docker-crontab/docker-entrypoint

#!/usr/bin/env bash
set -e

# for local testing only
#HOME_DIR=.

CONFIG=${HOME_DIR}/config.json
DOCKER_SOCK=/var/run/docker.sock
CRONTAB_FILE=/etc/crontabs/docker

make_image_cmd() {
    DOCKERARGS=$(echo ${1} | jq -r .dockerargs)
    if [ "${DOCKERARGS}" == "null" ]; then DOCKERARGS=; fi
    IMAGE=$(echo ${1} | jq -r .image)
    TMP_COMMAND=$(echo ${1} | jq -r .command)
    echo "docker run ${DOCKERARGS} ${IMAGE} ${TMP_COMMAND}"
}

make_container_cmd() {
    DOCKERARGS=$(echo ${1} | jq -r .dockerargs)
    if [ "${DOCKERARGS}" == "null" ]; then DOCKERARGS=; fi
    PROJECT=$(echo ${1} | jq -r .project)
    CONTAINER=$(echo ${1} | jq -r .container)
    TMP_COMMAND=$(echo ${1} | jq -r .command)

    COMMAND_ARR=()

    if [ "${PROJECT}" != "null" ]; then

        # create bash script to detect all running containers
        SCRIPT_NAME=$(cat /proc/sys/kernel/random/uuid)
cat << EOF > ${HOME_DIR}/projects/${SCRIPT_NAME}.sh
#!/usr/bin/env bash
set -e

CONTAINERS=\$(docker ps --format '{{.Names}}' | grep -E "^${PROJECT}_${CONTAINER}_[0-9]+")
for CONTAINER_NAME in \$CONTAINERS; do
    docker exec ${DOCKERARGS} \${CONTAINER_NAME} ${TMP_COMMAND}
done
EOF
        echo "/bin/bash ${HOME_DIR}/projects/${SCRIPT_NAME}.sh"
    else
        echo "docker exec ${DOCKERARGS} ${CONTAINER} ${TMP_COMMAND}"
    fi
}

make_cmd() {
    if [ "$(echo ${1} | jq -r .image)" != "null" ]; then
        make_image_cmd "$1"
    elif [ "$(echo ${1} | jq -r .container)" != "null" ]; then
        make_container_cmd "$1"
    else
        echo ${1} | jq -r .command
    fi
}

parse_schedule() {
	case $1 in
        "@yearly")
            echo "0 0 0 1 1 *"
            ;;
        "@annually")
            echo "0 0 0 1 1 *"
            ;;
        "@monthly")
            echo "0 0 0 1 * *"
            ;;
        "@weekly")
            echo "0 0 0 * * 0"
            ;;
        "@daily")
            echo "0 0 0 * * *"
            ;;
        "@midnight")
            echo "0 0 0 * * *"
            ;;
        "@hourly")
            echo "0 0 * * * *"
            ;;
        "@every")
            TIME=$2
            TOTAL=0

            M=$(echo $TIME | grep -o '[0-9]\+m')
            H=$(echo $TIME | grep -o '[0-9]\+h')
            D=$(echo $TIME | grep -o '[0-9]\+d')

            if [ -n "${M}" ]; then
                TOTAL=$(($TOTAL + ${M::-1}))
            fi
            if [ -n "${H}" ]; then
                TOTAL=$(($TOTAL + ${H::-1} * 60))
            fi
            if [ -n "${D}" ]; then
                TOTAL=$(($TOTAL + ${D::-1} * 60 * 24))
            fi

            echo "*/${TOTAL} * * * * *"
            ;;
        *)
            echo "${@}"
            ;;
    esac
}

function build_crontab() {
    rm -rf ${CRONTAB_FILE}

    ONSTART=()
    while read i ; do

        SCHEDULE=$(jq -r .[$i].schedule ${CONFIG} | sed 's/\*/\\*/g')
        if [ "${SCHEDULE}" == "null" ]; then
            echo "Schedule Missing: $(jq -r .[$i].schedule ${CONFIG})"
            continue
        fi
        SCHEDULE=$(parse_schedule ${SCHEDULE} | sed 's/\\//g')

        if [ "$(jq -r .[$i].command ${CONFIG})" == "null" ]; then
            echo "Command Missing: $(jq -r .[$i].command ${CONFIG})"
            continue
        fi

        COMMAND=$(make_cmd "$(jq -c .[$i] ${CONFIG})")
        if [ "$(jq -r .[$i].trigger ${CONFIG})" != "null" ]; then
            while read j ; do
                if [ "$(jq .[$i].trigger[$j].command ${CONFIG})" == "null" ]; then
                    echo "Command Missing: $(jq -r .[$i].trigger[$j].command ${CONFIG})"
                    continue
                fi
                TRIGGER_COMMANDS=$(make_cmd "$(jq -c .[$i].trigger[$j] ${CONFIG})")
                COMMAND="${COMMAND} && ${TRIGGER_COMMANDS}"
            done < <(jq -r '.['$i'].trigger|keys[]' ${CONFIG})
        fi

        NAME=$(jq -r .[$i].name ${CONFIG})
        COMMENT=$(jq -r .[$i].comment ${CONFIG})
        if [ "${NAME}" != "null" ] && [ "${COMMENT}" != "null" ]; then
            echo "# ${NAME}: ${COMMENT}" >> ${CRONTAB_FILE}
        elif [ "${COMMENT}" != "null" ]; then
            echo "# ${COMMENT}" >> ${CRONTAB_FILE}
        fi

        echo "${SCHEDULE} ${COMMAND}" >> ${CRONTAB_FILE}

        if [ "$(jq -r .[$i].onstart ${CONFIG})" == "true" ]; then
            ONSTART+=("${COMMAND}")
        fi
    done < <(jq -r '.|keys[]' ${CONFIG})

    echo "crontab generation complete"
    cat ${CRONTAB_FILE}

    # Run onstart commands
    for COMMAND in "${ONSTART}"; do
        ${COMMAND}
    done
}

if [ "$1" = "crond" ]; then
    if [ -f ${CONFIG} ]; then
        build_crontab
    else
        echo "Unable to find ${HOME_DIR}/config.json"
    fi
fi

echo "$@"
exec "$@"