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docs:guide-developer:procd-init-script-example [2019/03/10 23:10] – OpenWrt spelling tmomasdocs:guide-developer:procd-init-script-example [2024/02/10 17:38] (current) – [Enabling the service] systemcrash
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-====== Service configuration with procd======+====== Create a sample procd init script======
 <WRAP center round info 80%> <WRAP center round info 80%>
-This article is a verbatim copy of https://joostoostdijk.com/posts/service-configuration-with-procd/ any credit goes to the original author, **Joost Oostdijk** \\+This article is a mostly verbatim copy of [[https://web.archive.org/web/20220518121856/https://joostoostdijk.com/posts/service-configuration-with-procd|this archived article]], all credit goes to the original author, **Joost Oostdijk** \\ 
 +It was adapted to use an equivalent shell script instead of NodeJS JavaScript, because it's lighter and better for a simple testing setup on most OpenWrt devices.
 </WRAP> </WRAP>
  
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 =====Setting up===== =====Setting up=====
  
-As example, lets say we’d want to create a Node.js app as a service and that this service can be configured with a message and a timeout in order for us to be reminded to get up from ur desks once in a while. Our service name will be mynodeservice and it depends on the following script +As example, lets say we’d want to create shell script as a service and that this service can be configured with a message and a timeout in order for us to be reminded to get up from ur desks once in a while. Our service name will be myservice and it depends on the following script 
-<code javascript> +<code bash> 
-/** +#!/bin/sh 
- * /var/mynodeservice.js + 
- */ +#these if statements will check input and place default values if no input is given 
-const name = process.argv[2] || 'You'; +#they will also check if input is a number so you can call  
-const every = process.argv[3] || 5000;+#this script with just a time and it will still work correctly 
 + 
 +if [ "$1" = '' ]; then 
 +    name="You" 
 +else 
 +    if echo "$1" | egrep -q '^[0-9]+$'; then 
 +        name="You" 
 +    else 
 +        name="$1" 
 +    fi 
 +fi 
 + 
 +if [ "$2" = '' ]; then 
 +    every="5" 
 +else 
 +    every="$2" 
 +fi 
 + 
 +if echo "$1" | egrep -q '^[0-9]+$'; then 
 +    every="$1" 
 +fi 
 + 
 +#endless loop, will print the message every X seconds as indicated in the $every variable 
 + 
 +while [ 1 ]; do  
 +    echo "Hey, $name, it's time to get up" 
 +    sleep $every 
 +done 
 + 
 +exit 0 
  
-setInterval(function(){ 
-  console.log(`Hey, ${name}, it's time to get up`); 
-}, every); 
-view raw 
 </code> </code>
  
-Place it in **/var/mynodeservice** and test it by running on OpenWrt+Place it in **/var/myscript.sh** and test it by running on OpenWrt
  
-<code>$ node /var/mynodeservice.js <your-name></code>+<code>$ /bin/sh /var/myscript.sh "Name Surname"</code>
  
 =====Creating a basic procd script===== =====Creating a basic procd script=====
  
-Now that we have a working script, we can make a service out of it. Create a file in /etc/init.d/mynodeservice with the following content+Now that we have a working script, we can make a service out of it. Create a file in /etc/init.d/myservice with the following content
 <code bash> <code bash>
 #!/bin/sh /etc/rc.common #!/bin/sh /etc/rc.common
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 start_service() { start_service() {
     procd_open_instance     procd_open_instance
-    procd_set_param command /usr/bin/node "/var/mynodeservice.js"+    procd_set_param command /bin/sh "/var/myscript.sh"
     procd_close_instance     procd_close_instance
 } }
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 To tell OpenWrt that we have a new service we would need to run To tell OpenWrt that we have a new service we would need to run
  
-<code> /etc/init.d/mynodeservice enable</code>+<code> /etc/init.d/myservice enable</code>
  
-This will install a symlink for us in directory /etc/rc.d/ called S90mynodeservice which point to our respective service script in /etc/init.d/. OpenWrt will start the services according the the order of S* scripts in /etc/rc.d/. To see the order you could simply run+This will install a symlink for us in directory /etc/rc.d/ called S95myservice (because ''START=95'') which points to our respective service script in /etc/init.d/. OpenWrt will start the services according the the order of S* scripts in /etc/rc.d/. To see the order you could simply run
  
 <code>$ ls -la /etc/rc.d/S*</code> <code>$ ls -la /etc/rc.d/S*</code>
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 then enable (if you havent done that yet), and start the service. then enable (if you havent done that yet), and start the service.
  
