feat(kv): add error pages configuration.

provider/kv/filler_test.go

@@ -81,6 +81,18 @@ func withPair(key string, value string) func(map[string]string) {
 	}
 }
 
+func withErrorPage(name string, backend, query, status string) func(map[string]string) {
+	return func(pairs map[string]string) {
+		if len(name) == 0 {
+			return
+		}
+
+		withPair(pathFrontendErrorPages+name+pathFrontendErrorPagesBackend, backend)(pairs)
+		withPair(pathFrontendErrorPages+name+pathFrontendErrorPagesQuery, query)(pairs)
+		withPair(pathFrontendErrorPages+name+pathFrontendErrorPagesStatus, status)(pairs)
+	}
+}
+
 func TestFiller(t *testing.T) {
 	expected := []*store.KVPair{
 		{Key: "traefik/backends/backend.with.dot.too", Value: []byte("")},

provider/kv/kv_config.go

@@ -35,6 +35,8 @@ func (p *Provider) buildConfiguration() *types.Configuration {
 
 		// Frontend functions
 		"getRedirect":   p.getRedirect,
+		"getErrorPages": p.getErrorPages,
+
 		// Backend functions
 		"getSticky":               p.getSticky,
 		"hasStickinessLabel":      p.hasStickinessLabel,
@@ -96,6 +98,28 @@ func (p *Provider) getRedirect(rootPath string) *types.Redirect {
 	return nil
 }
 
+func (p *Provider) getErrorPages(rootPath string) map[string]*types.ErrorPage {
+	var errorPages map[string]*types.ErrorPage
+
+	pathErrors := p.list(rootPath, pathFrontendErrorPages)
+
+	for _, pathPage := range pathErrors {
+		if errorPages == nil {
+			errorPages = make(map[string]*types.ErrorPage)
+		}
+
+		pageName := p.last(pathPage)
+
+		errorPages[pageName] = &types.ErrorPage{
+			Backend: p.get("", pathPage, pathFrontendErrorPagesBackend),
+			Query:   p.get("", pathPage, pathFrontendErrorPagesQuery),
+			Status:  p.splitGet(pathPage, pathFrontendErrorPagesStatus),
+		}
+	}
+
+	return errorPages
+}
+
 func (p *Provider) listServers(backend string) []string {
 	serverNames := p.list(backend, pathBackendServers)
 	return fun.Filter(p.serverFilter, serverNames).([]string)

provider/kv/kv_config_test.go

@@ -770,3 +770,52 @@ func TestProviderGetRedirect(t *testing.T) {
 		})
 	}
 }
+
+func TestProviderGetErrorPages(t *testing.T) {
+	testCases := []struct {
+		desc     string
+		rootPath string
+		kvPairs  []*store.KVPair
+		expected map[string]*types.ErrorPage
+	}{
+		{
+			desc:     "2 errors pages",
+			rootPath: "traefik/frontends/foo",
+			kvPairs: filler("traefik",
+				frontend("foo",
+					withErrorPage("foo", "error", "/test1", "500-501, 503-599"),
+					withErrorPage("bar", "error", "/test2", "400-405"))),
+			expected: map[string]*types.ErrorPage{
+				"foo": {
+					Backend: "error",
+					Query:   "/test1",
+					Status:  []string{"500-501", "503-599"},
+				},
+				"bar": {
+					Backend: "error",
+					Query:   "/test2",
+					Status:  []string{"400-405"},
+				},
+			},
+		},
+		{
+			desc:     "return nil when no errors pages",
+			rootPath: "traefik/frontends/foo",
+			kvPairs:  filler("traefik", frontend("foo")),
+			expected: nil,
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+		t.Run(test.desc, func(t *testing.T) {
+			t.Parallel()
+
+			p := newProviderMock(test.kvPairs)
+
+			actual := p.getErrorPages(test.rootPath)
+
+			assert.Equal(t, test.expected, actual)
+		})
+	}
+}

templates/kv.tmpl

@@ -78,6 +78,19 @@
       replacement = "{{ $redirect.Replacement }}"
     {{end}}
 
+    {{ $errorPages := getErrorPages $frontend }}
+    {{ if $errorPages }}
+    [frontends."{{$frontendName}}".errors]
+      {{ range $pageName, $page := $errorPages }}
+      [frontends."{{$frontendName}}".errors.{{ $pageName }}]
+        status = [{{range $page.Status}}
+          "{{.}}",
+          {{end}}]
+        backend = "{{$page.Backend}}"
+        query = "{{$page.Query}}"
+      {{end}}
+    {{end}}
+
     {{range $route := List $frontend "/routes/"}}
     [frontends."{{$frontendName}}".routes."{{Last $route}}"]
       rule = "{{Get "" $route "/rule"}}"