fix(doctor): Use systeminformation for memory availability

os.freemem() doesn't account for memory used in buffers / caches in
linux, so it doesn't give an accurate reading of the available memory of
a system

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

@@ -1,16 +1,19 @@
 'use strict';
-const os = require('os');
+const sysinfo = require('systeminformation');
 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();
+    return sysinfo.mem().then((memoryInfo) => {
+        const availableMemory = memoryInfo.available / 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 = {

package.json

@@ -79,6 +79,7 @@
     "stat-mode": "0.2.2",
     "strip-ansi": "4.0.0",
     "symlink-or-copy": "1.2.0",
+    "systeminformation": "3.37.8",
     "tail": "1.2.3",
     "update-notifier": "2.3.0",
     "validator": "7.2.0",

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

@@ -2,7 +2,7 @@
 const expect = require('chai').expect;
 const sinon = require('sinon');
 
-const os = require('os');
+const sysinfo = require('systeminformation');
 const errors = require('../../../../../lib/errors');
 
 const modulePath = '../../../../../lib/commands/doctor/checks/check-memory';
@@ -34,29 +34,34 @@ describe('Unit: Doctor Checks > Memory', function () {
         expect(memCheck.enabled(ctx)).to.be.true;
     });
 
+    it('uses systeminformation to determine memory availability', function () {
+        const memStub = sandbox.stub(sysinfo, 'mem').rejects(new Error('systeminformation'));
+        const memCheck = require(modulePath);
+
+        return memCheck.task().catch(error => {
+            expect(error).to.be.an('error');
+            expect(error.message).to.equal('systeminformation');
+            expect(memStub.calledOnce).to.be.true;
+        });
+    });
+
     it('fails if not enough memory is available', function () {
-        const osStub = sandbox.stub(os, 'freemem').returns(10);
+        const memStub = sandbox.stub(sysinfo, 'mem').resolves({available: 10});
         const memCheck = require(modulePath);
-        const ctx = {
-            argv: {'check-mem': true}
-        };
 
-        return memCheck.task(ctx).catch((error) => {
+        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;
+            expect(memStub.calledOnce).to.be.true;
         });
     });
 
     it('passes if there is enough memory', function () {
-        const osStub = sandbox.stub(os, 'freemem').returns(157286400);
+        const memStub = sandbox.stub(sysinfo, 'mem').resolves({available: 157286400});
         const memCheck = require(modulePath);
-        const ctx = {
-            argv: {'check-mem': true}
-        };
 
-        return memCheck.task(ctx).then(() => {
-            expect(osStub.calledOnce).to.be.true;
+        return memCheck.task().then(() => {
+            expect(memStub.calledOnce).to.be.true;
         });
     });
 });

yarn.lock

@@ -4204,6 +4204,10 @@ [email protected]:
   version "1.2.0"
   resolved "https://registry.yarnpkg.com/symlink-or-copy/-/symlink-or-copy-1.2.0.tgz#5d49108e2ab824a34069b68974486c290020b393"
 
+[email protected]:
+  version "3.37.8"
+  resolved "https://registry.yarnpkg.com/systeminformation/-/systeminformation-3.37.8.tgz#0b42af1faf3c0b77788bbc5b56ca5f0e9f58ee73"
+
 [email protected]:
   version "4.0.2"
   resolved "https://registry.yarnpkg.com/table/-/table-4.0.2.tgz#a33447375391e766ad34d3486e6e2aedc84d2e36"