[ci] use conda-forge in Windows CI jobs and Docker images (#4993)

* Update dockerfile-python

* Update README.md

* Update dockerfile.gpu

* Update dockerfile.gpu

* Update .vsts-ci.yml

* Update .appveyor.yml

* Update test_windows.ps1

.appveyor.yml

@@ -38,5 +38,7 @@ install:
 build: false
 
 test_script:
+  - conda config --add channels conda-forge
+  - conda config --set channel_priority strict
   - conda init powershell
   - powershell.exe -ExecutionPolicy Bypass -File %APPVEYOR_BUILD_FOLDER%\.ci\test_windows.ps1

.ci/test_windows.ps1

@@ -50,7 +50,9 @@ if ($env:TASK -eq "swig") {
   Exit 0
 }
 
-conda install -q -y -n $env:CONDA_ENV joblib matplotlib numpy pandas psutil pytest python-graphviz scikit-learn scipy ; Check-Output $?
+conda install -q -y -n $env:CONDA_ENV joblib matplotlib numpy pandas psutil pytest scikit-learn scipy ; Check-Output $?
+# python-graphviz has to be installed separately to prevent conda from downgrading to pypy
+conda install -q -y -n $env:CONDA_ENV python-graphviz ; Check-Output $?
 
 if ($env:TASK -eq "regular") {
   mkdir $env:BUILD_SOURCESDIRECTORY/build; cd $env:BUILD_SOURCESDIRECTORY/build

.vsts-ci.yml

@@ -281,6 +281,8 @@ jobs:
     condition: eq(variables['TASK'], 'bdist')
     displayName: 'Install OpenCL'
   - script: |
+      cmd /c "conda config --add channels conda-forge"
+      cmd /c "conda config --set channel_priority strict"
       cmd /c "conda init powershell"
       cmd /c "powershell -ExecutionPolicy Bypass -File %BUILD_SOURCESDIRECTORY%/.ci/test_windows.ps1"
     displayName: Test

docker/dockerfile-python

 FROM ubuntu:16.04
 
-ARG CONDA_DIR=/opt/conda
+ARG CONDA_DIR=/opt/miniforge
 ENV PATH $CONDA_DIR/bin:$PATH
 
 RUN apt-get update && \
@@ -13,8 +13,8 @@ RUN apt-get update && \
         curl \
         git && \
     # python environment
-    curl -sL https://repo.anaconda.com/miniconda/Miniconda3-latest-Linux-x86_64.sh -o conda.sh && \
-    /bin/bash conda.sh -f -b -p $CONDA_DIR && \
+    curl -sL https://github.com/conda-forge/miniforge/releases/latest/download/Miniforge3-Linux-x86_64.sh -o miniforge.sh && \
+    /bin/bash miniforge.sh -f -b -p $CONDA_DIR && \
     export PATH="$CONDA_DIR/bin:$PATH" && \
     conda config --set always_yes yes --set changeps1 no && \
     # lightgbm

docker/gpu/README.md

@@ -18,7 +18,7 @@ LightGBM can be utilized in GPU and CPU modes and via Python.
 ## Contents
 
 - LightGBM (cpu + gpu)
-- Python 3.8 (conda) + scikit-learn, notebooks, pandas, matplotlib
+- Python (conda) + scikit-learn, notebooks, pandas, matplotlib
 
 Running the container starts a Jupyter Notebook at `localhost:8888`.
 

docker/gpu/dockerfile.gpu

@@ -63,18 +63,18 @@ RUN mkdir -p /etc/OpenCL/vendors && \
 #           CONDA
 #################################################################################################################
 
-ARG CONDA_DIR=/opt/conda
+ARG CONDA_DIR=/opt/miniforge
 # add to path
 ENV PATH $CONDA_DIR/bin:$PATH
 
-# Install miniconda
+# Install miniforge
 RUN echo "export PATH=$CONDA_DIR/bin:"'$PATH' > /etc/profile.d/conda.sh && \
-    curl -sL https://repo.anaconda.com/miniconda/Miniconda3-latest-Linux-x86_64.sh -o ~/miniconda.sh && \
-    /bin/bash ~/miniconda.sh -b -p $CONDA_DIR && \
-    rm ~/miniconda.sh
+    curl -sL https://github.com/conda-forge/miniforge/releases/latest/download/Miniforge3-Linux-x86_64.sh -o ~/miniforge.sh && \
+    /bin/bash ~/miniforge.sh -b -p $CONDA_DIR && \
+    rm ~/miniforge.sh
 
 RUN conda config --set always_yes yes --set changeps1 no && \
-    conda create -y -q -n py3 python=3.8 mkl numpy scipy scikit-learn jupyter notebook ipython pandas matplotlib
+    conda create -y -q -n py3 numpy scipy scikit-learn jupyter notebook ipython pandas matplotlib
 
 #################################################################################################################
 #           LightGBM