Merge pull request #28 from retail-ai-inc/feature/error-handler-middl…

…eware

SCT-156 Build: ErrorHandlerMiddleware pattern in Bean framework

internal/project/framework/bean.go

@@ -10,21 +10,32 @@ import (
 	/**#bean*/
 	validate "demo/framework/internals/validator"
 	/*#bean.replace(validate "{{ .PkgPath }}/framework/internals/validator")**/
-
+	/**#bean*/
+	berror "demo/framework/internals/error"
+	/*#bean.replace(berror "{{ .PkgPath }}/framework/internals/error")**/
 	"github.com/go-playground/validator/v10"
 	"github.com/labstack/echo/v4"
 	"github.com/spf13/viper"
 )
 
 type Bean struct {
-	Validate        func(c echo.Context, vd *validator.Validate)
-	BeforeBootstrap func()
+	Validate                func(c echo.Context, vd *validator.Validate)
+	BeforeBootstrap         func()
+	errorHandlerMiddlewares []berror.ErrorHandlerMiddleware
 }
 
 func (b *Bean) Bootstrap() {
 	// Create a new echo instance
 	e := bootstrap.New()
 
+	b.UseErrorHandlerMiddleware(
+		berror.ValidationErrorHanderMiddleware,
+		berror.APIErrorHanderMiddleware,
+		berror.HTTPErrorHanderMiddleware,
+		berror.DefaultErrorHanderMiddleware,
+	)
+
+	e.HTTPErrorHandler = berror.ErrorHandlerChain(b.errorHandlerMiddlewares...)
 	// before bean bootstrap
 	if b.BeforeBootstrap != nil {
 		b.BeforeBootstrap()
@@ -44,3 +55,10 @@ func (b *Bean) Bootstrap() {
 		e.Logger.Fatal(err)
 	}
 }
+
+func (b *Bean) UseErrorHandlerMiddleware(errorHandlerMiddleware ...berror.ErrorHandlerMiddleware) {
+	if b.errorHandlerMiddlewares == nil {
+		b.errorHandlerMiddlewares = []berror.ErrorHandlerMiddleware{}
+	}
+	b.errorHandlerMiddlewares = append(b.errorHandlerMiddlewares, errorHandlerMiddleware...)
+}

internal/project/framework/bootstrap/kernel.go

@@ -16,9 +16,6 @@ import (
 	"demo/framework/internals/binder"
 	/*#bean.replace("{{ .PkgPath }}/framework/internals/binder")**/
 	/**#bean*/
-	ierror "demo/framework/internals/error"
-	/*#bean.replace(ierror "{{ .PkgPath }}/framework/internals/error")**/
-	/**#bean*/
 	"demo/framework/internals/global"
 	/*#bean.replace("{{ .PkgPath }}/framework/internals/global")**/
 	/**#bean*/
@@ -55,9 +52,6 @@ func New() *echo.Echo {
 	// Initialize the global echo instance. This is useful to print log from `internals` packages.
 	global.EchoInstance = e
 
-	// This will handle invalid JSON and other errors.
-	e.HTTPErrorHandler = ierror.HTTPErrorHandler
-
 	// Hide default `Echo` banner during startup.
 	e.HideBanner = true
 

