Genopi

Generate OpenAPI 3.0 documentation from Go src documentation.

Code template

Comment functions in the source code with the following template:

// Function summary
// METHOD /path/{path}
// {path:type} This is a path param, must exist in path above
// (query:type) This is a query param
// [header:type] This is a header param
// <package.BodyStruct>
// RESPONSE_CODE package.ResponseStruct
func rest(w http.ResponseWriter, r *http.Request) {
    ...
}

The first line must be a function summary, followed by a method and path. The rest is optional. If there are path variables, they must exist in the path. Structs must have package names and be separated by a dot. Structs must exist in the working directory, or a subdirectory, from where genopi is run so make sure to create a vendor directory if using external structs. Params can be optional using ? and for structs they are optional if they are pointers, see examples below. If struct variables are annotated with json:"name", name will be used instead of the variables name.

Some special types are allowed:

• time.Time becomes type string with format date
• uuid.UUID becomes type string with format uuid

Examples

Minimal

// Ping the server
// GET /ping
func ping(w http.ResponseWriter, r *http.Request) {
    ...
}

Get with path param

package myapp

type User struct {
    ID uuid.UUID `json:"id"`
}

type Message struct {
    Created time.Time `json:"created"`
    Message string    `json:"message"`
}

// Get user by id
// GET /users/{user_id}
// {user_id:uuid} User id path param
// (optional_param?:string) Optional query param
// 200 myapp.User
// 400 myapp.Message
func getUser(w http.ResponseWriter, r *http.Request) {
    ...
}

Post with body and optional params. Skip struct if response code provides empty response.

package myapp

type Body struct {
    Required string
    Optional *string
}

// Add user info
// POST /users/{user_id}/info
// <myapp.Body>
// 204
// 400
func addUserInfo(w http.ResponseWriter, r *http.Request) {
    ...
}

Installing and running

Flags:

• -t Api title
• -u Api base url
• -v Api version
• -o Path to store generated api documentation

Generating api documentation:

1. go get github.com/marcjamot/genopi/cmd/genopi
2. cd $GOPATH/src/your/project
3. genopi -t "Api title" -u "https://api.url" -v "1.0" -o "docs/api.yaml"

Roadmap

• Parse api from comments in source code
• Generate OpenAPI 3.0 documentation
• Provide api tests using golang.org/pkg/testing/quick
• Clean up code and make it extensible for additional generators and parsers