I am trying to generate random numbers with a canister implemented with rust but when I try to import (use rand::Rng) I get an error (subject). How can I import/use a non IC rust library within a rust canister? ------ sample code below use rand::Rng; #[ic_cdk_macros::query] fn getRandom() → Str…

I changed to ‘update’ but I get the same error (below) Compiling rust_hello v0.1.0 (/home/ildefons/rstest/rust_hello/src/rust_hello) error[E0433]: failed to resolve: could not find CanisterId in ic_cdk → src/rust_hello/src/lib.rs:55:39 | 55 | let management_canister = ic_cdk::CanisterId::from(…

I solved the previous error but I get a new one. Specifically, the call “ic_cdk::call” says that "the trait for<'a> ArgumentDecoder<'a> is not implemented for std::vec::Vec<u8>" Any idea what I can be doing wrong? #[ic_cdk_macros::update] pub async fn subnet_raw_rand() -> Result<Vec<u8>, String> …

[image] ildefons: let rnd_buffer: Vec<u8> = match ic_cdk::call(management_canister, "raw_rand", ()).await { let (rnd_buffer,): (Vec<u8>,) = match ic_cdk::call(management_canister, "raw_rand", ()).await {

It fixes the error But now I get the following candid syntax error: "subnet_raw_rand": () -> (Result<Vec<u8>, String>); ^ Unknown token < The " ^" symbol is below the first “<” symbol How should I declare a candid interface for this update meth…

Something like: service { subnet_raw_rand : () -> (opt variant { ok : vec nat8; error : text }); } [image] ildefons: is there a guide I can follow? See https://sdk.dfinity.org/docs/candid-guide/candid-concepts.html and Smart Contracts on the Internet Computer

It now compiles and deploys correctly, but I get a “FIX ME!” execution error (below). Could it be related to the candid interface? Maybe should I call the update method in a different way? --------Execution error: ildefons@ildefons-VirtualBox:~/rstest/rust_hello$ dfx canister call rust_hello subne…

Maybe @chenyan knows but it might be due to a type mismatch.

It looks like there are 2 threads going about the same issue. [image] Rust Wasm __getrandom_custom Developers It’s confusing, but the return type of the call here is a tuple. Try this: let rnd_buffer: (Vec<u8>,) =

Rust result type uses capitalized tags, so the candid interface is service : { subnet_raw_rand : () -> (opt variant { Ok : vec nat8; Err : text }); }

[image] chenyan: } It works now. Thank you everyone for your help!

error[E0432]: unresolved import `rand`

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paulyoung April 18, 2022, 3:45pm 17

It looks like there are 2 threads going about the same issue.

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error[E0432]: unresolved import `rand`

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