Merge pull request #2683 from node-red/write-to-temp

Update util.writeFile to write to tmp file before rename

packages/node_modules/@node-red/runtime/lib/storage/localfilesystem/util.js

@@ -17,7 +17,6 @@
 var fs = require('fs-extra');
 var fspath = require('path');
 var when = require('when');
-var nodeFn = require('when/node/function');
 
 var log = require("@node-red/util").log; // TODO: separate module
 
@@ -80,32 +79,51 @@ module.exports = {
     * the write hits disk.
     */
     writeFile: function(path,content,backupPath) {
+        var backupPromise;
         if (backupPath) {
-            if (fs.existsSync(path)) {
+            backupPromise = fs.copy(path,backupPath);
-                fs.renameSync(path,backupPath);
+        } else {
+            backupPromise = Promise.resolve();
         }
+
+        const dirname = fspath.dirname(path);
+        const tempFile = `${path}.$$$`;
+
+        return backupPromise.then(() => {
+            if (backupPath) {
+                log.trace(`utils.writeFile - copied ${path} TO ${backupPath}`)
             }
-        return when.promise(function(resolve,reject) {
+            return fs.ensureDir(dirname)
-            fs.ensureDir(fspath.dirname(path), (err)=>{
+        }).then(() => {
-                if (err) {
+            return new Promise(function(resolve,reject) {
-                    reject(err);
+                var stream = fs.createWriteStream(tempFile);
-                    return;
-                }
-                var stream = fs.createWriteStream(path);
                 stream.on('open',function(fd) {
                     stream.write(content,'utf8',function() {
                         fs.fsync(fd,function(err) {
                             if (err) {
-                                log.warn(log._("storage.localfilesystem.fsync-fail",{path: path, message: err.toString()}));
+                                log.warn(log._("storage.localfilesystem.fsync-fail",{path: tempFile, message: err.toString()}));
                             }
                             stream.end(resolve);
                         });
                     });
                 });
                 stream.on('error',function(err) {
+                    log.warn(log._("storage.localfilesystem.fsync-fail",{path: tempFile, message: err.toString()}));
                     reject(err);
                 });
             });
+        }).then(() => {
+            log.trace(`utils.writeFile - written content to ${tempFile}`)
+            return new Promise(function(resolve,reject) {
+                fs.rename(tempFile,path,err => {
+                    if (err) {
+                        log.warn(log._("storage.localfilesystem.fsync-fail",{path: path, message: err.toString()}));
+                        return reject(err);
+                    }
+                    log.trace(`utils.writeFile - renamed ${tempFile} to ${path}`)
+                    resolve();
+                })
+            });
         });
     },
     readFile: readFile,