add alert for ubuntu 16

src/cloudron.js

@@ -167,6 +167,10 @@ function runStartupTasks() {
 function getConfig(callback) {
     assert.strictEqual(typeof callback, 'function');
 
+    const release = safe.fs.readFileSync('/etc/lsb-release', 'utf-8');
+    if (release === null) return callback(new BoxError(BoxError.FS_ERROR, safe.error.message));
+    const ubuntuVersion = release.match(/DISTRIB_DESCRIPTION="(.*)"/)[1];
+
     settings.getAll(function (error, allSettings) {
         if (error) return callback(error);
 
@@ -178,6 +182,7 @@ function getConfig(callback) {
             adminFqdn: settings.dashboardFqdn(),
             mailFqdn: settings.mailFqdn(),
             version: constants.VERSION,
+            ubuntuVersion,
             isDemo: settings.isDemo(),
             cloudronName: allSettings[settings.CLOUDRON_NAME_KEY],
             footer: branding.renderFooter(allSettings[settings.FOOTER_KEY] || constants.FOOTER),
@@ -209,7 +214,8 @@ function runSystemChecks(callback) {
 
     async.parallel([
         checkMailStatus,
-        checkRebootRequired
+        checkRebootRequired,
+        checkUbuntuVersion
     ], callback);
 }
 
@@ -237,6 +243,14 @@ function checkRebootRequired(callback) {
     });
 }
 
+function checkUbuntuVersion(callback) {
+    assert.strictEqual(typeof callback, 'function');
+
+    const isXenial = fs.readFileSync('/etc/lsb-release', 'utf-8').includes('16.04');
+
+    if (isXenial) notifications.alert(notifications.ALERT_UPDATE_UBUNTU, 'Ubuntu Upgrade Required', 'Ubuntu 16.04 has reached end of life and will not receive security and maintenance updates. Please follow https://docs.cloudron.io/guides/upgrade-ubuntu-18/ to upgrade to Ubuntu 18 at the earliest.', callback);
+}
+
 function getLogs(unit, options, callback) {
     assert.strictEqual(typeof unit, 'string');
     assert(options && typeof options === 'object');