anchor.diff:  COPY entrypoint.sh /usr/local/bin
   COPY ydls.json /etc
   
  -# make sure all binaries work and do some sanity checks (https, DNS)
  +# make sure all binaries work
   RUN \
     youtube-dl --version && \
  -  ffmpeg -version && \
  -  ffprobe -version && \
  -  ydls -version && \
  -  ffmpeg -i https://www.google.com 2>&1 | grep -q "Invalid data found when processing input"
  +  ydls -version
   
   USER nobody
   EXPOSE $PORT/tcp
  
positive.code:   python \
    rtmpdump \
    mplayer
  COPY --from=ffmpeg-builder \
    /usr/local/bin/ffmpeg \
    /usr/local/bin/ffprobe \
    /usr/local/bin/
  COPY --from=ydls-builder \
    /go/bin/ydls \
    /usr/local/bin/youtube-dl \
  
negative.code: RUN \
    curl -L -o /usr/local/bin/youtube-dl https://yt-dl.org/downloads/$YDL_VERSION/youtube-dl && \
    chmod a+x /usr/local/bin/youtube-dl
  COPY --from=mwader/static-ffmpeg:3.4.2 /* /usr/local/bin/
  
  COPY cmd /go/src/github.com/wader/ydls/cmd
  COPY internal /go/src/github.com/wader/ydls/internal
  