show version in UI

Dockerfile

@@ -12,9 +12,16 @@ RUN go mod download
 # Copy the rest of the source
 COPY . .
 
+ARG BUILD_TIME=""
+ARG GIT_COMMIT="unknown"
+ARG VERSION="dev"
+
 # Build a static-ish binary (alpine musl)
-RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 \
+RUN BUILD_TIME="${BUILD_TIME:-$(date -u +%Y-%m-%dT%H:%M:%SZ)}" && \
-    go build -trimpath -ldflags="-s -w" -o /out/ingestd ./cmd/ingestd
+    CGO_ENABLED=0 GOOS=linux GOARCH=amd64 \
+    go build -trimpath \
+      -ldflags="-s -w -X main.buildTime=${BUILD_TIME} -X main.gitCommit=${GIT_COMMIT} -X main.version=${VERSION}" \
+      -o /out/ingestd ./cmd/ingestd
 
 # ---- runtime stage ----
 FROM alpine:3.22

cmd/ingestd/buildinfo.go

@@ -0,0 +1,59 @@
+package main
+
+import (
+	"runtime/debug"
+	"strings"
+)
+
+var (
+	version   = "dev"
+	gitCommit = "unknown"
+	buildTime = "unknown"
+)
+
+type binaryBuildInfo struct {
+	Version   string `json:"version"`
+	GitCommit string `json:"git_commit"`
+	BuildTime string `json:"build_time"`
+}
+
+func currentBuildInfo() binaryBuildInfo {
+	out := binaryBuildInfo{
+		Version:   version,
+		GitCommit: gitCommit,
+		BuildTime: buildTime,
+	}
+
+	if bi, ok := debug.ReadBuildInfo(); ok {
+		if out.Version == "" || out.Version == "dev" {
+			if bi.Main.Version != "" && bi.Main.Version != "(devel)" {
+				out.Version = bi.Main.Version
+			}
+		}
+		for _, s := range bi.Settings {
+			if s.Key == "vcs.revision" && (out.GitCommit == "" || out.GitCommit == "unknown") {
+				if len(s.Value) > 12 {
+					out.GitCommit = s.Value[:12]
+				} else {
+					out.GitCommit = s.Value
+				}
+			}
+			if s.Key == "vcs.time" && (out.BuildTime == "" || out.BuildTime == "unknown") {
+				out.BuildTime = s.Value
+			}
+		}
+	}
+
+	out.Version = normalizeBuildField(out.Version, "dev")
+	out.GitCommit = normalizeBuildField(out.GitCommit, "unknown")
+	out.BuildTime = normalizeBuildField(out.BuildTime, "unknown")
+	return out
+}
+
+func normalizeBuildField(v string, fallback string) string {
+	v = strings.TrimSpace(v)
+	if v == "" {
+		return fallback
+	}
+	return v
+}

cmd/ingestd/web.go

@@ -21,12 +21,14 @@ type webServer struct {
 	db    *db.DB
 	site  providers.Site
 	model string
+	build binaryBuildInfo
 }
 
 type dashboardResponse struct {
 	GeneratedAt         time.Time                `json:"generated_at"`
 	Site                string                   `json:"site"`
 	Model               string                   `json:"model"`
+	Build               binaryBuildInfo          `json:"build"`
 	RangeStart          time.Time                `json:"range_start"`
 	RangeEnd            time.Time                `json:"range_end"`
 	Observations        []db.ObservationPoint    `json:"observations"`
@@ -46,6 +48,7 @@ func runWebServer(ctx context.Context, d *db.DB, site providers.Site, model, add
 		db:    d,
 		site:  site,
 		model: model,
+		build: currentBuildInfo(),
 	}
 
 	mux := http.NewServeMux()
@@ -53,7 +56,10 @@ func runWebServer(ctx context.Context, d *db.DB, site providers.Site, model, add
 	mux.HandleFunc("/api/dashboard", ws.handleDashboard)
 	mux.HandleFunc("/api/health", func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", "application/json")
-		_, _ = w.Write([]byte(`{"ok":true}`))
+		_ = json.NewEncoder(w).Encode(map[string]any{
+			"ok":    true,
+			"build": ws.build,
+		})
 	})
 	mux.HandleFunc("/chart", func(w http.ResponseWriter, r *http.Request) {
 		serveIndex(w, sub)
@@ -193,6 +199,7 @@ func (s *webServer) handleDashboard(w http.ResponseWriter, r *http.Request) {
 		GeneratedAt:         time.Now().UTC(),
 		Site:                s.site.Name,
 		Model:               s.model,
+		Build:               s.build,
 		RangeStart:          start,
 		RangeEnd:            end,
 		Observations:        observations,

cmd/ingestd/web/app.js

@@ -615,7 +615,35 @@ function extendForecastTo(points, endTime) {
   return [...points, { ...last, ts: new Date(endTs).toISOString() }];
 }
 
-function updateSiteMeta(site, model, tzLabel) {
+function formatBuildStamp(build) {
+  if (!build) {
+    return "build --";
+  }
+
+  const parts = [];
+  const rawBuildTime = build.build_time;
+  if (rawBuildTime && rawBuildTime !== "unknown") {
+    const dt = new Date(rawBuildTime);
+    if (Number.isNaN(dt.getTime())) {
+      parts.push(rawBuildTime);
+    } else {
+      parts.push(formatDateTime(dt));
+    }
+  } else {
+    parts.push("--");
+  }
+
+  if (build.git_commit && build.git_commit !== "unknown") {
+    parts.push(`commit ${build.git_commit}`);
+  }
+  if (build.version && build.version !== "dev") {
+    parts.push(`version ${build.version}`);
+  }
+
+  return `build ${parts.join(", ")}`;
+}
+
+function updateSiteMeta(site, model, tzLabel, build) {
   const home = document.getElementById("site-home");
   const suffix = document.getElementById("site-meta-suffix");
   if (home) {
@@ -623,7 +651,7 @@ function updateSiteMeta(site, model, tzLabel) {
     home.setAttribute("href", "/");
   }
   if (suffix) {
-    suffix.textContent = ` | model ${model || "--"} | ${tzLabel}`;
+    suffix.textContent = ` | model ${model || "--"} | ${tzLabel} | ${formatBuildStamp(build)}`;
   }
 }
 
@@ -686,7 +714,7 @@ function baseOptions(range) {
 function renderDashboard(data) {
   const latest = data.latest;
   const tzLabel = state.tz === "utc" ? "UTC" : "Local";
-  updateSiteMeta(data.site, data.model, tzLabel);
+  updateSiteMeta(data.site, data.model, tzLabel, data.build);
   updateText("last-updated", `updated ${formatDateTime(data.generated_at)}`);
   const forecastMeta = data.forecast && data.forecast.points && data.forecast.points.length
     ? `forecast retrieved ${formatDateTime(data.forecast.retrieved_at)}`