Using OpenApi to describe your services

Orbital can use OpenApi specs to understand what APIs exist, and how to call them.

Orbital uses Semantic schemas to describe how data relates between systems. For OpenAPI, this means enriching return types and input parameters with metadata to describe them semantically.

To do this, we embed Taxi metadata within the OpenApi specs.

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Adding Taxi annotations to OpenApi specs

Taxi annotations use a custom x-taxi-type block within OpenApi specs.

Example:

x-taxi-type:
  # The name of the type
  name: com.acme.MyType
  # Optional.  Indicates if the type should be created if not already present.
  create: false

The create element is optional, and overrides the default behaviour.

If create is set to false, then schemas which attempt to publish types that aren’t already defined on the schema server are rejected as compilation errors.

This is to prevent accidental typos.

However, the default behaviour for create is different between response models and attribute types:

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Describing response types

Response models returned from API calls can be enriched to include semantic metadata

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Assigning Taxi type names to models

You can optionally define a custom type name for response types being published to Orbital. If omitted, then the type name is inferred from the rest of the schema

components:
  schemas:
    Pet:
      # Assign a Taxi type name to the model.
      # Optional
      x-taxi-type:
        name: petstore.Pet
      # Everything else is standard OpenApi spec...
      allOf:
        - $ref: '#/components/schemas/NewPet'
        - required:

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Adding type annotations to attributes

Enrich attributes with semantic type metadata

NewPet:
  required:
    - name
  properties:
    name:
      x-taxi-type:
        name: petstore.Name
      type: string
    tag:
      x-taxi-type:
        name: petstore.Tag
      type: string

By default, it’s expected that types referred to in x-taxi-type within attributes have already been defined on the schema server, as part of your core taxonomy.

However, if you are intentionally publishing new types from your OpenApi spec, then set create to true:

NewPet:
  required:
    - name
  properties:
    name:
      x-taxi-type:
        name: petstore.Name
        # petstore.Name will be created if not present
        create: true
      type: string

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Describing service parameters

Inputs into services can also be enriched, to annotate the semantic data required.

Simply add a x-taxi-type annotation to each input, containing a name attribute with a reference to the name of the type from your core taxonomy

## ... OpenApi spec trimmed...
paths:
  /pets/{id}:
    get:
      description: Returns a user based on a single ID, if the user does not have access to the pet
      operationId: find pet by id
      parameters:
        - name: id
          in: path
          description: ID of pet to fetch
          required: true
          schema:
            type: integer
            format: int64
            x-taxi-type:
              name: petstore.PetId  # <-- Name of type from core taxonomy

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Publishing OpenAPI specs to Orbital

Once you have added taxi annotations to your OpenApi spec, you’re ready to publish it to Orbital.

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Importing through the UI

In the Orbital UI, navigate to Schemas, and click “Add New Sources”. Alternatively, navigate to /schema-importer within your Orbital UI.

Next, choose Import, and select Swagger / Open API

• Either provide the OpenApi spec file directly, or enter a Url to load the spec from.
• Provide a default namespace. (eg: com.petflix.pets). Services from your OpenAPI spec are imported into this namespace
• If your OpenAPI spec doesn’t define a base url (ie.,: servers/url), then specify a Base url. All paths in the OpenApi spec are treated as relative to this path.
• Then click Create

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Preview your imported schema

Your imported OpenApi spec will be available for you to browse, to make sure everything looks correct.

Any types that have been defined as create: true within the Yaml spec should appear wihtin the Types section.

Services and operations should’ve been created for all endpoints within your OpenApi spec.

At this point, you can edit types (by clicking on the blue underlined type names) to further refine your schema. Once you’re happy, click Save, and the OpenApi spec will be imported.

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Pushing using the Taxi cli

We’re working on a CLI to enable publishing OpenApi specs to Orbital from within CI/CD workflows.

If you’d like to be an early adopter, ping us on slack!