Support for Windows services, event logging, UAC, and several helper methods for interacting with the OS.
The number of issues between this project and it's sister projects (node-mac & node-linux) are accruing at a rate that deserves more attention than I can provide on my own. I'm actively looking for maintainers to help run this project. Please get in touch via gitter if you're interested.
This README provides a pretty good overview of what node-windows has to offer, but better documentation is now available at the node-windows documentation portal.
This is a standalone module, originally designed for internal use in NGN. However; it is capable of providing the same features for Node.JS scripts independently of NGN.
The following features are available in node-windows:
execcommand as a sudoer.
The recommended way to install node-windows is with npm, using the global flag:
npm install -g node-windows
Then, in your project root, run:
npm link node-windows
However; it is possible to use node-windows without the global flag (i.e. install directly into the project root). More details regarding why this is not the recommended approach are available throughout this Readme.
Using native node modules on Windows can suck. Most native modules are not distributed in a binary format.
Instead, these modules rely on
npm to build the project, utilizing node-gyp.
This means developers need to have Visual Studio (and potentially other software) installed on the system,
just to install a native module. This is portable, but painful... mostly because Visual Studio
itself is over 2GB.
node-windows does not use native modules. There are some binary/exe utilities, but everything needed to run more complex tasks is packaged and distributed in a readily usable format. So, no need for Visual Studio... at least not for this module.
node-windows has a utility to run Node.js scripts as Windows services. Please note that like all Windows services, creating one requires administrative privileges. To create a service with node-windows, prepare a script like:
var Service = Service;// Create a new service objectvar svc =name:'Hello World'description: 'The nodejs.org example web server.'script: 'C:\\path\\to\\helloworld.js';// Listen for the "install" event, which indicates the// process is available as a service.svc;svc;
The code above creates a new
Service object, providing a pretty name and description.
script attribute identifies the Node.js script that should run as a service. Upon running
this, the script will be visible from the Windows Services utility.
Service object emits the following events:
In the example above, the script listens for the
install event. Since this event
is fired when a service installation is complete, it is safe to start the service.
Services created by node-windows are similar to most other services running on Windows.
They can be started/stopped from the windows service utility, via
NET START or
NET STOP commands,
or even managed using the sc
Sometimes you may want to provide a service with static data, passed in on creation of the service. You can do this by setting environment variables in the service config, as shown below:
var svc =name:'Hello World'description: 'The nodejs.org example web server.'script: 'C:\\path\\to\\helloworld.js'env:name: "HOME"value: processenv"USERPROFILE" // service is now able to access the user who created its' home directory;
You can also supply an array to set multiple environment variables:
var svc =name:'Hello World'description: 'The nodejs.org example web server.'script: 'C:\\path\\to\\helloworld.js'env:name: "HOME"value: processenv"USERPROFILE" // service is now able to access the user who created its' home directoryname: "TEMP"value: path // use a temp directory in user's home directory;
If you need to specify a specific user or particular credentials to manage a service, the following attributes may be helpful.
user attribute is an object with three keys:
This can be used to identify which user the service library should use to perform system commands.
By default, the domain is set to the local computer name, but it can be overridden with an Active Directory
or LDAP domain. For example:
var Service = Service;// Create a new service objectvar svc =name:'Hello World'script:;svcuserdomain = 'mydomain.local';svcuseraccount = 'username';svcuserpassword = 'password';...
Both the account and password must be explicitly defined if you want the service module to
run commands as a specific user. By default, it will run using the user account that launched
the process (i.e. who launched
The other attribute is
sudo. This attribute has a single property called
password. By supplying
this, the service module will attempt to run commands using the user account that launched the
process and the password for that account. This should only be used for accounts with administrative
var Service = Service;// Create a new service objectvar svc =name:'Hello World'script:;svcsudopassword = 'password';...
Uninstalling a previously created service is syntactically similar to installation.
var Service = Service;// Create a new service objectvar svc =name:'Hello World'script:;// Listen for the "uninstall" event so we know when it's done.svc;// Uninstall the service.svc;
The uninstall process only removes process-specific files. It does NOT delete your Node.js script!
Lots of things!
Long Running Processes & Monitoring:
The built-in service recovery for Windows services is fairly limited and cannot easily be configured from code. Therefore, node-windows creates a wrapper around the Node.js script. This wrapper is responsible for restarting a failed service in an intelligent and configurable manner. For example, if your script crashes due to an unknown error, node-windows will attempt to restart it. By default, this occurs every second. However; if the script has a fatal flaw that makes it crash repeatedly, it adds unnecessary overhead to the system. node-windows handles this by increasing the time interval between restarts and capping the maximum number of restarts.
Smarter Restarts That Won't Pummel Your Server:
Using the default settings, node-windows adds 25% to the wait interval each time it needs to restart
the script. With the default setting (1 second), the first restart attempt occurs after one second.
The second occurs after 1.25 seconds. The third after 1.56 seconds (1.25 increased by 25%) and so on.
