feat(doctor): check memory before running memory-intensive tasks

lib/commands/doctor/checks/check-memory.js

@@ -0,0 +1,20 @@
+'use strict';
+const os = require('os');
+const SystemError = require('../../../errors').SystemError;
+
+const MB_IN_BYTES = 1048576;
+const MIN_MEMORY = 150;
+
+function checkMemory() {
+    const availableMemory = os.freemem() / MB_IN_BYTES;
+    if (availableMemory < MIN_MEMORY) {
+        return Promise.reject(new SystemError(`Ghost recommends you have at least ${MIN_MEMORY} MB of memory available for smooth operation. It looks like you have ${parseInt(availableMemory)} MB available.`));
+    }
+    return Promise.resolve();
+}
+
+module.exports = {
+    title: 'Checking memory availability',
+    task: checkMemory,
+    category: ['install', 'start', 'update']
+};

lib/commands/doctor/checks/index.js

@@ -7,6 +7,7 @@ const validateConfig = require('./validate-config');
 const folderPermissions = require('./folder-permissions');
 const filePermissions = require('./file-permissions');
 const contentFolder = require('./content-folder');
+const checkMemory = require('./check-memory');
 
 module.exports = [
     nodeVersion,
@@ -16,5 +17,6 @@ module.exports = [
     validateConfig,
     folderPermissions,
     filePermissions,
-    contentFolder
+    contentFolder,
+    checkMemory
 ];

test/unit/commands/doctor/checks/check-memory-spec.js

@@ -0,0 +1,44 @@
+'use strict';
+const expect = require('chai').expect;
+const sinon = require('sinon');
+
+const os = require('os');
+const errors = require('../../../../../lib/errors');
+
+const modulePath = '../../../../../lib/commands/doctor/checks/check-memory';
+
+describe('Unit: Doctor Checks > Memory', function () {
+    const sandbox = sinon.sandbox.create();
+
+    afterEach(() => {
+        sandbox.restore();
+    });
+
+    it('exports proper task', function () {
+        const checkMem = require(modulePath);
+
+        expect(checkMem.title).to.equal('Checking memory availability');
+        expect(checkMem.task).to.be.a('function');
+        expect(checkMem.category).to.deep.equal(['install', 'start', 'update']);
+    });
+
+    it('errors if not enough memory is available', function () {
+        const osStub = sandbox.stub(os, 'freemem').returns(10);
+        const memCheck = require(modulePath);
+
+        return memCheck.task().catch((error) => {
+            expect(error).to.be.an.instanceof(errors.SystemError);
+            expect(error.message).to.match(/MB of memory available for smooth operation/);
+            expect(osStub.calledOnce).to.be.true;
+        });
+    });
+
+    it('works if there is enough memory', function () {
+        const osStub = sandbox.stub(os, 'freemem').returns(157286400);
+        const memCheck = require(modulePath);
+
+        return memCheck.task().then(() => {
+            expect(osStub.calledOnce).to.be.true;
+        });
+    });
+});