fix(systemd): improve setup checks of extension and process manager

closes TryGhost#291
- add function to double check that linux-user has been run
- make help messaging more clear

extensions/systemd/get-uid.js

@@ -0,0 +1,28 @@
+'use strict';
+
+const fs = require('fs');
+const execa = require('execa');
+
+/**
+ * Helper function used by both the extension setup method
+ * and the systemd process manager
+ */
+module.exports = function getUid(dir) {
+    try {
+        let uid = execa.shellSync('id -u ghost').stdout;
+        let stat = fs.lstatSync(dir);
+
+        if (stat.uid !== uid) {
+            // Ghost user is not the owner of this folder, return null
+            return null;
+        }
+
+        return uid;
+    } catch (e) {
+        if (!e.message.match(/no such user/)) {
+            throw e;
+        }
+
+        return null;
+    }
+};

extensions/systemd/index.js

@@ -2,10 +2,10 @@
 
 const fs = require('fs-extra');
 const path = require('path');
-const execa = require('execa');
 const template = require('lodash/template');
 
 const cli = require('../../lib');
+const getUid = require('./get-uid');
 
 class SystemdExtension extends cli.Extension {
     setup(cmd, argv) {
@@ -17,15 +17,9 @@ class SystemdExtension extends cli.Extension {
     }
 
     _setup(argv, ctx, task) {
-        let uid;
-
-        try {
-            uid = execa.shellSync('id -u ghost').stdout;
-        } catch (e) {
-            if (!e.message.match(/no such user/)) {
-                return Promise.reject(e);
-            }
+        let uid = getUid(ctx.instance.dir);
 
+        if (!uid) {
             this.ui.log('Ghost user has not been set up, please run `ghost setup linux-user` first', 'yellow');
             return task.skip();
         }

extensions/systemd/systemd.js

@@ -3,40 +3,29 @@
 const fs = require('fs');
 const execa = require('execa');
 const cli = require('../../lib');
+const getUid = require('./get-uid');
 
 class SystemdProcessManager extends cli.ProcessManager {
     get systemdName() {
         return `ghost_${this.instance.name}`;
     }
 
     start() {
-        if (!this._precheck()) {
-            return Promise.reject(
-                new cli.errors.SystemError('Systemd process manager has not been set up. Run `ghost setup systemd` and try again.')
-            );
-        }
+        this._precheck();
 
         return this.ui.sudo(`systemctl start ${this.systemdName}`)
             .catch((error) => Promise.reject(new cli.errors.ProcessError(error)));
     }
 
     stop() {
-        if (!this._precheck()) {
-            return Promise.reject(
-                new cli.errors.SystemError('Systemd process manager has not been set up. Run `ghost setup systemd` and try again.')
-            );
-        }
+        this._precheck();
 
         return this.ui.sudo(`systemctl stop ${this.systemdName}`)
             .catch((error) => Promise.reject(new cli.errors.ProcessError(error)));
     }
 
     restart() {
-        if (!this._precheck()) {
-            return Promise.reject(
-                new cli.errors.SystemError('Systemd process manager has not been set up. Run `ghost setup systemd` and try again.')
-            );
-        }
+        this._precheck();
 
         return this.ui.sudo(`systemctl restart ${this.systemdName}`)
             .catch((error) => Promise.reject(new cli.errors.ProcessError(error)));
@@ -82,17 +71,23 @@ class SystemdProcessManager extends cli.ProcessManager {
     }
 
     _precheck() {
+        let uid = getUid(this.instance.dir);
+
+        if (!uid) {
+            throw new cli.errors.SystemError('Systemd process manager has not been set up. Run `ghost setup linux-user systemd` and try again.')
+        }
+
         if (this.instance.cliConfig.get('extension.systemd', false)) {
-            return true;
+            throw new cli.errors.SystemError('Systemd process manager has not been set up. Run `ghost setup systemd` and try again.');
         }
 
         // service file exists but for some reason the right property in cliConfig hasn't been set
         if (fs.existsSync(`/lib/systemd/system/${this.systemdName}.service`)) {
             this.instance.cliConfig.set('extension.systemd', true);
-            return true;
+            return;
         }
 
-        return false;
+        throw new cli.errors.SystemError('Systemd process manager has not been set up. Run `ghost setup systemd` and try again.');
     }
 
     static willRun() {