From 199c7dea3fc3d305bdcf523ca6a9438cb12206fb Mon Sep 17 00:00:00 2001 From: Pierre-Olivier Mercier Date: Thu, 23 Apr 2026 11:20:29 +0700 Subject: [PATCH] checker: add /check route for standalone human-facing web UI Providers that implement the new CheckerInteractive interface (RenderForm + ParseForm) get a built-in HTML form on GET /check and a consolidated result page on POST /check that runs the standard Collect -> Evaluate -> GetHTMLReport / ExtractMetrics pipeline. This lets a checker be used directly from a browser outside of happyDomain, with the checker itself resolving what the host would normally auto-fill (typically via its own DNS queries). Also guards NewServer against a nil Definition() so providers that advertise CheckerDefinitionProvider without a ready definition no longer panic at registration. --- README.md | 21 +++ checker/interactive.go | 347 ++++++++++++++++++++++++++++++++++++ checker/interactive_test.go | 245 +++++++++++++++++++++++++ checker/server.go | 49 +++-- 4 files changed, 644 insertions(+), 18 deletions(-) create mode 100644 checker/interactive.go create mode 100644 checker/interactive_test.go diff --git a/README.md b/README.md index 7f47eb8..e224fdf 100644 --- a/README.md +++ b/README.md @@ -56,6 +56,27 @@ Patterns that collide with built-in routes panic at registration — pick non-overlapping paths. Custom handlers are not wrapped by the load-tracking middleware unless you opt in via `TrackWork`. +## Standalone human UI (`/check`) + +Providers that implement `CheckerInteractive` get a built-in human-facing +web form on `/check`, usable outside of happyDomain: + +```go +type CheckerInteractive interface { + RenderForm() []CheckerOptionField + ParseForm(r *http.Request) (CheckerOptions, error) +} +``` + +- `GET /check` renders a form derived from `RenderForm()`. +- `POST /check` calls `ParseForm` to obtain `CheckerOptions`, runs the + standard `Collect` → `Evaluate` → `GetHTMLReport` / `ExtractMetrics` + pipeline, and returns a consolidated HTML page. + +`ParseForm` is where the checker replaces what happyDomain would normally +auto-fill (zone records, service payload, …) — typically by issuing its +own DNS queries from the human-supplied inputs. + ## License Apache License 2.0. See [LICENSE](LICENSE) and [NOTICE](NOTICE). diff --git a/checker/interactive.go b/checker/interactive.go new file mode 100644 index 0000000..b3473bc --- /dev/null +++ b/checker/interactive.go @@ -0,0 +1,347 @@ +// Copyright 2020-2026 The happyDomain Authors +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package checker + +import ( + "bytes" + "encoding/json" + "fmt" + "html/template" + "log" + "net/http" + "time" +) + +// CheckerInteractive is an optional interface that observation providers +// can implement to expose a human-facing web form usable standalone, +// outside of a happyDomain host. Detect support with a type assertion: +// _, ok := provider.(CheckerInteractive). +// +// When the provider implements it, Server binds GET and POST on /check. +// GET renders an HTML form built from RenderForm(). POST calls ParseForm +// to obtain the CheckerOptions, then runs the standard pipeline +// (Collect, Evaluate, GetHTMLReport, ExtractMetrics) and renders a +// consolidated result page. +// +// Unlike /evaluate, which relies on happyDomain to fill AutoFill-backed +// options from execution context, a CheckerInteractive implementation is +// responsible for resolving whatever it needs from the human inputs +// (typically via direct DNS queries) before Collect runs. +type CheckerInteractive interface { + // RenderForm returns the fields the human must fill in to bootstrap + // a check. Typically a minimal set (domain name, nameserver to + // query, …) that ParseForm expands into the full CheckerOptions + // that Collect expects. + RenderForm() []CheckerOptionField + + // ParseForm reads the submitted form and returns the CheckerOptions + // ready to feed Collect. It is the checker's responsibility to do + // whatever lookups or resolutions are needed to populate fields + // that would normally be auto-filled by happyDomain. Returning an + // error causes the SDK to re-render the form with the error + // displayed. + ParseForm(r *http.Request) (CheckerOptions, error) +} + +// checkResult holds everything the result page needs to render. +type checkResult struct { + Title string + States []CheckState + Metrics []CheckMetric + ReportHTML string + CollectErr string + ReportErr string + MetricsErr string +} + +type checkFormPage struct { + Title string + Fields []CheckerOptionField + Error string +} + +func (s *Server) handleCheckForm(w http.ResponseWriter, r *http.Request) { + s.renderCheckForm(w, s.interactive.RenderForm(), "") +} + +func (s *Server) handleCheckSubmit(w http.ResponseWriter, r *http.Request) { + if err := r.ParseForm(); err != nil { + s.renderCheckForm(w, s.interactive.RenderForm(), fmt.Sprintf("invalid form: %v", err)) + return + } + + opts, err := s.interactive.ParseForm(r) + if err != nil { + s.renderCheckForm(w, s.interactive.RenderForm(), err.Error()) + return + } + + result := &checkResult{Title: s.checkPageTitle()} + + data, err := s.provider.Collect(r.Context(), opts) + if err != nil { + result.CollectErr = err.Error() + s.renderCheckResult(w, result) + return + } + + raw, err := json.Marshal(data) + if err != nil { + result.CollectErr = fmt.Sprintf("failed to marshal collected data: %v", err) + s.renderCheckResult(w, result) + return + } + + if s.definition != nil { + obs := &mapObservationGetter{data: map[ObservationKey]json.RawMessage{ + s.provider.Key(): raw, + }} + result.States = s.evaluateRules(r.Context(), obs, opts, nil) + } + + ctx := NewReportContext(raw, nil) + + if reporter, ok := s.provider.(CheckerHTMLReporter); ok { + html, rerr := reporter.GetHTMLReport(ctx) + if rerr != nil { + result.ReportErr = rerr.Error() + } else { + result.ReportHTML = html + } + } + + if reporter, ok := s.provider.(CheckerMetricsReporter); ok { + metrics, merr := reporter.ExtractMetrics(ctx, time.Now()) + if merr != nil { + result.MetricsErr = merr.Error() + } else { + result.Metrics = metrics + } + } + + s.renderCheckResult(w, result) +} + +func (s *Server) checkPageTitle() string { + if s.definition != nil && s.definition.Name != "" { + return s.definition.Name + } + return "Checker" +} + +func renderHTML(w http.ResponseWriter, status int, tpl *template.Template, data any) { + var buf bytes.Buffer + if err := tpl.Execute(&buf, data); err != nil { + log.Printf("render %s: %v", tpl.Name(), err) + http.Error(w, "failed to render page", http.StatusInternalServerError) + return + } + w.Header().Set("Content-Type", "text/html; charset=utf-8") + w.WriteHeader(status) + w.Write(buf.Bytes()) +} + +func (s *Server) renderCheckForm(w http.ResponseWriter, fields []CheckerOptionField, errMsg string) { + status := http.StatusOK + if errMsg != "" { + status = http.StatusBadRequest + } + renderHTML(w, status, checkFormTemplate, checkFormPage{ + Title: s.checkPageTitle(), + Fields: fields, + Error: errMsg, + }) +} + +func (s *Server) renderCheckResult(w http.ResponseWriter, result *checkResult) { + renderHTML(w, http.StatusOK, checkResultTemplate, result) +} + +func statusClass(s Status) string { + switch s { + case StatusOK: + return "ok" + case StatusInfo: + return "info" + case StatusWarn: + return "warn" + case StatusCrit: + return "crit" + case StatusError: + return "error" + default: + return "unknown" + } +} + +// defaultString avoids printing the literal "" for unset defaults. +func defaultString(v any) string { + if v == nil { + return "" + } + switch t := v.(type) { + case string: + return t + case bool: + if t { + return "true" + } + return "" + default: + return fmt.Sprintf("%v", v) + } +} + +func defaultBool(v any) bool { + b, _ := v.(bool) + return b +} + +var templateFuncs = template.FuncMap{ + "statusClass": statusClass, + "statusString": Status.String, + "defaultString": defaultString, + "defaultBool": defaultBool, +} + +const baseCSS = ` +body { font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif; max-width: 960px; margin: 2rem auto; padding: 0 1rem; color: #222; } +h1, h2 { border-bottom: 1px solid #eee; padding-bottom: 0.3rem; } +form { display: grid; gap: 1rem; } +label { display: block; font-weight: 600; margin-bottom: 0.25rem; } +.required::after { content: " *"; color: #c00; } +.desc { font-weight: normal; color: #666; font-size: 0.9rem; display: block; margin-top: 0.1rem; } +input[type=text], input[type=password], input[type=number], select, textarea { + width: 100%; padding: 0.5rem; border: 1px solid #bbb; border-radius: 4px; box-sizing: border-box; font: inherit; +} +textarea { min-height: 6rem; } +button { padding: 0.6rem 1.2rem; background: #0b63c5; color: #fff; border: 0; border-radius: 4px; font: inherit; cursor: pointer; } +button:hover { background: #084c98; } +.err { background: #fee; border: 1px solid #fbb; color: #900; padding: 0.6rem 0.8rem; border-radius: 4px; margin: 1rem 0; } +table { border-collapse: collapse; width: 100%; margin: 0.5rem 0 1.5rem; } +th, td { text-align: left; padding: 0.5rem 0.6rem; border-bottom: 1px solid #eee; vertical-align: top; } +th { background: #f7f7f7; } +.badge { display: inline-block; padding: 0.15rem 0.5rem; border-radius: 3px; font-size: 0.8rem; font-weight: 600; color: #fff; } +.badge.ok { background: #2a9d3c; } +.badge.info { background: #3277cc; } +.badge.warn { background: #d08a00; } +.badge.crit { background: #c0392b; } +.badge.error { background: #7a1f1f; } +.badge.unknown { background: #777; } +iframe.report { width: 100%; min-height: 480px; border: 1px solid #ccc; border-radius: 4px; } +.actions { margin-top: 1.5rem; } +.actions a { color: #0b63c5; text-decoration: none; } +.actions a:hover { text-decoration: underline; } +` + +var checkFormTemplate = template.Must(template.New("form").Funcs(templateFuncs).Parse(` + + + +{{.Title}} – Check + + + +

