Get containers info and stats using the Docker Remote API

docker-stats.sh

#!/bin/bash -eu
# 
# @description    Get containers info and stats using the Docker Remote API 
# @deps           curl, jq
# @usage          docker-stats.sh host-42 101.0.0.42

DOCKER_HOSTNAME=$1
DOCKER_IP=$2
DOCKER_PORT=2376
CERT_DIR=~/.docker/machines/.client
VERBOSE=1

[[ "$(which curl 2>/dev/null)" == "" ]] && echo "error: install curl (http://curl.haxx.se/download.html)" && exit 1
[[ "$(which jq 2>/dev/null)" == "" ]] && echo "error: install jq (http://stedolan.github.io/jq/download/)" && exit 1

api() {
    local endpoint=$1
    local options=$2

    curl -sk $options \
        https://$DOCKER_IP:$DOCKER_PORT/$endpoint  \
        --cert   $CERT_DIR/cert.pem \
        --key    $CERT_DIR/key.pem  \
        --cacert $CERT_DIR/ca.pem 
}

PREFIX=/tmp/docker-container-$(date +%s)

w_container_json() {
    local id=$1

    log "GET containers/$id/json"
    api containers/$id/json "" > $PREFIX-$id-json 

    name=$(r "$(cat $PREFIX-$id-json)" ".Name" | sed -e 's|"||' -e 's|/||')
    echo "$name" > $PREFIX-$id-name
    log "SET name $name"
}

w_container_stats() {
    local id=$1

    log "GET /containers/$containerId/stats"    
    api containers/$id/stats "-m 2" | tail -1 > $PREFIX-$id-stats
}

wf() {
    local id=$1
    local kind=$2
    cat $PREFIX-$id-$kind >> JSON
}

w() {
    echo "$1" >> JSON 
}

r() {
    local json="$1"
    local jqexpr="$2"

    echo "$json" | jq -r "$jqexpr"
}

log() {
    [[ $VERBOSE -eq 1 ]] && echo " [dstats] $1" || nothing=todo
}

################################

> JSON

log "GET /containers/json"    

containers="$(api containers/json "")"

total_containers=$(r "$containers" '. | length')

w '{
    "'$DOCKER_HOSTNAME'": {
        "total_containers": '$total_containers',
        "containers": ['

s=""; nb_proc=0
while read containerId; do

    w_container_json $containerId &
    sleep 0.0$RANDOM
    w_container_stats $containerId &

    nb_proc=$(($nb_proc+2))
    if [ "$nb_proc" -ge $((total_containers*2)) ]; then
        wait
        nb_proc=0
    fi

s=","
done < <(r "$containers" '.[] | .Id')

wait

log "Write JSON"

s=""
while read containerId; do
    name=$(cat $PREFIX-$containerId-name)

    w $s' {
        "'$name'": {
            "info": '
                wf $containerId json
    w ',
            "stats": '
                wf $containerId stats
    w '
        }
    }'

s=","
done < <(r "$containers" '.[] | .Id')

w '      ]
    }
}'

rm -f $PREFIX*
cat JSON | jq . >/dev/null 2>&1 \
    && log "Successful" || log "Error"