Timeout middleware implementation, and added go build tag so it build from go1.13 only

Author: Ilija Matoski

middleware/timeout.go

@@ -0,0 +1,81 @@
+// +build go1.13
+
+package middleware
+
+import (
+	"context"
+	"github.com/labstack/echo/v4"
+	"time"
+)
+
+type (
+	// TimeoutConfig defines the config for Timeout middleware.
+	TimeoutConfig struct {
+		// Skipper defines a function to skip middleware.
+		Skipper Skipper
+		// ErrorHandler defines a function which is executed for a timeout
+		// It can be used to define a custom timeout error
+		ErrorHandler TimeoutErrorHandlerWithContext
+		// Timeout configures a timeout for the middleware, defaults to 0 for no timeout
+		Timeout time.Duration
+	}
+
+	// TimeoutErrorHandlerWithContext is an error handler that is used with the timeout middleware so we can
+	// handle the error as we see fit
+	TimeoutErrorHandlerWithContext func(error, echo.Context) error
+)
+
+var (
+	// DefaultTimeoutConfig is the default Timeout middleware config.
+	DefaultTimeoutConfig = TimeoutConfig{
+		Skipper:      DefaultSkipper,
+		Timeout:      0,
+		ErrorHandler: nil,
+	}
+)
+
+// Timeout returns a middleware which recovers from panics anywhere in the chain
+// and handles the control to the centralized HTTPErrorHandler.
+func Timeout() echo.MiddlewareFunc {
+	return TimeoutWithConfig(DefaultTimeoutConfig)
+}
+
+// TimeoutWithConfig returns a Timeout middleware with config.
+// See: `Timeout()`.
+func TimeoutWithConfig(config TimeoutConfig) echo.MiddlewareFunc {
+	// Defaults
+	if config.Skipper == nil {
+		config.Skipper = DefaultTimeoutConfig.Skipper
+	}
+
+	return func(next echo.HandlerFunc) echo.HandlerFunc {
+		return func(c echo.Context) error {
+			if config.Skipper(c) || config.Timeout == 0 {
+				return next(c)
+			}
+
+			ctx, cancel := context.WithTimeout(c.Request().Context(), config.Timeout)
+			defer cancel()
+
+			// this does a deep clone of the context, wondering if there is a better way to do this?
+			c.SetRequest(c.Request().Clone(ctx))
+
+			done := make(chan error, 1)
+			go func() {
+				// This goroutine will keep running even if this middleware times out and
+				// will be stopped when ctx.Done() is called down the next(c) call chain
+				done <- next(c)
+			}()
+
+			select {
+			case <-ctx.Done():
+				if config.ErrorHandler != nil {
+					return config.ErrorHandler(ctx.Err(), c)
+				}
+				return ctx.Err()
+			case err := <-done:
+				return err
+			}
+		}
+	}
+}

