Systemd with two services and a target unit

salmanmanekiaa · 03-17-2020, 06:43 PM

Hi,

I am new to the forum and systemd. Using both for the first time

I have a scenario, in which I have a node js application running and data coming from bluetooth. The nodejs app has a socket open to the bluetooth data. The sequence in which I want to do this is

1. Run the node.js app
2. Run the script that listens to the bluetooth and pass on to the socket.
3. If the node app crashes/restarts/exits then delete the socket

Following is what I have done so far. I have create two service and a unit target but it fails when it tries to execute the bluewalker.sh in the bluetooth.service.

app-gateway.target

Code:

    
    [Unit]
    Description=Gateway application
    Requires=r-bluetooth.service r-gateway.service
    After=r-bluetooth.service r-gateway.service
    
    [Install]
    WantedBy=multi-user.target

r-bluetooth.service

Code:

 
    [Unit]
    Description=bluetooth socket
    PartOf=app-gateway.target
    
    [Service]
    ExecStartPre=-rm -f /tmp/data.sock
    ExecStart=/usr/bin/sudo /bin/bash /home/pi/gateway/bluewalker.sh
    Restart=always
    
    Environment=PATH=/usr/bin:/usr/local/bin
    
    [Install]
    WantedBy=app-gateway.target

r-gateway.service

Code:

    [Unit]
    Description=Tag gateway
    PartOf=app-gateway.target
    
    [Service]
    Type=forking
    ExecStart=node /home/pi/gateway/index.js
    User=pi
        
    Environment=PATH=/usr/bin:/usr/local/bin
    
    [Install]
    WantedBy=app-gateway.target

and the bluewalker.sh

Code:

    #!/bin/bash
    SOCKETPATH="/tmp/data.sock"
    
    hciconfig hci0 down
    /home/pi/go/bin/bluewalker -device hci0 -ruuvi -active -json -duration -1 -unix $SOCKETPATH

astrogeek · 03-18-2020, 01:31 PM

As you have not received any replies in the Programming forum, and this appears to be more a configuration problem than an actual programming question, you may receive a better response in the Software, Server or Networking forums.

To request the thread be moved to another forum please use the Report button at bottom of your post.

Good luck!

scasey · 03-18-2020, 02:13 PM

I don’t see a question in the OP. Does the setup not work as desired?
If not, what happens? What’s in the log file?

salmanmanekiaa · 03-18-2020, 04:31 PM

I will try to ellobrate further what I am doing, below I will also post the log and a simple node.js application for test purpose. The problem lies when trying to run the ./bluetooth.sh in ruuvi-bluetooth.service. As seen from the second log the problem is that it cannot connect to the unix socket as its not able to find file/directory. I can confirm that the socket is there and giving `ls` gives -> srwxr-xr-x 1 pi pi 0 Mar 18 23:19 ruuvi.sock

Quote:

pi@raspberrypi:/etc/systemd/system $ sudo systemctl status ruuvi-bluetooth.service
● ruuvi-bluetooth.service - Ruuvi tag bluetooth socket
Loaded: loaded (/etc/systemd/system/ruuvi-bluetooth.service; disabled; vendor preset: enabled)
Drop-In: /etc/systemd/system/ruuvi-bluetooth.service.d
└─override.conf
Active: failed (Result: exit-code) since Wed 2020-03-18 23:19:07 EET; 1min 30s ago
Process: 28160 ExecStart=/usr/bin/sudo /bin/bash /home/pi/cerulean/ruuvi-tag-gateway/bluewalker.sh (code=exited, status=255/EXCEPTION)

The output of

Quote:

journalctl -u ruuvi-bluetooth.service -n 1000 --no-pager

is the following

Quote:

Mar 18 23:19:05 raspberrypi sudo[28089]: root : TTY=unknown ; PWD=/home/pi/cerulean/ruuvi-tag-gateway ; USER=root ; COMMAND=/bin/bash /home/pi/cerulean/ruuvi-tag-gateway/bluewalker.sh
Mar 18 23:19:05 raspberrypi sudo[28089]: pam_unix(sudo:session): session opened for user root by (uid=0)
Mar 18 23:19:05 raspberrypi sudo[28089]: Error: Unable to open unix socket at /tmp/ruuvi.sock (dial unix /tmp/ruuvi.sock: connect: no such file or directory)
Mar 18 23:19:05 raspberrypi sudo[28089]: pam_unix(sudo:session): session closed for user root

Below my node.js application

Code:

var net = require("net");

var unixSocket = net.createServer(function(client) {
	client.on('data', function(data) {
		console.log(data);
	})
})

astrogeek · 03-20-2020, 05:42 PM

Moved: This thread is more suitable in Software forum and has been moved per your request to help your thread/question get the exposure it deserves.

Good luck!