Heroku Buildpack: Monit

Run Monit on Heroku.

Usage:

Create a new directory and git repository:

mkdir heroku-monit
cd heroku-monit
git init .

Initialise the Heroku app:

heroku create --buildpack=https://github.com/matiaskorhonen/monit-buildpack.git

Then create a monitrc file (see below) and push to Heroku.

Your repository structure should look like this (the conf.d directory is optional):

.
├── conf.d
│   └── example
└── monitrc

monitrc must exist and at the very minimum it should have this content:

## Start Monit in the background (run as a daemon):
set daemon  60              # check services at 1-minute intervals

## Set the location of the Monit id file which stores the unique id for the
## Monit instance. The id is generated and stored on first Monit start. By 
## default the file is placed in $HOME/.monit.id.
set idfile /app/tmp/.monit.id

## Monit has an embedded web server which can be used to view status of 
## services monitored and manage services from a web interface.
set httpd port ${PORT}
    allow ${HTTP_USER}:${HTTP_PASSWD}

check system ${SYSTEM_NAME}

## It is possible to include additional configuration parts from other files or
## directories.
#
# include /app/conf.d/*
#

You should also set the HTTP_USER and HTTP_PASSWD environment variables:

heroku config:add HTTP_USER=grimlock HTTP_PASSWD=supersecret

Environment variables in the monitrc file and in files in the conf.d directory will be substituted for the actual values as long as you use the correct format (i.e. ${MY_VARIABLE}).

The SYSTEM_NAME variable defaults to "Heroku", but you can override it if you wish:

heroku config:add SYSTEM_NAME=Grimlock

Important: Keep Monit Alive

You need to have a uptime monitor (such as Pingdom or Uptime Robot) monitoring your monit instance to make sure that it stays alive.

For this use I suggest configuring a read-only user, e.g.

set httpd port ${PORT}
    allow ${HTTP_USER}:${HTTP_PASSWD}
    allow ${READ_USER}:${READ_PASSWD} read-only

And of course set the READ_USER and READ_PASSWD variables…

For more information on how to configure Monit, see the Monit manual.

Working Example

See the heroku-monit repository for a working example: https://github.com/matiaskorhonen/heroku-monit

A slightly modified version of the heroku-monit example is publicly available at https://monit-demo.herokuapp.com/ (User: monit | Password: monit).

License

See the LICENSE file for more details.

Dependencies

Monit is downloaded as source code and built on Heroku and is licensed independently under the GNU Affero General Public License.