Please note that the extreme delay in updates has been largely out of my control. That said, I anticipate getting back to all of the node-* projects the first week of May.
This README provides a pretty good overview of what node-mac has to offer, but better documentation is now available at the node-mac 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.
This module helps create/manage native processes and event logs for Node.js applications on Mac OSX.
To start, install node-mac via:
npm install node-mac
node-mac is a utility for creating/managing Node.js scripts as OSX daemons. Please note that like all OSX daemons, creating one requires sudo/root privileges. To create a service with node-mac, prepare a script like:
var Service = Service;// Create a new service objectvar svc =name:'Hello World'description: 'The nodejs.org example web server.'script: '/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 Activity Monitor.
Service object emits the following events:
- install - Fired when the script is installed as a service.
- alreadyinstalled - Fired if the script is already known to be a service.
- invalidinstallation - Fired if an installation is detected but missing required files.
- uninstall - Fired when an uninstallation is complete.
- start - Fired when the new service is started.
- stop - Fired when the service is stopped.
- error - Fired in some instances when an error occurs.
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-mac are similar to most other services running on OSX. They can be stopped from the Activity Monitor and make logs available in the Console app.
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: '/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: '/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;
Cleaning Up: Uninstall a Service
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, but it will remove the logs! This process also removes the plist file for the service.
What Makes node-mac Services Unique?
Lots of things!
Long Running Processes & Monitoring:
The built-in service recovery for OSX services is fairly limited and cannot easily be configured from code. Therefore, node-mac 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-mac 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-mac 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-mac 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: '/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-mac
supports two kinds of caps. Using
maxRetries will cap the maximum total number of times the service
restarts itself before it kills the process. By default, this is unlimited. Setting it to 3 would tell the
process to stop restarting itself (i.e. leave the dead process alone) after it tries to restart it 3 times.
Another option is
maxRestarts, which caps the number of restarts attempted within a 60 second period.
For example, if this is set to 3 (the default) and the process crashes/restarts repeatedly,
node-mac will stop restarting the process after the 3rd crash within a 60 second timeframe.
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.
How Services Are Made
node-mac uses the
launchd utility to create a unique process
for each Node.js script deployed as a service. A plist file is created in
by default. Additionally, two log files are generated in
/Library/Logs/<name> for general output
and error logging.
Services created with node-mac have two event logs that can be viewed through the Console app.
A log source named
myappname.log provides basic logging for the service. It can be used to see
when the entire service starts/stops. A second log, named
myappname_error.log stores error output.
By default, any
console.error or other output will be made available
in one of these two files.
Copyright (c) 2013 Corey Butler
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