[SPARK-30879][DOCS] Refine workflow for building docs

### What changes were proposed in this pull request?

This PR makes the following refinements to the workflow for building docs:
* Install Python and Ruby consistently using pyenv and rbenv across both the docs README and the release Dockerfile.
* Pin the Python and Ruby versions we use.
* Pin all direct Python and Ruby dependency versions.
* Eliminate any use of `sudo pip`, which the Python community discourages, or `sudo gem`.

### Why are the changes needed?

This PR should increase the consistency and reproducibility of the doc-building process by managing Python and Ruby in a more consistent way, and by eliminating unused or outdated code.

Here's a possible example of an issue building the docs that would be addressed by the changes in this PR: apache#27459 (comment)

### Does this PR introduce any user-facing change?

No.

### How was this patch tested?

Manual tests:
* I was able to build the Docker image successfully, minus the final part about `RUN useradd`.
    * I am unable to run `do-release-docker.sh` because I am not a committer and don't have the required GPG key.
* I built the docs locally and viewed them in the browser.

I think I need a committer to more fully test out these changes.

Closes apache#27534 from nchammas/SPARK-30731-building-docs.

Authored-by: Nicholas Chammas <[email protected]>
Signed-off-by: Sean Owen <[email protected]>

Author: nchammas

.gitignore

@@ -18,6 +18,8 @@
 .idea_modules/
 .project
 .pydevproject
+.python-version
+.ruby-version
 .scala_dependencies
 .settings
 /lib/

dev/create-release/do-release-docker.sh

@@ -96,7 +96,7 @@ fcreate_secure "$GPG_KEY_FILE"
 $GPG --export-secret-key --armor "$GPG_KEY" > "$GPG_KEY_FILE"
 
 run_silent "Building spark-rm image with tag $IMGTAG..." "docker-build.log" \
-  docker build -t "spark-rm:$IMGTAG" --build-arg UID=$UID "$SELF/spark-rm"
+  docker build --no-cache -t "spark-rm:$IMGTAG" --build-arg UID=$UID "$SELF/spark-rm"
 
 # Write the release information to a file with environment variables to be used when running the
 # image.

dev/create-release/spark-rm/Dockerfile

@@ -20,9 +20,9 @@
 # Includes:
 # * Java 8
 # * Ivy
-# * Python (2.7.15/3.6.7)
+# * Python 3.7
+# * Ruby 2.7
 # * R-base/R-base-dev (3.6.1)
-# * Ruby 2.3 build utilities
 
 FROM ubuntu:18.04
 
@@ -33,15 +33,11 @@ ENV DEBCONF_NONINTERACTIVE_SEEN true
 # These arguments are just for reuse and not really meant to be customized.
 ARG APT_INSTALL="apt-get install --no-install-recommends -y"
 
-ARG BASE_PIP_PKGS="setuptools wheel"
-ARG PIP_PKGS="pyopenssl numpy sphinx"
+ARG PIP_PKGS="sphinx==2.3.1 mkdocs==1.0.4 numpy==1.18.1"
+ARG GEM_PKGS="jekyll:4.0.0 jekyll-redirect-from:0.16.0 rouge:3.15.0"
 
