
/*
* defines an AWS Lambda resource to pull from our sqs_queue
*/
_functionSubscribe = new Lambda.Function(this, "SQSSubscribeLambdaHandler", new Lambda.FunctionProps
{
Runtime = Lambda.Runtime.NODEJS_12_X, // execution environment
Handler = "lambda.handler", // file is "lambda", function is "handler"
Code = Lambda.Code.FromAsset("lambda_fns/subscribe"), // code loaded from the "lambda_fns/subscribe" directory
Environment = new Dictionary <string, string>
{
{ "queueURL", _queueRds.QueueUrl },
{ "tableName", _dynamoDbTable.TableName }
},
ReservedConcurrentExecutions = 2 // throttle lambda to 2 concurrent invocations
});
_queueRds.GrantConsumeMessages(_functionSubscribe);
_functionSubscribe.AddEventSource(new LambdaEvents.SqsEventSource(_queueRds));
_dynamoDbTable.GrantReadWriteData(_functionSubscribe);
/**
* API Gateway Proxy
* Used to expose the webhook through a URL
*
* defines an API Gateway REST API resource backed by our "sqs_publish_lambda" function.
*/
new APIG.LambdaRestApi(this, "Endpoint", new APIG.LambdaRestApiProps
{
Handler = _functionPublish
});
}
internal TheStateMachineStack(Construct scope, string id, IStackProps props = null) : base(scope, id, props)
{
// Step Function Starts Here
// The first thing we need to do is see if they are asking for pineapple on a pizza
_pineppaleCheckHandler = new Lambda.Function(this, "pineappleCheckLambdaHandler", new Lambda.FunctionProps
{
Runtime = Lambda.Runtime.NODEJS_12_X,
Code = Lambda.Code.FromAsset("lambda_fns"),
Handler = "orderPizza.handler"
});
/*
* Step functions are built up of steps, we need to define our first step
* This step was refactored due to Deprecated function
*/
_orderPizzaTask = new StepFuncionTasks.LambdaInvoke(this, "Order Pizza Job", new StepFuncionTasks.LambdaInvokeProps
{
LambdaFunction = _pineppaleCheckHandler,
InputPath = "$.flavour",
ResultPath = "$.pineappleAnalysis",
PayloadResponseOnly = true
});
// Pizza Order failure step defined
_jobFailed = new StepFunction.Fail(this, "Sorry, We Dont add Pineapple", new StepFunction.FailProps
{
Cause = "Failed To Make Pizza",
Error = "They asked for Pineapple"
});
// If they didnt ask for pineapple let's cook the pizza
_cookPizza = new StepFunction.Pass(this, "Lets make your pizza");
// If they ask for a pizza with pineapple, fail. Otherwise cook the pizza
_chainDefinition = StepFunction.Chain
.Start(_orderPizzaTask)
.Next(new StepFunction.Choice(this, "With Pineapple?") // Logical choice added to flow
.When(StepFunction.Condition.BooleanEquals("$.pineappleAnalysis.containsPineapple", true), _jobFailed)
.Otherwise(_cookPizza));
// Building the state machine
_stateMachine = new StepFunction.StateMachine(this, "StateMachine", new StepFunction.StateMachineProps
{
Definition = _chainDefinition,
Timeout = Duration.Minutes(5)
});
/**
* Dead Letter Queue Setup
* SQS creation
* https://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/sqs-dead-letter-queues.html
*/
_deadeLetterQueue = new SQS.Queue(this, "stateMachineLambdaDLQ", new SQS.QueueProps
{
VisibilityTimeout = Duration.Seconds(300)
});
// defines an AWS Lambda resource to connect to our API Gateway
_stateMachineHandler = new Lambda.Function(this, "stateMachineLambdaHandler", new Lambda.FunctionProps
{
Runtime = Lambda.Runtime.NODEJS_12_X,
Code = Lambda.Code.FromAsset("lambda_fns"),
Handler = "stateMachineLambda.handler",
DeadLetterQueue = _deadeLetterQueue,
Environment = new Dictionary <string, string>
{
{ "statemachine_arn", _stateMachine.StateMachineArn }
}
});
// Grants to state machine execution
_stateMachine.GrantStartExecution(_stateMachineHandler);
/*
* Simple API Gateway proxy integration
*/
// defines an API Gateway REST API resource backed by our "sqs_publish_lambda" function.
new APIGateway.LambdaRestApi(this, "Endpoint", new APIGateway.LambdaRestApiProps
{
Handler = _stateMachineHandler
});
}