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domingo, 3 de enero de 2016
GOA, a Go-based HTTP Microservice Framework
El lenguje de google no se toma respiro y sigue creciendo. Ahora tengo el agrado de presentar a GOA, que es un framework hecho en Go y que permite definir servicios a través de un DSL y luego se genera el código y la documentación.
Veamos un ejemplo:
package design
import (
. "github.com/raphael/goa/design" // "dot" imports make the DSL easier to read.
. "github.com/raphael/goa/design/dsl"
)
var _ = API("winecellar", func() { // The API function defines an API given its name.
Description("The winecellar service API")
BasePath("/cellar") // Base path or prefix to all requests.
// Can be overridden in action definitions using an
// absolute path starting with //.
Host("cellar.goa.design") // Default API host used by clients and Swagger.
Scheme("http") // Supported API URL scheme used by clients and Swagger.
Scheme("https") // Scheme("http", "https") works too
})
var _ = Resource("Bottle", func() { // Define the Bottle resource
DefaultMedia(BottleMedia) // Default media type used to render the bottle resources
BasePath("/bottles") // Gets appended to the API base path
Action("show", func() { // Define the show action on the Bottle resource
Routing(GET("/:bottleID")) // The relative path to the show endpoint. The full path is
// built concatenating the API and resource base paths with it.
// Uses a wildcard to capture the requested bottle ID.
// Wildcards can start with : to capture a single path segment
// or with * to capture the rest of the path.
Description("Retrieve bottle with given ID")
Params(func() { // Define the request parameters found in the URI (wildcards)
// and the query string.
Param( // Define a single parameter
"bottleID", // Here it corresponds to the path segment captured by :bottleID
Integer, // The JSON type of the parameter
"The name of the bottle to retrieve", // An optional description
)
})
Response(OK) // Define a potential response
Response(NotFound) // An action may define any number of responses.
// Their content is defined through ResponseTemplates (not shown
// in this simplistic example). Here we use the default response
// templates defined in goa.
})
})
var BottleMedia = MediaType("application/vnd.goa.example.bottle+json", func() {
Description("A bottle of wine")
Attributes(func() {
Attribute("id", Integer, "ID of bottle") // Attribute defines a single field in
// the media type data structure given its
// name, type and description.
Attribute("href") // The default type for attributes is String.
Attribute("name", String "The bottle name", func() { // Like with API, Resource and Action an
// attribute definition may use an anonymous function
// as last argument to define additional properties.
MinLength(1) // Here we define validation rules specifying a
MaxLength(255) // minimum and maximum number of characters in a bottle
// name.
})
Attribute("color", func() { // Descriptions are optional.
Enum("red", "white", "rose", "yellow", "sparkling") // Possible field values
})
Attribute("sweetness", Integer, func() {
Minimum(1) // Minimum and maximum int field values.
Maximum(5)
})
View("default", func() { // Views are used to render a media type.
Attribute("id") // A media type can have one or more views
Attribute("href") // and must define the "default" view.
Attribute("name") // The view simply lists the fields to render.
Attribute("color") // It can also specify the view to use to render
Attribute("sweetness") // fields whose type is itself a media type
// (the "default" view by default). Not used here.
})
})
})
Parece cimplejo a simple vista pero pensemos que estamos codificando y documentando un servicio REST.
A la vez este framework se encuentra documentado en Go academy.
Dejo link:
https://blog.gopheracademy.com/advent-2015/goaUntanglingMicroservices/