If you have recently created a contract with this template, you probably could use some help on how to build and test the contract, as well as prepare it for production. This file attempts to provide a brief overview, assuming you have installed a recent version of Rust already (eg. 1.51.0+).
Before starting, make sure you have rustup along with a
recent rustc and cargo version installed. Currently, we are testing on 1.51.0+.
And you need to have the wasm32-unknown-unknown target installed as well.
You can check that via:
rustc --version
cargo --version
rustup target list --installed
# if wasm32 is not listed above, run this
rustup target add wasm32-unknown-unknownNow that you created your custom contract, make sure you can compile and run it before making any changes. Go into the repository and do:
# this will produce a wasm build in ./target/wasm32-unknown-unknown/release/YOUR_NAME_HERE.wasm
cargo wasm
# this runs unit tests with helpful backtraces
RUST_BACKTRACE=1 cargo unit-test
# auto-generate json schema
cargo schemaThe main code is in src/contract.rs and the unit tests there run in pure rust,
which makes them very quick to execute and give nice output on failures, especially
if you do RUST_BACKTRACE=1 cargo unit-test.
We consider testing critical for anything on a blockchain, and recommend to always keep the tests up to date.
While the Wasm calls (instantiate, execute, query) accept JSON, this is not enough
information to use it. We need to expose the schema for the expected messages to the
clients. You can generate this schema by calling cargo schema, which will output
4 files in ./schema, corresponding to the 3 message types the contract accepts,
as well as the internal State.
These files are in standard json-schema format, which should be usable by various client side tools, either to auto-generate codecs, or just to validate incoming json wrt. the defined schema.
Before we upload it to a chain, we need to ensure the smallest output size possible, as this will be included in the body of a transaction. We also want to have a reproducible build process, so third parties can verify that the uploaded Wasm code did indeed come from the claimed rust code.
To solve both these issues, we have produced rust-optimizer, a docker image to
produce an extremely small build output in a consistent manner. The suggest way
to run it is this:
docker run --rm -v "$(pwd)":/code \
--mount type=volume,source="$(basename "$(pwd)")_cache",target=/code/target \
--mount type=volume,source=registry_cache,target=/usr/local/cargo/registry \
cosmwasm/workspace-optimizer:0.12.11Or, If you're on an arm64 machine, you should use a docker image built with arm64.
docker run --rm -v "$(pwd)":/code \
--mount type=volume,source="$(basename "$(pwd)")_cache",target=/code/target \
--mount type=volume,source=registry_cache,target=/usr/local/cargo/registry \
cosmwasm/workspace-optimizer-arm64:0.12.11We must mount the contract code to /code. You can use a absolute path instead
of $(pwd) if you don't want to cd to the directory first. The other two
volumes are nice for speedup. Mounting /code/target in particular is useful
to avoid docker overwriting your local dev files with root permissions.
Note the /code/target cache is unique for each contract being compiled to limit
interference, while the registry cache is global.
This is rather slow compared to local compilations, especially the first compile of a given contract. The use of the two volume caches is very useful to speed up following compiles of the same contract.
This produces an artifacts directory with a PROJECT_NAME.wasm, as well as
checksums.txt, containing the Sha256 hash of the wasm file.
The wasm file is compiled deterministically (anyone else running the same
docker on the same git commit should get the identical file with the same Sha256 hash).
It is also stripped and minimized for upload to a blockchain (we will also
gzip it in the uploading process to make it even smaller).