Add service pkg and deprecate micro pkg

micro/request.go

@@ -15,189 +15,29 @@ package micro
 
 import (
 	"context"
-	"encoding/json"
-	"errors"
-	"fmt"
 
-	"github.com/nats-io/nats.go"
+	"github.com/nats-io/nats.go/service"
 )
 
 type (
-	// Handler is used to respond to service requests.
-	Handler interface {
-		Handle(Request)
-	}
-
-	// HandlerFunc is a function implementing [Handler].
-	// It allows using a function as a request handler, without having to implement Handle
-	// on a separate type.
-	HandlerFunc func(Request)
-
-	// Request represents service request available in the service handler.
-	// It exposes methods to respond to the request, as well as
-	// getting the request data and headers.
-	Request interface {
-		// Respond sends the response for the request.
-		// Additional headers can be passed using [WithHeaders] option.
-		Respond([]byte, ...RespondOpt) error
-
-		// RespondJSON marshals the given response value and responds to the request.
-		// Additional headers can be passed using [WithHeaders] option.
-		RespondJSON(any, ...RespondOpt) error
-
-		// Error prepares and publishes error response from a handler.
-		// A response error should be set containing an error code and description.
-		// Optionally, data can be set as response payload.
-		Error(code, description string, data []byte, opts ...RespondOpt) error
-
-		// Data returns request data.
-		Data() []byte
-
-		// Headers returns request headers.
-		Headers() Headers
-
-		// Subject returns underlying NATS message subject.
-		Subject() string
-	}
-
-	// Headers is a wrapper around [*nats.Header]
-	Headers nats.Header
-
-	// RespondOpt is a function used to configure [Request.Respond] and [Request.RespondJSON] methods.
-	RespondOpt func(*nats.Msg)
-
-	// request is a default implementation of Request interface
-	request struct {
-		msg          *nats.Msg
-		respondError error
-	}
-
-	serviceError struct {
-		Code        string `json:"code"`
-		Description string `json:"description"`
-	}
+	Handler     = service.Handler
+	HandlerFunc = service.HandlerFunc
+	Request     = service.Request
+	Headers     = service.Headers
+	RespondOpt  = service.RespondOpt
 )
 
 var (
-	ErrRespond         = errors.New("NATS error when sending response")
-	ErrMarshalResponse = errors.New("marshaling response")
-	ErrArgRequired     = errors.New("argument required")
+	ErrRespond         = service.ErrRespond
+	ErrMarshalResponse = service.ErrMarshalResponse
+	ErrArgRequired     = service.ErrArgRequired
 )
 
-func (fn HandlerFunc) Handle(req Request) {
-	fn(req)
-}
-
-// ContextHandler is a helper function used to utilize [context.Context]
-// in request handlers.
 func ContextHandler(ctx context.Context, handler func(context.Context, Request)) Handler {
-	return HandlerFunc(func(req Request) {
-		handler(ctx, req)
-	})
-}
-
-// Respond sends the response for the request.
-// Additional headers can be passed using [WithHeaders] option.
-func (r *request) Respond(response []byte, opts ...RespondOpt) error {
-	respMsg := &nats.Msg{
-		Data: response,
-	}
-	for _, opt := range opts {
-		opt(respMsg)
-	}
-
-	if err := r.msg.RespondMsg(respMsg); err != nil {
-		r.respondError = fmt.Errorf("%w: %s", ErrRespond, err)
-		return r.respondError
-	}
-
-	return nil
-}
-
-// RespondJSON marshals the given response value and responds to the request.
-// Additional headers can be passed using [WithHeaders] option.
-func (r *request) RespondJSON(response any, opts ...RespondOpt) error {
-	resp, err := json.Marshal(response)
-	if err != nil {
-		return ErrMarshalResponse
-	}
-	return r.Respond(resp, opts...)
-}
-
-// Error prepares and publishes error response from a handler.
-// A response error should be set containing an error code and description.
-// Optionally, data can be set as response payload.
-func (r *request) Error(code, description string, data []byte, opts ...RespondOpt) error {
-	if code == "" {
-		return fmt.Errorf("%w: error code", ErrArgRequired)
-	}
-	if description == "" {
-		return fmt.Errorf("%w: description", ErrArgRequired)
-	}
-	response := &nats.Msg{
-		Header: nats.Header{
-			ErrorHeader:     []string{description},
-			ErrorCodeHeader: []string{code},
-		},
-	}
-	for _, opt := range opts {
-		opt(response)
-	}
-
-	response.Data = data
-	if err := r.msg.RespondMsg(response); err != nil {
-		r.respondError = err
-		return err
-	}
-	r.respondError = &serviceError{
-		Code:        code,
-		Description: description,
-	}
-
-	return nil
+	return service.ContextHandler(ctx, handler)
 }
 
 // WithHeaders can be used to configure response with custom headers.
 func WithHeaders(headers Headers) RespondOpt {
-	return func(m *nats.Msg) {
-		if m.Header == nil {
-			m.Header = nats.Header(headers)
-			return
-		}
-
-		for k, v := range headers {
-			m.Header[k] = v
-		}
-	}
-}
-
-// Data returns request data.
-func (r *request) Data() []byte {
-	return r.msg.Data
-}
-
-// Headers returns request headers.
-func (r *request) Headers() Headers {
-	return Headers(r.msg.Header)
-}
-
-// Subject returns underlying NATS message subject.
-func (r *request) Subject() string {
-	return r.msg.Subject
-}
-
-// Get gets the first value associated with the given key.
-// It is case-sensitive.
-func (h Headers) Get(key string) string {
-	return nats.Header(h).Get(key)
-}
-
-// Values returns all values associated with the given key.
-// It is case-sensitive.
-func (h Headers) Values(key string) []string {
-	return nats.Header(h).Values(key)
-}
-
-func (e *serviceError) Error() string {
-	return fmt.Sprintf("%s:%s", e.Code, e.Description)
+	return service.WithHeaders(headers)
 }