Node-Red: Checking network service port status + UI status indicator

This post is about how to do two simple things using Node-Red:

1. Check if network service on the machine running Node-Red is available by checking the corresponding listening port.
2. The Node-Red UI doesn’t have a status indicator available, so I’ve built one

The only limitation on the following solution is that it only tests for ports for services that are running on the same server, where Node-Red is also running.

Preparation:

We need to install the Is Port Available NPM Module and make it available into our Node-Red instance.

For doing so, in Linux we must do the following:

root@server:~# cd .node-red/
root@server:~/.node-red# npm i --save is-port-available

We need now to make this node module available to Node-Red by editing the settings.js file:

root@server:~/.node-red# vi settings.js

Add the module to the global context on the function named functionGlobalContext:

    functionGlobalContext: {
        // os:require('os'),
        // octalbonescript:require('octalbonescript'),
        // jfive:require("johnny-five"),
        // j5board:require("johnny-five").Board({repl:false})

        portavail:require('is-port-available')
    },

You might have other modules configured, so we need to add the above portavail:require(‘is-port-available’) line to that list preceded by a comma.

We need to restart Node-Red to make the module available to the flows.

The testing flow
In our Function nodes, we can now use the global context object portavail to access the is-port-available module.

For example for testing the InfluxDB server port (1086/TCP) we can write the following function:

    // Instantiate locally on the flow the is-port-available module
    const isPortAvailable = context.global.portavail;

    msg.payload = {};   // Zero out the message. Not really necessary
     
    var port = 1086; // Replace this with your service port number. In this case 1086 is the Influx DB port
    
    isPortAvailable(port).then( status => {
        if(status) {
            //console.log('Port ' + port + ' IS available!');
            msg.payload = {'InfluxDB':false,"title":"InfluxDB","color":"red"};   // The port is available, hence the server is NOT running
            node.send(msg);
        } else {
            //console.log('Port ' + port + ' IS NOT available!');
            //console.log('Reason : ' + isPortAvailable.lastError);
            msg.payload = {'InfluxDB':true,"title":"InfluxDB","color":"green"};    // The port is not available, so the server MIGHT be running
            node.send(msg);
           
        }
    });

    // Note that we DO NOT return a message here since the above code is asynchronous and it will emit the message in the future. 

Since the test is using promises, Node-Red will continue executing without waiting for the test response (the isPortAvailable(port) code ). So we do not send any message further on the normal Node-Red execution flow (hence there is no return msg; object) and the message is only emitted when the promise fulfils. When that happens we just send the message with the node.send(msg) statement.

The message payload can be anything, being the only important properties the title and color that are used for creating the UI status indicator.

The status indicator is a simple Angularjs template that displays the title and a status circle with the chosen colour.

Since pasting CSS and HTML code in WordPress is recipe to disaster, the template code can be accessed on this gist or on the complete test flow below:

