Merge pull request #24 from blackskad/go-build-version

Add a build information page to the debug handler
tmeire · Sep 11, 2024 · 6f37a15 · 6f37a15
2 parents 923b087 + 46aae65
commit 6f37a15
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diff --git a/pkg/o11y/debug-info.html b/pkg/o11y/debug-info.html
@@ -0,0 +1,39 @@
+<html>
+    <head>
+        <title>Application build information</title>
+        <style>
+            dt {
+                font-weight: bold;
+            }
+        </style>
+    </head>
+    <body>
+        <h1>Application build information</h1>
+        <h2>Base info</h2>
+        <dl>
+            <dt>Go version</dt>
+            <dd>{{ .GoVersion }}</dd>
+        </dl>
+        <h2>Module</h2> 
+        <dl>
+            <dt>Path</dt>
+            <dd>{{ .Main.Path }}</dd>
+            <dt>Version</dt>
+            <dd>{{ .Main.Version }}</dd>
+            <dt>Sum</dt>
+            <dd>{{ .Main.Sum }}</dd>
+        </dl>
+        <h2>Settings</h2>
+        <dl>
+        {{ range .Settings }}
+            <dt>{{ .Key }}</dt>
+            <dd>{{ .Value }}</dd>
+        {{ end }}
+        </dl>
+        <h2>Modules</h2>
+        <ul>
+        {{ range .Deps }}
+            <li>{{ .Path }} {{ .Version }}</li>
+        {{ end }}
+    </body>
+</html>
diff --git a/pkg/o11y/pprof.go b/pkg/o11y/pprof.go
@@ -1,19 +1,41 @@
 package o11y
 
 import (
+	_ "embed"
+	"html/template"
 	"log/slog"
 	"net/http"
 	_ "net/http/pprof"
+	"runtime/debug"
 )
 
 func StartPProfServer() {
 	go runPProfServer()
 }
 
+//go:embed debug-info.html
+var debugInfoPage string
+
+var debugInfoTPL = template.Must(template.New("debug-info").Parse(debugInfoPage))
+
 // runPProfServer starts an HTTP server on port 6060 that exposes /debug/pprof
 // This function blocks until an error occurs
 // This is a separate function to make stacktraces more readable
 func runPProfServer() {
+	http.HandleFunc("/debug/info", func(w http.ResponseWriter, r *http.Request) {
+		debugInfo, ok := debug.ReadBuildInfo()
+		if !ok {
+			http.Error(w, "unable to load build info", http.StatusInternalServerError)
+			return
+		}
+
+		err := debugInfoTPL.ExecuteTemplate(w, "debug-info", debugInfo)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+	})
+
 	err := http.ListenAndServe(":6060", nil)
 	if err != nil {
 		slog.Warn("pprof http server shut down", slog.Any("error", err))