How to derive storage keys in rust-sdk?

Rust SDK
1

I need to set initial values for storage at deployment time using the rust sdk.

How can I derive the key for a specific storage slot?

2

Hey @svimes you can the key for a specific storage slot inside your Sway project under the directory out/debug/my-contract-storage_slots.json after you have built your project.

For example

  1. After writing my contract with some initial storage
contract;

storage {
    secret_number: u64 = 777
}

abi MyContract {
    fn test_function() -> bool;
}

impl MyContract for Contract {
    fn test_function() -> bool {
        true
    }
}
  1. Build contract in terminal

forc build

  1. Inside out/debug/my-contract-storage_slots.json you can see something like
[
  {
    "key": "f383b0ce51358be57daa3b725fe44acdb2d880604e367199080b4379c41bb6ed",
    "value": "0000000000000309000000000000000000000000000000000000000000000000"
  }
]

Hope this helps! :slight_smile:

3

Thanks, I was aware of the storage_slots.json.

Unfortunately, I was looking for a way to do it programmatically.

With multiple variables sometimes spanning over multiple slots, doing this manually is messy, it also isn’t the most sustainable.

4

This is currently being worked on here Storage name based slots and namespaces. by esdrubal · Pull Request #6064 · FuelLabs/sway · GitHub. After it is merged and released we can plan on having a helper in the sdk.

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