Using Dockerfile to build C++ applications

01 Oct 2023

Docker is a powerful tool that allows you to package your applications and their dependencies into containers, providing consistent and reproducible builds across different environments. In this blog post, we will explore how to use a Dockerfile to build C++ applications.

Step 1: Create a Dockerfile

First, we need to create a Dockerfile in the root directory of our C++ project. The Dockerfile is a plain text file that contains instructions to build the Docker image. Here is an example Dockerfile:

# Base image
FROM gcc:latest

# Set the working directory
WORKDIR /app

# Copy the source code to the container
COPY . .

# Build the C++ application
RUN g++ -o myapp main.cpp

# Set the entry point
CMD ["./myapp"]

Let’s break down the Dockerfile:

FROM gcc:latest: This line specifies the base image to use, which in this case is the latest version of the GCC compiler. You can choose a different base image depending on your project’s requirements.
WORKDIR /app: This sets the working directory inside the container to /app.
COPY . .: This line copies the entire current directory (project files) to the /app directory inside the container.
RUN g++ -o myapp main.cpp: This command compiles the main.cpp file using the GCC compiler and creates an executable named myapp.
CMD ["./myapp"]: This sets the default command to run when the container is started. In this case, it will execute the myapp executable.

Step 2: Build the Docker Image

To build the Docker image, open the terminal and navigate to the directory where the Dockerfile is located. Then, run the following command:

docker build -t myapp-image .

This command will build a Docker image named myapp-image using the instructions specified in the Dockerfile. The dot . at the end of the command indicates that the Dockerfile is in the current directory.

Step 3: Run the C++ Application in a Docker Container

After successfully building the Docker image, we can now run our C++ application inside a Docker container. Use the following command:

docker run myapp-image

This command will start a Docker container using the myapp-image image. The C++ application will run inside the container, and you will see the output in the terminal.

Conclusion

Using a Dockerfile to build C++ applications provides many benefits, such as consistency, reproducibility, and portability. By following the steps outlined in this blog post, you can easily containerize your C++ projects and run them in any environment that supports Docker.

#docker #cplusplus #containerization