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📦🛠️ Build the Docker Image

To create a Docker image from your project, use the following command:

docker build -t express-docker-image .

  • docker build: Tells Docker to create a new image.

  • -t express-docker-image: Tags the image with the name express-docker-image.

  • .: Tells Docker to use the Dockerfile in the current directory

  1. Run a Container

docker run --name express-docker-container -d -p 4000:4000 express-docker-image

Explaination command :

  • -d → Run in background (detached mode)

  • -p 4000:4000 → Map host port 4000 → container port 4000

  • --name my-app → Give container a name (easier to manage)

2. Stop a Running Container

docker stop my-app

3.Delete a Container

docker rm my-app

force remove (if stuck) docker rm -f my-app

4. Delete a Docker Image docker rmi express-docker-app

Command ----> What It Does

docker ps ----> List running containers

docker ps -a ----> List all containers (including stopped)

docker images ----> List all images

docker logs my -f ----> View container logs, -f : follow the log output

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HOT RE-LOAD

two way binding ( Two-Way Sync (Local ↔ Container) ) docker run -d -p 4000:4000 --name myapp-container -v "path of project":/app my-node-image

or:

docker run -d -p 4000:4000 --name myapp-container -v ${pwd}:/app my-node-image

  • async local files with files in container

  • Changes in local files auto-update in the container.

  • No need to rebuild/restart

one way binding ( One-Way Sync (Read-Only) ) docker run -d -p 4000:4000 --name myapp-container -v "path of project":/app:ro my-node-image

  • ro: read only, container can’t modify local files

I want folders do not change in the container even though I change them locally (Exclude Folders from Sync).

docker run -d -p 4000:4000 --name myapp-container -v "path of project":/app:ro -v /app/node_modules my-node-image

result : Keeps node_modules intact (ignores local changes).

test: delete folder , pause container , run it again, folder will be returned again

last command : docker run --name express-container -v ${pwd}/src:/app/src:ro -d -p 4000:4000 my-node-image

just read the modification inside src folder(delete, update...etc)

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OPEN TERMINAL IN CONTAINER :

docker exec -it my-app-container sh

==================================================

make the command is short !!

build : docker-compose.yml run : docker-compose up -d -d : for prevent bringing terminal of container to local terminal

docker-compose up --build # Rebuilds images before running docker-compose down # Stops and removes containers

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Environment varibles

1- inside docker file write :

ENV PORT=4000

EXPOSE $PORT

2- with the command in terminal :

docker run --name express-container -v ${pwd}/src:/app/src:ro --env PORT=4000 --env NODE_env=development -d -p 4000:4000 my-node-image

Test

run command using second method

open terminal in container

run to see environment varibles :

printenv

3- inside .env file :

docker run --name express-container -v ${pwd}/src:/app/src:ro --env-file ./.env -d -p 4000:4000 my-node-image

4-inside docker-compose.yml file

=======================================================

Managing Docker Across Environments

Solution: Create separate docker-compose files for each environment (development, staging, production).

Why? Each environment has unique requirements:

Different configurations (ports, volumes)

Environment-specific dependencies

Separate security rules and scaling needs

Example : Development vs Production Volumes : docker-compose-dev.yml (Development) volumes:

  • ./src:/app/src # Live code updates (edit locally → auto-updates in container)

docker-compose-prod.yml (Production) No volumes → Code stays static in container (better security & stability)

Why? Development: You need instant code changes → volumes sync your local files

Production: Code shouldn't change after deployment → no volumes = safer/faster

▶️To run with a specific Compose file docker-compose -f docker-compose.dev.yml up -d docker-compose -f docker-compose.dev.yml down

Use -f to choose the desired file.

====================================================

🧼 Clean Docker Compose Setup

📁
docker-compose.yml – Contains common configuration for all environments.

docker-compose.dev.yml – Contains development-specific overrides.

docker-compose.prod.yml – Contains production-specific overrides.

