properly handle echo http wrapped errors

internal/api/router.go

@@ -98,22 +98,31 @@ func (r *Router) Routes(rg *echo.Group) {
 
 func errorMiddleware(next echo.HandlerFunc) echo.HandlerFunc {
 	return func(c echo.Context) error {
-		err := next(c)
+		origErr := next(c)
 
-		if err == nil {
+		if origErr == nil {
 			return nil
 		}
 
-		// If error is an echo.HTTPError simply return it
-		if _, ok := err.(*echo.HTTPError); ok {
-			return err
+		var (
+			checkErr = origErr
+			echoMsg  []any
+		)
+
+		// If error is an echo.HTTPError, extract it's message to be reused if status is rewritten.
+		// Additionally we unwrap the internal error which is then checked instead of the echo error.
+		if eerr, ok := origErr.(*echo.HTTPError); ok {
+			echoMsg = []any{eerr.Message}
+			checkErr = eerr.Internal
 		}
 
 		switch {
-		case errors.Is(err, context.Canceled):
-			return echo.ErrUnprocessableEntity.WithInternal(err)
+		// Only if the error is a context canceled error and the request context has been canceled.
+		// If the request was not canceled, then the context canceled error probably came from the service.
+		case errors.Is(checkErr, context.Canceled) && errors.Is(c.Request().Context().Err(), context.Canceled):
+			return echo.NewHTTPError(http.StatusUnprocessableEntity, echoMsg...).WithInternal(checkErr)
 		default:
-			return err
+			return origErr
 		}
 	}
 }

internal/api/router_test.go

@@ -2,6 +2,7 @@ package api
 
 import (
 	"context"
+	"encoding/json"
 	"io"
 	"net/http"
 	"net/http/httptest"
@@ -19,6 +20,8 @@ func TestErrorMiddleware(t *testing.T) {
 	ctx := context.Background()
 
 	e := echo.New()
+	e.Debug = true
+
 	e.Use(echoTestLogger(t, e))
 	e.Use(errorMiddleware)
 
@@ -27,7 +30,15 @@ func TestErrorMiddleware(t *testing.T) {
 
 		select {
 		case <-c.Request().Context().Done():
-			return c.Request().Context().Err()
+			err := c.Request().Context().Err()
+
+			switch errType {
+			case "":
+			case "echo":
+				return echo.NewHTTPError(http.StatusInternalServerError, "some message").WithInternal(err)
+			}
+
+			return err
 		case <-time.After(time.Second):
 		}
 
@@ -37,6 +48,8 @@ func TestErrorMiddleware(t *testing.T) {
 			return echo.ErrTeapot
 		case "other":
 			return io.ErrUnexpectedEOF
+		case "internalCancel":
+			return echo.NewHTTPError(http.StatusInternalServerError, "service error").WithInternal(context.Canceled)
 		}
 
 		return nil
@@ -97,6 +110,55 @@ func TestErrorMiddleware(t *testing.T) {
 				assert.Equal(t, http.StatusUnprocessableEntity, res.Success.Code)
 			},
 		},
+		{
+			Name: "Canceled echo",
+			Input: testinput{
+				path:  "/test?error=echo",
+				delay: time.Second / 2,
+			},
+			CheckFn: func(_ context.Context, t *testing.T, res testingx.TestResult[*httptest.ResponseRecorder]) {
+				require.NoError(t, res.Err)
+				require.NotNil(t, res.Success)
+
+				require.Equal(t, http.StatusUnprocessableEntity, res.Success.Code)
+
+				resp := map[string]string{}
+
+				err := json.Unmarshal(res.Success.Body.Bytes(), &resp)
+				require.NoError(t, err, "no error expected decoding response body")
+
+				expect := map[string]string{
+					"error":   "code=422, message=some message, internal=context canceled",
+					"message": "some message",
+				}
+
+				assert.Equal(t, expect, resp, "unexpected response")
+			},
+		},
+		{
+			Name: "Canceled echo internal",
+			Input: testinput{
+				path: "/test?error=internalCancel",
+			},
+			CheckFn: func(_ context.Context, t *testing.T, res testingx.TestResult[*httptest.ResponseRecorder]) {
+				require.NoError(t, res.Err)
+				require.NotNil(t, res.Success)
+
+				require.Equal(t, http.StatusInternalServerError, res.Success.Code)
+
+				resp := map[string]string{}
+
+				err := json.Unmarshal(res.Success.Body.Bytes(), &resp)
+				require.NoError(t, err, "no error expected decoding response body")
+
+				expect := map[string]string{
+					"error":   "code=500, message=service error, internal=context canceled",
+					"message": "service error",
+				}
+
+				assert.Equal(t, expect, resp, "unexpected response")
+			},
+		},
 	}
 
 	testFn := func(ctx context.Context, input testinput) testingx.TestResult[*httptest.ResponseRecorder] {