GRPC: Log user-initiated cancellations as HTTP 408 (#5546)

- Log user-initiated cancellations as HTTP 408 instead of HTTP 500
- Only check status code of `err` if an error was intercepted

Fixes #5444

grpc/interceptors.go

@@ -15,6 +15,7 @@ import (
 	"google.golang.org/grpc/status"
 
 	berrors "github.com/letsencrypt/boulder/errors"
+	"github.com/letsencrypt/boulder/probs"
 )
 
 const (
@@ -201,12 +202,15 @@ func (ci *clientInterceptor) intercept(
 	err := invoker(localCtx, fullMethod, req, reply, cc, opts...)
 	if err != nil {
 		err = unwrapError(err, respMD)
-	}
-	if status.Code(err) == codes.DeadlineExceeded {
-		return deadlineDetails{
-			service: service,
-			method:  method,
-			latency: ci.clk.Since(begin),
+		switch status.Code(err) {
+		case codes.DeadlineExceeded:
+			return deadlineDetails{
+				service: service,
+				method:  method,
+				latency: ci.clk.Since(begin),
+			}
+		case codes.Canceled:
+			return probs.Canceled(err.Error())
 		}
 	}
 	return err

grpc/interceptors_test.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"log"
 	"net"
+	"net/http"
 	"strconv"
 	"strings"
 	"sync"
@@ -16,9 +17,11 @@ import (
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/status"
 
 	"github.com/letsencrypt/boulder/grpc/test_proto"
 	"github.com/letsencrypt/boulder/metrics"
+	"github.com/letsencrypt/boulder/probs"
 	"github.com/letsencrypt/boulder/test"
 )
 
@@ -33,8 +36,11 @@ func testHandler(_ context.Context, i interface{}) (interface{}, error) {
 }
 
 func testInvoker(_ context.Context, method string, _, _ interface{}, _ *grpc.ClientConn, opts ...grpc.CallOption) error {
-	if method == "-service-brokeTest" {
+	switch method {
+	case "-service-brokeTest":
 		return errors.New("")
+	case "-service-requesterCanceledTest":
+		return status.Error(1, context.Canceled.Error())
 	}
 	fc.Sleep(time.Second)
 	return nil
@@ -71,6 +77,14 @@ func TestClientInterceptor(t *testing.T) {
 
 	err = ci.intercept(context.Background(), "-service-brokeTest", nil, nil, nil, testInvoker)
 	test.AssertError(t, err, "ci.intercept didn't fail when handler returned a error")
+
+	err = ci.intercept(context.Background(), "-service-requesterCanceledTest", nil, nil, nil, testInvoker)
+	test.AssertError(t, err, "ci.intercept didn't fail when handler returned a error")
+
+	var probDetails *probs.ProblemDetails
+	test.AssertErrorWraps(t, err, &probDetails)
+	test.AssertEquals(t, probDetails.Type, probs.MalformedProblem)
+	test.AssertEquals(t, probDetails.HTTPStatus, http.StatusRequestTimeout)
 }
 
 // TestFailFastFalse sends a gRPC request to a backend that is

probs/probs.go

@@ -161,6 +161,19 @@ func Malformed(detail string, args ...interface{}) *ProblemDetails {
 	}
 }
 
+// Canceled returns a ProblemDetails with a MalformedProblem and a 408 Request
+// Timeout status code.
+func Canceled(detail string, args ...interface{}) *ProblemDetails {
+	if len(args) > 0 {
+		detail = fmt.Sprintf(detail, args...)
+	}
+	return &ProblemDetails{
+		Type:       MalformedProblem,
+		Detail:     detail,
+		HTTPStatus: http.StatusRequestTimeout,
+	}
+}
+
 // BadSignatureAlgorithm returns a ProblemDetails with a BadSignatureAlgorithmProblem
 // and a 400 Bad Request status code.
 func BadSignatureAlgorithm(detail string, a ...interface{}) *ProblemDetails {