[{"id":"1f506795.4be25","type":"inject","z":"53f8b852.885c6","name":"Check todos os 60s","topic":"","payload":"","payloadType":"date","repeat":"60","crontab":"","once":true,"x":260,"y":96,"wires":[["5d180fc7.9ad06","27e67f9b.4f9158"]]},{"id":"5d180fc7.9ad06","type":"function","z":"53f8b852.885c6","name":"Test Influx DB","func":"    const isPortAvailable = context.global.portavail;\n    msg.payload = {};\n     \n    var port = 8086;\n    \n    isPortAvailable(port).then( status =>{\n        if(status) {\n            //console.log('Port ' + port + ' IS available!');\n            msg.payload = {'InfluxDB':false,\"title\":\"InfluxDB\",\"color\":\"red\"};   // The port is available, hence the server is NOT running\n            node.send(msg);\n        } else {\n            //console.log('Port ' + port + ' IS NOT available!');\n            //console.log('Reason : ' + isPortAvailable.lastError);\n            msg.payload = {'InfluxDB':true,\"title\":\"InfluxDB\",\"color\":\"green\"};    // The port is not available, so the server MIGHT be running\n            node.send(msg);\n           \n        }\n    });\n    ","outputs":1,"noerr":0,"x":533.5,"y":97,"wires":[["3f3f8226.c9bfb6"]]},{"id":"3f3f8226.c9bfb6","type":"ui_template","z":"53f8b852.885c6","group":"44e5d7ea.043b2","name":"Status Icon","order":0,"width":0,"height":0,"format":"\n.dot {\n    height: 25px;\n    width: 25px;\n    background-color: #bbb;\n    border-radius: 50%;\n    display: inline-block;\n    float: right;\n}\n\n\n
{{msg.payload.title}}\n         \n
","storeOutMessages":true,"fwdInMessages":true,"x":780,"y":96,"wires":[[]]},{"id":"27e67f9b.4f9158","type":"function","z":"53f8b852.885c6","name":"Test MongoDB","func":"    const isPortAvailable = context.global.portavail;\n    msg.payload = {};\n     \n    var port = 27017;\n    \n    isPortAvailable(port).then( status =>{\n        if(status) {\n            //console.log('Port ' + port + ' IS available!');\n            msg.payload = {'MongoDB':false,\"title\":\"MongoDB\",\"color\":\"red\"};   // The port is available, hence the server is NOT running\n            node.send(msg);\n        } else {\n            //console.log('Port ' + port + ' IS NOT available!');\n            //console.log('Reason : ' + isPortAvailable.lastError);\n            msg.payload = {'MongoDB':true,\"title\":\"MongoDB\",\"color\":\"green\"};    // The port is not available, so the server MIGHT be running\n            node.send(msg);\n           \n        }\n    });\n    ","outputs":1,"noerr":0,"x":533,"y":158,"wires":[["2e85d9d.cc25126"]]},{"id":"2e85d9d.cc25126","type":"ui_template","z":"53f8b852.885c6","group":"44e5d7ea.043b2","name":"Status Icon","order":0,"width":0,"height":0,"format":"\n.dot {\n    height: 25px;\n    width: 25px;\n    background-color: #bbb;\n    border-radius: 50%;\n    display: inline-block;\n    float: right;\n}\n\n\n
{{msg.payload.title}}\n         \n
","storeOutMessages":true,"fwdInMessages":true,"x":781,"y":161,"wires":[[]]},{"id":"44e5d7ea.043b2","type":"ui_group","z":"","name":"System Status","tab":"7011ff77.15cb18","disp":true,"width":"6"},{"id":"7011ff77.15cb18","type":"ui_tab","z":"","name":"Home","icon":"dashboard"}]

The result:

The above flow and Node UI status indicator template should produce the following result:

Node-Red UI Status Indicator

Using Node-Red and Grafana WorldMap for geolocalized data visualization

Based on my previous posts we are now able to build a system that can receive, store and visualize data by using Node-Red, InfluxDB and Graphana. Grafana allows us build dashboards, query and visualize the stored data across time efficiently by using, in our case, the InfluxDB database engine. So far we’ve used simple line/bar charts to visualize data but we can use both Node-Red and Grafana to plot data onto a map:

1. NodeRed Contrib World Map: Openstreet UI based map for plotting data with several options, including icon types, vectors, circles and heatmaps totally controlled through nodered flows.
2. Grafana WorldMap plugin: Grafana panel with also an OpenStreet map for visualizing data.

Both have pros and cons, but the main differences between the two is that Node-Red Worldmap is suited more to real time display, and the Grafana plugin is better adapted to display data based on some time based query. Other major difference is that Node-Red Worldmap would require some coding, but, at least I consider it, at an easy level, and the Grafana plugin is much harder to make it work.

Mapping data using Node-Red Worldmap:
One of the easiest ways for mapping data in real time is using Node Red Worldmap node. The map is plotted and updated in real time.

cd ~
cd .node-red
npm install node-red-contrib-web-worldmap

After restarting and deploying a worldmap node, the map should be available at: http://server:1880/worldmap or other URL depending on the Node-Red base configuration.

One thing to keep in mind is that Node-Red is single user, so all instances of world maps (several different clients/browsers) will always have the same view.
The simplest way to start using the worldmap is just to copy and deploy the demo workflow provided by the node, but the key concept is that each point has a name and a set of coordinates.

msg.payload = {};
msg.payload.name = "CentralLX";
msg.payload.lat = 38.7223;
msg.payload.lon = -9.1393;
msg.payload.layer = "SensorData";
msg.payload.UVLevel = getUVLevel() ;
msg.payload.Temperature = getTemp();

The cool thing is that if we inject repeatedly the above message (keeping the same name) but with different coordinates, the data point will move across the map in real time, and as I said earlier, the move will be reflect onto every client.

