RI-5036: Comment dockerfile to explain rationale and describe steps

Author: nelsonwellsredis

Dockerfile

@@ -1,32 +1,57 @@
+# this dockerfile has two stages, a build stage and the executable stage.
+# the build stage is responsible for building the frontend, the backend,
+# and the frontend's static assets. ideally, we could build the frontend and backend
+# independently and in parallel in different stages, but there is a dependency
+# on the backend to build those assets. until we fix that, this approach is
+# the best way to minimize the number of node_module restores and build steps
+# while still keeping the final image small.
+
 FROM node:18.15.0-alpine as build
+
+# build time args and environment variables
+ARG SERVER_TLS_CERT
+ARG SERVER_TLS_KEY
+ARG SEGMENT_WRITE_KEY
+ENV SERVER_TLS_CERT=${SERVER_TLS_CERT}
+ENV SERVER_TLS_KEY=${SERVER_TLS_KEY}
+ENV SEGMENT_WRITE_KEY=${SEGMENT_WRITE_KEY}
+
+# update apk repository and install build dependencies
 RUN apk update
 RUN apk add --no-cache --virtual .gyp \
         python3 \
         make \
         g++ \
         net-tools
+
+# set workdir
 WORKDIR /usr/src/app
+
+# restore node_modules for front-end
 COPY package.json yarn.lock babel.config.cjs tsconfig.json ./
 RUN SKIP_POSTINSTALL=1 yarn install
+
+# prepare backend by copying scripts/configs and installing node modules
+# this is required to build the static assets
 COPY configs ./configs
 COPY scripts ./scripts
 COPY redisinsight ./redisinsight
 RUN yarn --cwd redisinsight/api install
-ARG SERVER_TLS_CERT
-ARG SERVER_TLS_KEY
-ARG SEGMENT_WRITE_KEY
-ENV SERVER_TLS_CERT=${SERVER_TLS_CERT}
-ENV SERVER_TLS_KEY=${SERVER_TLS_KEY}
-ENV SEGMENT_WRITE_KEY=${SEGMENT_WRITE_KEY}
+
+# build the frontend, static assets, and backend api
 RUN yarn build:web
 RUN yarn build:statics
 RUN yarn build:prod
+
+# install backend _again_ to build native modules and remove dev dependencies,
+# then run autoclean to remove additional unnecessary files
 RUN yarn --cwd ./redisinsight/api install --production
 COPY ./redisinsight/api/.yarnclean.prod ./redisinsight/api/.yarnclean
 RUN yarn --cwd ./redisinsight/api autoclean --force
 
 FROM node:18.15.0-alpine
 
+# runtime args and environment variables
 ARG NODE_ENV=production
 ARG SERVER_TLS_CERT
 ARG SERVER_TLS_KEY
@@ -37,16 +62,24 @@ ENV SEGMENT_WRITE_KEY=${SEGMENT_WRITE_KEY}
 ENV NODE_ENV=${NODE_ENV}
 ENV SERVER_STATIC_CONTENT=true
 ENV BUILD_TYPE='DOCKER_ON_PREMISE'
+
+# set workdir
 WORKDIR /usr/src/app
+
+# copy artifacts built in previous stage to this one
 COPY --from=build /usr/src/app/redisinsight/api/dist ./redisinsight/api/dist
 COPY --from=build /usr/src/app/redisinsight/api/node_modules ./redisinsight/api/node_modules
 COPY --from=build /usr/src/app/redisinsight/ui/dist ./redisinsight/ui/dist
 
+# copy the docker entry point script and make it executable
 COPY ./docker-entry.sh ./
 RUN chmod +x docker-entry.sh
 
+# since RI is hard-code to port 5000, expose it from the container
 EXPOSE 5000
 
+# don't run the node process as root
 USER node
 
+# serve the application 🚀
 ENTRYPOINT ["./docker-entry.sh", "node", "redisinsight/api/dist/src/main"]

docker-entry.sh

@@ -7,8 +7,7 @@
 # `docker run`
 set -e
 
-echo "Running docker-entry.sh as:"
-whoami
+echo "Running docker-entry.sh"
 
 # Run the application's entry script with the exec command so it catches SIGTERM properly
 exec "$@"