internal/project/framework/internals/error/error_middleware.go

@@ -0,0 +1,109 @@
+/**#bean*/ /*#bean.replace({{ .Copyright }})**/
+
+package error
+
+import (
+	/**#bean*/
+	"demo/framework/internals/sentry"
+	/*#bean.replace("{{ .PkgPath }}/framework/internals/sentry")**/
+	/**#bean*/
+	"demo/framework/internals/validator"
+	/*#bean.replace("{{ .PkgPath }}/framework/internals/validator")**/
+	"github.com/labstack/echo/v4"
+	"net/http"
+	"strings"
+)
+
+// return value: bool is true when HandlerMiddleware match the error,otherwise false
+// return value: error will be sent to sentry if not nil
+
+type ErrorHandlerMiddleware func(err error, c echo.Context) (bool, error)
+
+func ErrorHandlerChain(middlewares ...ErrorHandlerMiddleware) echo.HTTPErrorHandler {
+	return func(err error, c echo.Context) {
+
+		if c.Response().Committed {
+			return
+		}
+
+		for _, middleware := range middlewares {
+			catched, e := middleware(err, c)
+			if e != nil {
+				sentry.PushData(c, e, nil, true)
+			}
+			if catched {
+				break
+			}
+		}
+	}
+}
+
+func ValidationErrorHanderMiddleware(e error, c echo.Context) (bool, error) {
+	he, ok := e.(*validator.ValidationError)
+	if !ok {
+		return false, nil
+	}
+	err := c.JSON(http.StatusUnprocessableEntity, errorResp{
+		ErrorCode: API_DATA_VALIDATION_FAILED,
+		Errors:    he.ErrCollection(),
+		ErrorMsg:  nil,
+	})
+
+	return ok, err
+}
+
+func APIErrorHanderMiddleware(e error, c echo.Context) (bool, error) {
+	he, ok := e.(*APIError)
+	if !ok {
+		return false, nil
+	}
+
+	if he.HTTPStatusCode >= 404 {
+		sentry.PushData(c, he, nil, true)
+	}
+
+	err := c.JSON(he.HTTPStatusCode, errorResp{
+		ErrorCode: he.GlobalErrCode,
+		Errors:    nil,
+		ErrorMsg:  he.Error(),
+	})
+
+	return ok, err
+}
+
+func HTTPErrorHanderMiddleware(e error, c echo.Context) (bool, error) {
+	he, ok := e.(*echo.HTTPError)
+	if !ok {
+		return false, nil
+	}
+
+	// Just in case to capture this unused type error.
+	err := c.JSON(he.Code, errorResp{
+		ErrorCode: UNKNOWN_ERROR_CODE,
+		Errors:    nil,
+		ErrorMsg:  he.Message,
+	})
+
+	return ok, err
+}
+
+func DefaultErrorHanderMiddleware(_ error, c echo.Context) (bool, error) {
+	// Get Content-Type parameter from request header to identify the request content type. If the request is for
+	// html then we should display the error in html.
+	contentType := c.Request().Header.Get("Content-Type")
+
+	if strings.ToLower(contentType) == "text/html" {
+		err := c.HTML(http.StatusInternalServerError, "<strong>Internal server error.</strong>")
+		return true, err
+	}
+
+	// All other panic errors.
+	// Sentry already captured the panic and send notification in sentry-recover middleware.
+	err := c.JSON(http.StatusInternalServerError, errorResp{
+		ErrorCode: INTERNAL_SERVER_ERROR,
+		Errors:    nil,
+		ErrorMsg:  nil, // TODO: Put some generic message.
+	})
+
+	return true, err
+}