So all we need is an Inject node to a function node with the above code and feed it to the world map:

At the end we get this at the URL http://server:1880/worldmap:

Mapping data using Grafana Worldmap plugin:

The Grafana Worldmap plugin can get the location data in several ways. One of them is to use geohash data that is associated to the values/measurements.
There is a Node Red Geohash node that generates the geohash value from the latitude and longitude of data location. As usual we install the node:

cd ~
cd .node-red
npm install node-red-node-geohash

and then the Grafana plugin. We just follow the plugin instructions:

cd ~
grafana-cli plugins install grafana-worldmap-panel
/etc/init.d/grafana-server restart

With this per-requisites installed we can now feed data onto the database, in our case InfluxDB, that will be used by Grafana. We just need make sure that we add the geohash field. The geohash node will calculate from the node-red message properties lat – latitude and lon – longitude the required info:

A simple example:

Using the Influx tool, we can query our database and see that the geohash localization is now set:

> select * from SensorData limit 2
name: DemoValue
time                Temp UVLevel geohash    lat       lon        
----                ---- ------- -------   ---------- ----------  
1490706639630929463 22   8       eyckpjywh 38.7045055 -9.1754669  
1490706651606553077 21   7       eyckpjzjr 38.7044008 -9.1746488 

Anyway for setting up the World map plugin to display the above data was not straight forward, so the following instructions are more for a startup point rather than a solution.

The first thing to know is that the plugin is waiting for two fields: geohash and metric. With this in mind, before wasting too much time with the map plugin, a table panel that is filled with the required query is a precious tool to debug the query:

After we infer from the table that the data is more or less the data we want, we just transfer the query to WorldMap plugin:

Notice two important things: The aliasing for the query field to metric with the alias(metric) instruction, and the Format as: Table.

We can now setup the specific Worldmap settings:

On the Map Visual Options , I’ve centered the map in my location and set the zoom level. Fiddling around here can be seen in real time.

On the Map Data Options for this specific example, the Location Data comes from a table filled with the previous query (hence the format as table on the query output), and we want to see the current values with no aggregation.

When hoovering around a spot plotted on the map we can see a label: value, and the label used is obtained from a table field. In my case I just used geohash (not really useful…). Anyway these changes only work after saving and reloading the panel with F5 in my experience.

At the end we have now graphed data and localized data:

If we drag the selector on the left graphic panel, or select another time interval on top right menu of the grafana dashboard, the visualized information on the map changes.

Node Red Dashboard and UPS Monitoring

Just a quick hack to use the Node Red dashboard to monitor some of the UPS values that is attached to My Synology NAS.

Gathering the data and feeding it to Node-Red
First I thought to do some sort of Python or NodeJS program to run the upsc command, process the output and feed it, through MQTT, to Node Red.
But since it seemed to me a bit of overkill to just process a text output, transform it to JSON and push it through MQTT by using a program, I decided that I’ll use some shell scripting, bash to be more explicit.

I’m running on my Odroid C1+ “server” all the necessary components, namely Node Red with the Dashboard UI module.

So on Odroid I also have the ups monitoring tools, and upsc outputs a text with the ups status:

odroid@odroid:~$ upsc ups@192.168.1.16
Init SSL without certificate database
battery.charge: 100
battery.charge.low: 10
...
input.transfer.high: 300
input.transfer.low: 140
input.voltage: 230.0
...
ups.load: 7
ups.mfr: American Power Conversion
...
ups.model: Back-UPS XS 700U  
...

So all we need now is to transform the above output from that text format to JSON and feed it to MQTT.
This means that we need to put between ” the parameter names and values, replace the : by , and also we need to replace the . on parameter names to _ so that in Node Red javascript we don’t have problems working with the parameter names.

Since I’m processing each line of the output, I’m using gawk/awk that allows some text processing. The awk program is as follow:

BEGIN {print "{"}
 {
   print lline  "\42" $1 "\42:\42"$2"\42"
 }
 {lline =", "}
END {print "}"}

This will at the beginning print the opening JSON bracket, then line by line the parameter name and value between ” and separated by : .
The lline variable at the first line is empty, so it prints nothing, but at the following lines it prints , which separates the JSON values.
We just need awk now to recognize parameters and values, and that is easy since they are separated by :

So if the above code is saved as procupsc.awk file, then the following command:

 upsc ups@192.168.1.16 2>/dev/null | awk -F: -f ~/upsmon/procupsc.awk |  sed 's/[.]/_/g'

Transforms the upsc output into a JSON output, including the replacement of . on variable names into _

{
"battery_charge":" 100"
, "battery_charge_low":" 10"
, "battery_charge_warning":" 50"
...
, "ups_load":" 7"
..
, "ups_vendorid":" xxxx"
}

Now all we need is to feed the output to the MQTT broker, and for this I’ll use the mosquitto_pub command, that has a switch that accepts the message from the standard input:

upsc ups@192.168.1.16 2>/dev/null | awk -F: -f /home/odroid/upsmon/procupsc.awk |  sed 's/[.]/_/g' | mosquitto_pub -h 192.168.1.17 -t upsmon -s

So we define the host and the topic: upsmon and the message is the output of the previous command (the -s switch).

