Add healthcheck for client

frontend/local-client-cli/Dockerfile

@@ -16,10 +16,14 @@ LABEL org.opencontainers.image.licenses="MIT"
 LABEL org.opencontainers.image.authors="andras@schmelczer.dev"
 
 COPY --from=builder /build/local-client-cli/dist/cli.js /app/cli.js
+COPY --from=builder /build/local-client-cli/dist/healthcheck.js /app/healthcheck.js
+
+HEALTHCHECK --interval=10s --timeout=5s --start-period=10s --retries=1 \
+    CMD node /app/healthcheck.js /tmp/vaultlink-health.json
 
 WORKDIR /vault
 
 VOLUME ["/vault"]
 
-ENTRYPOINT ["node", "/app/cli.js"]
+ENTRYPOINT ["node", "/app/cli.js", "--health", "/tmp/vaultlink-health.json"]
 CMD ["--help"]

frontend/local-client-cli/src/args.ts

@@ -12,6 +12,7 @@ export interface CliArgs {
 	ignorePatterns?: string[];
 	webSocketRetryIntervalMs?: number;
 	logLevel: LogLevel;
+	health?: string;
 }
 
 export function parseArgs(argv: string[]): CliArgs {
@@ -51,6 +52,10 @@ export function parseArgs(argv: string[]): CliArgs {
 			"[OPTIONAL] Log level (DEBUG, INFO, WARNING, ERROR)",
 			"INFO"
 		)
+		.option(
+			"--health <path>",
+			"[OPTIONAL] Path to health status file for Docker healthcheck"
+		)
 		.addHelpText(
 			"after",
 			`
@@ -78,6 +83,7 @@ Examples:
 		| number
 		| undefined;
 	const logLevelStr = (opts.logLevel as string | undefined) ?? "INFO";
+	const health = opts.health as string | undefined;
 	/* eslint-enable @typescript-eslint/no-unsafe-type-assertion */
 
 	if (localPath === undefined) {
@@ -117,6 +123,7 @@ Examples:
 		maxFileSizeMB: maxFileSizeMb,
 		ignorePatterns: ignorePattern,
 		webSocketRetryIntervalMs: websocketRetryIntervalMs,
-		logLevel
+		logLevel,
+		health
 	};
 }

frontend/local-client-cli/src/cli.ts

@@ -1,5 +1,7 @@
 import * as path from "path";
 import * as fs from "fs/promises";
+import * as fsSync from "fs";
+import type { NetworkConnectionStatus } from "sync-client";
 import {
 	SyncClient,
 	DEFAULT_SETTINGS,
@@ -13,6 +15,19 @@ import { FileWatcher } from "./file-watcher";
 import { formatLogLine, colorize, styleText } from "./logger-formatter";
 import packageJson from "../package.json";
 
+function writeHealthStatus(
+	filePath: string,
+	connectionStatus: NetworkConnectionStatus
+): void {
+	try {
+		fsSync.writeFileSync(filePath, JSON.stringify(connectionStatus));
+	} catch (error) {
+		console.error(
+			`Failed to write health status to ${filePath}: ${error instanceof Error ? error.message : String(error)}`
+		);
+	}
+}
+
 const LOG_LEVEL_ORDER = {
 	[LogLevel.DEBUG]: 0,
 	[LogLevel.INFO]: 1,
@@ -78,6 +93,7 @@ async function main(): Promise<void> {
 		syncConcurrency:
 			args.syncConcurrency ?? DEFAULT_SETTINGS.syncConcurrency,
 		maxFileSizeMB: args.maxFileSizeMB ?? DEFAULT_SETTINGS.maxFileSizeMB,
+		diffCacheSizeMB: DEFAULT_SETTINGS.diffCacheSizeMB,
 		ignorePatterns,
 		webSocketRetryIntervalMs:
 			args.webSocketRetryIntervalMs ??
@@ -119,6 +135,15 @@ async function main(): Promise<void> {
 		nativeLineEndings: process.platform === "win32" ? "\r\n" : "\n"
 	});
 
+	if (args.health !== undefined) {
+		const healthFile = args.health;
+		setInterval(() => {
+			void client.checkConnection().then((status) => {
+				writeHealthStatus(healthFile, status);
+			});
+		}, 30 * 1000); // every 30 seconds
+	}
+
 	// Add colored log formatter with level filtering
 	client.logger.addOnMessageListener((logLine) => {
 		// Only show messages at or above the configured log level
@@ -132,7 +157,10 @@ async function main(): Promise<void> {
 	const fileWatcher = new FileWatcher(absolutePath, client);
 
 	client.addWebSocketStatusChangeListener(() => {
-		client.logger.info("WebSocket status changed");
+		const isConnected = client.isWebSocketConnected;
+		client.logger.info(
+			`WebSocket status changed: ${isConnected ? "connected" : "disconnected"}`
+		);
 	});
 
 	client.addRemainingSyncOperationsListener((remaining) => {

frontend/local-client-cli/src/healthcheck.ts

@@ -0,0 +1,59 @@
+#!/usr/bin/env node
+
+/**
+ * Healthcheck script for Docker container
+ * Checks if the sync client is connected to the server
+ */
+
+import * as fs from "fs";
+import type { NetworkConnectionStatus } from "sync-client";
+
+function isHealthStatus(value: unknown): value is NetworkConnectionStatus {
+	if (typeof value !== "object" || value === null) {
+		return false;
+	}
+
+	return true;
+}
+
+function main(): void {
+	if (process.argv.length < 3) {
+		console.error("Usage: healthcheck <path-to-health-file>");
+		process.exit(1);
+	}
+	const [, , healthFile] = process.argv;
+
+	try {
+		// Check if health file exists
+		if (!fs.existsSync(healthFile)) {
+			console.error(`Health file does not exist: ${healthFile}`);
+			process.exit(1);
+		}
+
+		// Read and parse health status
+		const content = fs.readFileSync(healthFile, "utf-8");
+		const parsed: unknown = JSON.parse(content);
+
+		// Validate the parsed object using type guard
+		if (!isHealthStatus(parsed)) {
+			throw new Error("Invalid health status format");
+		}
+
+		const status = parsed;
+
+		if (!status.isSuccessful || !status.isWebSocketConnected) {
+			console.error("Not connected to server: " + status.serverMessage);
+			process.exit(1);
+		}
+
+		console.log("Healthy: Connected to server");
+		process.exit(0);
+	} catch (error) {
+		console.error(
+			`Health check failed: ${error instanceof Error ? error.message : String(error)}`
+		);
+		process.exit(1);
+	}
+}
+
+main();

frontend/local-client-cli/webpack.config.js

@@ -2,7 +2,10 @@ const path = require("path");
 const webpack = require("webpack");
 
 module.exports = {
-		entry: "./src/cli.ts",
+		entry: {
+			cli: "./src/cli.ts",
+			healthcheck: "./src/healthcheck.ts"
+		},
 		target: "node",
 		mode: "production",
 		optimization: {
@@ -21,7 +24,7 @@ module.exports = {
 		},
 		output: {
 			globalObject: "this",
-			filename: "cli.js",
+			filename: "[name].js",
 			path: path.resolve(__dirname, "dist")
 		},
 		plugins: [