chore(systemd): ignore error in get-uid and return null

refs TryGhost#587

Instead of returning an error in the `get-uid` util we can simplify it and just return null.

Explanation:

Possible reasons for error:
- Command is not known by OS or
- User doesn't exist

The first case is not very likely to happen, as systemd is never setup on a Windows. And the second case would exactly be the result we want. false if the user doesn't exist.

extensions/systemd/get-uid.js

@@ -22,12 +22,10 @@ module.exports = function getUid(dir) {
 
         return uid;
     } catch (e) {
-        if (!e.message.match(/no such user/i)) {
-            const errors = require('../../lib').errors;
-            // throw the error here so it'll be logged
-            throw new errors.ProcessError(e);
-        }
-
+        // CASE: the ghost user doesn't exist, hence can't be used
+        // We just return null and not doing anything with the error,
+        // as it would either mean, that the user doesn't exist (this
+        // is exactly what we want to know), or the command is not by the OS
         return null;
     }
 };

extensions/systemd/index.js

@@ -17,16 +17,9 @@ class SystemdExtension extends cli.Extension {
     }
 
     _setup(argv, ctx, task) {
-        let uid;
-
-        // getUid returns either the uid or null, but can also throw an error
-        try {
-            uid = getUid(ctx.instance.dir);
-        } catch (e) {
-            this.ui.log('The "ghost" user has not been created, please run `ghost setup linux-user` first', 'yellow');
-            return task.skip();
-        }
+        const uid = getUid(ctx.instance.dir);
 
+        // getUid returns either the uid or null
         if (!uid) {
             this.ui.log('The "ghost" user has not been created, please run `ghost setup linux-user` first', 'yellow');
             return task.skip();

extensions/systemd/systemd.js

@@ -60,6 +60,7 @@ class SystemdProcessManager extends cli.ProcessManager {
 
     isEnabled() {
         try {
+            // TODO: this should probably also run as sudo
             execa.shellSync(`systemctl is-enabled ${this.systemdName}`);
             return true;
         } catch (e) {
@@ -85,6 +86,7 @@ class SystemdProcessManager extends cli.ProcessManager {
 
     isRunning() {
         try {
+            // TODO: this should probably also run as sudo
             execa.shellSync(`systemctl is-active ${this.systemdName}`);
             return true;
         } catch (e) {
@@ -99,18 +101,9 @@ class SystemdProcessManager extends cli.ProcessManager {
     }
 
     _precheck() {
-        let uid;
-
-        // getUid returns either the uid or null, but can also throw an error
-        try {
-            uid = getUid(this.instance.dir);
-        } catch (e) {
-            // getuid throws a ProcessError, we add a message and help and just throw it
-            e.message = 'Systemd process manager has not been set up or is corrupted.';
-            e.options.help = `Run ${chalk.green('ghost setup linux-user systemd')} and try again.`
-            throw e;
-        }
+        const uid = getUid(this.instance.dir);
 
+        // getUid returns either the uid or null
         if (!uid) {
             throw new cli.errors.SystemError({
                 message: 'Systemd process manager has not been set up or is corrupted.',

extensions/systemd/test/extension-spec.js

@@ -53,25 +53,6 @@ describe('Unit: Systemd > Extension', function () {
     });
 
     describe('setup stage', function () {
-        it('can handle getUid error', function () {
-            const uidStub = sinon.stub().throws(new errors.ProcessError({stderr: 'something went wrong'}));
-
-            const SystemdExtension = proxyquire(modulePath, {
-                './get-uid': uidStub
-            });
-
-            const logStub = sinon.stub();
-            const skipStub = sinon.stub();
-            const testInstance = new SystemdExtension({log: logStub}, {}, {}, path.join(__dirname, '..'));
-
-            testInstance._setup({}, {instance: {dir: '/some/dir'}}, {skip: skipStub});
-            expect(uidStub.calledOnce).to.be.true;
-            expect(uidStub.calledWithExactly('/some/dir')).to.be.true;
-            expect(logStub.calledOnce).to.be.true;
-            expect(logStub.args[0][0]).to.match(/"ghost" user has not been created/);
-            expect(skipStub.calledOnce).to.be.true;
-        });
-
         it('skips stage if ghost user hasn\'t been set up', function () {
             const uidStub = sinon.stub().returns(false);
 

extensions/systemd/test/get-uid-spec.js

@@ -6,21 +6,15 @@ const proxyquire = require('proxyquire').noCallThru();
 const modulePath = '../get-uid';
 
 describe('Unit: Systemd > get-uid util', function () {
-    it('throws ProcessError if execa error is not an expected one, but is stderr', function () {
+    it('catches error but returns null', function () {
         const shellStub = sinon.stub().throws(new Error('some error'));
         const getUid = proxyquire(modulePath, {
             execa: {shellSync: shellStub}
         });
 
-        try {
-            getUid('/some/dir');
-            expect(false, 'error should have been thrown').to.be.true;
-        } catch (e) {
-            const errors = require('../../../lib/errors');
-            expect(e).to.be.an.instanceof(errors.ProcessError);
-            expect(e.message).to.equal('some error');
-            expect(shellStub.calledOnce).to.be.true;
-        }
+        const result = getUid('/some/dir');
+        expect(result).to.be.null;
+        expect(shellStub.calledOnce).to.be.true;
     });
 
     it('returns null if ghost user doesn\'t exist', function () {

extensions/systemd/test/systemd-spec.js

@@ -301,23 +301,7 @@ describe('Unit: Systemd > Process Manager', function () {
             proxyOpts = {'./get-uid': sinon.stub().returns(true)};
         });
 
-        it('can handle when uid throws error', function () {
-            proxyOpts['./get-uid'] = sinon.stub().throws(new errors.ProcessError({stderr: 'something went wrong'}));
-            const ext = makeSystemd(proxyOpts);
-            try {
-                ext._precheck();
-                expect(false, 'An error should have been thrown').to.be.true;
-            } catch (error) {
-                expect(proxyOpts['./get-uid'].calledOnce).to.be.true;
-                expect(error).to.be.ok;
-                expect(error).to.be.instanceOf(errors.ProcessError);
-                expect(error.message).to.match(/Systemd process manager has not been set up or is corrupted./);
-                expect(error.options.help).to.match(/ghost setup linux-user systemd/);
-                expect(error.options.stderr).to.match(/something went wrong/);
-            }
-        });
-
-        it('Errors if uid doesn\'t been set', function () {
+        it('Errors if uid hasn\'t been set', function () {
             proxyOpts['./get-uid'] = sinon.stub().returns(null);
             const ext = makeSystemd(proxyOpts);
             try {