feat(local): handle v4 boot events in local process manager

no issue:
- Ghost in v4+ emits two events on successful start: 'started' and 'ready', so we need to handle both
- The error message structure in v4 events also changes, so we need to handle things there as well

lib/commands/run.js

@@ -1,4 +1,5 @@
 const spawn = require('child_process').spawn;
+const semver = require('semver');
 const Command = require('../command');
 
 class RunCommand extends Command {
@@ -50,14 +51,16 @@ class RunCommand extends Command {
     }
 
     useDirect(instance) {
+        const isV4 = semver.major(instance.version) >= 4;
+
         this.child = spawn(process.execPath, ['current/index.js'], {
             cwd: instance.dir,
             stdio: [0, 1, 'pipe', 'ipc']
         });
 
-        let started = false;
+        let started = false, ready = false;
         this.child.stderr.on('data', (data) => {
-            if (!started || process.stderr.isTTY) {
+            if (!ready || process.stderr.isTTY) {
                 process.stderr.write(data);
             }
         });
@@ -71,13 +74,28 @@ class RunCommand extends Command {
             if (message.started) {
                 started = true;
 
+                if (!isV4) {
+                    ready = true;
+                    instance.process.success();
+                }
+
+                return;
+            }
+
+            if (isV4 && message.ready) {
+                ready = true;
                 instance.process.success();
                 return;
             }
 
             // NOTE: Backwards compatibility of https://github.com/TryGhost/Ghost/pull/9440
             setTimeout(() => {
-                instance.process.error({message: message.error});
+                let errMsg = isV4 ? message.error.message : message.error;
+                if (isV4 && started) {
+                    errMsg = `Ghost was able to start, but errored during boot with: ${errMsg}`;
+                }
+
+                instance.process.error({message: errMsg});
             }, 1000);
         });
     }

test/unit/commands/run-spec.js

@@ -159,7 +159,7 @@ describe('Unit: Commands > Run', function () {
         const errorStub = sinon.stub();
         const exitStub = sinon.stub(process, 'exit');
 
-        instance.useDirect({dir: '/var/www/ghost', process: {success: successStub, error: errorStub}}, {delayErrorChaining: false});
+        instance.useDirect({dir: '/var/www/ghost', version: '3.0.0', process: {success: successStub, error: errorStub}}, {delayErrorChaining: false});
 
         expect(spawnStub.calledOnce).to.be.true;
         expect(spawnStub.calledWithExactly(process.execPath, ['current/index.js'], {
@@ -202,6 +202,62 @@ describe('Unit: Commands > Run', function () {
         }, 2000);
     });
 
+    it('useDirect spawns child process and handles events correctly (v4+)', async function () {
+        this.timeout(10000);
+
+        const childStub = new EventEmitter();
+        childStub.stderr = getReadableStream();
+
+        const spawnStub = sinon.stub().returns(childStub);
+        const RunCommand = proxyquire(modulePath, {
+            child_process: {spawn: spawnStub}
+        });
+        const instance = new RunCommand({}, {});
+        const successStub = sinon.stub();
+        const errorStub = sinon.stub();
+
+        instance.useDirect({dir: '/var/www/ghost', version: '4.0.0', process: {success: successStub, error: errorStub}}, {delayErrorChaining: false});
+
+        expect(spawnStub.calledOnce).to.be.true;
+        expect(spawnStub.calledWithExactly(process.execPath, ['current/index.js'], {
+            cwd: '/var/www/ghost',
+            stdio: [0, 1, 'pipe', 'ipc']
+        })).to.be.true;
+        expect(instance.child).to.equal(childStub);
+
+        // Check error prior to started
+        expect(successStub.called).to.be.false;
+        expect(errorStub.called).to.be.false;
+        childStub.emit('message', {error: {message: 'test error'}});
+        await new Promise((resolve) => {
+            setTimeout(resolve, 2000);
+        });
+        expect(successStub.called).to.be.false;
+        expect(errorStub.calledOnceWithExactly({message: 'test error'}));
+
+        errorStub.reset();
+
+        // emit started message
+        childStub.emit('message', {started: true});
+        expect(successStub.called).to.be.false;
+        expect(errorStub.called).to.be.false;
+
+        // check error after started
+        childStub.emit('message', {error: {message: 'test error'}});
+        await new Promise((resolve) => {
+            setTimeout(resolve, 2000);
+        });
+        expect(successStub.called).to.be.false;
+        expect(errorStub.calledOnceWithExactly({message: 'Ghost was able to start, but errored during boot with: test error'}));
+
+        errorStub.reset();
+
+        // finally, check ready event
+        childStub.emit('message', {ready: true});
+        expect(successStub.calledOnce).to.be.true;
+        expect(errorStub.called).to.be.false;
+    });
+
     describe('cleanup handler', function () {
         const RunCommand = require(modulePath);