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The handler.construct() method is a trap for the [[Construct]] object internal method, which is used by operations such as the new operator. In order for the new operation to be valid on the resulting Proxy object, the target used to initialize the proxy must itself be a valid constructor.
CONSTRUCT is an AEC educational program and exhibition that has the goal of bringing together the different disciplines within the construction industry to help improve the future of the built environment.
Breaking down the barriers between the different players within the construction process allows for a more collaborative work environment. CONSTRUCT is the place to share the latest in standards and best practices, industry trends, and emerging technologies.
CONSTRUCT is an AEC educational program and exhibition that has the goal of bringing together the different disciplines within the construction industry to help improve the future of the built environment.
In very pragmatic terms, this studio asked how we might design and construct thousands of infill housing units in just a few years. To answer that question technically, we emphasized the use of simulated and automated design and construction methodologies. To answer it politically, we first needed to redesign the rules.
A construct can represent a single AWS resource, such as an Amazon Simple Storage Service (Amazon S3) bucket. A construct can also be a higher-level abstraction consisting of multiple related AWS resources. Examples of such components include a worker queue with its associated compute capacity, or a scheduled job with monitoring resources and a dashboard.
The AWS CDK includes a collection of constructs called the AWS Construct Library, containing constructs for every AWS service. Construct Hub is a resource to help you discover additional constructs from AWS, third parties, and the open-source CDK community.
This library includes constructs that represent all the resources available on AWS. For example, the s3.Bucket class represents an Amazon S3 bucket, and the dynamodb.Table class represents an Amazon DynamoDB table.
There are three different levels of constructs in this library, beginning with low-level constructs, which we call CFN Resources (or L1, short for "layer 1"). These constructs directly represent all resources available in AWS CloudFormation. CFN Resources are periodically generated from the AWS CloudFormation Resource Specification. They are named CfnXyz, where Xyz is name of the resource. For example, CfnBucket represents the AWS::S3::Bucket AWS CloudFormation resource. When you use Cfn resources, you must explicitly configure all resource properties. This requires a complete understanding of the details of the underlying AWS CloudFormation resource model.
The next level of constructs, L2, also represent AWS resources, but with a higher-level, intent-based API. They provide similar functionality, but incorporate the defaults, boilerplate, and glue logic you'd be writing yourself with a CFN Resource construct. AWS constructs offer convenient defaults and reduce the need to know all the details about the AWS resources they represent. They also provide convenience methods that make it simpler to work with the resource. For example, the s3.Bucket class represents an Amazon S3 bucket with additional properties and methods, such as bucket.addLifeCycleRule(), which adds a lifecycle rule to the bucket.
Finally, the AWS Construct Library includes L3 constructs, which we call patterns. These constructs are designed to help you complete common tasks in AWS, often involving multiple kinds of resources. For example, the aws-ecs-patterns.ApplicationLoadBalancedFargateService construct represents an architecture that includes an AWS Fargate container cluster employing an Application Load Balancer. The aws-apigateway.LambdaRestApi construct represents an Amazon API Gateway API that's backed by an AWS Lambda function.
Composition is the key pattern for defining higher-level abstractions through constructs. A high-level construct can be composed from any number of lower-level constructs. In turn, those could be composed from even lower-level constructs, which eventually are composed from AWS resources.
From a bottom-up perspective, you use constructs to organize the individual AWS resources that you want to deploy. You use whatever abstractions are convenient for your purpose, with as many layers as you need.
Composition lets you define reusable components and share them like any other code. For example, a team can define a construct that implements the company's best practice for a DynamoDB table with backup, global replication, automatic scaling, and monitoring. The team can share the construct with other teams in their organization, or publicly.
Teams can use this construct in their preferred programming language like they would use any other library package to define their tables and comply with best practices. When the library is updated, developers will get access to the new version's bug fixes and improvements through the workflows they already have for their other types of code.
Identifiers need only be unique within a scope. This lets you instantiate and reuse constructs without concern for the constructs and identifiers they might contain, and enables composing constructs into higher-level abstractions. In addition, scopes make it possible to refer to groups of constructs all at once. Examples include for tagging, or specifying where the constructs will be deployed.
As you can see, you need a scope within which to define your bucket. Resources eventually need to be deployed as part of an AWS CloudFormation stack into an AWS environment. The environment covers a specific AWS account and AWS Region. AWS constructs, such as s3.Bucket, must be defined within the scope of a Stack.
Stacks in AWS CDK apps extend the Stack base class, as shown in the previous example. The following example is a common pattern when creating a stack within your AWS CDK app. It shows how to extend the Stack class, define a constructor that accepts scope, id, and props, and invoke the base class constructor via super with the received scope, id, and props.
In Python, these properties are represented by types defined as inner classes of the L1 construct. For example, the optional property cors_configuration of a CfnBucket requires a wrapper of type CfnBucket.CorsConfigurationProperty. Here we are defining cors_configuration on a CfnBucket instance.
In Java, these properties are represented by types defined as inner classes of the L1 construct. For example, the optional property corsConfiguration of a CfnBucket requires a wrapper of type CfnBucket.CorsConfigurationProperty. Here we are defining corsConfiguration on a CfnBucket instance.
In C#, these properties are represented by types defined as inner classes of the L1 construct. For example, the optional property CorsConfiguration of a CfnBucket requires a wrapper of type CfnBucket.CorsConfigurationProperty. Here we are defining CorsConfiguration on a CfnBucket instance.
In Go, these types are named using the name of the L1 construct, an underscore, and the property name. For example, the optional property CorsConfiguration of a CfnBucket requires a wrapper of type CfnBucket_CorsConfigurationProperty. Here we are defining CorsConfiguration on a CfnBucket instance.
You can't use L2 property types with L1 constructs, or vice versa. When working with L1 constructs, always use the types defined for the L1 construct you're using. Do not use types from other L1 constructs (some may have the same name, but they are not the same type).
Some of our language-specific API references currently have errors in the paths to L1 property types, or don't document these classes at all. We hope to fix this soon. In the meantime, remember that such types are always inner classes of the L1 construct they are used with.
Most constructs accept props as their third argument (or in Python, keyword arguments), a name/value collection that defines the construct's configuration. The following example defines a bucket with AWS Key Management Service (AWS KMS) encryption and static website hosting enabled. Since it does not explicitly specify an encryption key, the Bucket construct defines a new kms.Key and associates it with the bucket.
AWS constructs are designed around the concept of "sensible defaults." Most constructs have a minimal required configuration, enabling you to quickly get started while also providing full control over the configuration when you need it.
Constructs are classes that extend the base Construct class. After you instantiate a construct, the construct object exposes a set of methods and properties that let you interact with the construct and pass it around as a reference to other parts of the system.
The AWS CDK framework doesn't put any restrictions on the APIs of constructs. Authors can define any API they want. However, the AWS constructs that are included with the AWS Construct Library, such as s3.Bucket, follow guidelines and common patterns. This provides a consistent experience across all AWS resources.
Most AWS constructs have a set of grant methods that you can use to grant AWS Identity and Access Management (IAM) permissions on that construct to a principal. The following example grants the IAM group data-science permission to read from the Amazon S3 bucket raw-data.
In addition to using existing constructs like s3.Bucket, you can also write your own constructs, and then anyone can use them in their apps. All constructs are equal in the AWS CDK. An AWS CDK construct (such as s3.Bucket or sns.Topic) behaves the same as a construct from a third-party library published via NPM, Maven, or PyPI. Constructs published to your company's internal package repository also behave the same way.
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