# Ic-cdk wasi feature

**URL:** <https://forum.dfinity.org/t/ic-cdk-wasi-feature/21796>\
**Category:** Developers\
**Created:** [July 28, 2023, 9:33pm UTC](https://forum.dfinity.org/t/ic-cdk-wasi-feature/21796 "2023-07-28T21:33:24Z")\
**Posts on this page:** 8\
**Page:** 1

<div class="post-metadata">

**Author:** ![lastmjs](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/lastmjs/32/3406_2.png) [@lastmjs](https://forum.dfinity.org/u/lastmjs)\
**Post date:** [July 28, 2023, 9:33pm UTC](https://forum.dfinity.org/t/ic-cdk-wasi-feature/21796/1 "2023-07-28T21:33:24Z")

</div>

How does the new Wasi feature work for `ic-cdk`? I don’t really see any documentation. I’m trying to get Azle updated to wasi, which is a prerequisite to swapping out the current engine for QuickJS. I’d also like to take advantage of the new Candid generation capabilities.

So far I’m getting a bunch of weird errors with `ic-cdk` 0.10.0 when I turn on the wasi feature. Do I need to use the ic-wasi-polyfill? Do I need to use wasi2ic?

Errors:

```bash
error: duplicate init method
     --> src/src/lib.rs:13438:4
      |
13438 | fn init() {
      | ^^^^

error: duplicate method name getRandomnessDirectly
     --> src/src/lib.rs:13515:10
      |
13515 | async fn _cdk_user_defined_getRandomnessDirectly() -> (ic_cdk::api::call::ManualReply<
      | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: duplicate method name getRandomnessIndirectly
     --> src/src/lib.rs:13567:10
      |
13567 | async fn _cdk_user_defined_getRandomnessIndirectly() -> (ic_cdk::api::call::ManualReply<
      | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: duplicate method name getRandomnessSuperIndirectly
     --> src/src/lib.rs:13619:10
      |
13619 | async fn _cdk_user_defined_getRandomnessSuperIndirectly() -> (ic_cdk::api::call::ManualReply<
      | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: duplicate method name returnPromiseVoid
     --> src/src/lib.rs:13671:10
      |
13671 | async fn _cdk_user_defined_returnPromiseVoid() -> (ic_cdk::api::call::ManualReply<()>) {
      | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error[E0425]: cannot find function `init` in this scope
     --> src/src/lib.rs:13438:4
      |
13438 | fn init() {
      | ^^^^ not found in this scope

error[E0425]: cannot find function `_cdk_user_defined_getRandomnessDirectly` in this scope
     --> src/src/lib.rs:13515:10
      |
13513 | #[ic_cdk_macros::update(name = "getRandomnessDirectly", manual_reply = true)]
      | ----------------------------------------------------------------------------- similarly named function `_cdk_user_defined_getRandomnessDirectly_3_` defined here
13514 | #[candid::candid_method(update, rename = "getRandomnessDirectly")]
13515 | async fn _cdk_user_defined_getRandomnessDirectly() -> (ic_cdk::api::call::ManualReply<
      | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: a function with a similar name exists: `_cdk_user_defined_getRandomnessDirectly_3_`

error[E0425]: cannot find function `_cdk_user_defined_getRandomnessIndirectly` in this scope
     --> src/src/lib.rs:13567:10
      |
13565 | #[ic_cdk_macros::update(name = "getRandomnessIndirectly", manual_reply = true)]
      | ------------------------------------------------------------------------------- similarly named function `_cdk_user_defined_getRandomnessIndirectly_4_` defined here
13566 | #[candid::candid_method(update, rename = "getRandomnessIndirectly")]
13567 | async fn _cdk_user_defined_getRandomnessIndirectly() -> (ic_cdk::api::call::ManualReply<
      | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: a function with a similar name exists: `_cdk_user_defined_getRandomnessIndirectly_4_`

error[E0425]: cannot find function `_cdk_user_defined_getRandomnessSuperIndirectly` in this scope
     --> src/src/lib.rs:13619:10
      |
13617 | #[ic_cdk_macros::update(name = "getRandomnessSuperIndirectly", manual_reply = true)]
      | ------------------------------------------------------------------------------------ similarly named function `_cdk_user_defined_getRandomnessSuperIndirectly_5_` defined here
13618 | #[candid::candid_method(update, rename = "getRandomnessSuperIndirectly")]
13619 | async fn _cdk_user_defined_getRandomnessSuperIndirectly() -> (ic_cdk::api::call::ManualReply<
      | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: a function with a similar name exists: `_cdk_user_defined_getRandomnessSuperIndirectly_5_`

error[E0425]: cannot find function `_cdk_user_defined_returnPromiseVoid` in this scope
     --> src/src/lib.rs:13671:10
      |
13669 | #[ic_cdk_macros::update(name = "returnPromiseVoid", manual_reply = true)]
      | ------------------------------------------------------------------------- similarly named function `_cdk_user_defined_returnPromiseVoid_6_` defined here
13670 | #[candid::candid_method(update, rename = "returnPromiseVoid")]
13671 | async fn _cdk_user_defined_returnPromiseVoid() -> (ic_cdk::api::call::ManualReply<()>) {
      | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: a function with a similar name exists: `_cdk_user_defined_returnPromiseVoid_6_`

