Start / stop / restart scripts in TMUX

run_in_tmux.sh

#!/bin/bash
 
#if [[ $EUID -ne 0 ]]; then
#    echo "Script MUST be run as a root user"
#    exit 1
#fi
 
session="bg-apps"
logs_dir=~/tmux-logs
 
mkdir -p "$logs_dir"
 
# Start session if it doesn't exist
if (tmux has-session -t "$session" 2> /dev/null); then
    echo "Session $session exists."
else
    echo "Starting session $session."
    # tmux doesn't allow nested sessions, and if this situation is not caught here then the
    # 'tmux new-session' command will fail.  Although, since the session is being started
    # detached, it is probably okay.  So maybe it would be better to just temporarily unset the
    # TMUX variable before running new-session.
    if [ "$TMUX" != "" ]; then
        echo "Error: cannot start session from within tmux."
        exit 1
    fi
    tmux new-session -d -s "$session" "bash"
fi
 
function run_in_window {
    name="$1"
    cmd="$2"
    if window_is_open "$name"; then
        echo "Already running: $name"
    else
        echo "Starting: $name"
        echo "Started at $(date)" >  $logs_dir/$name.log
        echo "Command: $cmd"      >> $logs_dir/$name.log
        echo "-------"            >> $logs_dir/$name.log
        # Create new window and run command.
        tmux new-window -t "$session" -n "$name"
        # Check if in BASH, if not, start BASH
        # When this script is run via cron, it doesn't initiate BASH, this fixes that
        tmux send-keys -t "$session:$name" "if [ -z \$BASH ]; then bash; fi" C-m
        tmux send-keys -t "$session:$name" "$cmd" C-m
    fi
}
 
function stop_something {
    name="$1"
    
    if window_is_open "$name"; then
        echo "Stopping: $name"
        tmux send-keys -t "$session:$name" C-c
    else
        echo "Not running: $name"
    fi
}
 
function window_is_open {
    name="$1"
    
    if (tmux list-windows -t "$session" -F '#{window_name}' | grep "^$name\$" > /dev/null); then
        return 0
    else
        return 1
    fi
}

##################################
# This is the function to change #
##################################
function start_something {
    name="$1"
 
    case "$name" in
        # define the different types of commands to trigger inside of the TMUX session here

        myapp)
            run_in_window "$name" "echo 'change this echo statement'"
            ;;
        *)
            echo "Unrecognized command: $1"
    esac
}
##################################
# END
##################################
 
if [ "$1" = "" ]; then
    # set the default command to run here (name from case in start_something function)
    cmd="myapp"
else
    cmd="$1"
fi
 
case "$2" in
    status)
        if window_is_open "$cmd"; then
            echo "$cmd appears to be running"
        else
            echo "$cmd is not running"
        fi
        ;;
    stop)
        stop_something "$cmd"
        ;;
    restart)
        stop_something "$cmd"
        
        i=0
        while window_is_open "$cmd"; do
            if [ $i -gt 10 ]; then
                echo "Taking too long, force-quiting"
                tmux kill-window -t "$session:$cmd"
                break
            else
                echo "Window still open, waiting..."
                sleep 2
                ((i++))
            fi
        done
        
        start_something "$cmd"
        ;;
    *)
        start_something "$cmd"
esac