nac is a simple app control and monitoring daemon written in node
Unlike other process monitors, nac doesn't allow for random spawning and adding of processes. Instead, nac expects you to add "apps" defined by their name and nacfile (procfile-like configuration files)
The nacfile allows you to specify many other things about the process, such as arguments, environment variable configuration, working directory, custom scripts etc.
nac remembers your apps and will restart them the next time its started.
nac can optionally be multi-user aware: a single daemon can run as root and all clients will talk to it. Apps however are run under the uid of the user that added the application, and each user can only control his own apps.
npm install nac -g
Run the nac daemon.
Create a simple YAML nacfile for your app
in the same directory where your
command: node args: [app.js] env: NODE_ENV: production PORT: 5000
Add the nacfile to git, clone the app on your server and run the commands:
$ nac myapp create ~/projects/myapp/nacfile.yaml myapp created (/home/spion/projects/myapp/nacfile.yaml) $ nac myapp start
running as root
You can alternatively run the daemon as root. There is no need for concern - it will run apps under the priviledges of the user that added them (by setting the uid and gid). Users can only administer the apps they've added themselves.
su root nacd --daemon
Warning! The root daemon will not read the apps that were added to existing user daemons. Users will need to re-add their apps.
other configuration options
There are two types of configuration files in nac:
- app configuration (nacfile)
- server daemon configuration (nacd.yaml)
Here is a complete example nacfile:
# command to execute. It has to be executable: if using a JS file directly, # use chmod +x file.js first and add a shebang line at the top containing: # #!/usr/bin/env node command: ./myapp-cluster.js # working dir relative to the nacfile cwd: . # extra arguments to add: either an array args: - first - '--other' - third # OR # alternatively you can pass a fancy object args: # long arguments are automatically prefixed with -- longarg: value # one-letter arguments are prefixed with - s: shortarg value # you can add an explicit prefix if you wish --explicit-form: value -e: value # and you can define a list of additional arguments _: [even, more, arguments here] # environment variables env: NODE_ENV: production # clustering is best left to the app, configuration is passed by env vars workers: 4 # you can add additional scripts which will become available as commands for # the specific project scripts: deploy: ./scripts/deploy.sh report: ./scripts/statusReport.sh # if the app dies, nac will attempt to respawn it. the respawn setting # controls the behavior of the respawner. The respawner will begin by # waiting respawn.min seconds before restarting the process, then if the # process keeps dying it will exponentially backoff up to respawn.max seconds # on every respawn attempt. respawn: min: 0.1 max: 30 # override options on a per-server-tag basis servers: two.myapp.com: env: REDIS_SERVER: one.myapp.com one.myapp.com: env: # even though nac doesnt handle clustering, it # can pass clustering configuration via env or args # on a per-server basis workers: 6 REDIS_SERVER: localhost
User-level nacd daemons can be configured by creating
A root-level nacd daemon is configured via
nacd.yaml for the first server:
tags: - one.myapp.com - one - myapp-servers
Since this server has the tag "one.myapp.com", it will apply the specified config overrides for that tag
nac myapp create nacfile.yaml
Adds the specified app with its nacfile to the daemon.
The name specified must be unique for that server and user. If the user already has an app running under that name, on that server, nac will complain.
start, stop, restart
nac myapp [start|stop|restart]
Start/stop/restart the app
myapp using the command, arguments and
environment variables specified in the config file.
nac myapp kill <signal>
Send the specified named signal to the app's process. Useful for user-defined signals such as cluster reloading
nac myapp destroy
Will remove the project and its nacfile from the daemon and stop the app process
nac myapp update [configpath]
Will update the configuration file. If you omit the path,
nacd will attempt
to reload the configuration file from the same location as previously
specified. If you specify the config path,
nacd will update the apps's
configuration and update the location of the config file for that app
nac myapp logs
Show stdout/stderr logs for the project. Logs will be displayed in the format
[date] [time] [stdout|stderr]: content
- --tag - show just stdout
- --last - show last N lines in log (default 100)
- --past - show just the past days/hours/minutes/seconds e.g. --past 2m
- --duration - show the specified duration (--past required)
nac myapp run script [args]
Run one of the scripts for the project with the specified arguments. Will display the output of the script.
nac help [command]
Display detailed help for the command. If the command is omitted, nac will print a list of commands.
When running the app or its custom script,
nac sets the following extra
- NACFILE - full path to the nacfile
- NACDIR - absolute working directory of the app
- NACNAME - the name of the app (e.g. myapp)
forever migration guide
For more info on replacing forever and using nac for deployment, read the forever migration guide