Add friendly development error page for 502

a53f27c6 · Jacob Vosmaer · Nick Thomas · 6425eb4d · a53f27c6 · a53f27c6
Commit a53f27c6 authored Feb 13, 2020 by Jacob Vosmaer Committed by Nick Thomas Feb 13, 2020
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Showing with 109 additions and 7 deletions

internal/badgateway/roundtripper.go internal/badgateway/roundtripper.go +53 -7

internal/badgateway/roundtripper_test.go internal/badgateway/roundtripper_test.go +56 -0

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--- a/internal/badgateway/roundtripper.go
+++ b/internal/badgateway/roundtripper.go
@@ -3,8 +3,10 @@ package badgateway
 import (
 	"bytes"
 	"fmt"
+	"html/template"
 	"io/ioutil"
 	"net/http"
+	"strings"
 	"time"

 	"gitlab.com/gitlab-org/labkit/log"
@@ -46,11 +48,6 @@ func (t *roundTripper) RoundTrip(r *http.Request) (*http.Response, error) {
 		fields,
 	)

-	message := "GitLab is not responding"
-	if t.developmentMode {
-		message = err.Error()
-	}
-
 	injectedResponse := &http.Response{
 		StatusCode: http.StatusBadGateway,
 		Status:     http.StatusText(http.StatusBadGateway),
@@ -61,9 +58,58 @@ func (t *roundTripper) RoundTrip(r *http.Request) (*http.Response, error) {
 		Proto:      r.Proto,
 		Header:     make(http.Header),
 		Trailer:    make(http.Header),
-		Body:       ioutil.NopCloser(bytes.NewBufferString(message)),
 	}
-	injectedResponse.Header.Set("Content-Type", "text/plain")
+
+	message := "GitLab is not responding"
+	contentType := "text/plain"
+	if t.developmentMode {
+		message, contentType = developmentModeResponse(err)
+	}
+
+	injectedResponse.Body = ioutil.NopCloser(strings.NewReader(message))
+	injectedResponse.Header.Set("Content-Type", contentType)

 	return injectedResponse, nil
 }
+
+func developmentModeResponse(err error) (body string, contentType string) {
+	data := TemplateData{
+		Time:          time.Now().Format("15:04:05"),
+		Error:         err.Error(),
+		ReloadSeconds: 5,
+	}
+
+	buf := &bytes.Buffer{}
+	if err := developmentErrorTemplate.Execute(buf, data); err != nil {
+		return data.Error, "text/plain"
+	}
+
+	return buf.String(), "text/html"
+}
+
+type TemplateData struct {
+	Time          string
+	Error         string
+	ReloadSeconds int
+}
+
+var developmentErrorTemplate = template.Must(template.New("error502").Parse(`
+<html>
+<head>
+<title>502: GitLab is not responding</title>
+<script>
+window.setTimeout(function() { location.reload() }, {{.ReloadSeconds}} * 1000)
+</script>
+</head>
+
+<body>
+<h1>502</h1>
+<p>GitLab is not responding. The error was:</p>
+
+<pre>{{.Error}}</pre>
+
+<p>If you just started GDK it can take 30-60 seconds before GitLab has finished booting. This page will automatically reload every {{.ReloadSeconds}} seconds.</p>
+<footer>Generated by gitlab-workhorse running in development mode at {{.Time}}.</footer>
+</body>
+</html>
+`))
--- a/internal/badgateway/roundtripper_test.go
+++ b/internal/badgateway/roundtripper_test.go
+package badgateway
+
+import (
+	"errors"
+	"io/ioutil"
+	"net/http"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+type roundtrip502 struct{}
+
+func (roundtrip502) RoundTrip(*http.Request) (*http.Response, error) {
+	return nil, errors.New("something went wrong")
+}
+
+func TestErrorPage502(t *testing.T) {
+	tests := []struct {
+		name            string
+		devMode         bool
+		contentType     string
+		responseSnippet string
+	}{
+		{
+			name:            "production mode",
+			contentType:     "text/plain",
+			responseSnippet: "GitLab is not responding",
+		},
+		{
+			name:            "development mode",
+			devMode:         true,
+			contentType:     "text/html",
+			responseSnippet: "This page will automatically reload",
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			req, err := http.NewRequest("GET", "/", nil)
+			require.NoError(t, err, "build request")
+
+			rt := NewRoundTripper(tc.devMode, roundtrip502{})
+			response, err := rt.RoundTrip(req)
+			require.NoError(t, err, "perform roundtrip")
+			defer response.Body.Close()
+
+			body, err := ioutil.ReadAll(response.Body)
+			require.NoError(t, err)
+
+			require.Equal(t, tc.contentType, response.Header.Get("content-type"), "content type")
+			require.Equal(t, 502, response.StatusCode, "response status")
+			require.Contains(t, string(body), tc.responseSnippet)
+		})
+	}
+}