From 1c16efd8726f43d162cbf7edefbaddc8ae624e20 Mon Sep 17 00:00:00 2001
From: jarek <jkrochmalski@gmail.com>
Date: Mon, 2 Mar 2026 13:10:03 +0100
Subject: [PATCH] v1.0.20

---
 Dockerfile                           |  5 +++--
 src/lib/data/changelog.json          |  3 ++-
 src/lib/server/subprocess-manager.ts | 27 +++++++++++++++++++++++++--
 3 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/Dockerfile b/Dockerfile
index f37da8d..d1c409f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -90,10 +90,11 @@ RUN rm -rf node_modules \
     && rm -rf node_modules/@types
 
 # Build Go collector
-FROM golang:1.24 AS go-builder
+FROM --platform=$BUILDPLATFORM golang:1.24 AS go-builder
+ARG TARGETARCH
 WORKDIR /app
 COPY collector/ ./collector/
-RUN cd collector && CGO_ENABLED=0 go build -o /app/bin/collection-worker .
+RUN cd collector && CGO_ENABLED=0 GOARCH=$TARGETARCH go build -o /app/bin/collection-worker .
 
 # -----------------------------------------------------------------------------
 # Stage 3: Final Image (Scratch + Custom Wolfi OS)
diff --git a/src/lib/data/changelog.json b/src/lib/data/changelog.json
index 57ff30c..3bdec1f 100644
--- a/src/lib/data/changelog.json
+++ b/src/lib/data/changelog.json
@@ -3,7 +3,8 @@
     "version": "1.0.20",
     "date": "2026-03-02",
     "changes": [
-      { "type": "fix", "text": "regression on Synology DSM" }
+      { "type": "fix", "text": "regression on Synology DSM" },
+      { "type": "fix", "text": "Fix ARM64 regression: Go collector crashing on Raspberry Pi and other ARM devices" }
     ],
     "imageTag": "fnsys/dockhand:v1.0.20"
   },
diff --git a/src/lib/server/subprocess-manager.ts b/src/lib/server/subprocess-manager.ts
index d14c4c1..4b0f487 100644
--- a/src/lib/server/subprocess-manager.ts
+++ b/src/lib/server/subprocess-manager.ts
@@ -84,6 +84,10 @@ let lineBuffer: Buffer = Buffer.alloc(0);
 let restartDelay = 1000;
 const MAX_RESTART_DELAY = 60000;
 
+// Ready-signal plumbing: resolved when Go sends {"type":"ready"}
+let readyResolve: (() => void) | null = null;
+let readyPromise: Promise<void> | null = null;
+
 // Dedup cache for events
 const recentEvents: Map<string, number> = new Map();
 // Disk warning cooldown per env
@@ -147,6 +151,8 @@ function handleLine(line: string): void {
 		case 'ready':
 			console.log('[SubprocessManager] Go worker ready');
 			restartDelay = 1000; // Reset backoff on successful start
+			readyResolve?.();
+			readyResolve = null;
 			break;
 
 		case 'metrics':
@@ -531,6 +537,9 @@ export async function startSubprocesses(): Promise<void> {
 	const workerPath = resolveWorkerPath();
 	console.log(`[SubprocessManager] Starting Go worker (${workerPath})...`);
 
+	// Set up ready promise BEFORE spawning so we don't miss the signal
+	readyPromise = new Promise<void>(resolve => { readyResolve = resolve; });
+
 	proc = spawn(workerPath, [], {
 		stdio: ['pipe', 'pipe', 'inherit']
 	});
@@ -540,6 +549,10 @@ export async function startSubprocesses(): Promise<void> {
 
 	// Handle process exit
 	proc.on('exit', (code) => {
+		// Clear stale ready promise if process exits before signalling ready
+		readyResolve = null;
+		readyPromise = null;
+
 		if (!isShuttingDown) {
 			console.warn(`[SubprocessManager] Go worker exited with code ${code}, restarting in ${restartDelay / 1000}s...`);
 			proc = null;
@@ -554,8 +567,18 @@ export async function startSubprocesses(): Promise<void> {
 		proc = null;
 	});
 
-	// Wait a moment for the process to start, then send configs
-	await new Promise(resolve => setTimeout(resolve, 100));
+	// Wait for Go to signal it's ready and reading stdin, then send configs.
+	// This fixes a race on DietPi where stdin closes transiently before the
+	// old blind 100ms wait ends, causing configure messages to be silently dropped.
+	try {
+		await Promise.race([
+			readyPromise,
+			new Promise<void>((_, reject) => setTimeout(() => reject(new Error('timeout')), 5000))
+		]);
+	} catch {
+		console.warn('[SubprocessManager] Go worker ready timeout, sending configs anyway');
+	}
+	readyPromise = null;
 	await sendEnvironmentConfigs();
 
 	// Start dedup cleanup interval