I'm looking for a way to safely save the state of my program to the filesystem. My application needs to perform multiple filesystem operations, such as writing to one file and creating another. If one of these operations fails while the other succeeds, my program will end up in an inconsistent state, making recovery difficult. I want to ensure that either all operations succeed or none at all. Is there an architectural approach or a specific solution, preferably in Rust, that can help me achieve this? Is this a common problem in computer science that's hard to solve?
2 Answers
For atomic filesystem operations, explore the concept of atomic transactions. You can make use of modern Linux filesystems that support rollbacks. If you prefer a manual approach, you can collect all your operations and implement a rollback feature, but you'll need to be careful about how you handle file deletions and overwrites. An alternative is creating snapshots of files before making changes, which can be restored if something goes wrong. Just keep in mind these methods may come with some complexity and system risks, especially if power outages occur.
You can back up existing files by creating a copy with a .bak extension or use new temporary files. Once your operations succeed, swap these temporary files with the originals. However, this strategy can be a bit tricky when you have multiple files to handle, so keep that in mind.
What if the rollback fails? Is that a risk you're willing to take?