How to Set Up a Flask CI/CD Pipeline with Jenkins in 2026

In 2026, setting up a Continuous Integration and Continuous Deployment (CI/CD) pipeline for a Flask application with Jenkins has become an essential practice for developers aiming for rapid and reliable software delivery. This guide provides a step-by-step process to establish an efficient pipeline that automates testing, building, and deploying your Flask app.

Prerequisites

Python 3.11 or later installed on your machine
Jenkins server set up and running
Git repository hosting your Flask application
Docker installed for containerization
Access to a cloud environment or server for deployment

Step 1: Prepare Your Flask Application

Ensure your Flask project has a requirements.txt file listing all dependencies and a Dockerfile for containerization.

Example requirements.txt:

requirements.txt

Flask==2.2.3
gunicorn==20.1.0

Example Dockerfile:

Dockerfile

FROM python:3.11-slim
WORKDIR /app
COPY . /app
RUN pip install -r requirements.txt
CMD [“gunicorn”, “app:app”, “–bind”, “0.0.0.0:8000”]

Step 2: Configure Jenkins

Install necessary plugins such as Git plugin, Docker plugin, and Pipeline plugin. Create a new pipeline job and connect it to your Git repository.

Sample Jenkinsfile

Place this Jenkinsfile in your repository root:

Jenkinsfile

pipeline {
  agent any
  stages {
    stage(‘Build’) {
      steps {
        script {
          dockerImage = docker.build(‘flask-app’)
        }
      }
    }
    stage(‘Test’) {
      steps {
        sh ‘docker run –rm flask-app pytest’
      }
    }
    stage(‘Deploy’) {
      steps {
        sh ‘docker push your-dockerhub-username/flask-app:latest’
        // Add deployment commands here
      }
    }
  }
}

Step 3: Automate Building and Testing

Configure Jenkins to automatically trigger builds on code commits. Use the Dockerfile to build container images and run tests inside containers to ensure consistency.

Step 4: Deployment

Push the Docker image to a registry such as Docker Hub or a private registry. Automate deployment to your production environment using scripts or orchestration tools like Kubernetes.

Best Practices

Use environment variables to manage secrets and configurations securely.
Implement automated rollback strategies for failed deployments.
Regularly update dependencies and base images for security.
Monitor your pipeline and application performance continuously.

By following these steps, you can establish a robust CI/CD pipeline for your Flask application in 2026, ensuring rapid, reliable, and scalable deployments.

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