Improving Developer Efficiency with the 12-Factor App Methodology: Best Practices for Modern Application Development & Deployment
Introduction
Companies rely on complex software applications to smoothen their operations and serve their customers efficiently in today’s digital and business landscape. Over the years, the need for the development and deployment of software applications has been at a high velocity with no chance of slowing down soon.
However, building and maintaining a secure, highly available, and scalable software application can be complex. That is why it must be developed with accuracy to ensure its job is well-executed.
12-Factor App Methodology
According to Wikipedia,
The Twelve-Factor App is a methodology adopted for building large-scale, software-as-a-service applications.
They are the best practices that help software developers, and DevOps engineers build applications with precision, high availability, and resilience with a seamless deployment to the web.
In this article, we will provide you with a complete breakdown of the 12-factor app principles, and how to implement them in your software development process in this highly competitive software world.
Introducing the 12-factor App Methodology
1. Codebase
One codebase tracked in revision control, many deploys
The reason is, in several development environments, different engineers usually come together to work on the same codebase.
While working, there is a lot of code sharing. Engineers tend to push their code into a centralized codebase, and if they are not careful, conflicts could arise that could break the app in production. That is why engineers adopt Git and its strategies to help them collaborate efficiently.
While developing your application, everyone installs git and pulls from the center and works on their feature branches, adds their changes, and pushes it back. The centralized hub can be GitHub, GitLab, or other code repositories that make work easier.
2. Dependencies
Explicitly declare and isolate dependencies
Whenever developers build applications, a lot of them fail to explicitly declare their dependencies, thereby leaving these dependencies to “Latest”. Whenever someone else tries to use their app with the “Latest” version, the app crashes, causing problems for both the developers and the users.
A good, reliable, and high-available software-as-a-service never relies on the implicit existence of system packages. By explicitly declaring dependencies, developers working on the codebase will not install different package versions leading to engineering conflict in a production environment.
A typical example of explicitly declaring your dependencies is the “package.json” file that exists in most Javascript applications. It ensures that there are no external dependencies that interfere with the application, and the same version applies across all environments.
3. Config
Store config in the environment
All application configurations must be stored in environmental variables to help distinguish the application across multiple environments. This works better rather than hardcoding this configuration within the code base.
By working with environment variables this way, you can easily configure your application to work without modifying the code. It helps you achieve better flexibility, and also better portability for the application.
Storing all your configurations using environment variables makes it easier to handle, and manage sensitive information. Sensitive information may include database strings, API keys, and passwords. With this, you can keep it separate from the codebase without changing the application code.
4. Backing services
Treat backing services as attached resources
Design your applications to rely on external backing services for resources that are not linked to the core functionality of the application. For example, when implementing a messaging queue, you should develop this application to connect to these messaging queue resources without affecting the behavior of the application.
The best practice here is to connect using environment variables. This will help the developer easily deploy the application without the need for manual configuration.
5. Build, release, run
Strictly separate build and run stages
The 12-factor app should use a strict separation of build, release, and run stages. This simply means that the build processes should be separated from the deployment process. At first, the application must be built using a build system like Gradle, Maven, or Make, must be consistent, and produce deployable artifacts.
The release stage means that the process should be automated, and packaged well to be deployed in different environments (dev, test, and prod). In cases like this, it is best practice to use a version control system to work on your releases.
This application should be executed in an isolated environment such as a container or virtual machine. With this in mind, it will be easier to manage the application dependencies and make your app run consistently in different environments.
6. Processes
Execute the app as one or more stateless processes
All processes that run within the application should not store any data locally, rather, they must rely on external data stores.
Applications that follow this method are designed with one or more stateless processes. This means that if data needs to persist between these instances, they should be stored in key-value or database stores using services like Redis, or Memcached.
This factor also encourages the use of external backing services such as file storage, message queue services, and email services. This will help separate activities that are not part of the main infrastructure logic from the core functionality of the application.
7. Port Binding
Export services via port binding
Applications must not rely on the injection of runtime on the web service to create a web-facing service. Instead, developers, or even DevOps should explicitly declare and bind to a port. This helps the engineers in charge of the application to start and stop the application during the dev, test, and production stages.
By binding to a port during your development process, you avoid conflicts with other applications running on the same host, especially when the application is hosted within containerized environments.
8. Concurrency
Scale out via the process model
Concurrency emphasizes the need to design and develop applications capable of handling a lot of simultaneous requests. At the infrastructure level, this methodology requests that the DevOps engineers use cloud-based infrastructure like load balancers, and auto-scalable groups that can provision, and delete resources whenever there is a change in demand. This will help handle the high-traffic surge rather than relying on a single instance to handle all the requests.
The benefit of applying this methodology is that helps to reduce the overhead costs associated with managing multiple processes. Here, you can handle multiple requests without dealing with performance bottlenecks.
9. Disposability
Maximize robustness with fast startup and graceful shutdown
Disposability in a software development lifecycle simply means that an engineer should be able to start up and shut down the application processes gracefully. This feature enables the application to be more resilient to failure and handle high traffic demands.
Just as the 6th-factor demands, the processes should be stateless, to enable scalability, and in return, disposability. All processes in the app should be able to shut down gracefully when they receive a SIGTERM signal from the process manager to avoid data loss.
10. Dev/prod parity
Keep development, staging, and production as similar as possible
This factor emphasizes the need to keep all environments (Dev & Prod) as similar as possible thereby reducing the chances of errors and bugs occurring in production.
To achieve this, you need to implement an automatic CD process to ensure that there is consistency, and less likelihood of human error, use similar hardware and software during the development, and deployment processes, and use the same dependencies across all environments.
By doing this all engineers will avoid the “It worked on my machine” problem during the production stage, reduce the risks of bugs, and produce a more reliable application.
11. Logs
Treat logs as event streams
Never underestimate the importance of logs. Here, these factors emphasize the importance of logs as event streams for proper code and error analysis. All the logs in the application should be written to the standard output of the application instead of files.
For complex analysis, you can choose centralized logging services such as ELK (Elasticsearch, Lodash, and Kibana) to search and analyze easier.
During your development processes, always keep your logs handy because they will help for troubleshoot and audit.
12. Admin Processes
Run admin/management tasks as one-off processes
Run all administrative processes and tasks separately from the main application, and execute them as one-off processes. You should not run administrative processes like database backups, migrations, log backups, and system analysis in the main application code.
Separating administrative tasks from the application code, and processes ensure that the application remains stable even when complex tasks are performed in the background. It helps to keep the application clean, and easier to manage.
Conclusion
The 12-factor app methodology offers developers, and DevOps engineers a unique guide for building modern, scalable, and highly available software applications. Following these principles, you can ensure that your applications are easy to deploy and maintainability which helps to reduce costs and deliver your application to the market faster.
Although not every application may strictly need to adhere to all the 12 factors, these guidelines are still relevant to set a solid foundation for the development of cloud-native applications. As the demand for cloud-based applications steadily increases, the 12-factor app becomes more important to meet the needs of today’s business environment.
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