📝 docs(_details): about docker

.github/workflows/snigdhaos-docker.yml

@@ -15,19 +15,19 @@ jobs:
     steps:
       # Checkout repository
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       # Set up QEMU for multi-architecture builds
       - name: Set up QEMU
-        uses: docker/setup-qemu-action@v2
+        uses: docker/setup-qemu-action@v3
 
       # Set up Docker Buildx for advanced builds (multi-arch, caching)
       - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v2
+        uses: docker/setup-buildx-action@v3
 
       # Login to Docker Hub using secrets for security
       - name: Login to Docker Hub
-        uses: docker/login-action@v2
+        uses: docker/login-action@v3
         with:
           username: ${{ secrets.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}

readme.md

@@ -0,0 +1,43 @@
+# INTRODUCTION TO DOCKER
+A **Dockerfile** is a text file that contains a set of instructions used to automate the creation of a Docker image. It defines the environment, software dependencies, configurations, and commands that will be executed inside a container when it is built and run. Dockerfiles are used by Docker to build images, which can then be used to create containers.
+
+Here's a breakdown of common Dockerfile instructions:
+
+1. **FROM**: Specifies the base image to use (e.g., `FROM ubuntu:20.04`).
+2. **RUN**: Executes commands inside the image, such as installing software packages (e.g., `RUN apt-get update`).
+3. **COPY**: Copies files or directories from your local filesystem to the image (e.g., `COPY . /app`).
+4. **ADD**: Similar to `COPY`, but can also handle URLs and unpack compressed files.
+5. **WORKDIR**: Sets the working directory for subsequent instructions (e.g., `WORKDIR /app`).
+6. **CMD**: Specifies the default command to run when a container is started (e.g., `CMD ["python", "app.py"]`).
+7. **EXPOSE**: Informs Docker that the container will listen on specific ports (e.g., `EXPOSE 80`).
+8. **ENV**: Sets environment variables in the container (e.g., `ENV APP_ENV=production`).
+9. **ENTRYPOINT**: Defines the command that will always run when the container starts, even if a different command is provided at runtime.
+10. **VOLUME**: Creates a mount point for volumes, allowing data persistence (e.g., `VOLUME /data`).
+
+### Example Dockerfile:
+```dockerfile
+# Use the official Python image as the base image
+FROM python:3.8-slim
+
+# Set the working directory in the container
+WORKDIR /app
+
+# Copy the current directory contents into the container
+COPY . /app
+
+# Install any necessary dependencies
+RUN pip install -r requirements.txt
+
+# Expose port 5000
+EXPOSE 5000
+
+# Define the default command to run the app
+CMD ["python", "app.py"]
+```
+
+### Key Uses of a Dockerfile:
+- **Reproducibility**: The same Dockerfile can be used to build the same environment across different systems, ensuring consistency.
+- **Automation**: A Dockerfile allows you to automate the process of building an image with specific configurations and software.
+- **Portability**: Once built, Docker images can be shared and run on any platform that supports Docker.
+
+In essence, a Dockerfile is a blueprint for creating Docker images, ensuring the environment is consistent and reproducible.