/
http.go
159 lines (142 loc) · 4.45 KB
/
http.go
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package aggtransport
import (
"bytes"
"context"
"encoding/json"
"errors"
"io"
"net/http"
"net/url"
"strings"
"time"
"github.com/go-kit/kit/circuitbreaker"
"github.com/go-kit/kit/endpoint"
"github.com/go-kit/kit/ratelimit"
"github.com/go-kit/kit/transport"
httptransport "github.com/go-kit/kit/transport/http"
"github.com/go-kit/log"
"github.com/mcgtrt/toll-tracker/go-kit-example/aggsvc/aggendpoint"
"github.com/mcgtrt/toll-tracker/go-kit-example/aggsvc/aggservice"
"github.com/sony/gobreaker"
"golang.org/x/time/rate"
)
func NewHTTPHandler(endpoints aggendpoint.Set, logger log.Logger) http.Handler {
options := []httptransport.ServerOption{
httptransport.ServerErrorEncoder(errorEncoder),
httptransport.ServerErrorHandler(transport.NewLogErrorHandler(logger)),
}
m := http.NewServeMux()
m.Handle("/aggregate", httptransport.NewServer(
endpoints.AggregateEndpoint,
decodeHTTPAggregateRequest,
encodeHTTPGenericResponse,
options...,
))
m.Handle("/invoice", httptransport.NewServer(
endpoints.CalculateEndpoint,
decodeHTTPCalculateRequest,
encodeHTTPGenericResponse,
options...,
))
return m
}
func NewHTTPClient(instance string, logger log.Logger) (aggservice.Service, error) {
if !strings.HasPrefix(instance, "http") {
instance = "http://" + instance
}
u, err := url.Parse(instance)
if err != nil {
return nil, err
}
limiter := ratelimit.NewErroringLimiter(rate.NewLimiter(rate.Every(time.Second), 100))
var options []httptransport.ClientOption
var aggregateEndpoint endpoint.Endpoint
{
aggregateEndpoint = httptransport.NewClient(
"POST",
copyURL(u, "/sum"),
encodeHTTPGenericRequest,
decodeHTTPAggregateResponse,
options...,
).Endpoint()
aggregateEndpoint = limiter(aggregateEndpoint)
aggregateEndpoint = circuitbreaker.Gobreaker(gobreaker.NewCircuitBreaker(gobreaker.Settings{
Name: "Sum",
Timeout: 30 * time.Second,
}))(aggregateEndpoint)
}
// The Concat endpoint is the same thing, with slightly different
// middlewares to demonstrate how to specialize per-endpoint.
var calculateEndpoint endpoint.Endpoint
{
calculateEndpoint = httptransport.NewClient(
"POST",
copyURL(u, "/concat"),
encodeHTTPGenericRequest,
decodeHTTPCalculateResponse,
options...,
).Endpoint()
calculateEndpoint = limiter(calculateEndpoint)
calculateEndpoint = circuitbreaker.Gobreaker(gobreaker.NewCircuitBreaker(gobreaker.Settings{
Name: "Concat",
Timeout: 10 * time.Second,
}))(calculateEndpoint)
}
// Returning the endpoint.Set as a service.Service relies on the
// endpoint.Set implementing the Service methods. That's just a simple bit
// of glue code.
return aggendpoint.Set{
AggregateEndpoint: aggregateEndpoint,
CalculateEndpoint: calculateEndpoint,
}, nil
}
func decodeHTTPAggregateRequest(_ context.Context, r *http.Request) (interface{}, error) {
var req aggendpoint.AggregateRequest
err := json.NewDecoder(r.Body).Decode(&req)
return req, err
}
func decodeHTTPAggregateResponse(_ context.Context, r *http.Response) (interface{}, error) {
if r.StatusCode != http.StatusOK {
return nil, errors.New(r.Status)
}
var resp aggendpoint.AggregateResponse
err := json.NewDecoder(r.Body).Decode(&resp)
return resp, err
}
func decodeHTTPCalculateRequest(_ context.Context, r *http.Request) (interface{}, error) {
var req aggendpoint.CalculateRequest
err := json.NewDecoder(r.Body).Decode(&req)
return req, err
}
func decodeHTTPCalculateResponse(_ context.Context, r *http.Response) (interface{}, error) {
if r.StatusCode != http.StatusOK {
return nil, errors.New(r.Status)
}
var resp aggendpoint.CalculateResponse
err := json.NewDecoder(r.Body).Decode(&resp)
return resp, err
}
func encodeHTTPGenericRequest(_ context.Context, r *http.Request, request interface{}) error {
var buf bytes.Buffer
if err := json.NewEncoder(&buf).Encode(request); err != nil {
return err
}
r.Body = io.NopCloser(&buf)
return nil
}
func encodeHTTPGenericResponse(ctx context.Context, w http.ResponseWriter, response interface{}) error {
if f, ok := response.(endpoint.Failer); ok && f.Failed() != nil {
errorEncoder(ctx, f.Failed(), w)
return nil
}
w.Header().Set("Content-Type", "application/json; charset=utf-8")
return json.NewEncoder(w).Encode(response)
}
func errorEncoder(_ context.Context, err error, w http.ResponseWriter) {
json.NewEncoder(w).Encode(map[string]string{"err": err.Error()})
}
func copyURL(base *url.URL, path string) *url.URL {
next := *base
next.Path = path
return &next
}