Course Title: Functional Programming with Haskell: From Fundamentals to Advanced Concepts Section Title: Haskell Deployment and Ecosystem Topic: Package and deploy a Haskell application to a cloud environment.(Lab topic)

Introduction

In this lab, you will learn how to package a Haskell application and deploy it to a cloud environment. This process is crucial for making your application accessible to users. We will cover the necessary steps for packaging and deploying a Haskell application using tools like Stack and Cabal. We will also explore deploying the application to a cloud platform.

Step 1: Package the Haskell application

Before deploying your application to a cloud environment, you need to package it properly. You can use the Stack tool to create an executable for your application. To do this, create a stack.yaml file in the root directory of your project with the following content:

resolver: lts-16.27

packages:
- .

extra-deps:
- conduit-1.3.4
- conduit-extra-1.3.4

executables:
  my-app:
    main: Main.hs
    source-dirs: src
    dependencies:
    - conduit
    - conduit-extra

Then, navigate to your project directory and run the following command:

stack setup
stack build

This will build your application and create an executable file in the .stack-work/dist/x86_64-linux/Cabal-2.4.0.0/build/my-app/my-app directory.

Step 2: Create a Docker image

To deploy your application to a cloud environment, you can use Docker to create a container image. To do this, create a Dockerfile in the root directory of your project with the following content:

FROM haskell:8.10.7
WORKDIR /app
COPY . .
RUN stack setup
RUN stack build
COPY stack.yaml .
COPY .stack-work .
EXPOSE 8080
CMD ["stack", "exec", "my-app", "--", "yesod", " devel"]

This Dockerfile uses the official Haskell image as a base, sets up the project directory, installs dependencies using Stack, and copies the executable file.

Step 3: Push the Docker image to a container registry

To deploy your application to a cloud environment, you need to push your Docker image to a container registry. You can use Docker Hub for this purpose. First, create an account on Docker Hub and create a new repository. Then, navigate to your project directory and run the following command:

docker login
docker build -t <username>/<repository-name> .
docker push <username>/<repository-name>

Replace <username> and <repository-name> with your actual Docker Hub username and repository name.

Step 4: Deploy the Docker image to a cloud environment

Once you have pushed your Docker image to a container registry, you can deploy it to a cloud environment. You can use the docker-compose command to create a cloud-agnostic deployment configuration. To do this, create a docker-compose.yml file in the root directory of your project with the following content:

version: "3.7"

services:
  my-app:
    image: <username>/<repository-name>
    ports:
      - "8080:8080"

Replace <username> and <repository-name> with your actual Docker Hub username and repository name.

To deploy the application to a cloud platform like AWS or Google Cloud, you can use tools like AWS Elastic Container Service (ECS) or Google Kubernetes Engine (GKE). You can also use serverless deployment platforms like AWS Lambda or Google Cloud Functions.

Practical Takeaways

• Use Stack or Cabal to package your Haskell application.
• Create a Docker image using the official Haskell image as a base.
• Push the Docker image to a container registry like Docker Hub.
• Deploy the Docker image to a cloud environment using tools like docker-compose, AWS ECS, or Google Kubernetes Engine.
• Consider using serverless deployment platforms like AWS Lambda or Google Cloud Functions.

Exercise

Deploy a simple Haskell web application to a cloud environment using the steps outlined above.

Resources

• Haskell Stack Documentation
• Docker Hub
• AWS Elastic Container Service
• Google Kubernetes Engine

Conclusion

In this lab, you learned how to package and deploy a Haskell application to a cloud environment using tools like Stack, Docker, and container registries. You also learned how to deploy the application to a cloud platform using tools like docker-compose and serverless deployment platforms. With this knowledge, you can now deploy your Haskell applications to cloud environments and make them accessible to users.

Leave a comment below if you have any questions or need further clarification on any of the topics covered in this lab.