> A pointer to something held in an immutable log will never become invalid or otherwise point to garbage data in the future.
Now I'm wondering if we can have immutable versioned APIs
Now I'm wondering if we can have immutable versioned APIs
Know how they have this tool Terraform that "orchestrates infrastructure" ? It's actually a configuration management tool for APIs; it expects the state to unexpectedly change under it, and it will attempt to "fix" it (in some cases). Because the APIs don't support immutable versioned calls, the result can (and does) randomly fail or result in different outcomes each time you run Terraform. There's really no way to know if a call will succeed until you call it, leading to regular situations where production is half-deployed, half-broken, until someone can manually fix it. Not only that, but multiple people can apply conflicting changes to different components one after the other, leading to an untested and possibly broken result. (Terraform makes an attempt to track its own changes in a state file, but the state file is not the same as the actual state of AWS, so often the state file actually prevents Terraform from fixing conflicts)
The only way to avoid that whole mess of constantly-mutating unreliable changes is for the APIs to support immutable operations, so that all changes necessary can be applied at once, and you can safely revert to previous tested state if necessary.
Semi-relatedly, Stripe has a great post[0] on how they handle backwards-compatibility with their API.