Add a simple UI.

prometheus-community · Nov 24, 2017 · 546ee64 · 546ee64
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commit 546ee64
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diff --git a/cmd/jiralert/content.go b/cmd/jiralert/content.go
@@ -0,0 +1,113 @@
+package main
+
+import (
+	"fmt"
+	"html/template"
+	"net/http"
+
+	"github.com/free/jiralert"
+)
+
+const (
+	docsUrl   = "https://github.com/free/jiralert#readme"
+	templates = `
+    {{ define "page" -}}
+      <html>
+      <head>
+        <title>JIRAlert</title>
+        <style type="text/css">
+          body { margin: 0; font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; font-size: 14px; line-height: 1.42857143; color: #333; background-color: #fff; }
+          .navbar { display: flex; background-color: #222; margin: 0; border-width: 0 0 1px; border-style: solid; border-color: #080808; }
+          .navbar > * { margin: 0; padding: 15px; }
+          .navbar * { line-height: 20px; color: #9d9d9d; }
+          .navbar a { text-decoration: none; }
+          .navbar a:hover, .navbar a:focus { color: #fff; }
+          .navbar-header { font-size: 18px; }
+          body > * { margin: 15px; padding: 0; }
+          pre { padding: 10px; font-size: 13px; background-color: #f5f5f5; border: 1px solid #ccc; }
+          h1, h2 { font-weight: 500; }
+          a { color: #337ab7; }
+          a:hover, a:focus { color: #23527c; }
+        </style>
+      </head>
+      <body>
+        <div class="navbar">
+          <div class="navbar-header"><a href="/">JIRAlert</a></div>
+          <div><a href="/config">Configuration</a></div>
+          <div><a href="/metrics">Metrics</a></div>
+          <div><a href="/debug/pprof">Profiling</a></div>
+          <div><a href="{{ .DocsUrl }}">Help</a></div>
+        </div>
+        {{template "content" .}}
+      </body>
+      </html>
+    {{- end }}
+
+    {{ define "content.home" -}}
+      <p>This is <a href="{{ .DocsUrl }}">JIRAlert</a>, a
+        <a href="https://prometheus.io/docs/alerting/configuration/#webhook_config">webhook receiver</a> for
+        <a href="https://prometheus.io/docs/alerting/alertmanager/">Prometheus Alertmanager</a>.
+    {{- end }}
+
+    {{ define "content.config" -}}
+      <h2>Configuration</h2>
+      <pre>{{ .Config }}</pre>
+    {{- end }}
+
+    {{ define "content.error" -}}
+      <h2>Error</h2>
+      <pre>{{ .Err }}</pre>
+    {{- end }}
+    `
+)
+
+type tdata struct {
+	DocsUrl string
+
+	// `/config` only
+	Config string
+
+	// `/error` only
+	Err error
+}
+
+var (
+	allTemplates   = template.Must(template.New("").Parse(templates))
+	homeTemplate   = pageTemplate("home")
+	configTemplate = pageTemplate("config")
+	errorTemplate  = pageTemplate("error")
+)
+
+func pageTemplate(name string) *template.Template {
+	pageTemplate := fmt.Sprintf(`{{define "content"}}{{template "content.%s" .}}{{end}}{{template "page" .}}`, name)
+	return template.Must(template.Must(allTemplates.Clone()).Parse(pageTemplate))
+}
+
+// HomeHandlerFunc is the HTTP handler for the home page (`/`).
+func HomeHandlerFunc() func(http.ResponseWriter, *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
+		homeTemplate.Execute(w, &tdata{
+			DocsUrl: docsUrl,
+		})
+	}
+}
+
+// ConfigHandlerFunc is the HTTP handler for the `/config` page. It outputs the configuration marshaled in YAML format.
+func ConfigHandlerFunc(config *jiralert.Config) func(http.ResponseWriter, *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
+		configTemplate.Execute(w, &tdata{
+			DocsUrl: docsUrl,
+			Config:  config.String(),
+		})
+	}
+}
+
+// HandleError is an error handler that other handlers defer to in case of error. It is important to not have written
+// anything to w before calling HandleError(), or the 500 status code won't be set (and the content might be mixed up).
+func HandleError(err error, metricsPath string, w http.ResponseWriter, r *http.Request) {
+	w.WriteHeader(http.StatusInternalServerError)
+	errorTemplate.Execute(w, &tdata{
+		DocsUrl: docsUrl,
+		Err:     err,
+	})
+}
diff --git a/cmd/jiralert/main.go b/cmd/jiralert/main.go
@@ -98,6 +98,9 @@ func main() {
 		requestTotal.WithLabelValues(conf.Name, "200").Inc()
 	})
 
+	http.HandleFunc("/", HomeHandlerFunc())
+	http.HandleFunc("/config", ConfigHandlerFunc(config))
+	http.HandleFunc("/healthz", func(w http.ResponseWriter, r *http.Request) { http.Error(w, "OK", http.StatusOK) })
 	http.Handle("/metrics", promhttp.Handler())
 
 	if os.Getenv("PORT") != "" {