middleware/timeout_test.go

@@ -0,0 +1,177 @@
+// +build go1.13
+
+package middleware
+
+import (
+	"context"
+	"errors"
+	"github.com/labstack/echo/v4"
+	"github.com/stretchr/testify/assert"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"reflect"
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestTimeoutSkipper(t *testing.T) {
+	t.Parallel()
+	m := TimeoutWithConfig(TimeoutConfig{
+		Skipper: func(context echo.Context) bool {
+			return true
+		},
+	})
+
+	req := httptest.NewRequest(http.MethodGet, "/", nil)
+	rec := httptest.NewRecorder()
+
+	e := echo.New()
+	c := e.NewContext(req, rec)
+
+	err := m(func(c echo.Context) error {
+		assert.NotEqual(t, "*context.timerCtx", reflect.TypeOf(c.Request().Context()).String())
+		return nil
+	})(c)
+
+	assert.NoError(t, err)
+}
+
+func TestTimeoutWithTimeout0(t *testing.T) {
+	t.Parallel()
+	m := TimeoutWithConfig(TimeoutConfig{
+		Timeout: 0,
+	})
+
+	req := httptest.NewRequest(http.MethodGet, "/", nil)
+	rec := httptest.NewRecorder()
+
+	e := echo.New()
+	c := e.NewContext(req, rec)
+
+	err := m(func(c echo.Context) error {
+		assert.NotEqual(t, "*context.timerCtx", reflect.TypeOf(c.Request().Context()).String())
+		return nil
+	})(c)
+
+	assert.NoError(t, err)
+}
+
+func TestTimeoutIsCancelable(t *testing.T) {
+	t.Parallel()
+	m := TimeoutWithConfig(TimeoutConfig{
+		Timeout: time.Minute,
+	})
+
+	req := httptest.NewRequest(http.MethodGet, "/", nil)
+	rec := httptest.NewRecorder()
+
+	e := echo.New()
+	c := e.NewContext(req, rec)
+
+	err := m(func(c echo.Context) error {
+		assert.EqualValues(t, "*context.timerCtx", reflect.TypeOf(c.Request().Context()).String())
+		return nil
+	})(c)
+
+	assert.NoError(t, err)
+}
+
+func TestTimeoutErrorOutInHandler(t *testing.T) {
+	t.Parallel()
+	m := Timeout()
+
+	req := httptest.NewRequest(http.MethodGet, "/", nil)
+	rec := httptest.NewRecorder()
+
+	e := echo.New()
+	c := e.NewContext(req, rec)
+
+	err := m(func(c echo.Context) error {
+		return errors.New("err")
+	})(c)
+
+	assert.Error(t, err)
+}
+
+func TestTimeoutTimesOutAfterPredefinedTimeoutWithErrorHandler(t *testing.T) {
+	t.Parallel()
+	m := TimeoutWithConfig(TimeoutConfig{
+		Timeout: time.Second,
+		ErrorHandler: func(err error, e echo.Context) error {
+			assert.EqualError(t, err, context.DeadlineExceeded.Error())
+			return errors.New("err")
+		},
+	})
+
+	req := httptest.NewRequest(http.MethodGet, "/", nil)
+	rec := httptest.NewRecorder()
+
+	e := echo.New()
+	c := e.NewContext(req, rec)
+
+	err := m(func(c echo.Context) error {
+		time.Sleep(time.Minute)
+		return nil
+	})(c)
+
+	assert.EqualError(t, err, errors.New("err").Error())
+}
+
+func TestTimeoutTimesOutAfterPredefinedTimeout(t *testing.T) {
+	t.Parallel()
+	m := TimeoutWithConfig(TimeoutConfig{
+		Timeout: time.Second,
+	})
+
+	req := httptest.NewRequest(http.MethodGet, "/", nil)
+	rec := httptest.NewRecorder()
+
+	e := echo.New()
+	c := e.NewContext(req, rec)
+
+	err := m(func(c echo.Context) error {
+		time.Sleep(time.Minute)
+		return nil
+	})(c)
+
+	assert.EqualError(t, err, context.DeadlineExceeded.Error())
+}
+
+func TestTimeoutTestRequestClone(t *testing.T) {
+	t.Parallel()
+	req := httptest.NewRequest(http.MethodPost, "/uri?query=value", strings.NewReader(url.Values{"form": {"value"}}.Encode()))
+	req.AddCookie(&http.Cookie{Name: "cookie", Value: "value"})
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+	rec := httptest.NewRecorder()
+
+	m := TimeoutWithConfig(TimeoutConfig{
+		// Timeout has to be defined or the whole flow for timeout middleware will be skipped
+		Timeout: time.Second,
+	})
+
+	e := echo.New()
+	c := e.NewContext(req, rec)
+
+	err := m(func(c echo.Context) error {
+		// Cookie test
+		cookie, err := c.Request().Cookie("cookie")
+		if assert.NoError(t, err) {
+			assert.EqualValues(t, "cookie", cookie.Name)
+			assert.EqualValues(t, "value", cookie.Value)
+		}
+
+		// Form values
+		if assert.NoError(t, c.Request().ParseForm()) {
+			assert.EqualValues(t, "value", c.Request().FormValue("form"))
+		}
+
+		// Query string
+		assert.EqualValues(t, "value", c.Request().URL.Query()["query"][0])
+		return nil
+	})(c)
+
+	assert.NoError(t, err)
+
+}