Better messages when interaction cannot be fonud

hack/generated/pkg/testcommon/error_translating_roundtripper.go

@@ -0,0 +1,100 @@
+/*
+Copyright (c) Microsoft Corporation.
+Licensed under the MIT license.
+*/
+
+package testcommon
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+
+	"github.com/dnaeon/go-vcr/cassette"
+	"github.com/dnaeon/go-vcr/recorder"
+	"github.com/google/go-cmp/cmp"
+)
+
+// translateErrors wraps the given Recorder to handle any "Requested interaction not found"
+// and log better information about what the expected request was.
+//
+// By default the error will be returned to the controller which might ignore/retry it
+// and not log any useful information. So instead here we find  the recorded request with
+// the body that most closely matches what was sent and report the "expected" body.
+//
+// Ideally we would panic on this error but we don't have a good way to deal with the following
+// problem at the moment:
+// - during record the controller does GET (404), PUT, … GET (OK)
+// - during playback the controller does GET (which now returns OK), DELETE, PUT, …
+//   and fails due to a missing DELETE recording
+func translateErrors(r *recorder.Recorder, cassetteName string) http.RoundTripper {
+	return errorTranslation{r, cassetteName, nil}
+}
+
+type errorTranslation struct {
+	recorder     *recorder.Recorder
+	cassetteName string
+
+	cassette *cassette.Cassette
+}
+
+func (w errorTranslation) ensure_cassette() *cassette.Cassette {
+	if w.cassette == nil {
+		cassette, err := cassette.Load(w.cassetteName)
+		if err != nil {
+			panic(fmt.Sprintf("unable to load casette %q", w.cassetteName))
+		}
+
+		w.cassette = cassette
+	}
+
+	return w.cassette
+}
+
+func (w errorTranslation) RoundTrip(req *http.Request) (*http.Response, error) {
+	resp, originalErr := w.recorder.RoundTrip(req)
+	// sorry, go-vcr doesn't expose the error type or message
+	if originalErr == nil || !strings.Contains(originalErr.Error(), "interaction not found") {
+		return resp, originalErr
+	}
+
+	sentBodyString := "<nil>"
+	if req.Body != nil {
+		bodyBytes, bodyErr := io.ReadAll(req.Body)
+		if bodyErr != nil {
+			// see invocation of SetMatcher in the createRecorder, which does this
+			panic("io.ReadAll(req.Body) failed, this should always succeed because req.Body has been replaced by a buffer")
+		}
+
+		sentBodyString = string(bodyBytes)
+	}
+
+	// find all request bodies for the specified method/URL combination
+	urlString := req.URL.String()
+	var bodiesForMethodAndURL []string
+	for _, interaction := range w.ensure_cassette().Interactions {
+		if urlString == interaction.URL && req.Method == interaction.Request.Method &&
+			req.Header.Get(COUNT_HEADER) == interaction.Request.Headers.Get(COUNT_HEADER) {
+			bodiesForMethodAndURL = append(bodiesForMethodAndURL, interaction.Request.Body)
+			break
+		}
+	}
+
+	if len(bodiesForMethodAndURL) == 0 {
+		fmt.Printf("\n*** Cannot find go-vcr recording for request (no responses recorded for this method/URL): %s %s (attempt: %s)\n\n", req.Method, req.URL.String(), req.Header.Get(COUNT_HEADER))
+		return nil, originalErr
+	}
+
+	// locate the request body with the shortest diff from the sent body
+	shortestDiff := ""
+	for i, bodyString := range bodiesForMethodAndURL {
+		diff := cmp.Diff(sentBodyString, bodyString)
+		if i == 0 || len(diff) < len(shortestDiff) {
+			shortestDiff = diff
+		}
+	}
+
+	fmt.Printf("\n*** Cannot find go-vcr recording for request (body mismatch): %s %s\nShortest body diff: %s\n\n", req.Method, req.URL.String(), shortestDiff)
+	return nil, originalErr
+}

hack/generated/pkg/testcommon/test_context.go

@@ -7,7 +7,7 @@ package testcommon
 
 import (
 	"bytes"
-	"io/ioutil"
+	"io"
 	"log"
 	"net/http"
 	"strings"
@@ -56,7 +56,8 @@ func NewTestContext(region string, recordReplay bool) TestContext {
 }
 
 func (tc TestContext) ForTest(t *testing.T) (PerTestContext, error) {
-	authorizer, subscriptionID, recorder, err := createRecorder(t.Name(), tc.RecordReplay)
+	cassetteName := "recordings/" + t.Name()
+	authorizer, subscriptionID, recorder, err := createRecorder(cassetteName, tc.RecordReplay)
 	if err != nil {
 		return PerTestContext{}, errors.Wrapf(err, "creating recorder")
 	}
@@ -68,7 +69,7 @@ func (tc TestContext) ForTest(t *testing.T) (PerTestContext, error) {
 
 	// replace the ARM client transport (a bit hacky)
 	httpClient := armClient.RawClient.Sender.(*http.Client)
-	httpClient.Transport = recorder
+	httpClient.Transport = translateErrors(recorder, cassetteName)
 
 	t.Cleanup(func() {
 		if !t.Failed() {
@@ -92,9 +93,7 @@ func (tc TestContext) ForTest(t *testing.T) (PerTestContext, error) {
 	}, nil
 }
 
-func createRecorder(testName string, recordReplay bool) (autorest.Authorizer, string, *recorder.Recorder, error) {
-	cassetteName := "recordings/" + testName
-
+func createRecorder(cassetteName string, recordReplay bool) (autorest.Authorizer, string, *recorder.Recorder, error) {
 	var err error
 	var r *recorder.Recorder
 	if recordReplay {
@@ -134,7 +133,7 @@ func createRecorder(testName string, recordReplay bool) (autorest.Authorizer, st
 			return false
 		}
 
-		r.Body = ioutil.NopCloser(&b)
+		r.Body = io.NopCloser(&b)
 		return cassette.DefaultMatcher(r, i) && (b.String() == "" || b.String() == i.Body)
 	})