Retrieve registered and remaining CPU resources in an Amazon ECS cluster

ecs-cluster-cpu.sh

#!/bin/sh

aws ecs describe-container-instances \
        --region ${REGION}           \
        --cluster ${CLUSTER}         \
        --container-instances $(aws ecs list-container-instances \
                                        --region ${REGION}       \
                                        --cluster ${CLUSTER}   | \
                                jq -r '.containerInstanceArns | 
                                       map(match("container-instance/(.*)").captures[].string)[]') | \
jq '.containerInstances |
    map([{
        "remainingResources": .remainingResources |
                                map(select(.name == "CPU")) |
                                map(.integerValue)[0],
        "registeredResources": .registeredResources | 
                                 map(select(.name == "CPU")) | 
                                 map(.integerValue)[0]
    }]) |
    reduce .[] as $item ([]; . + $item) |
    reduce .[] as $item ({
        "remainingResources": 0,
        "registeredResources": 0
    }; {
        "remainingResources": (.remainingResources + $item.remainingResources),
        "registeredResources": (.registeredResources + $item.registeredResources)
    }) | 
    . + {
        "usedResources": (.registeredResources - .remainingResources)
    }'