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package addtransport
import (
"context"
"time"
"golang.org/x/time/rate"
"github.com/sony/gobreaker"
"github.com/go-kit/kit/circuitbreaker"
"github.com/go-kit/kit/endpoint"
"github.com/go-kit/kit/ratelimit"
"github.com/go-kit/kit/examples/addsvc/pkg/addendpoint"
"github.com/go-kit/kit/examples/addsvc/pkg/addservice"
addthrift "github.com/go-kit/kit/examples/addsvc/thrift/gen-go/addsvc"
)
type thriftServer struct {
ctx context.Context
endpoints addendpoint.Set
}
// NewThriftServer makes a set of endpoints available as a Thrift service.
func NewThriftServer(endpoints addendpoint.Set) addthrift.AddService {
return &thriftServer{
endpoints: endpoints,
}
}
func (s *thriftServer) Sum(ctx context.Context, a int64, b int64) (*addthrift.SumReply, error) {
request := addendpoint.SumRequest{A: int(a), B: int(b)}
response, err := s.endpoints.SumEndpoint(ctx, request)
if err != nil {
return nil, err
}
resp := response.(addendpoint.SumResponse)
return &addthrift.SumReply{Value: int64(resp.V), Err: err2str(resp.Err)}, nil
}
func (s *thriftServer) Concat(ctx context.Context, a string, b string) (*addthrift.ConcatReply, error) {
request := addendpoint.ConcatRequest{A: a, B: b}
response, err := s.endpoints.ConcatEndpoint(ctx, request)
if err != nil {
return nil, err
}
resp := response.(addendpoint.ConcatResponse)
return &addthrift.ConcatReply{Value: resp.V, Err: err2str(resp.Err)}, nil
}
// NewThriftClient returns an AddService backed by a Thrift server described by
// the provided client. The caller is responsible for constructing the client,
// and eventually closing the underlying transport. We bake-in certain middlewares,
// implementing the client library pattern.
func NewThriftClient(client *addthrift.AddServiceClient) addservice.Service {
// We construct a single ratelimiter middleware, to limit the total outgoing
// QPS from this client to all methods on the remote instance. We also
// construct per-endpoint circuitbreaker middlewares to demonstrate how
// that's done, although they could easily be combined into a single breaker
// for the entire remote instance, too.
limiter := ratelimit.NewErroringLimiter(rate.NewLimiter(rate.Every(time.Second), 100))
// Each individual endpoint is an http/transport.Client (which implements
// endpoint.Endpoint) that gets wrapped with various middlewares. If you
// could rely on a consistent set of client behavior.
var sumEndpoint endpoint.Endpoint
{
sumEndpoint = MakeThriftSumEndpoint(client)
sumEndpoint = limiter(sumEndpoint)
sumEndpoint = circuitbreaker.Gobreaker(gobreaker.NewCircuitBreaker(gobreaker.Settings{
Name: "Sum",
Timeout: 30 * time.Second,
}))(sumEndpoint)
}
// The Concat endpoint is the same thing, with slightly different
// middlewares to demonstrate how to specialize per-endpoint.
var concatEndpoint endpoint.Endpoint
{
concatEndpoint = MakeThriftConcatEndpoint(client)
concatEndpoint = limiter(concatEndpoint)
concatEndpoint = circuitbreaker.Gobreaker(gobreaker.NewCircuitBreaker(gobreaker.Settings{
Name: "Concat",
Timeout: 10 * time.Second,
}))(concatEndpoint)
}
// 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 addendpoint.Set{
SumEndpoint: sumEndpoint,
ConcatEndpoint: concatEndpoint,
}
}
// MakeThriftSumEndpoint returns an endpoint that invokes the passed Thrift client.
// Useful only in clients, and only until a proper transport/thrift.Client exists.
func MakeThriftSumEndpoint(client *addthrift.AddServiceClient) endpoint.Endpoint {
return func(ctx context.Context, request interface{}) (interface{}, error) {
req := request.(addendpoint.SumRequest)
reply, err := client.Sum(ctx, int64(req.A), int64(req.B))
if err == addservice.ErrIntOverflow {
return nil, err // special case; see comment on ErrIntOverflow
}
return addendpoint.SumResponse{V: int(reply.Value), Err: err}, nil
}
}
// MakeThriftConcatEndpoint returns an endpoint that invokes the passed Thrift
// client. Useful only in clients, and only until a proper
// transport/thrift.Client exists.
func MakeThriftConcatEndpoint(client *addthrift.AddServiceClient) endpoint.Endpoint {
return func(ctx context.Context, request interface{}) (interface{}, error) {
req := request.(addendpoint.ConcatRequest)
reply, err := client.Concat(ctx, req.A, req.B)
return addendpoint.ConcatResponse{V: reply.Value, Err: err}, nil
}
}
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