From 58e628d0de1876e212082e46c18ad4ddf95e3052 Mon Sep 17 00:00:00 2001
From: Piyush Bhaskar <102078527+Piyush-r-bhaskar@users.noreply.github.com>
Date: Mon, 21 Oct 2024 18:28:10 +0200
Subject: [PATCH]  Update Dockerfile: Added Comments to briefly explain the
 instructions.

---
 Dockerfile | 78 +++++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 60 insertions(+), 18 deletions(-)

diff --git a/Dockerfile b/Dockerfile
index 71219244bf..1b3d5d16b6 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,60 +1,102 @@
+# This Dockerfile defines a multi-stage build process for building and deploying an application using Yarn workspaces, TurboRepo for efficient monorepo management, and Alpine Linux for a minimal image size.
+
+# === Base Stage ===
+# Builds a base image with necessary system dependencies.
 FROM node:20-alpine3.19 AS base
-# Check https://github.com/nodejs/docker-node/tree/b4117f9333da4138b03a546ec926ef50a31506c3#nodealpine to understand why libc6-compat might be needed
-RUN apk update && apk add --no-cache libc6-compat python3 make g++ py3-pip && rm -rf /var/cache/apk/*
-RUN ln -sf python3 /usr/bin/python
-ENV TURBO_TELEMETRY_DISABLED=1
 
-# ===
+# Install system packages required for building and running the application.
+# - libc6-compat: Provides compatibility for libraries compiled against glibc. [# Check https://github.com/nodejs/docker-node/tree/b4117f9333da4138b03a546ec926ef50a31506c3#nodealpine to understand why libc6-compat might be needed]
+# - python3, make, g++: Essential build tools for various dependencies.
+# - py3-pip: Package installer for Python 3.
+RUN apk update && \
+    apk add --no-cache libc6-compat python3 make g++ py3-pip && \
+    rm -rf /var/cache/apk/* && \
+    ln -sf python3 /usr/bin/python 
+
+# Disable telemetry in the Turbo build system.
+ENV TURBO_TELEMETRY_DISABLED=1
 
+# === Builder Stage ===
+# Builds the application using TurboRepo, taking advantage of its caching mechanisms.
 FROM base AS builder
-# Set working directory
+
+# Set the working directory inside the container to /app.
 WORKDIR /app
+
+# Install TurboRepo globally for managing the monorepo build.
 RUN yarn global add turbo@^2
+
+# Copy the entire project directory into the container.
 COPY . .
-# copy packages that @altairgraphql/api depends on to out directory
-RUN turbo prune --scope=@altairgraphql/api --docker
 
-# ===
+# Prune the workspace to prepare for building the @altairgraphql/api sub-project, ensuring only its dependencies are included, minimizing the final image size.
+RUN turbo prune --scope=@altairgraphql/api --docker
 
-# Add lockfile and package.json's of isolated subworkspace
+# === Installer Stage ===
+# This stage prepares the final runtime image by copying build artifacts and installing production dependencies.
 FROM base AS installer
+
+# Set the working directory inside the container to /app.
 WORKDIR /app
-# First install dependencies (as they change less often)
+
+# Copy the .gitignore file to avoid adding unnecessary files to the image.
 COPY .gitignore .gitignore
+
 # FIXME: running yarn install with --ignore-scripts means that some packages may not get built correctly. Skipping these steps for now.
 # COPY --from=builder /app/out/json/ .
 # COPY --from=builder /app/out/yarn.lock ./yarn.lock
 # # install node_modules without running scripts (scripts depend on the source files)
 # RUN yarn install --ignore-scripts
-# Build the project and its dependencies
+
+# Copy the built application code from the builder stage.
 COPY --from=builder /app/out/full/ .
+
+# Copy configuration files for TurboRepo and Nx (a build system used within the project).
 COPY turbo.json turbo.json
 COPY nx.json nx.json
 COPY tsconfig.json tsconfig.json
 COPY CHECKS CHECKS
-# build the project, running the prepare scripts
+
+# Install production dependencies.
 RUN yarn
-RUN yarn turbo run build --filter=@altairgraphql/api...
 
-# ===
+# Build the @altairgraphql/api project, utilizing Turbo's caching for speed.
+RUN yarn turbo run build --filter=@altairgraphql/api...
 
+# === Runner Stage ===
+# This stage defines the final runtime environment for the application.
 FROM base AS runner
+
+# Set the working directory inside the container to /app.
 WORKDIR /app
 
+# Set the NODE_ENV environment variable to "production".
 ARG NODE_ENV=production
 ENV NODE_ENV=${NODE_ENV}
+
+# Set the application port.
 ARG PORT=3000
 ENV PORT=${PORT}
-# Don't run production as root
+
+# Create a non-root user for running the application for improved security.
 RUN addgroup --system --gid 1001 nodejs
 RUN adduser --system --uid 1001 nodejs
+
+# Switch to the newly created user.
 USER nodejs
+
+# Copy the built application and its dependencies from the installer stage.
 COPY --from=installer /app .
-# new relic env variables
+
+# Configure New Relic monitoring.
 ENV NEW_RELIC_NO_CONFIG_FILE=true
 ENV NEW_RELIC_DISTRIBUTED_TRACING_ENABLED=true
 ENV NEW_RELIC_LOG=stdout
 
-# EXPOSE ${PORT}
+#--------------
+# SUGGESTION - Define a health check to ensure the container is running correctly. This example assumes a /health endpoint is available. Adjust according to your application.
+# HEALTHCHECK --interval=30s --timeout=10s CMD curl --fail http://localhost:${PORT}/health || exit 1
+#--------------
 
+# Start the application.
 CMD ["yarn", "start:api:prod"]