scaling.sh

#!/bin/bash

set -e

# depend on awscli
export AWS_DEFAULT_REGION=ap-northeast-1
export AWS_ACCESS_KEY_ID=
export AWS_SECRET_ACCESS_KEY=


# 1. Parse the arguments
mode=${1}
case "$mode" in
  "up" ) echo "Start scale up" ;;
  "down" ) echo "Start scale down" ;;
  * ) echo "Please specify arg (up or down)" && exit 1 ;;
esac

# 2. Get the auto scaling groups
asGroups=$(aws autoscaling describe-auto-scaling-groups --query 'AutoScalingGroups[].AutoScalingGroupName' --output text)
if [ "x${asGroups}" == "x" ]; then
    echo "${asGroups} does not exist" && exit 1
fi
echo "${asGroups}"

# 3. Get the auto scaling group for prod env from asGroups
codeDeployProd=""
for group in $asGroups; do
    if [[ $group = *"CodeDeploy_prod"* ]]; then
        codeDeployProd=$group
        break
    fi
done
if [ "x${codeDeployProd}" == "x" ]; then
    echo "Target auto scaling group does not exist" && exit 1
fi
echo "Target auto scaling group is $codeDeployProd"

# 4. Get the current desired capacity
cap=$(aws autoscaling describe-auto-scaling-groups --auto-scaling-group-names "$codeDeployProd" --query 'AutoScalingGroups[].DesiredCapacity' --output text)
echo "DesiredCapacity is $cap"

# 5. Set the desired capacity
newCap=$((cap + 1))
if [ "${mode}" == "down" ]; then
    newCap=$((cap - 1))
    if [ "$newCap" -le 0 ]; then
        echo "New DesiredCapacity is less than 0" && exit 1
    fi
fi

echo "New DesiredCapacity is $newCap"
aws autoscaling set-desired-capacity --auto-scaling-group-name "$codeDeployProd" --desired-capacity "$newCap"
if [ $? != 0 ]; then
    echo "Failed to set DesiredCapacity" && exit 1
fi

echo "Success"