Cloud Assembly Schema¶--- ![cdk-constructs: Stable](https://img.shields.io/badge/cdk--constructs-stable-success.svg?style=for-the-badge) ---
This module is part of the AWS Cloud Development Kit project.
The Cloud Assembly is the output of the synthesis operation. It is produced as part of the ``cdk synth` <https://github.com/aws/aws-cdk/tree/master/packages/aws-cdk#cdk-synthesize>`_ command, or the ``app.synth()` <https://github.com/aws/aws-cdk/blob/master/packages/@aws-cdk/core/lib/app.ts#L135>`_ method invocation.
Its essentially a set of files and directories, one of which is the
manifest.json file. It defines the set of instructions that are
needed in order to deploy the assembly directory.
For example, when
cdk deployis executed, the CLI reads this file and performs its instructions:
Build container images.
Deploy CloudFormation templates.
Therefore, the assembly is how the CDK class library and CDK CLI (or any other consumer) communicate. To ensure compatibility between the assembly and its consumers, we treat the manifest file as a well defined, versioned schema.
This module contains the typescript structs that comprise the
manifest.json file, as well as the
The schema version is specified in the ``cloud-assembly.version.json` <./schema/cloud-assembly.schema.json>`_ file, under the
It follows semantic versioning, but with a small twist.
When we add instructions to the assembly, they are reflected in the manifest file and the json-schema accordingly. Every such instruction, is crucial for ensuring the correct deployment behavior. This means that to properly deploy a cloud assembly, consumers must be aware of every such instruction modification.
For this reason, every change to the schema, even though it might not strictly break validation of the json-schema format,
major version bump.
How to consume¶
Consumers must take into account the
major version of the schema they are consuming. They should reject cloud assemblies
major version that is higher than what they expect. While schema validation might pass on such assemblies, the deployment integrity
cannot be guaranteed because some instructions will be ignored.
For example, if your consumer was built when the schema version was 2.0.0, you should reject deploying cloud assemblies with a manifest version of 3.0.0.