@azure-tools/adl v0.14.0

ADL - An Api Description Language using TypeScript

Goals today:

• parse and persist an ADL model
• convert from/to OpenAPI (as much as we can)
• some docs that illustrate the ideas

Aspiration

An alternative to OpenAPI, Swagger means of descrbing an API surface, that facilitates describing multiple API versions of an API.

• provide a better authoring experience for OpenAPI specifications
• handle multiple api-versions without significantly increasing complexity.
• provide a more natural language for expressing an API surface
• protocol agnostic
• existing tools available, not reinventing the wheel.

Reasoning

OpenAPI is a fairly valuable standard for generating wire-protocol documentation for Http APIs.

Unfortunately, it has a few pain-points, that ratchet up the complexity the deeper you get:

• multiple API versions - docmenting an evolving surface
• multipe files ($refs as a means to connect pieces is fragile.)
• YAML/JSON as an encoding format renders the content to be merely data.
• JSON Schema lacks sufficent fidelity to manage a lot of cases easily
• content aware editors are nearly non-existant
• Path Centric model taints the API both in design and expression

Alternatives

Of course, there are an incredible number of ways to document APIs:

• OpenAPI - YAML/JSON
• Smithy -
• RAML -
• GraphQL -
• CSDL

Priorities

In deciding a path,

• Leverage existing tooling as much as possible
• Language should be able to capture an API, however it's constructed
• Project-specific linting/constraints should easy to build and enforce
• Typical change scenarios need to have the lowest friction