 # Install extra needed repos and refresh.
 # - CRAN repo
-# - Ruby repo (for doc generation)
-#
-# This is all in a single "RUN" command so that if anything changes, "apt update" is run to fetch
-# the most current package versions (instead of potentially using old versions cached by docker).
 RUN apt-get clean && apt-get update && $APT_INSTALL gnupg ca-certificates && \
   echo 'deb https://cloud.r-project.org/bin/linux/ubuntu bionic-cran35/' >> /etc/apt/sources.list && \
   gpg --keyserver keyserver.ubuntu.com --recv-key E298A3A825C0D65DFD57CBB651716619E084DAB9 && \
@@ -50,36 +46,43 @@ RUN apt-get clean && apt-get update && $APT_INSTALL gnupg ca-certificates && \
   rm -rf /var/lib/apt/lists/* && \
   apt-get clean && \
   apt-get update && \
-  $APT_INSTALL software-properties-common && \
-  apt-add-repository -y ppa:brightbox/ruby-ng && \
-  apt-get update && \
   # Install openjdk 8.
   $APT_INSTALL openjdk-8-jdk && \
   update-alternatives --set java /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java && \
   # Install build / source control tools
   $APT_INSTALL curl wget git maven ivy subversion make gcc lsof libffi-dev \
-    pandoc pandoc-citeproc libssl-dev libcurl4-openssl-dev libxml2-dev && \
+    pandoc pandoc-citeproc libssl-dev libcurl4-openssl-dev libxml2-dev
+
+ENV PATH "$PATH:/root/.pyenv/bin:/root/.pyenv/shims"
+RUN curl -L https://github.com/pyenv/pyenv-installer/raw/dd3f7d0914c5b4a416ca71ffabdf2954f2021596/bin/pyenv-installer | bash
+RUN $APT_INSTALL libbz2-dev libreadline-dev libsqlite3-dev
+RUN pyenv install 3.7.6
+RUN pyenv global 3.7.6
+RUN python --version
+RUN pip install --upgrade pip
+RUN pip --version
+RUN pip install $PIP_PKGS
+
+ENV PATH "$PATH:/root/.rbenv/bin:/root/.rbenv/shims"
+RUN curl -fsSL https://github.com/rbenv/rbenv-installer/raw/108c12307621a0aa06f19799641848dde1987deb/bin/rbenv-installer | bash
+RUN rbenv install 2.7.0
+RUN rbenv global 2.7.0
+RUN ruby --version
+RUN $APT_INSTALL g++
+RUN gem --version
+RUN gem install --no-document $GEM_PKGS
+
+RUN \
   curl -sL https://deb.nodesource.com/setup_11.x | bash && \
-  $APT_INSTALL nodejs && \
-  # Install needed python packages. Use pip for installing packages (for consistency).
-  $APT_INSTALL libpython3-dev python3-pip && \
-  # Change default python version to python3.
-  update-alternatives --install /usr/bin/python python /usr/bin/python2.7 1 && \
-  update-alternatives --install /usr/bin/python python /usr/bin/python3.6 2 && \
-  update-alternatives --set python /usr/bin/python3.6 && \
-  pip3 install $BASE_PIP_PKGS && \
-  pip3 install $PIP_PKGS && \
-  # Install R packages and dependencies used when building.
-  # R depends on pandoc*, libssl (which are installed above).
+  $APT_INSTALL nodejs
+
+# Install R packages and dependencies used when building.
+# R depends on pandoc*, libssl (which are installed above).
+RUN \
   $APT_INSTALL r-base r-base-dev && \
   $APT_INSTALL texlive-latex-base texlive texlive-fonts-extra texinfo qpdf && \
   Rscript -e "install.packages(c('curl', 'xml2', 'httr', 'devtools', 'testthat', 'knitr', 'rmarkdown', 'roxygen2', 'e1071', 'survival'), repos='https://cloud.r-project.org/')" && \
-  Rscript -e "devtools::install_github('jimhester/lintr')" && \
-  # Install tools needed to build the documentation.
-  $APT_INSTALL ruby2.3 ruby2.3-dev mkdocs && \
-  gem install jekyll --no-rdoc --no-ri -v 3.8.6 && \
-  gem install jekyll-redirect-from -v 0.15.0 && \
-  gem install rouge
+  Rscript -e "devtools::install_github('jimhester/lintr')"
 
 WORKDIR /opt/spark-rm/output
 

docs/README.md

@@ -31,19 +31,49 @@ whichever version of Spark you currently have checked out of revision control.
 The Spark documentation build uses a number of tools to build HTML docs and API docs in Scala, Java,
 Python, R and SQL.
 
-You need to have [Ruby](https://www.ruby-lang.org/en/documentation/installation/) and
-[Python](https://docs.python.org/2/using/unix.html#getting-and-installing-the-latest-version-of-python)
-installed. Also install the following libraries:
+You need to have Ruby 2 (preferably Ruby 2.6+) and Python 3 (preferably Python 3.7+) installed.
+
+You'll also need to install the following libraries:
+
+```sh
+gem install jekyll:4.0.0 jekyll-redirect-from:0.16.0 rouge:3.15.0
+```
+
+### Using rbenv and pyenv
+
+A handy way to install and manage various versions of Ruby and Python is with [`rbenv`] and [`pyenv`].
+
+[`rbenv`]: https://github.com/rbenv/rbenv
+[`pyenv`]: https://github.com/pyenv/pyenv
+
+On macOS you can install them with Homebrew:
 
 ```sh
-$ sudo gem install jekyll jekyll-redirect-from rouge
+brew install rbenv pyenv
 ```
 
-Note: If you are on a system with both Ruby 1.9 and Ruby 2.0 you may need to replace gem with gem2.0.
+To activate them, you'll need to run these commands or add them to the end of your `.bash_profile`:
+
+```sh
+eval "$(rbenv init -)"
+eval "$(pyenv init -)"
+```
+
+You can now use them to install specific versions of Ruby and Python and associate them with 
+the Spark home directory. Whenever you navigate to this directory or any of its subdirectories, these versions of Ruby and Python will be automatically activated.
+
+```sh
+rbenv install 2.7.0
+pyenv install 3.7.6
+
+cd /path/to/spark/root
+rbenv local 2.7.0
+pyenv local 3.7.6
+```
 
 ### R Documentation
 
-If you'd like to generate R documentation, you'll need to [install Pandoc](https://pandoc.org/installing.html)
+If you'd like to generate R documentation, you'll need to install R, [install Pandoc](https://pandoc.org/installing.html),
 and install these libraries:
 
 ```sh
@@ -58,7 +88,7 @@ Note: Other versions of roxygen2 might work in SparkR documentation generation b
 To generate API docs for any language, you'll need to install these libraries:
 
 ```sh
-$ sudo pip install sphinx mkdocs numpy
+pip install sphinx==2.3.1 mkdocs==1.0.4 numpy==1.18.1
 ```
 
 ## Generating the Documentation HTML