Bash – How can i send notification once if a service is not running?

I am running the following script to check if my docker services are running. If a service isn’t running, the script sent a message to my rocketchat app via webhook like this:

#!/bin/sh
# Shell script to monitor docker services every minute
# -------------------------------------------------------------------------------------------

# set webhook url
RocketURL=https://example.com/webhook;
# get all containers 
Containers=$(docker ps -a | awk '{if(NR>1) print $NF}')

for i in $Containers
do
  isServiceRunning=$(docker inspect --format="{{.State.Running}}" $i)
  if [ $isServiceRunning = false ]; then
    /home/user/scripts/sendMessage.sh -b "The Docker Service: $i is not running. Please fix it" -u $RocketURL
  fi
done

It works, but if a docker service is not running, i receive the message every minute again, because the script is running every minute via cronjob. So how can i prevent this? I only want to get one message, when the service is not running. How can i do that?

Answer

Create a file when sending the message, and only send the message when the file doesn’t exist. Delete the file if the service is running.

for container in $Containers ; do
    processed=/tmp/noturn."$container"
    isServiceRunning=$(docker inspect --format="{{.State.Running}}" "$container")
    if [ "$isServiceRunning" = false ] ; then
        if [ ! -e "$processed" ] ; then
            /home/user/scripts/sendMessage.sh -b "The Docker Service: $i is not running. Please fix it" -u "$RocketURL"
        fi
        touch "$processed"
    else
        rm -f "$processed"
    fi
done