All we need now is on Node Red to subscribe to the upsmon topic and process the received JSON object.

Since I’m running this periodically on crontab, I also add the PATH variable so that all files and commands are found.
The complete script is as follows:

upsmon.sh

PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
upsc ups@192.168.1.16 2>/dev/null | awk -F: -f /home/odroid/upsmon/procupsc.awk |  sed 's/[.]/_/g' | mosquitto_pub -h 192.168.1.17 -t upsmon -s

and on Crontab:

# m h  dom mon dow   command
*/5 * * * * /home/odroid/upsmon/upsmon.sh

Node Red processing and visualization
On node red side, now is easy. We receive the above upsc JSON object as a string on msg.payload, and we use the JSON node to separate into different msg.# variables.
From here we just feed the data to charts and gauges. The code is:

[{"id":"603732e7.bb8464","type":"mqtt in","z":"a8b82890.09ca7","name":"","topic":"upsmon","qos":"2","broker":"2a552b3c.de8d2c","x":114.5,"y":91,"wires":[["193a550.2b0ea2b"]]},{"id":"f057bae4.8e4678","type":"debug","z":"a8b82890.09ca7","name":"","active":true,"console":"false","complete":"payload","x":630.5,"y":88,"wires":[]},{"id":"563ec2f5.6475e4","type":"ui_gauge","z":"a8b82890.09ca7","name":"UPS Load","group":"ba196e43.b35398","order":0,"width":0,"height":0,"gtype":"donut","title":"Load","label":"%","format":"{{value}}","min":0,"max":"100","colors":["#00b500","#e6e600","#ca3838"],"x":630.5,"y":173,"wires":[]},{"id":"dbdb6731.531e8","type":"function","z":"a8b82890.09ca7","name":"UPS_Load","func":"msg.payload = Number(msg.payload.ups_load);\nreturn msg;","outputs":1,"noerr":0,"x":372.5,"y":175,"wires":[["563ec2f5.6475e4","f057bae4.8e4678","57bc92ab.ce4234"]]},{"id":"193a550.2b0ea2b","type":"json","z":"a8b82890.09ca7","name":"To Json","x":129.5,"y":178,"wires":[["dbdb6731.531e8","5433b116.a93b4","52604271.71f43c","11ad64b4.f70ad3","589635b3.9bacc4"]]},{"id":"57bc92ab.ce4234","type":"ui_chart","z":"a8b82890.09ca7","name":"Ups Load/Time","group":"ba196e43.b35398","order":0,"width":0,"height":0,"label":"Load/Time","chartType":"line","legend":"false","xformat":"HH:mm","interpolate":"linear","nodata":"","ymin":"0","ymax":"100","removeOlder":1,"removeOlderPoints":"","removeOlderUnit":"3600","cutout":0,"x":639.5,"y":226,"wires":[[],[]]},{"id":"5433b116.a93b4","type":"function","z":"a8b82890.09ca7","name":"Battery Status","func":"var Vbats = msg.payload.battery_voltage;\n\nvar Vbat = Vbats.replace(\"_\",\".\");\n\nmsg.payload = Number(Vbat);\n\nreturn msg;","outputs":1,"noerr":0,"x":400.5,"y":336,"wires":[["8c6f269f.87b618"]]},{"id":"52604271.71f43c","type":"function","z":"a8b82890.09ca7","name":"V IN","func":"var Vins = msg.payload.input_voltage;\n\nvar Vin = Vins.replace(\"_\",\".