untested but should be a basic hls -> access frame

Dockerfile

FROM python:3.7-stretch

RUN apt update && apt -y install \
    autopoint \
    autotools-dev \
    bison \
    build-essential \
    ffmpeg \
    flex \
    git \
    gtk-doc-tools \
    libgirepository1.0-dev \
    librtmp-dev \
    libx264-dev \
    openssh-client \
    python3-venv \
    yasm \
    curl \
    libsoup2.4-1 \
    libsoup2.4-dev \
    && rm -rf /var/lib/apt/lists/*

WORKDIR /gstreamer

COPY . .

RUN sh install.sh && rm -rf ./*/ && rm -rf ./*.tar.xz

ENV LD_LIBRARY_PATH=/usr/local/lib:/usr/local/lib/cuda-9.2:${LD_LIBRARY_PATH}
ENV GI_TYPELIB_PATH=/usr/local/lib/girepository-1.0:${GI_TYPELIB_PATH}
ENV GST_PLUGIN_PATH=/usr/local/lib/gstreamer-1.0:${GST_PLUGIN_PATH}

hls_hello_world.py

import numpy as np

import gi
gi.require_version("Gst", "1.0")
from gi.repository import Gst, GLib
Gst.init(None)

HLS_U    = "http://some/playlist.m3u8"
demux = None
pipeline = None

def on_frame(_, buf, pad):
    caps = pad.get_current_caps()
    caps_structure = caps.get_structure(0)
    width = caps_structure.get_int("width").value
    height = caps_structure.get_int("height").value

    (_result, mapinfo) = buf.map(Gst.MapFlags.READ)
    nparr = np.fromstring(
            mapinfo.data, np.uint8).reshape(height, width, 3)
    buf.unmap(mapinfo)
    timestamp = buf.pts


def on_message(_, message):
    pass

def demux_pad_added(element, pad):
    if element != demux:
        return

    caps_string = pad.get_current_caps().to_string()
    if "video" in caps_string:
        h264parse = Gst.ElementFactory.make("h264parse")
        h264dec = Gst.ElementFactory.make("avdec_h264")

        videorate = Gst.ElementFactory.make("videorate")
        videoconvert = Gst.ElementFactory.make("videoconvert")
        capsfilter = Gst.ElementFactory.make("capsfilter", name)
        caps = Gst.Caps.from_string("video/x-raw,framerate=1/1,format=BGR")
        capsfilter.set_property("caps", caps)

        fakesink_queue = Gst.ElementFactory.make("queue")
        fakesink_queue.set_property("leaky", 2)

        fakesink = Gst.ElementFactory.make("fakesink")
        fakesink.set_property("signal-handoffs", True)
        fakesink.connect(
            "handoff", on_frame)

        elements = [h264parse, h264dec, videorate, videoconvert,
                    capsfilter, fakesink_queue, fakesink]

        for e in elements:
            pipeline.add(e)

        pad.link(h264parse.get_static_pad("sink"))
        Gst.Element.link(h264parse, h264dec)
        Gst.Element.link(h264dec, videorate)
        Gst.Element.link(videorate, videoconvert)
        Gst.Element.link(videoconvert, capsfilter)
        Gst.Element.link(capsfilter, fakesink_queue)
        Gst.Element.link(fakesink_queue, fakesink)

        for e in elements:
            e.set_state(Gst.State.PLAYING)

try:
    loop = GLib.MainLoop()
    loop.run()

    pipeline = Gst.Pipeline.new("SOME_NAME")
    bus = pipeline.get_bus()
    bus.add_signal_watch()
    bus_message_connection = bus.connect(
            "message", on_message)

    src = Gst.ElementFactory.make("souphttpsrc")
    src.set_property("location", HLS_URL)
    demux = Gst.ElementFactory.make("hlsdemux")
    queue = Gst.ElementFactory.make("queue") 

    pipeline.add(src)
    pipeline.add(queue)
    pipeline.add(demux)

    Gst.Element.link(src, queue)
    Gst.Element.link(queue, demux)

    demux.connect("pad-added", demux_pad_added)

    pipeline.set_state(Gst.State.PLAYING)

except KeyboardInterrupt:
    sys.exit(0)
except Exception as e:
    sys.exit(1)

install.sh

LD_LIBRARY_PATH=/usr/local/lib

set -e
set -x

### gstreamer
wget https://gstreamer.freedesktop.org/src/gstreamer/gstreamer-1.14.4.tar.xz
tar xvf gstreamer-1.14.4.tar.xz

cd gstreamer-1.14.4

./autogen.sh --enable-introspection --disable-failing-tests --disable-gtk-doc
make -j4

make install

cd ..

## base
wget https://gstreamer.freedesktop.org/src/gst-plugins-base/gst-plugins-base-1.14.4.tar.xz
tar xvf gst-plugins-base-1.14.4.tar.xz
cd gst-plugins-base-1.14.4
./autogen.sh --enable-introspection --disable-failing-tests --disable-gtk-doc
make -j4
make install
cd ..

## good 
wget https://gstreamer.freedesktop.org/src/gst-plugins-good/gst-plugins-good-1.14.4.tar.xz
tar xvf gst-plugins-good-1.14.4.tar.xz
cd gst-plugins-good-1.14.4
./autogen.sh --enable-introspection --disable-failing-tests --disable-gtk-doc
make -j4
make install
cd ..

## bad 
wget https://gstreamer.freedesktop.org/src/gst-plugins-bad/gst-plugins-bad-1.14.4.tar.xz
tar xvf gst-plugins-bad-1.14.4.tar.xz
cd gst-plugins-bad-1.14.4
./autogen.sh --enable-introspection --disable-failing-tests --disable-gtk-doc
make -j4
make install
cd ..

## ugly 
wget https://gstreamer.freedesktop.org/src/gst-plugins-ugly/gst-plugins-ugly-1.14.4.tar.xz
tar xvf gst-plugins-ugly-1.14.4.tar.xz
cd gst-plugins-ugly-1.14.4
./autogen.sh --enable-introspection --disable-failing-tests --disable-gtk-doc
make -j4
make install
cd ..

## av 
wget https://gstreamer.freedesktop.org/src/gst-libav/gst-libav-1.14.4.tar.xz
tar xvf gst-libav-1.14.4.tar.xz
cd gst-libav-1.14.4
./autogen.sh --enable-introspection --disable-failing-tests --disable-gtk-doc
make -j4
make install