What is the easiest method to copy files and directories in dockerfile
<p>I tried to copy some files from source to destination (flask app) in a dockerfile but it seems things are not working as expected when building the image. With last 2 line showing:</p>

<pre><code>Step 3 : COPY pkl_objects/* /home/jovyan/work/movieclassifier/pkl_objects/
No source files were specified
</code></pre>

<p>This is the docker file.</p>

<pre><code>FROM jupyter/datascience-notebook

RUN pip install flask flask-wtf

COPY pkl_objects/* /home/jovyan/work/movieclassifier/pkl_objects/
COPY static/* /home/jovyan/work/movieclassifier/static/
COPY templates/* /home/jovyan/work/movieclassifier/templates/


COPY app.py /home/jovyan/work/movieclassifier
COPY reviews.sqlite /home/jovyan/work/movieclassifier
COPY vectorizer.py /home/jovyan/work/movieclassifier


WORKDIR /home/jovyan/work/movieclassifier
ENV FLASK_APP=app.py
# ENV FLASK_DEBUG=0
CMD ["flask", "run", "--host=0.0.0.0"]
</code></pre>