From 21040d7d4c00e001f9a0b7195d7f978fb98c23ce Mon Sep 17 00:00:00 2001
From: Nico <47644445+nicotsx@users.noreply.github.com>
Date: Mon, 5 Jan 2026 07:07:35 +0100
Subject: [PATCH] feat: detect if a custom docker hostname was set before
 defaulting to zerobyte (#298)

---
 README.md                 |  2 +-
 app/server/core/config.ts | 27 +++++++++++++++++++++++++--
 2 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index 9ee4f1eb..2b91dfb8 100644
--- a/README.md
+++ b/README.md
@@ -79,7 +79,7 @@ Zerobyte can be customized using environment variables. Below are the available
 | Variable              | Description                                                                                                   | Default    |
 | :-------------------- | :------------------------------------------------------------------------------------------------------------ | :--------- |
 | `PORT`                | The port the web interface and API will listen on.                                                            | `4096`     |
-| `RESTIC_HOSTNAME`     | The hostname used by Restic when creating snapshots. Useful for identifying which machine a backup came from. | `zerobyte` |
+| `RESTIC_HOSTNAME`     | The hostname used by Restic when creating snapshots. Automatically detected if a custom hostname is set in Docker. | `zerobyte` |
 | `LOG_LEVEL`           | Logging verbosity. Options: `debug`, `info`, `warn`, `error`.                                                 | `info`     |
 | `SERVER_IDLE_TIMEOUT` | Idle timeout for the server in seconds.                                                                       | `60`       |
 | `TZ`                  | Timezone for the container (e.g., `Europe/Paris`). **Crucial for accurate backup scheduling.**                | `UTC`      |
diff --git a/app/server/core/config.ts b/app/server/core/config.ts
index 7e3ef811..38d09bec 100644
--- a/app/server/core/config.ts
+++ b/app/server/core/config.ts
@@ -1,11 +1,34 @@
+import { readFileSync } from "node:fs";
+import os from "node:os";
 import { type } from "arktype";
 import "dotenv/config";
 
+const getResticHostname = () => {
+	try {
+		const mountinfo = readFileSync("/proc/self/mountinfo", "utf-8");
+		const hostnameLine = mountinfo.split("\n").find((line) => line.includes(" /etc/hostname "));
+		const hostname = os.hostname();
+
+		if (hostnameLine) {
+			const containerIdMatch = hostnameLine.match(/[0-9a-f]{64}/);
+			const containerId = containerIdMatch ? containerIdMatch[0] : null;
+
+			if (containerId?.startsWith(hostname)) {
+				return "zerobyte";
+			}
+
+			return hostname || "zerobyte";
+		}
+	} catch {}
+
+	return "zerobyte";
+};
+
 const envSchema = type({
 	NODE_ENV: type.enumerated("development", "production", "test").default("production"),
 	SERVER_IP: 'string = "localhost"',
 	SERVER_IDLE_TIMEOUT: 'string.integer.parse = "60"',
-	RESTIC_HOSTNAME: "string = 'zerobyte'",
+	RESTIC_HOSTNAME: "string?",
 	PORT: 'string.integer.parse = "4096"',
 	MIGRATIONS_PATH: "string?",
 	APP_VERSION: "string = 'dev'",
@@ -14,7 +37,7 @@ const envSchema = type({
 	environment: s.NODE_ENV,
 	serverIp: s.SERVER_IP,
 	serverIdleTimeout: s.SERVER_IDLE_TIMEOUT,
-	resticHostname: s.RESTIC_HOSTNAME,
+	resticHostname: s.RESTIC_HOSTNAME || getResticHostname(),
 	port: s.PORT,
 	migrationsPath: s.MIGRATIONS_PATH,
 	appVersion: s.APP_VERSION,