Node-RED on TinyCore Linux

Installation

First, install Node.js:

$ tce-load -w- i node

Then install Node-RED through the Node Package Manager [5] (npm):

$ sudo npm install -g --unsafe-perm node-red

Unfortunately, having a custom package manager does not go well with the philosophy of TinyCore extensions. Packages installed through npm will not be persisted and are lost on reboot.

Two things can be done to prevent this:

• install packages into a location which is backed up and restored, e.g. one of the /home/* directories. This will be the solution for additional node packages.
• Create tce's for every package. We will do this for the Node-RED package only.

To create a tce for the node-red package:

$ mkdir -p /tmp/node-red/usr/local/lib/node_modules
$ sudo mv /usr/local/lib/node_modules/node-red /tmp/node-red/usr/local/lib/node_modules
$ mkdir -p /tmp/node-red/usr/local/bin
$ cd /tmp/node-red/usr/local/bin
$ ln -s ../lib/node_modules/node-red/red.js node-red
$ ln -s ../lib/node_modules/node-red/bin/node-red-pi node-red-pi
$ cd ~
$ sudo chown root:root -R /tmp/node-red/
$ tce-load -wo squashfs-tools
$ tce-load -il squashfs-tools
$ mksquashfs /tmp/node-red/ /tmp/node-red.tcz
$ sudo rm -r /tmp/node-red/
$ mv /tmp/node-red.tcz /etc/sysconfig/tcedir/optional/

Now, after a reboot, the node-red installation should be gone. But it can now be installed with:

$ tce-load -i node-red

To make sure that Node-RED is reinstalled on boot, add it to onboot.lst:

$ echo node-red.tcz >> /etc/sysconfig/tcedir/onboot.lst

Finally, we need to secure the Node-RED configuration and data files. These are stored in $HOME/.node-red and we add it to /opt/.filetool.lst. Or rather: make sure that home directories are present (they are, by default).

Additional Node Packages

Additional node packages will be installed in the /home/nodered/.node-red, assuming the the nodered user will run the application. This is done like this:

$ cd /home/nodered/.node.red
$ npm install node-red-contrib-foo

User

Next, we need to create the nodered user which we will use to run the service.

$ sudo adduser -S nodered

Start Script

To start the service at boot, edit /opt/bootlocal.sh. Since Node-RED only implements logging to the console, we redirect its output into a log file:

# start Node-RED with nodered-user in a subshell
NR_LOG=/var/log/node-red.log
touch "$NR_LOG"
chown nodered:root "$NR_LOG"
(su nodered -c /usr/local/bin/node-red -s /bin/sh >> "$NR_LOG") &

Monitoring (with monit)

This is how monit [6] can be used to monitor that Node-RED is up and running. This assumes a working installation of monit on TinyCore Linux.

Adding checks for Node-RED is done by editing a configuration file. The file is located in /usr/local/etc/monit.d. Actually, monit's configuration file is /usr/local/etc/monitrc but it is possible to split the configuration into several files by adding this line to monitrc:

include /usr/local/etc/monit.d/*

So, inside monit.d/, create a new file named node-red and add a check which looks for the Node-red process and make a HTTP request against the Node-RED Admin API [7], specifically its auth endpoint. The auth endpoint lists the currently active authentication scheme and is available even if authentication is on.

The endpoint should return either a JSON object with details on the authentication scheme or an empty JSON object. In any case, a pair of curly braces.

We will also make sure that the application is running with the intended user.

The check looks like this:

# list authentication scheme from Admin-API - see
# http://nodered.org/docs/api/admin/oauth
check process node-red matching node-red
    group node-red
    if failed
        port 1880
        with protocol http
        request /auth/login
        content = "\{.*?\}"
    then alert

    if failed uid nodered then alert