fix: add information about target response into error message if inte… (#8281)

# Which Problems Are Solved

Execution responses with HTTP StatusCode not equal to 200 interrupt the
client request silently.

# How the Problems Are Solved

Adds information about the recieved StatusCode and Body into the error
if StatusCode not 200.

# Additional Context

Closes #8177

---------

Co-authored-by: Elio Bischof <elio@zitadel.com>
Co-authored-by: Livio Spring <livio.a@gmail.com>

internal/execution/execution.go

@@ -3,12 +3,14 @@ package execution
 import (
 	"bytes"
 	"context"
+	"encoding/json"
 	"io"
 	"net/http"
 	"time"
 
 	"github.com/zitadel/logging"
 
+	zhttp "github.com/zitadel/zitadel/internal/api/http"
 	"github.com/zitadel/zitadel/internal/domain"
 	"github.com/zitadel/zitadel/internal/telemetry/tracing"
 	"github.com/zitadel/zitadel/internal/zerrors"
@@ -114,9 +116,35 @@ func Call(ctx context.Context, url string, timeout time.Duration, body []byte) (
 	}
 	defer resp.Body.Close()
 
+	return HandleResponse(resp)
+}
+
+func HandleResponse(resp *http.Response) ([]byte, error) {
+	data, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
 	// Check for success between 200 and 299, redirect 300 to 399 is handled by the client, return error with statusCode >= 400
 	if resp.StatusCode >= 200 && resp.StatusCode <= 299 {
-		return io.ReadAll(resp.Body)
+		var errorBody ErrorBody
+		if err := json.Unmarshal(data, &errorBody); err != nil {
+			// if json unmarshal fails, body has no ErrorBody information, so will be taken as successful response
+			return data, nil
+		}
+		if errorBody.ForwardedStatusCode != 0 || errorBody.ForwardedErrorMessage != "" {
+			if errorBody.ForwardedStatusCode >= 400 && errorBody.ForwardedStatusCode < 500 {
+				return nil, zhttp.HTTPStatusCodeToZitadelError(nil, errorBody.ForwardedStatusCode, "EXEC-reUaUZCzCp", errorBody.ForwardedErrorMessage)
+			}
+			return nil, zerrors.ThrowPreconditionFailed(nil, "EXEC-bmhNhpcqpF", errorBody.ForwardedErrorMessage)
+		}
+		// no ErrorBody filled in response, so will be taken as successful response
+		return data, nil
 	}
-	return nil, zerrors.ThrowUnknown(nil, "EXEC-dra6yamk98", "Errors.Execution.Failed")
+
+	return nil, zerrors.ThrowPreconditionFailed(nil, "EXEC-dra6yamk98", "Errors.Execution.Failed")
+}
+
+type ErrorBody struct {
+	ForwardedStatusCode   int    `json:"forwardedStatusCode,omitempty"`
+	ForwardedErrorMessage string `json:"forwardedErrorMessage,omitempty"`
 }