Optimize Dockerfile to reduce image size

[jaehee329]

Description

ref #135

Changed docker base image from ubuntu:20.04 to python:3.8-slim-buster
Reduced the number of layers

Reduced 0.31GB of the image size

build time also decreased from 5.5 min to 2 min in my environment (Win10, i5-10400F, 16GB RAM)

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Documentation update
• Refactoring, Maintenance
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

[jongwooo]

To provide for multiple platforms instead of just one, the setting must be excluded from the FROM statement. For more information, see https://docs.docker.com/build/building/multi-platform/

Suggested change

	FROM --platform=linux/amd64 python:3.8-slim-buster
	FROM python:3.8-slim-buster

[jongwooo]

noninteractive mode is useful when we need zero interaction while installing or upgrading the system via apt. However, setting this environment variable to noninteractive has an adverse effect. Because it is inherited by all images and containers built from the image, effectively changing their behavior.

Suggested change

ENV DEBIAN_FRONTEND=noninteractive

Let's look for an alternative.

[jongwooo]

Suggested change

	apt-get update && \
	apt-get install -y sudo build-essential \
	apt-get update && \
	apt-get install --no-install-recommends -y \
	build-essential \

[jongwooo]

Consider changing the pull request title and commit message to Optimize Dockerfile to reduce image size.

[jaehee329]

@jongwooo
Thanks for your kind review. Followed your suggestions.

I have a question about using multi-stage build now.
Can you please check this Dockerfile appropriate?
Since it's my first time to use multi-stage build, I'm not sure is it okay to copy only the executable file from builder.

# Copyright (c) 2021 LG Electronics Inc.
# SPDX-License-Identifier: Apache-2.0
FROM python:3.8-slim-buster AS builder

RUN ln -sf /bin/bash /bin/sh && \
    apt-get update && \
    apt-get install --no-install-recommends -y \
    build-essential \
    python3 python3-distutils python3-pip python3-dev python3-magic \
    libxml2-dev libxslt1-dev libhdf5-dev bzip2 xz-utils zlib1g libpopt0 && \
    apt-get clean && \
    rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*

WORKDIR	/app

COPY . /app

RUN pip3 install --upgrade pip && \
    pip3 install . && \
    pip3 install dparse && \
    rm -rf ~/.cache/pip /root/.cache/pipe

FROM python:3.8-slim-buster AS production

COPY --from=builder /usr/local/bin/fosslight_source /usr/local/bin/fosslight_source

ENTRYPOINT ["/usr/local/bin/fosslight_source"]