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mtfurlan/ip-script.Dockerfile

Created May 10, 2024 17:50
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  1. mtfurlan created this gist May 10, 2024.
    67 changes: 67 additions & 0 deletions ip-script.Dockerfile
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    FROM alpine:latest

    # gluetun doens't support post vpn up scripts
    # this will cron and run a script on change, at most once every hour
    # TODO: confirm that it's not once every 2 cause it runs once every 1,
    # but bash script also has a too recent check

    # use this like:
    # ip_bullshit:
    # network_mode: service:vpn
    # build:
    # dockerfile: ./ip-script.Dockerfile
    # environment:
    # - CHANGE_SCRIPT=/vpn-startup-scripts/myanonamouse.sh
    # volumes:
    # - ./config/vpn-startup-scripts:/vpn-startup-scripts

    RUN apk --no-cache add curl

    RUN touch crontab.tmp \
    && echo '@reboot /detect.sh' >> crontab.tmp \
    && echo '0 * * * * /detect.sh' >> crontab.tmp \
    #&& echo '* * * * * sh -c /detect.sh ' >> crontab.tmp \
    && crontab crontab.tmp \
    && rm -rf crontab.tmp

    CMD ["/usr/sbin/crond", "-f", "-l", "2"]

    RUN cat <<'EOF' > /detect.sh
    #!/bin/sh
    set -eu

    cIP=/tmp/currentIP
    cD=/tmp/currentDate
    lIP=/tmp/lastIP
    lD=/tmp/lastDate

    if [ -e "$lD" ] || [ -e "$lD" ]; then
    lastDate=$(date -d "$(cat "$lD")" -D "%Y-%m-%d %H:%M:%SZ" +"%s")
    now=$(date +%s)
    if [ "$(( now - 3600 ))" -lt "$lastDate" ]; then
    echo "too recent"
    exit 0
    fi
    fi

    wget ifconfig.co -O "$cIP"
    date +"%Y-%m-%d %H:%M:%SZ" > "$cD"

    if [ ! -e "$lIP" ] || ! cmp -s "$cIP" "$lIP" ; then
    echo "IP changed from"
    echo "$(cat "$lIP") at $(cat "$lD")"
    echo "to"
    echo "$(cat "$cIP") at $(cat "$cD")"
    if [ -e "${CHANGE_SCRIPT:-/not/a/real/path}" ]; then
    "$CHANGE_SCRIPT" "$(cat "$cIP")"
    else
    echo >&2 "please set CHANGE_SCRIPT"
    fi

    cp "$cIP" "$lIP"
    cp "$cD" "$lD"
    else
    echo "no change"
    fi
    EOF
    RUN chmod +x /detect.sh