Serverless OpenAPI Documentation Plugin


Generates OpenAPI 3.0.0 documentation from serverless configuration files. OpenAPI is formerly known as Swagger. The configuration is inspired by the format used in serverless-aws-documentation.

Works well with ReDoc.

---

- Usage
- Options
- Configuration
- Models
- Functions
- queryParams
- pathParams
- cookieParams
- requestModels
- methodResponses
- Example configuration
- Install

---

Usage

This plugin requires additional configuration to use, see the "Configuration" section for how to configure the plugin to generate documentation.

Below are the commandline options to run the generator:

``bash
serverless openapi generate [options]
`

$3

`bash
Plugin: ServerlessOpenAPIDocumentation
openapi generate ...................... Generate OpenAPI v3 Documentation
--output / -o ...................... Output file location [default: openapi.yml|json]
--format / -f ...................... OpenAPI file format (yml|json) [default: yml]
--indent / -i ...................... File indentation in spaces [default: 2]
--help / -h ...................... Help
`

$3

To configure this plugin to generate valid OpenAPI documentation there are two places you'll need to modify in your serverless.yml file, the custom variables section and the http event section for each given function in your service.

This plugin is compatible with the same documentation configuration structure in serverless-aws-documentation and can run beside it.

The custom section of your serverless.yml can be configured as below:

`yml
custom:
documentation:
version: '1'
title: 'My API'
description: 'This is my API'
# https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#securitySchemeObject
securitySchemes: {}
# https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#security-requirement-object
security: {}
models: {}
`

These configurations can be quite verbose; you can separate it out into it's own file, such as serverless.doc.yml as below:

`yml
custom:
documentation: ${file(serverless.doc.yml):documentation}

functions:
myFunc:
events:
- http:
path: getStuff
method: get
documentation: ${file(serverless.doc.yml):endpoints.myFunc}
`

For more info on serverless.yml syntax, see their docs.

#### Models

Models contain additional information that you can use to define schemas for endpoints. You must define the content type for each schema that you provide in the models.

The required directives for the models section are as follow:

* name: the name of the schema
* description: a description of the schema
* contentType: the content type of the described request/response (ie. application/json or application/xml).
* schema: The JSON Schema (website) that describes the model. You can either:
- use inline YAML to define these
- use serverless' functionality to merge in external schema file
- specify a path to json schema in which case if you reuse some types in multiple schemas - they will be included in resulting components once instead of duplicated for each referencing schema

`yml
custom:
documentation:
models:
- name: "PutDocumentRequest"
description: "Inline schema example"
contentType: "application/json"
schema:
$schema: "http://json-schema.org/draft-04/schema#"
properties:
SomeObject:
type: "object"
properties:
SomeAttribute:
type: "string"
- name: "PutDocumentResponse"
description: "External file merge example"
contentType: "application/json"
schema: ${file(models/PutDocumentResponse.json)}
- name: "ErrorResponse"
description: "Path to a schema example"
contentType: "application/json"
schema: models/ErrorResponse.json
`

#### Functions

To define the documentation for a given function event, you need to create a documentation attribute for your http event in your serverless.yml file.

The documentation section of the event configuration can contain the following attributes:

* summary: a short description of the method
* description: a detailed description of the method
* tags: an array of tags for this event
* deprecated: boolean indicator that indicates clients should migrate away from this function
* requestBody: contains description of the request
* description: a description of the request body
* requestModels: a list of models to describe the request bodies (see requestModels below)
* queryParams: a list of query parameters (see queryParams below)
* pathParams: a list of path parameters (see pathParams below)
* cookieParams: a list of cookie parameters (see cookieParams below)
* methodResponses: an array of response models and applicable status codes
* statusCode: applicable http status code (ie. 200/404/500 etc.)
* responseBody: contains description of the response
* description: a description of the body response
* responseHeaders: a list of response headers (see responseHeaders below)
* responseModels: a list of models to describe the request bodies (see responseModels below) for each Content-Type