Both the initial wait time and the growth rate are configuration options that can be passed to a new
Service. For example:
var svc =name:'Hello World'description: 'The nodejs.org example web server.'script: 'C:\\path\\to\\helloworld.js')wait: 2grow: 5;
In this example, the wait period will start at 2 seconds and increase by 50%. So, the second attempt would be 3 seconds later while the fourth would be 4.5 seconds later.
Don't DOS Yourself!
Repetitive recycling could potentially go on forever with a bad script. To handle these situations, node-windows
supports two kinds of caps. Using
maxRetries will cap the maximum number of restart attempts. By
default, this is unlimited. Setting it to 3 would tell the process to no longer restart a process
after it has failed 3 times. Another option is
maxRestarts, which caps the number of restarts attempted
within 60 seconds. For example, if this is set to 3 (the default) and the process crashes/restarts repeatedly,
node-windows will cease restart attempts after the 3rd cycle in a 60 second window. Both of these
configuration options can be set, just like
Finally, an attribute called
abortOnError can be set to
true if you want your script to not restart
at all when it exits with an error.
node-windows uses the winsw utility to create a unique
for each Node.js script deployed as a service. A directory called
daemon is created and populated
myappname.xml. The XML file is a configuration for the executable. Additionally,
winsw will create some logs for itself in this directory (which are viewable in the Event log).
myappname.exe file launches the node-windows wrapper, which is responsible for monitoring and managing
the script. Since this file is a part of node-windows, moving the node-windows directory could result in
.exe file not being able to find the Node.js script. However; this should not be a problem if
node-windows is installed globally, per the recommended installation instructions.
All of these daemon-specific files are created in a subdirectory called
daemon, which is created in the
same directory where the Node.js script is saved. Uninstalling a service will remove these files.
Services created with node-windows have two event logs that can be viewed through the Windows Event Viewer.
A log source named
myappname.exe provides basic logging for the executable file. It can be used to see
when the entire service starts/stops or has errors. A second log, named after your service name (i.e. My App Name),
is used by the node-windows monitor. It is possible to write to this log from the Node.js script using
the node-windows Event Logging.
New as of
v0.1.0 is a non-C++ based event logging utility. This utility can write to the event log,
making your logs visible from the Event Viewer.
To create a logger:
var EventLogger = EventLogger;var log = 'Hello World';log;log;log;
Looks similar to:
Some lesser-used options are also available through node-windows event logging.
Each log type (info, warn, error, auditSuccess, and auditFailure) method optionally accepts two additional
arguments, including a code and callback. By default, the event code is
1000 if not otherwise specified.
To provide a custom event code with a log message and write that message to the console, the following code could
By default, event logs are all part of the
APPLICATION scope. However; it is also possible to use the
To do this, a configuration object must be passed to the new log:
var EventLogger = EventLogger;var log =source: 'My Event Log'eventLog: 'SYSTEM';
node-windows ships with several commands to simplify tasks on MS Windows.
Elevate is similar to
sudo on Linux/Mac. It attempts to elevate the privileges of the
current user to a local administrator. Using this does not require a password, but it
does require that the current user have administrative privileges. Without these
privileges, the command will fail with a
access denied error.
On systems with UAC enabled, this may prompt the user for permission to proceed:
Sudo acts similarly to
sudo on Linux/Mac. Unlike elevate, it requires a password, but it
will not prompt the user for permission to proceed. Like elevate, this
still requires administrative privileges for the user, otherwise the command will fail.
The primary difference between this and elevate() is the prompt.
This asynchronous command determines whether the current user has administrative privileges.
It passes a boolean value to the callback, returning
true if the user is an administrator
false if it is not.
var wincmd = ;wincmd;
The list method queries the operating system for a list of running processes.
var wincmd = ;wincmd;
This returns an array of running processes. Supplying the optional
argument in the above example provides a list with verbose output. The output is
specific to the version of the operating system. Here is an example of verbose
output on a Windows 8 computer.
ImageName: 'cmd.exe'PID: '12440'SessionName: 'Console''Session#': '1'MemUsage: '1,736 K'Status: 'Unknown'UserName: 'Machine\\Corey'CPUTime: '0:00:00'WindowTitle: 'N/A'ImageName: 'tasklist.exe'PID: '1652'SessionName: 'Console''Session#': '1'MemUsage: '8,456 K'Status: 'Unknown'UserName: 'Machine\\Corey'CPUTime: '0:00:00'WindowTitle: 'N/A'
The regualar (non-verbose) output typically provides the
This method will kill a process by
var wincmd = ;wincmd;
In this example, process ID
12345 would be killed. It is important to note that the
user account executing this node script may require administrative privileges.
If you're experiencing issues with the examples, please review the
If you are encountering the invalidinstallation event, take a look at the
directory that is created during the installation to make sure the
files are there. In some circumstances, primarily during _un_installation, it is
possbile for the process to temporarily lock a log file, which prevents Windows
from removing it. In this scenario, simply run the uninstall again. In most cases this
will fix the issue. If not, manually remove the
daemon directory before running the
winsw and sudowin are the copyrights of their respective owners. winsw is distributed under an MIT license. sudowin is distributed under a BSD license.
All other scripts are Copyright (c) Corey Butler under an MIT license.
(The MIT License)
Copyright (c) 2013 Corey Butler
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.