Adding nodowntime scripts as used in the admin app

Adapted to look up instance name from instance Tags
Allows app to choose correct ELB to de/register with
Delivery apps exit with code 0 earlier in the process

scripts/register_with_elb.sh

@@ -0,0 +1,78 @@
+#!/bin/bash
+#
+# Copyright 2014 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License").
+# You may not use this file except in compliance with the License.
+# A copy of the License is located at
+#
+#  http://aws.amazon.com/apache2.0
+#
+# or in the "license" file accompanying this file. This file is distributed
+# on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+# express or implied. See the License for the specific language governing
+# permissions and limitations under the License.
+
+. $(dirname $0)/common_functions.sh
+
+msg "Running AWS CLI with region: $(get_instance_region)"
+
+# get this instance's ID
+INSTANCE_ID=$(get_instance_id)
+if [ $? != 0 -o -z "$INSTANCE_ID" ]; then
+    error_exit "Unable to get this instance's ID; cannot continue."
+fi
+
+# Get current time
+msg "Started $(basename $0) at $(/bin/date "+%F %T")"
+start_sec=$(/bin/date +%s.%N)
+
+msg "Getting relevant load balancer"
+
+INSTANCE_NAME=$(get_instance_name_from_tags $INSTANCE_ID)
+
+if [[ $INSTANCE_NAME =~ 'delivery' ]]; then
+    msg "NO ELBs for delivery"
+    exit 0
+fi
+
+get_elb_name_for_instance_name $INSTANCE_NAME
+get_elb_list $INSTANCE_ID $ELB_NAME
+
+msg "Checking that user set at least one load balancer"
+if test -z "$ELB_LIST"; then
+    error_exit "Must have at least one load balancer to register to"
+fi
+
+# Loop through all LBs the user set, and attempt to register this instance to them.
+for elb in $ELB_LIST; do
+    msg "Checking validity of load balancer named '$elb'"
+    validate_elb $INSTANCE_ID $elb
+    if [ $? != 0 ]; then
+        msg "Error validating $elb; cannot continue with this LB"
+        continue
+    fi
+
+    msg "Registering $INSTANCE_ID to $elb"
+    register_instance $INSTANCE_ID $elb
+
+    if [ $? != 0 ]; then
+        error_exit "Failed to register instance $INSTANCE_ID from ELB $elb"
+    fi
+done
+
+# Wait for all Registrations to finish
+msg "Waiting for instance to register to its load balancers"
+for elb in $ELB_LIST; do
+    wait_for_state "elb" $INSTANCE_ID "InService" $elb
+    if [ $? != 0 ]; then
+        error_exit "Failed waiting for $INSTANCE_ID to return to $elb"
+    fi
+done
+
+msg "Finished $(basename $0) at $(/bin/date "+%F %T")"
+
+end_sec=$(/bin/date +%s.%N)
+elapsed_seconds=$(echo "$end_sec - $start_sec" | /usr/bin/bc)
+
+msg "Elapsed time: $elapsed_seconds"