docker-hosts

#!/bin/bash

HOSTS_FILE="/etc/hosts"
START_MARK="##### START DOCKER #####"
END_MARK="##### END DOCKER #####"


clear_hosts() {
    START_LINE=$(grep -n "$START_MARK" $HOSTS_FILE | cut -d ':' -f 1)
    END_LINE=$(grep -n "$END_MARK" $HOSTS_FILE | tail -n 1 | cut -d ':' -f 1)

    if [ -z $START_LINE ] || [ -z $END_LINE ]; then
       echo "Nothing to clear."
       return 0
    fi

    echo "Deleting from $START_LINE to $END_LINE lines"
    sed -i "${START_LINE},${END_LINE}d" $HOSTS_FILE
}

add_hosts() {
    echo -e "$START_MARK" >> $HOSTS_FILE 
    CONTAINERS=$(docker ps --format="{{.ID}}")
    for CUR in $CONTAINERS; do
        HOSTS=$(docker inspect --format '{{range .NetworkSettings.Networks}}{{.IPAddress}} {{join .DNSNames " "}}{{printf "\n"}}{{end}}' $CUR)
        echo -e "$HOSTS" >> $HOSTS_FILE
    done
    echo -e "$END_MARK" >> $HOSTS_FILE
}

case "$1" in
add)
    echo -e "Adding hosts..."
    add_hosts
;;
replace)
    echo -e "Replacing..."
    clear_hosts
    add_hosts
;;
clear) 
    echo "Clearing..."
    clear_hosts
;;
*)
   echo -e "Usage: docker-hosts add|replace|clear"
esac