WASM vs. Docker Containers: A Comparison with Examples

WebAssembly (WASM) and Docker containers are two powerful technologies that have gained significant traction in the software development and deployment world. Both offer unique advantages, but they serve different purposes and have different use cases. This comparison will explore the key differences between WASM and Docker containers, providing examples to illustrate when and why you might choose one over the other.

What is WebAssembly (WASM)?

WebAssembly, or WASM, is a binary instruction format designed for safe and fast execution of code on web browsers. Initially developed to run code in a web environment, WASM has evolved to support server-side applications as well. It allows developers to write code in languages like Rust, C, and C++, which can then be compiled into WebAssembly bytecode and executed in any environment that supports WASM.

Deep Dive into WebAssembly (WASM)

WebAssembly (WASM) is a relatively new technology that enables developers to run code written in multiple languages (such as C, C++, Rust, and others) on the web with near-native performance. Initially created for client-side applications, WASM is now expanding its reach into server-side applications, edge computing, and even IoT devices.

How WASM Works

WASM code is compiled into a binary format that is executed in a secure, sandboxed environment within the web browser or other runtime environments. The binary nature of WASM ensures that it runs much faster than traditional JavaScript, making it ideal for performance-critical tasks. Since WASM is platform-independent, it can be executed on any device that supports the WebAssembly runtime, providing a high degree of portability.

Expanded Use Cases for WASM

Web-Based Games:

• Scenario: A game developer is creating a complex 3D game that needs to run smoothly in a web browser.
• Why WASM? WASM enables the developer to leverage existing C++ game engines and compile them to WebAssembly, allowing the game to run in the browser with high performance, near-native graphics, and minimal latency.

Data-Intensive Web Applications:

• Scenario: A financial services company needs to build a web-based application that performs real-time data analysis and visualization.
• Why WASM? By using WASM, the company can implement complex algorithms in Rust or C++ and run them directly in the browser, ensuring fast data processing without relying on server-side computations.

Edge Computing:

• Scenario: An IoT solution provider wants to deploy small, resource-constrained devices that can process data at the edge, such as in smart sensors.
• Why WASM? WASM's lightweight nature allows it to be used in edge devices where resources are limited. It provides the ability to run small, efficient code snippets that can process data locally, reducing latency and the need for constant communication with centralized servers.

How to create the simplest wasm file and the command you can run it with?

Creating a WebAssembly (WASM) file from a simple C program and running it is a straightforward process. Below are the steps to create the simplest WASM file and the commands needed to run it.

1. Install the Required Tools

First, you need to have the WebAssembly toolchain installed on your system. We'll use the following tools:

- Emscripten SDK (emcc): A complete compiler toolchain for WebAssembly.

To install Emscripten, you can follow these steps:

Clone the emsdk repository

git clone https://github.com/emscripten-core/emsdk.git

Navigate to the directory

cd emsdk

Fetch the latest version of the Emscripten SDK

./emsdk install latest

Activate the latest version

./emsdk activate latest

Set up the environment variables

source ./emsdk_env.sh

2. Write a Simple C Program

Create a simple C file that you want to compile into WebAssembly. For this example, let's create a file named `hello.c`:

#include <stdio.h>
int main() {
    printf("Hello, WebAssembly!\n");
    return 0;
}

3. Compile the C Program to WebAssembly

Use the `emcc` command to compile the C program into a WebAssembly file.

emcc hello.c -o hello.html

This command generates the following files:

- `hello.html`: A basic HTML file that includes the necessary JavaScript to run the WebAssembly module in a browser.

- `hello.js`: A JavaScript file that acts as a wrapper to load and execute the WebAssembly.

- `hello.wasm`: The actual WebAssembly binary file.

4. Run the WebAssembly File

You can run the generated WebAssembly file in any modern web browser. Simply open the `hello.html` file:

Start a simple HTTP server in the directory

python3 -m http.server

Now, open your browser and go to http://localhost:8000/hello.html

When you open the `hello.html` file in your browser, you should see "Hello, WebAssembly!" printed on the page.