```

---

<div class="post-metadata">

**Author:** ![lastmjs](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/lastmjs/32/3406_2.png) [@lastmjs](https://forum.dfinity.org/u/lastmjs)\
**Post date:** [July 28, 2023, 9:44pm UTC](https://forum.dfinity.org/t/ic-cdk-wasi-feature/21796/2 "2023-07-28T21:44:21Z")

</div>

So I’ve overcome the above errors, I had to remove all instances of `candid::candid_method` that I was using to help with Candid generation.

---

<div class="post-metadata">

**Author:** ![lastmjs](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/lastmjs/32/3406_2.png) [@lastmjs](https://forum.dfinity.org/u/lastmjs)\
**Post date:** [July 28, 2023, 9:44pm UTC](https://forum.dfinity.org/t/ic-cdk-wasi-feature/21796/3 "2023-07-28T21:44:57Z")

</div>

Everything compiles now but on deploy I get the following:

```auto
Error: Failed while trying to deploy canisters.
Caused by: Failed while trying to deploy canisters.
  Failed while trying to install all canisters.
    Failed to install wasm module to canister 'async_await'.
      Failed during wasm installation call: The replica returned a replica error: Replica Error: reject code CanisterError, reject message Canister bkyz2-fmaaa-aaaaa-qaaaq-cai trapped: unreachable, error code None

```

---

<div class="post-metadata">

**Author:** ![chenyan](https://avatars.discourse-cdn.com/v4/letter/c/35a633/32.png) [@chenyan](https://forum.dfinity.org/u/chenyan)\
**Post date:** [July 28, 2023, 9:46pm UTC](https://forum.dfinity.org/t/ic-cdk-wasi-feature/21796/4 "2023-07-28T21:46:00Z")

</div>

The wasi feature simply allow to generate a wasi binary that outputs the did file. To use this feature, the Rust shouldn’t have the `candid_method` attributes, you only need to add export\_service! at the end.

---

<div class="post-metadata">

**Author:** ![chenyan](https://avatars.discourse-cdn.com/v4/letter/c/35a633/32.png) [@chenyan](https://forum.dfinity.org/u/chenyan)\
**Post date:** [July 28, 2023, 9:47pm UTC](https://forum.dfinity.org/t/ic-cdk-wasi-feature/21796/5 "2023-07-28T21:47:00Z")

</div>

Right, that wasi binary cannot be deployed to the IC. It only generates the did file when you run it through wasmtime. To get the real wasm binary, you need to compile the binary without the `wasi` feature.

---

<div class="post-metadata">

**Author:** ![lastmjs](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/lastmjs/32/3406_2.png) [@lastmjs](https://forum.dfinity.org/u/lastmjs)\
**Post date:** [July 28, 2023, 9:47pm UTC](https://forum.dfinity.org/t/ic-cdk-wasi-feature/21796/6 "2023-07-28T21:47:21Z")

</div>

Oh I see, thank you.

---

<div class="post-metadata">

**Author:** ![lastmjs](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/lastmjs/32/3406_2.png) [@lastmjs](https://forum.dfinity.org/u/lastmjs)\
**Post date:** [July 28, 2023, 9:48pm UTC](https://forum.dfinity.org/t/ic-cdk-wasi-feature/21796/7 "2023-07-28T21:48:08Z")

</div>

So I have to compile the binary twice then? Have we reached the point where dfx will do all of this automatically yet?

---

<div class="post-metadata">

**Author:** ![chenyan](https://avatars.discourse-cdn.com/v4/letter/c/35a633/32.png) [@chenyan](https://forum.dfinity.org/u/chenyan)\
**Post date:** [July 28, 2023, 9:50pm UTC](https://forum.dfinity.org/t/ic-cdk-wasi-feature/21796/8 "2023-07-28T21:50:07Z")

</div>

Right. We are still working on the dfx integration, so that dfx will compile the binary twice for Rust canisters. For custom canisters, you need to include this script into your build process: [https://github.com/dfinity/cdk-rs/blob/main/examples/build.sh](https://github.com/dfinity/cdk-rs/blob/main/examples/build.sh)