Added support for displaying temporary warning banner

Author: zonia3000

.env

@@ -19,3 +19,4 @@ LOG_LEVEL_FILE=info
 LOG_LEVEL_CONSOLE=warn
 
 FRACTAL_API_V1_MODE=include
+#WARNING_BANNER_PATH=/path/to/banner.txt

.env.development

@@ -18,3 +18,4 @@ LOG_LEVEL_FILE=debug
 LOG_LEVEL_CONSOLE=info
 
 FRACTAL_API_V1_MODE=include
+#WARNING_BANNER_PATH=/path/to/banner.txt

docs/environment-variables.md

@@ -17,7 +17,8 @@ The following environment variables can be used to configure fractal-web.
 * `LOG_LEVEL_FILE`: the log level of logs that will be written to the file; the default value is `info`;
 * `LOG_LEVEL_CONSOLE`: the log level of logs that will be written to the console; the default value is `warn`;
 * `FRACTAL_API_V1_MODE`: include/exclude V1 pages and version switcher; the default value is `include`;
-* `PUBLIC_FRACTAL_VIZARR_VIEWER_URL`: URL to [fractal-vizarr-viewer](https://github.com/fractal-analytics-platform/fractal-vizarr-viewer) service (e.g. http://localhost:3000/vizarr for testing).
+* `PUBLIC_FRACTAL_VIZARR_VIEWER_URL`: URL to [fractal-vizarr-viewer](https://github.com/fractal-analytics-platform/fractal-vizarr-viewer) service (e.g. http://localhost:3000/vizarr for testing);
+* `WARNING_BANNER_PATH`: specifies the path to a text file containing the warning banner message displayed on the site; the banner is used to inform users about important issues, such as external resources downtime or maintenance alerts; if the variable is empty or unset no banner is displayed.
 
 When running directly using `node` command these extra variables can also be configured:
 

docs/quickstart.md

@@ -57,6 +57,9 @@ export LOG_FILE=fractal-web.log
 
 export FRACTAL_API_V1_MODE=include
 
+#export PUBLIC_FRACTAL_VIZARR_VIEWER_URL=
+#export WARNING_BANNER_PATH=
+
 # default values are usually fine for the following variables; remove comments if needed
 #export AUTH_COOKIE_NAME=fastapiusersauth
 #export AUTH_COOKIE_PATH=/

src/routes/+layout.server.js

@@ -1,5 +1,6 @@
 import { env } from '$env/dynamic/private';
 import { getLogger } from '$lib/server/logger.js';
+import fs from 'fs/promises';
 
 const logger = getLogger('page layout');
 
@@ -16,8 +17,24 @@ export async function load({ locals, request, url }) {
 		logger.error('pageInfo is missing, it should have been loaded by hooks.server.js');
 	}
 
+	const warningBanner = await getWarningBanner();
+
 	return {
 		...pageInfo,
+		warningBanner,
 		v1Enabled: env.FRACTAL_API_V1_MODE !== 'exclude'
 	};
 }
+
+async function getWarningBanner() {
+	if (!env.WARNING_BANNER_PATH) {
+		return null;
+	}
+	try {
+		const bannerData = await fs.readFile(env.WARNING_BANNER_PATH, { encoding: 'utf-8' });
+		return bannerData.trim();
+	} catch (err) {
+		logger.error('An error happened reading warning banner file %s', env.WARNING_BANNER_PATH, err);
+		return null;
+	}
+}

src/routes/+layout.svelte

@@ -11,6 +11,7 @@
 	$: server = $page.data.serverInfo || {};
 	/** @type {'v1'|'v2'} */
 	$: apiVersion = $page.url.pathname.startsWith('/v1') ? 'v1' : 'v2';
+	$: warningBanner = $page.data.warningBanner;
 	// @ts-ignore
 	// eslint-disable-next-line no-undef
 	let clientVersion = __APP_VERSION__;
@@ -220,6 +221,16 @@
 				Sorry, we are performing some maintenance on fractal-server. It will be back online soon.
 			</div>
 		{/if}
+		{#if warningBanner}
+			<div class="alert alert-warning">
+				{#each warningBanner.split('\n') as line, index}
+					{#if index > 0}
+						<br />
+					{/if}
+					{line}
+				{/each}
+			</div>
+		{/if}
 		{#if userLoggedIn && !$page.data.userInfo.is_verified}
 			<div class="row">
 				<div class="col">