{{.Title}}

+{{if .Error}}
{{.Error}}
{{end}} +
+{{range .Fields}}{{if not .Hide}} +
+ + {{if .Choices}} + + {{else if eq .Type "bool"}} + + {{else if .Textarea}} + + {{else if eq .Type "number"}} + + {{else if eq .Type "uint"}} + + {{else if .Secret}} + + {{else}} + + {{end}} +
+{{end}}{{end}} +
+
+ +`)) + +var checkResultTemplate = template.Must(template.New("result").Funcs(templateFuncs).Parse(` + + + +{{.Title}} – Result + + + +

{{.Title}}

+ +{{if .CollectErr}}
Collect failed: {{.CollectErr}}
{{end}} + +{{if .States}} +

Check states

+ + + + {{range .States}} + + + + + + + {{end}} + +
StatusCodeSubjectMessage
{{statusString .Status}}{{.Code}}{{.Subject}}{{.Message}}
+{{end}} + +{{if .Metrics}} +

Metrics

+ + + + {{range .Metrics}} + + + + + + + {{end}} + +
NameValueUnitLabels
{{.Name}}{{.Value}}{{.Unit}}{{range $k, $v := .Labels}}{{$k}}={{$v}} {{end}}
+{{end}} + +{{if .MetricsErr}}
Metrics error: {{.MetricsErr}}
{{end}} + +{{if .ReportHTML}} +

Report

+ +{{end}} + +{{if .ReportErr}}
Report error: {{.ReportErr}}
{{end}} + +
← Run another check
+ +`)) diff --git a/checker/interactive_test.go b/checker/interactive_test.go new file mode 100644 index 0000000..0a48512 --- /dev/null +++ b/checker/interactive_test.go @@ -0,0 +1,245 @@ +// Copyright 2020-2026 The happyDomain Authors +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package checker + +import ( + "context" + "errors" + "net/http" + "net/http/httptest" + "net/url" + "strings" + "testing" +) + +// interactiveProvider embeds testProvider and adds CheckerInteractive. +type interactiveProvider struct { + *testProvider + fields []CheckerOptionField + parseFn func(r *http.Request) (CheckerOptions, error) + parseErr error +} + +func (p *interactiveProvider) RenderForm() []CheckerOptionField { + return p.fields +} + +func (p *interactiveProvider) ParseForm(r *http.Request) (CheckerOptions, error) { + if p.parseErr != nil { + return nil, p.parseErr + } + if p.parseFn != nil { + return p.parseFn(r) + } + return CheckerOptions{"domain": r.FormValue("domain")}, nil +} + +func postForm(handler http.Handler, path string, values url.Values) *httptest.ResponseRecorder { + req := httptest.NewRequest("POST", path, strings.NewReader(values.Encode())) + req.Header.Set("Content-Type", "application/x-www-form-urlencoded") + rec := httptest.NewRecorder() + handler.ServeHTTP(rec, req) + return rec +} + +// minimalProvider implements only ObservationProvider. +type minimalProvider struct{ key ObservationKey } + +func (m *minimalProvider) Key() ObservationKey { return m.key } +func (m *minimalProvider) Collect(ctx context.Context, opts CheckerOptions) (any, error) { + return nil, nil +} + +func TestCheck_NotRegistered_WhenProviderLacksInterface(t *testing.T) { + p := &minimalProvider{key: "test"} + srv := NewServer(p) + defer srv.Close() + + rec := doRequest(srv.Handler(), "GET", "/check", nil, nil) + if rec.Code != http.StatusNotFound { + t.Fatalf("GET /check without CheckerInteractive = %d, want 404", rec.Code) + } +} + +func TestCheck_Form_Renders(t *testing.T) { + p := &interactiveProvider{ + testProvider: &testProvider{key: "test"}, + fields: []CheckerOptionField{ + {Id: "domain", Type: "string", Label: "Domain name", Required: true, Placeholder: "example.com"}, + {Id: "verbose", Type: "bool", Label: "Verbose", Default: true}, + {Id: "flavor", Type: "string", Choices: []string{"a", "b"}, Default: "b"}, + {Id: "hidden", Type: "string", Hide: true}, + }, + } + srv := NewServer(p) + defer srv.Close() + + rec := doRequest(srv.Handler(), "GET", "/check", nil, nil) + if rec.Code != http.StatusOK { + t.Fatalf("GET /check = %d, want 200", rec.Code) + } + body := rec.Body.String() + for _, want := range []string{ + `name="domain"`, + `placeholder="example.com"`, + `Domain name`, + `type="checkbox"`, + `name="verbose"`, + ` checked`, + `