Shell Script to Create Environment Variables for Marathon Application Dynamic IP and Port

mesos-app-ip-port-env.sh

#!/bin/bash

# Info: Shell Wrapper to populate Marathon Application
# Containers IP & Port ENV Variables.
#
# Variables:
# MARATHON_GROUP: marathon group name
# 	    e.g. Marathon APP - /group0/app
#            MARATHON_GROUP=group0
#       e.g. Marathon APP - /group0/group1/app
#            MARATHON_GROUP=group1-group0
#       e.g. Marathon APP - /app
#            MARATHON_GROUP=
#
# MARATHON_APPS: marathon apps name
#       e.g. Marathon Apps - /group/app0, /group/app1, /group/app2
#            MARATHON_APPS="app0 app1 app2"
#       e.g. Marathon Apps - /app0, /app1, /app2
#            MARATHON_APPS="app0 app1 app2"
#
# e.g.
# Marathon Apps - /web/nginx /web/apache /web/tomcat (Group Name: web, App Name: "nginx apache tomcat")
# MARATHON_GROUP=web
# MARATHON_APPS="nginx apache tomcat"
#
# Marathon App - /web/nginx (Group Name: web, App Name: nginx)
# MARATHON_GROUP=web
# MARATHON_APPS="nginx"
#
# Marathon App - /nginx (Group Name: , App Name: nginx)
# MARATHON_GROUP=
# MARATHON_APPS="nginx"

GROUP_VAR=$(echo $MARATHON_GROUP | tr -s '-' '_')

for APP in $MARATHON_APPS
do
  # for export variable name
  APP_VAR=$(echo $APP | tr -s '-' '_')
  COUNTER=0
  if [ -z "$MARATHON_GROUP" ]; then
    result=$(dig _${APP}._tcp.marathon.mesos SRV +short | grep mesos | awk '{print $3":"$4}')
  else
    result=$(dig _${APP}-${MARATHON_GROUP}._tcp.marathon.mesos SRV +short | grep mesos | awk '{print $3":"$4}')
  fi
  # for row in $(dig _${APP}-${MARATHON_GROUP}._tcp.marathon.mesos SRV +short | awk '{print $3":"$4}')
  for row in $result
  do
    port=$(echo $row | cut -f1 -d:)
    agent=$(echo $row | cut -f2 -d:)
    ip=$(dig $agent +short| xargs)
    if [ -z "$MARATHON_GROUP" ]; then
      export ${APP_VAR}_ip_${COUNTER}=$ip
      export ${APP_VAR}_port_${COUNTER}=$port
    else
      export ${APP_VAR}_${GROUP_VAR}_ip_${COUNTER}=$ip
      export ${APP_VAR}_${GROUP_VAR}_port_${COUNTER}=$port
    fi
    let COUNTER++
  done
done

# print apps environment variables
# if [ -z "$MARATHON_GROUP" ]; then
#  env | egrep -i `echo $MARATHON_APPS| sed -s -e 's/ /|/g' -e 's/-/_/g'` | sort
# else
#  env | grep $GROUP_VAR | sort
# fi