-<code>$ /etc/init.d/mynodeservice enable +<code>$ /etc/init.d/myservice enable 
-$ /etc/init.d/mynodeservice start</code>+$ /etc/init.d/myservice start</code>
  
 After about 5 seconds we should see the message repeat itself in the log, but we didn’t… After about 5 seconds we should see the message repeat itself in the log, but we didn’t…
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 start_service() { start_service() {
     procd_open_instance     procd_open_instance
-    procd_set_param command /usr/bin/node "/var/mynodeservice.js"+    procd_set_param command /bin/sh "/var/myscript.sh"
     procd_set_param stdout 1     procd_set_param stdout 1
     procd_set_param stderr 1     procd_set_param stderr 1
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 <code>$ logread -f <code>$ logread -f
-... ommitted ... node[20136]: Hey, You, it's time to get up +... ommitted ... Hey, You, it's time to get up 
-... ommitted ... node[20136]: Hey, You, it's time to get up +... ommitted ... Hey, You, it's time to get up 
-... ommitted ... node[20136]: Hey, You, it's time to get up +... ommitted ... Hey, You, it's time to get up 
-... ommitted ... node[20136]: Hey, You, it's time to get up +... ommitted ... Hey, You, it's time to get up 
-... ommitted ... node[20136]: Hey, You, it's time to get up +... ommitted ... Hey, You, it's time to get up 
-... ommitted ... node[20136]: Hey, You, it's time to get up+... ommitted ... Hey, You, it's time to get up
 ... ...
 </code> </code>
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 =====Service configuration===== =====Service configuration=====
  
-It’s time to get more personal, and to that we will use OpenWrts UCI configuration interface. Create a configuration file /etc/config/mynodeservice with the following content +It’s time to get more personal, and to that we will use OpenWrts UCI configuration interface. Create a configuration file /etc/config/myservice with the following content 
-<code>config mynodeservice 'hello'+<code>config myservice 'hello'
  option name 'Joost'  option name 'Joost'
-  option every '5000'+  option every '5'
 </code> </code>
  
 UCI will immediately pick this up and the config for our service can be inspected like UCI will immediately pick this up and the config for our service can be inspected like
  
-<code>$ uci show mynodeservice +<code>$ uci show myservice 
-mynodeservice.hello=mynodeservice +myservice.hello=myservice 
-mynodeservice.hello.name=Ninja +myservice.hello.name=Joost 
-mynodeservice.hello.every='5000'+myservice.hello.every='5'
 </code> </code>
 Also single options can be requested Also single options can be requested
  
-<code>$ uci get mynodeservice.hello.name</code>+<code>$ uci get myservice.hello.name</code>
  
 and we can also change specific configuration with UCI and we can also change specific configuration with UCI
  
-<code>$ uci set mynodeservice.hello.name=Knight+<code>$ uci set myservice.hello.name=Knight
 $ uci commit</code> $ uci commit</code>
  
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 STOP=01 STOP=01
  
-CONFIGURATION=mynodeservice+CONFIGURATION=myservice
  
 start_service() { start_service() {
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     # pass config to script on start     # pass config to script on start
-    procd_set_param command /usr/bin/node "/var/mynodeservice.js" "$name" "$every" +    procd_set_param command /bin/sh "/var/myscript.sh" "$name" "$every" 
-    procd_set_param file /etc/config/mynodeservice+    procd_set_param file /etc/config/myservice
     procd_set_param stdout 1     procd_set_param stdout 1
     procd_set_param stderr 1     procd_set_param stderr 1
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 We can pass new configuration by running We can pass new configuration by running
  
-<code>$ uci set mynodeservice.hello.name=Woodrow Wilson Smith+<code>$ uci set myservice.hello.name=Woodrow Wilson Smith
 $ uci commit $ uci commit
 </code> </code>
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 <code>... <code>...
-procd_set_param file /etc/config/mynodeservice+procd_set_param file /etc/config/myservice
 ...</code> ...</code>
  
-With that line in place we are able to only restart the service whenever our configuration has changed.+With that line in place we are able to restart the service whenever only our configuration has changed.
  
-<code>$ /etc/init.d/mynodeservice reload+<code>$ /etc/init.d/myservice reload
 </code> </code>
  
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 I’ll list a few here, but this is by no means covering everything. I’ll list a few here, but this is by no means covering everything.
  
-  * **respawn**\\ respawn your service automatically when it died for some reason.\\ <code bash>procd_set_param respawn \+  * **respawn**\\ respawn your service automatically when it terminates for some reason.\\ <code bash>procd_set_param respawn \
       ${respawn_threshold:-3600} \       ${respawn_threshold:-3600} \
-      ${respawn_timeout:-5} ${respawn_retry:-5}</code> \\ In this example we respawn if process dies sooner than respawn_threshold, it is considered crashed and after 5 retries the service is stopped+      ${respawn_timeout:-5} ${respawn_retry:-5}</code> \\ In this example we respawn if process terminates sooner than respawn_threshold, it is considered crashed and after 5 retries the service is stopped. However, if it terminates later than respawn_threshold, it would be respawned indefinitely.
  
   * **pidfile**\\ Configure where to store the pid file \\ <code bash>procd_set_param pidfile $PIDFILE</code>   * **pidfile**\\ Configure where to store the pid file \\ <code bash>procd_set_param pidfile $PIDFILE</code>
  • Last modified: 2019/03/10 23:10
  • by tmomas