Need for machine-readable “Application Interface”


Deepak Vij
 

Hi folks, I would like to start a thread on the need for machine-readable “Application Interface” supported at the platform level. Essentially, this interface describes details such as available methods/operations, inputs/outputs data types (schema), application dependencies etc. Any standard specifications language can be used for this purpose, as long as it clearly describes the schema of the requests and responses – one can use Web Application Description Language (WADL), Swagger, RESTful API Modeling Language (RAML), JSON Schema (something like JSON Schema for Heroku Platform APIs) or any other language that provides similar functionality. These specifications are to be automatically derived from the code and are typically part of the application development process (e.g. generated by the build system).

Such functionality can have lots of usage scenarios:

1. First and foremost, Deployment Governance for API Management (our main vested interest) – API Versioning & Backward Compatibility, Dependency Management and many more as part of the comprehensive telecom API Management capabilities which we are currently in the process of building out.

2. Auto-creating client libraries for your favorite programming language.

3. Automatic generation of up-to-date documentation.

4. Writing automatic acceptance and integration tests etc.

From historical perspective, in the early 2000s when SOA started out, the mindset was to author the application contract-first (application interface using WSDL at that time) and subsequently generate and author code from the application interface. With the advent of RESTful services, REST community initially took a stand against such metadata for applications. Although, a number of metadata standards have none-the-less emerged over the last couple of years, mainly fueled by the use case scenarios described earlier.

Based on my knowledge, none of this currently exists within Cloud Foundry at the platform level. It would be highly desirable to have a standard common “application interface” definition at the platform level, agnostic of the underlying application development frameworks.

I hope this all makes sense. I think this is something could be very relevant to the “Utilities” PMC. I will also copy&paste this text under “Utilities” PMC-notes on the github.

I would love to hear from the community on this. Thanks.

Regards,
Deepak Vij

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