ic-wasm

A library for transforming Wasm canisters running on the Internet Computer

Executable

To install the ic-wasm executable, run

$ cargo install ic-wasm

Metadata

Manage metadata in the Wasm module.

Usage: ic-wasm <input.wasm> [-o <output.wasm>] metadata [name] [-d <text content> | -f <file content>] [-v <public|private>]

• List current metadata sections

$ ic-wasm input.wasm metadata

• List a specific metadata content

$ ic-wasm input.wasm metadata candid:service

• Add/overwrite a private metadata section

$ ic-wasm input.wasm -o output.wasm metadata new_section -d "hello, world"

• Add/overwrite a public metadata section from file

$ ic-wasm input.wasm -o output.wasm metadata candid:service -f service.did -v public

Info

Print information about the Wasm canister

Usage: ic-wasm <input.wasm> info

Shrink

Remove unused functions and debug info

Usage: ic-wasm <input.wasm> -o <output.wasm> shrink

Resource

Limit resource usage, mainly used by Motoko Playground

Usage: ic-wasm <input.wasm> -o <output.wasm> resource --remove_cycles_transfer --limit_stable_memory_page 1024

Instrument (experimental)

Instrument canister method to emit execution trace to stable memory.

Usage: ic-wasm <input.wasm> -o <output.wasm> instrument

Current limitations:

• Logs are stored in the first few pages of stable memory (up to 32 pages). This may break:
  • break upgrade
  • break manual access to stable memory
  • canister_init in Motoko cannot be profiled, because it uses stable_size to decide if there are stable vars to decode
• If heartbeat is present, it's hard to measure any other method calls. It's also hard to measure a specific heartbeat event.
• We only store the first 2M of profiling data.
• We cannot measure query calls.
• No concurrent calls

Library

To use ic-wasm as a library, add this to your Cargo.toml:

[dependencies.ic-wasm]
default-features = false

Contribution

See our CONTRIBUTING to get started.