Kapusta

It`s middleware approach for using http.Client. You can wrap your client with different functionality:

• log every request
• append auth headers
• use http cache
• use etcd/consul for service discovery
• and whatever you want!

Just like a cabbage!

Client interface

Internal http package doesn`t have any interface for http clients, so Kapusta provides very simple client interface:

type Client interface {
	Do( *http.Request) (*http.Response, error)
}

http.Client supports it out of box!

Middlewares:

type MiddlewareFunc func(Client) Client

Kapusta provides some helpful middlewares for you:

• HeadersMiddleware(values map[string]string) Adds headers to requests
• HeaderMiddleware(name, value string) Like headers, but add only one header.
• RecoverMiddleware() Converts all panics into errors
• BaseURLMiddleware(baseURL string) Replaces scheme and host to baseURL value.

Usage

decoratedClient := kapusta.Chain(
    http.DefaultClient,
    middleware.HeaderMiddleware("X-Auth", "123"),
    middleware.RecoverMiddleware(), // better to place it last to recover panics from middlewares too
)

Create your own middleware

There are two ways of creating new middleware.

You can create some new struct:

struct AwesomeStuffClient {
    client kapusta.Client
}

func(c *AwesomeStuffClient) Do(ctx context.Context, r *http.Request) (*http.Response, error) {
    // some stuff before call
    res, err := c.client.Do(ctx, r)
    // some stuff after call
    
    return res, err
}

func AwesomeStuffDecorator(c kapusta.Client) kapusta.Client {
    return &AwesomeStuffClient{client: c}
}

Or you can create just a function with type:

type ClientFunc func(*http.Request) (*http.Response, error)

So the same example will be looks like:

func AwesomeStuffDecorator(c kapusta.Client) kapusta.Client {
	return kapusta.ClientFunc(func(r *http.Request) (*http.Response, error) {
		// some stuff before call
        res, err := c.client.Do(r)
        // some stuff after call
        
        return res, err
	})
}

Mock

Also kapusta provides mock package for testing purposes.

client := mock.NewClient() // implements kapusta.Client
	
	client.
		Get("/path").
		WithBody(`{"foo": "bar"}`).
		WillReturn(200, `{"bar": "foo"}`)
		
// now you can inject client to your code.