Don't strip trailing slashes when generating service profiles (#11519)

When using the `linkerd profile` command with the `--open-api` flag to generate a service profile from a swagger file, we combine each route's base path with it's relative path to get the full path used in the service profile.  However, we use `path.Join` to do so, which strips trailing slashes, leaving the final path different from the intended one.

We avoid using `path.Join`, instead joining the paths manually to avoid stripping trailing slashes.

Signed-off-by: Alex Leong <alex@buoyant.io>

pkg/profiles/openapi.go

@@ -4,8 +4,8 @@ import (
 	"fmt"
 	"io"
 	"net/http"
-	"path"
 	"sort"
+	"strings"
 
 	"github.com/go-openapi/spec"
 	sp "github.com/linkerd/linkerd2/controller/gen/apis/serviceprofile/v1alpha2"
@@ -67,9 +67,10 @@ func swaggerToServiceProfile(swagger spec.Swagger, namespace, name, clusterDomai
 		sort.Strings(paths)
 	}
 
+	base := strings.TrimRight(swagger.BasePath, "/")
 	for _, relPath := range paths {
 		item := swagger.Paths.Paths[relPath]
-		path := path.Join(swagger.BasePath, relPath)
+		path := base + "/" + strings.TrimLeft(relPath, "/")
 		pathRegex := PathToRegex(path)
 		if item.Delete != nil {
 			spec := MkRouteSpec(path, pathRegex, http.MethodDelete, item.Delete)

pkg/profiles/openapi_test.go

@@ -35,6 +35,11 @@ func TestSwaggerToServiceProfile(t *testing.T) {
 							},
 						},
 					},
+					"/path/with/trailing/slash/": {
+						PathItemProps: spec.PathItemProps{
+							Get: &spec.Operation{},
+						},
+					},
 				},
 			},
 		},
@@ -68,6 +73,13 @@ func TestSwaggerToServiceProfile(t *testing.T) {
 					IsRetryable: true,
 					Timeout:     "60s",
 				},
+				{
+					Name: "GET /path/with/trailing/slash/",
+					Condition: &sp.RequestMatch{
+						PathRegex: "/path/with/trailing/slash/",
+						Method:    "GET",
+					},
+				},
 			},
 		},
 	}