=====================================================================

🎯 Installing Environment-Specific Dependencies & Avoiding Nodemon in Production

🚧 1. Run the Project in Development Mode

To run the project without Nodemon (pure Node.js), add the following line under the relevant service in your docker-compose.dev.yml:

command: npm run start-dev

🚧 2. Install Dependencies Based on Environment

  • FIRST WAY :Using Build Arguments

Add the following to your configuration files:

🐳 Dockerfile

ARG NODE_ENV RUN if [ "$NODE_ENV" = "production" ]; then
npm install --only=production;
else
npm install;
fi

🧪 docker-compose.dev.yml
build:
context: .
args: - NODE_ENV=development
🚀 docker-compose.prod.yml
build:
context: .
args: - NODE_ENV=production
  • SECOND WAY: Multi-Stage Dockerfile

To manage dependencies efficiently in different environments (development vs production), we use a Multi-Stage Dockerfile.

✅ What This Setup Does:

🛠️ In development, it installs all dependencies (including dev ones).

🚀 In production, it installs only production dependencies.

🔁 Helps avoid using Nodemon in environments where it’s not needed.

Run Docker Compose with development configuration in detached mode and rebuild images:

docker-compose -f docker-compose.yml -f docker-compose.dev.yml up -d --build

📜 How Docker Compose reads files ??!

  • 1- Loads docker-compose.yml as the base.

  • 2- Applies overrides from docker-compose.dev.yml.

Stop it :

docker-compose -f docker-compose.yml -f docker-compose.dev.yml down

==============================================================

MongoDB Service in Docker Compose

Service Name: mongo

  • Image: Official MongoDB image from Docker Hub.

  • Restart Policy: always → Restarts if stopped or if Docker restarts.

  • Container Name: mongo_container

  • Environment Variables:

  • MONGO_INITDB_ROOT_USERNAME → Root username for MongoDB.

  • MONGO_INITDB_ROOT_PASSWORD → Root password for MongoDB.

  • Default Port: 27017 (exposed inside container).

======================================================================

⚠️ Problem connecting to MongoDB on localhost

Initial configuration (not working from Docker container):
MONGO_URI=mongodb://localhost:27017/node_with_docker
❌ Reason: localhost inside the container points to the container itself, not your host machine.
  • Fixed configuration (works from Docker container):
MONGO_URI=mongodb://host.docker.internal:27017/node_with_docker

✅ Explanation:

  • host.docker.internal points to your host machine from inside the container.

  • This allows your Node container to access the MongoDB running locally on your host.

================================================================

🐳 Inspect a Docker Container

  • Command:
docker inspect mongo_container
  • Shows detailed information about the container mongo_container

================================================================

List Docker Networks

docker network ls
  • Lists all Docker networks on your system.

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🌐 Connecting to online MongoDB from Docker

  • Example (❌ wrong):
const DB_HOST = '127.27.0.2'; // IP that probably doesn’t work, you must change it manually
  • Example (✅ correct):
const DB_HOST = 'mongo'; // Use the service name
  • mongo matches the service name in your docker-compose.yml.
  • Docker automatically resolves container names to IPs within the same network.

================================================================

docker exec -it mongo_container mongosh -u root -p example
  • ✅ Effect: You get an interactive MongoDB shell inside the running container.

==================================================================

Volumes list

docker volume ls

delete volume

docker volume rm name of volume
delete unused volumes
docker volume prune

===================================================================

🗄️ Persisting MongoDB Data in Docker

  • Problem: When you restart the MongoDB container, all data is lost because it is stored inside the container.

  • Solution: Use a Docker volume to persist MongoDB data across container restarts.

==================================================================

shut down container and delete volumes :

docker-compose -f docker-compose.yml -f docker-compose.dev.yml down -v

================================================================

📦 Types of volumes :

  • 1.Named volumes (like mongo-db) → Managed by Docker, stored in Docker’s default location.

  • 2.Bind mounts → Map a host machine directory to the container directory (e.g., ./data:/data/db).

  • 3.Anonymous volumes → Created automatically, unnamed, less controllable.