Update container build to use Alpine Linux and Gunicorn instead of CentOS and Apache. Fixes #3246

This results in a much more slim-line container, requiring fewer resources to run.
In addition, the majority of the build is now done using the Docker infrastructure, allowing for quicker rebuilds and better use of layers.

pkg/docker/Dockerfile

@@ -7,58 +7,63 @@
 #
 #########################################################################
 
-# Get the basics out of the way
-FROM centos:latest
+# First of all, build frontend with NodeJS in a separate builder container
+# Node-6 with ABI v48 is supported by all needed C++ packages
+FROM node:6 AS node-builder
 
-LABEL name="pgAdmin 4" \
-    vendor="The pgAdmin Development Team" \
-    license="PostgreSQL"
+COPY ./pgadmin4/web/ /pgadmin4/web/
+WORKDIR /pgadmin4/web
 
-# We only need the web/ directory, and a few other things
-COPY web /var/www/pgadmin
-COPY requirements.txt /var/www/pgadmin
+RUN yarn install --cache-folder ./ycache --verbose && \
+    yarn run bundle && \
+    rm -rf ./ycache ./pgadmin/static/js/generated/.cache
 
-# Install everything we need. Use easy_install to get pip, to avoid setting up EPEL
-RUN yum install -y python-setuptools python-devel httpd mod_wsgi mod_ssl gcc
-RUN easy_install pip
-RUN pip install j2cli
+# Build Sphinx documentation in separate container
+FROM python:3.6-alpine3.7 as docs-builder
 
-# Now install the Python runtime dependencies
-RUN pip install -r /var/www/pgadmin/requirements.txt
+# Install only dependencies absolutely required for documentation building
+RUN apk add --no-cache make
+RUN pip install --no-cache-dir \
+    sphinx flask_security flask_paranoid python-dateutil flask_sqlalchemy \
+    flask_gravatar simplejson
 
-# Create required directories for config
+COPY ./pgadmin4/ /pgadmin4
 
+RUN LC_ALL=en_US.UTF-8 LANG=en_US.UTF-8 make -C /pgadmin4/docs/en_US -f Makefile.sphinx html
 
-# Create required directories for running
-RUN mkdir -p /var/log/pgadmin
-RUN chown -R apache /var/log/pgadmin
-RUN mkdir -p /var/lib/pgadmin
-RUN chown -R apache /var/lib/pgadmin
-RUN mkdir -p /certs
-RUN chown -R apache /certs
-RUN chmod 700 /certs
+# Then install backend, copy static files and set up entrypoint
+# Need alpine3.7 to get pg_dump and friends in postgresql-client package
+FROM python:3.6-alpine3.7
 
-# Push logs to the container's output streams
-RUN ln -sf /proc/self/fd/1 /var/log/httpd/access_log && \
-    ln -sf /proc/self/fd/1 /var/log/httpd/ssl_access_log && \
-    ln -sf /proc/self/fd/2 /var/log/httpd/error_log && \
-    ln -sf /proc/self/fd/2 /var/log/httpd/ssl_error_log
+RUN pip --no-cache-dir install gunicorn
+RUN apk add --no-cache postgresql-client postgresql-libs
 
-# Apache config time
-RUN mkdir -p /templates
-COPY pgadmin4.conf.j2 /templates/
-COPY entry.sh /
+WORKDIR /pgadmin4
+ENV PYTHONPATH=/pgadmin4
 
-# Finally, remove packages we only needed for building
-RUN yum -y remove gcc cpp glibc-devel glibc-headers kernel-headers libgomp libmpc mpfr
+# Install build-dependencies, build & install C extensions and purge deps in one RUN step
+# so that deps do not increase the size of resulting image by remaining in layers
+COPY ./pgadmin4/requirements.txt /pgadmin4
+RUN set -ex && \
+    apk add --no-cache --virtual build-deps build-base postgresql-dev && \
+    pip install --no-cache-dir -r requirements.txt && \
+    apk del --no-cache build-deps
 
-# Default config options
-ENV PGADMIN_DEFAULT_EMAIL container@pgadmin.org
-ENV PGADMIN_DEFAULT_PASSWORD Conta1ner
-ENV PGADMIN_ENABLE_TLS False
-ENV PGADMIN_SERVER_NAME pgadmin4
+COPY --from=node-builder /pgadmin4/web/pgadmin/static/js/generated/ /pgadmin4/pgadmin/static/js/generated/
+COPY --from=docs-builder /pgadmin4/docs/en_US/_build/html/ /pgadmin4/docs/
 
+COPY ./pgadmin4/web /pgadmin4
+COPY ./run_pgadmin.py /pgadmin4
+COPY ./config_distro.py /pgadmin4
+
+RUN pip install --no-cache-dir -r requirements.txt
+
+# Precompile and optimize python code to save time and space on startup
+RUN python -O -m compileall /pgadmin4
+
+COPY ./entrypoint.sh /entrypoint.sh
+
+VOLUME /var/lib/pgadmin
 EXPOSE 80 443
 
-# Start the service
-ENTRYPOINT ["/bin/bash", "/entry.sh"]
+ENTRYPOINT ["/entrypoint.sh"]