`yml
functions:
createUser:
handler: "handler.create"
events:
- http:
path: "create"
method: "post"
documentation:
summary: "Create User"
description: "Creates a user and then sends a generated password email"
requestBody:
description: "A user information object"
requestModels:
application/json: "PutDocumentRequest"
pathParams:
- name: "username"
description: "The username for a user to create"
schema:
type: "string"
pattern: "^[-a-z0-9_]+$"
queryParams:
- name: "membershipType"
description: "The user's Membership Type"
schema:
type: "string"
enum:
- "premium"
- "standard"
cookieParams:
- name: "SessionId"
description: "A Session ID variable"
schema:
type: "string"
methodResponses:
- statusCode: 201
responseBody:
description: "A user object along with generated API Keys"
responseModels:
application/json: "PutDocumentResponse"
- statusCode: 500
responseBody:
description: "An error message when creating a new user"
responseModels:
application/json: "ErrorResponse"
`

#### queryParams

Query parameters can be described as follow:

* name: the name of the query variable
* description: a description of the query variable
* required: whether the query parameter is mandatory (boolean)
* schema: JSON schema (inline or file)

`yml
queryParams:
- name: "filter"
description: "The filter parameter"
required: true
schema:
type: "string"
`

#### pathParams

Path parameters can be described as follow:

* name: the name of the query variable
* description: a description of the query variable
* schema: JSON schema (inline or file)

`yml
pathParams:
- name: "usernameId"
description: "The usernameId parameter"
schema:
type: "string"
`

#### cookieParams

Cookie parameters can be described as follow:

* name: the name of the query variable
* description: a description of the query variable
* required: whether the query parameter is mandatory (boolean)
* schema: JSON schema (inline or file)

`yml
cookieParams:
- name: "sessionId"
description: "The sessionId parameter"
required: true
schema:
type: "string"
`

#### requestModels

The requestModels property allows you to define models for the HTTP Request of the function event. You can define a different model for each different Content-Type. You can define a reference to the relevant request model named in the models section of your configuration (see Defining Models section).

`yml
requestModels:
application/json: "CreateRequest"
application/xml: "CreateRequestXML"
`

#### methodResponses

You can define the response schemas by defining properties for your function event.

For an example of a methodResponses configuration for an event see below:

`yml
methodResponse:
- statusCode: 200
responseHeaders:
- name: "Content-Type"
description: "Content Type header"
schema:
type: "string"
responseModels:
application/json: "CreateResponse"
application/xml: "CreateResponseXML"
`

##### responseModels

The responseModels property allows you to define models for the HTTP Response of the function event. You can define a different model for each different Content-Type. You can define a reference to the relevant response model named in the models section of your configuration (see Defining Models section).

`yml
responseModels:
application/json: "CreateResponse"
application/xml: "CreateResponseXML"
`

##### responseHeaders and requestHeaders

The responseHeaders/requestHeaders section of the configuration allows you to define the HTTP headers for the function event.

The attributes for a header are as follow:

* name: the name of the HTTP Header
* description: a description of the HTTP Header
* schema: JSON schema (inline or file)

`yml
responseHeaders:
- name: "Content-Type"
description: "Content Type header"
schema:
type: "string"
requestHeaders:
- name: "Content-Type"
description: "Content Type header"
schema:
type: "string"
`

Example configuration

Please view the example serverless.yml.

Install

This plugin works for Serverless 1.x and up. Serverless 0.5 is not supported.

To add this plugin to your package.json:

Using npm:
`bash
npm install @cmubick/serverless-openapi-documentation --save-dev
`

Using Yarn:
`bash
yarn add @cmubick/serverless-openapi-documentation --dev
`

Next you need to add the plugin to the plugins section of your serverless.yml file.

`yml
plugins:
- @cmubick/serverless-openapi-documentation
`

You can confirm the plugin is correctly installed by running:

`bash
serverless | grep -i "ServerlessOpenAPIDocumentation"
`

It should return ServerlessOpenAPIDocumentation as one of the plugins on the list.

> Note: Add this plugin _after_ serverless-offline to prevent issues with String.replaceAll` being overridden incorrectly.

License

MIT