internal/project/framework/internals/error/error_middleware_test.go

@@ -0,0 +1,153 @@
+/**#bean*/ /*#bean.replace({{ .Copyright }})**/
+
+package error
+
+import (
+	/**#bean*/
+	bvalidator "demo/framework/internals/validator"
+	/*#bean.replace(bvalidator "{{ .PkgPath }}/framework/internals/validator")**/
+	"encoding/json"
+	"errors"
+	"github.com/go-playground/validator/v10"
+	"github.com/labstack/echo/v4"
+	"github.com/stretchr/testify/assert"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestErrorHandlerChain(t *testing.T) {
+	e := echo.New()
+	e.HTTPErrorHandler = ErrorHandlerChain(
+		FakeErrorHandlerMiddleware,
+		ValidationErrorHanderMiddleware,
+		APIErrorHanderMiddleware,
+		HTTPErrorHanderMiddleware,
+		DefaultErrorHanderMiddleware)
+
+	//assert fake error
+	fakeErr := newFakeError("fake error message")
+	checkFakeErr := func(response *httptest.ResponseRecorder, err error) {
+		assert.Equal(t, fakeErr, err)
+		assert.Equal(t, http.StatusInternalServerError, response.Code)
+		var res errorResp
+		e := json.Unmarshal(response.Body.Bytes(), &res)
+		assert.Nil(t, e)
+		assert.Equal(t, ErrorCode("fakeErrorCode"), res.ErrorCode)
+		assert.Nil(t, res.Errors)
+		assert.Equal(t, fakeErr.Error(), res.ErrorMsg)
+	}
+	run(e, fakeErr, checkFakeErr)
+
+	//assert api error
+	apiErr := NewAPIError(http.StatusUnauthorized, UNAUTHORIZED_ACCESS, errors.New("UNAUTHORIZED"))
+	checkAPIErr := func(response *httptest.ResponseRecorder, err error) {
+		assert.Equal(t, apiErr, err)
+		assert.Equal(t, http.StatusUnauthorized, response.Code)
+		var res errorResp
+		e := json.Unmarshal(response.Body.Bytes(), &res)
+		assert.Nil(t, e)
+		assert.Equal(t, UNAUTHORIZED_ACCESS, res.ErrorCode)
+		assert.Nil(t, res.Errors)
+		assert.Equal(t, apiErr.Error(), res.ErrorMsg)
+	}
+	run(e, apiErr, checkAPIErr)
+
+	//assert validation error
+	validationErr := &bvalidator.ValidationError{
+		Err: validator.ValidationErrors([]validator.FieldError{}),
+	}
+	checkValidationErr := func(response *httptest.ResponseRecorder, err error) {
+		assert.Equal(t, validationErr, err)
+		assert.Equal(t, http.StatusUnprocessableEntity, response.Code)
+		var res errorResp
+		e := json.Unmarshal(response.Body.Bytes(), &res)
+		assert.Nil(t, e)
+		assert.Equal(t, API_DATA_VALIDATION_FAILED, res.ErrorCode)
+		assert.Nil(t, res.ErrorMsg)
+	}
+	run(e, validationErr, checkValidationErr)
+
+	//assert http error
+	httpErr := &echo.HTTPError{
+		Code:    http.StatusNotFound,
+		Message: "404 Not Found",
+	}
+	checkHttpErr := func(response *httptest.ResponseRecorder, err error) {
+		assert.Equal(t, httpErr, err)
+		assert.Equal(t, http.StatusNotFound, response.Code)
+		var res errorResp
+		e := json.Unmarshal(response.Body.Bytes(), &res)
+		assert.Nil(t, e)
+		assert.Equal(t, UNKNOWN_ERROR_CODE, res.ErrorCode)
+		assert.Nil(t, res.Errors)
+		assert.Equal(t, httpErr.Message, res.ErrorMsg)
+	}
+	run(e, httpErr, checkHttpErr)
+
+	//assert default error
+	defaultErr := errors.New("default error")
+	checkDefaultErr := func(response *httptest.ResponseRecorder, err error) {
+		assert.Equal(t, defaultErr, err)
+		assert.Equal(t, http.StatusInternalServerError, response.Code)
+		var res errorResp
+		e := json.Unmarshal(response.Body.Bytes(), &res)
+		assert.Equal(t, http.StatusInternalServerError, response.Code)
+		assert.Nil(t, e)
+		assert.Equal(t, INTERNAL_SERVER_ERROR, res.ErrorCode)
+		assert.Nil(t, res.Errors)
+		assert.Nil(t, res.ErrorMsg)
+	}
+	run(e, defaultErr, checkDefaultErr)
+}
+
+func FakeErrorHandlerMiddleware(e error, c echo.Context) (bool, error) {
+	he, ok := e.(*fakeError)
+	if !ok {
+		return false, nil
+	}
+
+	err := c.JSON(http.StatusInternalServerError, errorResp{
+		ErrorCode: "fakeErrorCode",
+		Errors:    nil,
+		ErrorMsg:  he.Error(),
+	})
+
+	return ok, err
+}
+
+func run(e *echo.Echo,
+	err error,
+	assertFunc func(response *httptest.ResponseRecorder, err error),
+) {
+	req := httptest.NewRequest(http.MethodGet, "/", nil)
+	runWithRequest(e, req, err, assertFunc)
+}
+
+func runWithRequest(e *echo.Echo,
+	req *http.Request,
+	er error,
+	assertFunc func(response *httptest.ResponseRecorder, err error),
+) {
+	rec := httptest.NewRecorder()
+	c := e.NewContext(req, rec)
+	err := func(c echo.Context) error {
+		return er
+	}(c)
+	e.HTTPErrorHandler(err, c)
+	assertFunc(rec, err)
+}
+
+type fakeError struct {
+	Message string
+}
+
+func (f *fakeError) Error() string {
+	return f.Message
+}
+
+func newFakeError(msg string) error {
+	return &fakeError{
+		Message: msg,
+	}
+}

internal/project/main.go

@@ -37,5 +37,11 @@ func main() {
 		// Add your own validation function here.
 	}
 
+	// Below is an example of how you can set custom error handler middleware
+	// bean can call `UseErrorHandlerMiddleware` multiple times
+	bean.UseErrorHandlerMiddleware(func(e error, c echo.Context) (bool, error) {
+		return false, nil
+	})
+
 	bean.Bootstrap()
 }