Alternative: Running WASM with Node.js

If you want to run WebAssembly without a browser, you can use Node.js. First, you'll need to install `node` if you haven't already. To run the WebAssembly module with Node.js, you would typically write a simple JavaScript loader. Here's how you can do it:

const fs = require('fs');
const wasmBuffer = fs.readFileSync('./hello.wasm');
WebAssembly.instantiate(wasmBuffer).then(wasmModule => {
  const main = wasmModule.instance.exports.main;
  main();  // This will run the main function from the WebAssembly module
});

Run this script with Node.js:

node run_wasm.js

This will execute the `main` function from your WASM file, similar to how it runs in a browser.

Now let's take a quick view at Docker Containers

Docker containers are lightweight, portable, and isolated environments that allow developers to package applications and their dependencies together. Docker ensures that an application runs consistently regardless of where it is deployed, whether on a developer's laptop, a test environment, or in production. Docker containers are based on OS-level virtualization, providing isolation and resource management.

Deep Dive into Docker Containers

Docker containers have revolutionized the way applications are deployed and managed, providing a consistent environment for running applications regardless of the underlying infrastructure. Docker packages everything the application needs—including the code, runtime, libraries, and dependencies—into a single container, which can then be run on any system with Docker installed.

How Docker Works

Docker uses containerization to isolate applications from the underlying system, ensuring that they run consistently across different environments, such as development, testing, and production. Each container operates as an independent unit, allowing for easy scaling, updating, and management of applications.

Expanded Use Cases for Docker Containers

Microservices Architecture:

• Scenario: A tech company is building a large-scale application using a microservices architecture, where each service (e.g., user authentication, payment processing) is developed and deployed independently.
• Why Docker? Docker allows the company to package each microservice into its own container, ensuring that it can be developed, tested, and deployed independently. Docker Compose can be used to orchestrate and manage the different services, making it easier to scale and maintain the application.

CI/CD Pipelines:

• Scenario: A software development team wants to automate their deployment pipeline, from code integration to testing and production deployment.
• Why Docker? Docker containers provide a consistent environment for running tests, building applications, and deploying them to production. By using Docker in a CI/CD pipeline, the team can ensure that the application behaves the same in all stages of the pipeline, reducing the risk of deployment failures.

Multi-Cloud Deployments:

• Scenario: An enterprise needs to deploy its application across multiple cloud providers to ensure redundancy and availability.
• Docker containers can be easily deployed across different cloud environments, such as AWS, Azure, and Google Cloud, without requiring changes to the application. This flexibility allows the enterprise to achieve a multi-cloud strategy while minimizing infrastructure complexity.

Key Differences Between WASM and Docker Containers

1. Purpose and Use Case

- WASM: Primarily designed for running code securely and efficiently in web browsers, WASM is now extending into server-side applications, particularly for scenarios that require low overhead and fast startup times.

- Docker Containers: Docker is designed to containerize full applications, including their operating systems, libraries, and dependencies, making it ideal for deploying and managing microservices, complex applications, and consistent environments across different platforms.

2. Resource Overhead

- WASM: WASM modules are extremely lightweight, with minimal overhead. They are executed in a sandboxed environment, which makes them secure and fast. WASM is ideal for applications where performance is critical and resources are constrained.

- Docker Containers: While Docker containers are also lightweight compared to traditional virtual machines, they still include an entire runtime environment, which can add some overhead compared to WASM. However, Docker’s overhead is relatively small compared to full virtual machines.

3. Startup Time

- WASM: WASM modules can start almost instantaneously, making them suitable for real-time or near-real-time applications. This is because WASM does not require the initialization of a full operating system or runtime.

- Docker Containers: Docker containers are faster to start than traditional VMs but slower than WASM. Containers need to boot up their environment, which can take a few seconds depending on the complexity of the application.

