Dockerfile changes to facilitate Ubuntu 20 so as to tackle python version mismatch and resolved dependencies

docker/Dockerfile

@@ -1,9 +1,14 @@
-FROM nvidia/cuda:11.1.1-cudnn8-devel-ubuntu18.04
-# use an older system (18.04) to avoid opencv incompatibility (issue#3524)
+# Using Ubuntu 20.04 is creating an overall better impact in the download and installation
+# The previous Dockerfile with 18.04 ubuntu was causing multiple errors
+# This script creates a Docker image that can directly be run to get the output
+FROM nvidia/cuda:11.1.1-cudnn8-devel-ubuntu20.04
 
-ENV DEBIAN_FRONTEND noninteractive
-RUN apt-get update && apt-get install -y \
-	python3-opencv ca-certificates python3-dev git wget sudo ninja-build
+# Setting non-interactive terminal to avoid input during process
+ENV DEBIAN_FRONTEND=noninteractive
+
+# Installing necessary deps
+# A virtual environment gives better support overall
+RUN apt-get update && apt-get install -y python3-opencv python3-venv ca-certificates python3-dev git wget sudo ninja-build
 RUN ln -sv /usr/bin/python3 /usr/bin/python
 
 # create a non-root user
@@ -14,34 +19,44 @@ USER appuser
 WORKDIR /home/appuser
 
 ENV PATH="/home/appuser/.local/bin:${PATH}"
-RUN wget https://bootstrap.pypa.io/pip/3.6/get-pip.py && \
-	python3 get-pip.py --user && \
-	rm get-pip.py
 
 # install dependencies
-# See https://pytorch.org/ for other options if you use a different version of CUDA
-RUN pip install --user tensorboard cmake onnx   # cmake from apt-get is too old
-RUN pip install --user torch==1.10 torchvision==0.11.1 -f https://download.pytorch.org/whl/cu111/torch_stable.html
 
-RUN pip install --user 'git+https://github.com/facebookresearch/fvcore'
-# install detectron2
-RUN git clone https://github.com/facebookresearch/detectron2 detectron2_repo
-# set FORCE_CUDA because during `docker build` cuda is not accessible
-ENV FORCE_CUDA="1"
-# This will by default build detectron2 for all common cuda architectures and take a lot more time,
-# because inside `docker build`, there is no way to tell which architecture will be used.
+# Create a virtual env in the /tmp directory
+# Change path if you want
+RUN python3 -m venv /tmp/detectron_env
+
+# Set the Virtual ENV and Cuda ENV paths and add them to the base env PATHs
+# Add LD Library Path as well
+ENV VIRTUAL_ENV=/tmp/detectron_env
+ENV CUDA_HOME=/usr/local/cuda-11.1
+ENV PATH="$CUDA_HOME/bin:$VIRTUAL_ENV/bin:$PATH"
+ENV LD_LIBRARY_PATH="$CUDA_HOME/lib64"
+
+# Define all necessary CUDA architectures
 ARG TORCH_CUDA_ARCH_LIST="Kepler;Kepler+Tesla;Maxwell;Maxwell+Tegra;Pascal;Volta;Turing"
 ENV TORCH_CUDA_ARCH_LIST="${TORCH_CUDA_ARCH_LIST}"
 
-RUN pip install --user -e detectron2_repo
+# Install all necessary packages using pip in our virtual environment
+RUN pip install tensorboard cmake onnx   # cmake from apt-get is too old
+RUN pip install torch==1.10 torchvision==0.11.1 -f https://download.pytorch.org/whl/cu111/torch_stable.html
+RUN pip install opencv-python
+RUN pip install 'git+https://github.com/facebookresearch/fvcore'
+
+# Clone detectron repo install detectron2
+RUN git clone https://github.com/facebookresearch/detectron2 detectron2_repo
+RUN pip install -e detectron2_repo
 
 # Set a fixed model cache directory.
 ENV FVCORE_CACHE="/tmp"
 WORKDIR /home/appuser/detectron2_repo
 
+# The demo file does not run for some reason so omit that
+# If anyone does make changes to demo.py, make sure to let me know at [email protected]
+
 # run detectron2 under user "appuser":
-# wget http://images.cocodataset.org/val2017/000000439715.jpg -O input.jpg
-# python3 demo/demo.py  \
-	#--config-file configs/COCO-InstanceSegmentation/mask_rcnn_R_50_FPN_3x.yaml \
-	#--input input.jpg --output outputs/ \
-	#--opts MODEL.WEIGHTS detectron2://COCO-InstanceSegmentation/mask_rcnn_R_50_FPN_3x/137849600/model_final_f10217.pkl
+# RUN wget http://images.cocodataset.org/val2017/000000439715.jpg -O input.jpg
+# RUN python3 demo/demo.py  \
+# 	--config-file configs/COCO-InstanceSegmentation/mask_rcnn_R_50_FPN_3x.yaml \
+# 	--input input.jpg --output outputs/ \
+# 	--opts MODEL.WEIGHTS detectron2://COCO-InstanceSegmentation/mask_rcnn_R_50_FPN_3x/137849600/model_final_f10217.pkl