\");\n\nmsg.payload = Number(Vin);\nreturn msg;","outputs":1,"noerr":0,"x":369.5,"y":570,"wires":[["240f6e31.7aa5da","b37dffd2.1cb0d"]]},{"id":"8c6f269f.87b618","type":"ui_gauge","z":"a8b82890.09ca7","name":"","group":"421e19.192041e8","order":0,"width":0,"height":0,"gtype":"gage","title":"Curr. Bat. Voltage","label":"V. Bat","format":"{{value}}","min":"11","max":"15","colors":["#b50000","#e6e600","#00b500"],"x":616.5,"y":332,"wires":[]},{"id":"240f6e31.7aa5da","type":"ui_gauge","z":"a8b82890.09ca7","name":"Input AC Voltage","group":"4e74439e.ee7e74","order":0,"width":0,"height":0,"gtype":"gage","title":"VIN AC","label":"V AC","format":"{{value}}","min":"190","max":"240","colors":["#00b500","#e6e600","#ca3838"],"x":660.5,"y":569,"wires":[]},{"id":"11ad64b4.f70ad3","type":"function","z":"a8b82890.09ca7","name":"Bat Runtime","func":"msg.payload = Number(msg.payload.battery_runtime);\nreturn msg;","outputs":1,"noerr":0,"x":397.5,"y":397,"wires":[["98292081.f4f718","62bb1456.0f45ec"]]},{"id":"98292081.f4f718","type":"ui_gauge","z":"a8b82890.09ca7","name":"UPS Level","group":"fccb6f27.7691d8","order":0,"width":0,"height":0,"gtype":"wave","title":"UPS Runtime","label":"UPS Level","format":"{{value}}","min":0,"max":"1500","colors":["#00b500","#e6e600","#ca3838"],"x":642.5,"y":391,"wires":[]},{"id":"589635b3.9bacc4","type":"function","z":"a8b82890.09ca7","name":"Bat Charge","func":"var Vcharges = msg.payload.battery_charge;\n\nvar Vcharge = Vcharges.replace(\"_\",\".\");\n\nmsg.payload = Number(Vcharge);\n\n\nreturn msg;","outputs":1,"noerr":0,"x":405,"y":495,"wires":[["d2ab2543.d53a68"]]},{"id":"d2ab2543.d53a68","type":"ui_gauge","z":"a8b82890.09ca7","name":"Battery Charge","group":"421e19.192041e8","order":0,"width":0,"height":0,"gtype":"gage","title":"Battery Charge","label":"%","format":"{{value}}","min":0,"max":"100","colors":["#ff0000","#e6e600","#00ff01"],"x":661.5,"y":494,"wires":[]},{"id":"62bb1456.0f45ec","type":"ui_chart","z":"a8b82890.09ca7","name":"","group":"fccb6f27.7691d8","order":0,"width":0,"height":0,"label":"Runtime (sec)","chartType":"line","legend":"false","xformat":"HH:mm","interpolate":"linear","nodata":"","ymin":"","ymax":"","removeOlder":1,"removeOlderPoints":"","removeOlderUnit":"3600","cutout":0,"x":625.5,"y":441,"wires":[[],[]]},{"id":"b37dffd2.1cb0d","type":"ui_chart","z":"a8b82890.09ca7","name":"Vin/Time","group":"4e74439e.ee7e74","order":0,"width":0,"height":0,"label":"VAC In/Time","chartType":"line","legend":"false","xformat":"HH:mm","interpolate":"linear","nodata":"","ymin":"190","ymax":"240","removeOlder":"12","removeOlderPoints":"","removeOlderUnit":"3600","cutout":0,"x":635.5,"y":641,"wires":[[],[]]},{"id":"2a552b3c.de8d2c","type":"mqtt-broker","broker":"192.168.1.17","port":"1883","clientid":"node-red","usetls":false,"verifyservercert":true,"compatmode":true,"keepalive":15,"cleansession":true,"willQos":"0","birthQos":"0"},{"id":"ba196e43.b35398","type":"ui_group","z":"","name":"UPS Load","tab":"61ec3881.53526","disp":true,"width":"6"},{"id":"421e19.192041e8","type":"ui_group","z":"","name":"UPS Battery","tab":"61ec3881.53526","disp":true,"width":"6"},{"id":"4e74439e.ee7e74","type":"ui_group","z":"","name":"Input Voltage","tab":"61ec3881.53526","disp":true,"width":"6"},{"id":"fccb6f27.7691d8","type":"ui_group","z":"","name":"UPS Runtime","tab":"61ec3881.53526","disp":true,"width":"6"},{"id":"61ec3881.53526","type":"ui_tab","z":"","name":"UPS","icon":"dashboard","order":2}]

The final output is as follow:

Node Red UPS Monitoring