4. Isolation

- WASM: WASM provides sandboxing at the application level, which ensures security by preventing the code from accessing the host system directly. However, the level of isolation is less comprehensive compared to Docker containers.

- Docker Containers: Docker provides stronger isolation by encapsulating the entire application and its dependencies in a container. This includes file system isolation, network isolation, and resource limits, making Docker more suitable for multi-tenant environments.

5. Portability

- WASM: WASM is highly portable, allowing code to run on any platform that supports WebAssembly, without needing modifications. This makes WASM ideal for cross-platform web applications.

- Docker Containers: Docker containers are also portable, but they require Docker runtime to be installed on the host machine. They can run on any system that supports Docker, but they carry more dependencies than WASM.

6. Security:

• WASM: WASM’s security model is built around strict sandboxing, ensuring that the code cannot access the host system directly. This makes it ideal for running untrusted code, particularly in web applications.
• Docker: Docker provides a strong level of isolation, but since containers share the host OS kernel, they are not as isolated as virtual machines. However, Docker’s security can be enhanced through best practices like using minimal base images and following the principle of least privilege.

7. Performance:

• WASM: WASM is optimized for performance, with a focus on running compute-intensive tasks in the browser at near-native speed. Its binary format and low overhead make it ideal for scenarios where speed is critical.
• Docker: Docker containers are faster to start and run compared to traditional virtual machines, but they carry more overhead than WASM due to the inclusion of an operating system layer. Docker is optimized for running full applications rather than individual compute tasks.

8. Scalability:

• WASM: While WASM is lightweight and can scale quickly, it is not designed for managing complex multi-service architectures. It is better suited for specific tasks within larger applications.
• Docker: Docker excels in scenarios where scalability is needed, particularly in microservices architectures. Docker Swarm, Kubernetes, and other orchestration tools make it easy to scale containers up and down based on demand.

Let's check some examples

1. Example Use Case for WASM

- Scenario: You’re building a high-performance web application that requires running complex algorithms in the browser. You choose to write the algorithm in Rust, compile it to WASM, and execute it in the user's browser.

- Why WASM? The algorithm executes at near-native speed, with minimal startup time, providing a smooth and responsive user experience. WASM's lightweight nature ensures that the application remains fast even on low-powered devices.

2. Example Use Case for Docker Containers

- Scenario: You’re developing a microservices-based application that needs to run in various environments, from development to production. Each microservice has its own dependencies and requires isolated environments.

- Why Docker? Docker containers allow you to package each microservice with all its dependencies, ensuring consistency across environments. You can deploy the entire application stack, including databases, API servers, and front-end services, using Docker Compose.

When to Use WASM vs. Docker Containers

- Use WASM when:

- You need to execute code in a web browser with near-native performance.

- You require minimal resource overhead and fast startup times.

- You’re building cross-platform web applications that need to run consistently across different environments.

- Use Docker Containers when:

- You’re deploying full-fledged applications or microservices that need isolation and consistency across different environments.

- You need to manage complex application stacks with multiple services and dependencies.

- You want to ensure that your application behaves the same way in development, testing, and production.

Example Scenarios: When to Use WASM vs. Docker

WASM for Web-Based Image Editing:

• Scenario: You are building a web-based image editor that applies complex filters and transformations directly in the browser.
• Why WASM? WASM allows you to write the image processing logic in a high-performance language like C++ and run it in the browser with minimal latency, providing a seamless user experience.

Docker for E-Commerce Platform:

• Scenario: You are developing an e-commerce platform with multiple services, such as a product catalog, shopping cart, payment gateway, and user authentication.
• Why Docker? Docker enables you to package each service into a separate container, ensuring that they can be deployed, scaled, and updated independently. This makes it easier to manage the complexity of the platform and maintain high availability.

WASM and Docker containers serve different purposes but can complement each other in modern development workflows. WASM excels in scenarios requiring lightweight, fast-executing code, especially in web environments, while Docker is ideal for managing and deploying complete applications in isolated environments. Understanding the strengths and use cases of each can help you choose the right tool for your specific needs.