Using Version Control Systems for Continuous Deployment
Apr 13, 2023 by Anna Daugherty
Every developer has a story about the release that went wrong. How they deployed software at a customer location only to have it fail. How they had to roll back to a previous version and explain what went wrong to customers and managers.
Imagine what would happen if there was no definitive version to roll back to. How do you begin to reconstruct the original system if you have no verifiable source for the changes? For developers, it’s a waking nightmare unless they use version control systems (VCS) to track changes.
What Are Version Control Systems (VCS)?
Version control is a tool for tracking changes in documents, websites, or anything that may go through multiple iterations before it is released. Government documents often have a document history page that contains prior versions of the same document. The history page indicates which copy is the latest and may identify what was changed in each version.
Software development relies on version control systems to track software changes and control source code. A VCS tracks every addition, deletion, or modification, including who made the change and when it was made. This capability enables developers to work in parallel. Multiple programmers can work on the same files, and the VCS merges the changes. If conflicts occur, they are identified and resolved.
Types of VCS
The development environment may dictate the type of version control tool. Each developer may have a localized VCS, or everyone may work from a centralized repository. A distributed system with multiple repositories works in hybrid environments where programmers may not reside in an office.
Local Version Control Systems
Local systems track changes and revisions in a database on the developer’s computer. Using historical data, the system can recreate a prior version of the software. The system works well for a single programmer because it is easy to set up and use. However, merging multiple sets of localized code can be time-consuming and prone to error.
Centralized Version Control Systems
Centralized Version Control Systems allow development teams to work collaboratively. All changes are stored on a centralized server. When developers want to work on source code, they check out what they want to work on. When finished, they check in the modified code to the centralized server. This capability enabled multiple developers to work on the same software simultaneously.
Keeping source code in a single location makes it easier to administer and ensures that all developers are aware of what is being worked on. A single source for changes is also a single point for failure. If the server goes down, no one can interact with the version control system. Changes could be lost if files become corrupted unless regular backups are made.
Distributed Version Control Systems
The distributed system was designed to address the single point of failure in a centralized system. Every developer has a mirror image of the master repository on their computer. When they’re ready for changes to be part of the master database, developers push their changes to the primary repository. They pull a copy whenever they want to make added changes.
Creating clones allows programmers to work locally. If a server fails, the code can be reconstructed from the other repositories. Collaboration is more transparent. However, large repositories take up storage space, and pulls or pushes can take longer to transfer.
What is Continuous Deployment?
Continuous deployment is an automated system that releases code changes into production. When code is committed — meaning the developer believes the code is ready for release — it goes through automated testing. Once it passes testing, the code is placed into production. The end user experiences continuous improvement in the software.
This strategy removes humans from testing unproven code. The software doesn’t repeat the cycle of quality assurance testing, flaw detection, and code corrections before release. Instead, DevOps engineers oversee the implementation of best practices and thorough testing, so code can be automatically placed in production where it is monitored.
Why Use Version Control with Continuous Deployment?
Version control systems facilitate the automated practices of a continuous integration and deployment model. They enable faster deployment to correspond with agile development. The following benefits can be realized when VCS combines with continuous deployment (CD).
In a waterfall development model, all work stops prior to an upcoming release. Resources are devoted to testing and fixes. With VCS and CD, new releases are placed into production as soon as they have passed testing. The VCS tracks the changes as they are released, and CD automated testing, resulting in faster-to-market releases.
Collaboration occurs whether developers are in the office or working remotely. Transparency of VCS makes it easier for team members to see what others are doing or how they are implementing a change. This shared knowledge improves development speed and agility to address market changes.
VCS facilitates deployment by feeding committed code changes into an automated test system that releases software into production once tests are complete. Developers are more productive. There’s no test environment set up or test cases. Standardized testing happens automatically so technical staff can work on higher-value tasks.
VCS tracks software revisions. Code reviews improve programming integrity and identify flaws that can be corrected before release. If an error occurs after the code is in production, version history can help isolate the problem for quick resolution or identify the last stable release.
VCS merges code changes automatically. Conflicts that cannot be resolved are escalated for prompt correction. Automated testing of use cases makes error identification possible before deployment. Applying consistent tests ensures that all code encounters the same quality testing.
Individual changes must be validated before merging with the main line. The process ensures that team members do not accidentally submit a flawed piece of code. Consistency in the validation process ensures that each line of code receives the same scrutiny.
With a shared system, team members are aware of all activity. They can see when others are working on the same code. They can communicate with other team members to ensure that the overall design matches the requirements making for more efficient development and deployment.
Whether there are clones on multiple systems or a backup schedule for a centralized system, VCS ensures that a copy of the latest source code is always available. Work doesn’t stop if there’s a system failure, improving the speed of releases.
Combining VCS with continuous deployment requires that teams follow best practices for creating test suites. VCS is responsible for code control, but continuous deployment is responsible for code testing. Both are essential to a robust continuous deployment model.
For continuous deployment to work effectively, it needs version control systems that can generate finished code for testing. Removing the human element from the deployment or delivery process speeds up the release process. Faster deployment of working code increases customer satisfaction. Enhanced productivity means releasing more products as developers are not bogged down by testing.
Using automated tools such as VCS helps reduce the chaos that agile development can create if source code is not controlled. Incorporating automated test tools into continuous deployment improves workflows and helps deliver quality products to customers quickly. Implementing best practices ensures the process and product are helping to grow your business.
Starting with Armory
Armory makes continuous deployment possible. Our platform enables businesses to accelerate their time-to-market regardless of the scale. If you’re looking for ways to strengthen your competitive advantage, explore Armory’s continuous deployment platform today.