Directory structure

After creating a new project using Odra and running the tests, you will be presented with the following files and directories:

.
├── Cargo.lock
├── Cargo.toml
├── CHANGELOG.md
├── Odra.toml
├── README.md
├── build.rs
├── rust-toolchain
├── src/
│   ├── flipper.rs
│   └── lib.rs
├── bin/
|   |── build_contract.rs
|   |── build_schema.rs
|   └── cli.rs
├── target/
└── wasm/

note

wasm/ only appears once you have produced wasm files - that is, after cargo odra build or cargo odra test -b casper. A plain cargo odra test runs on OdraVM and creates no wasm/ folder.

Cargo.toml

Let's first take a look at Cargo.toml file:

[package]
name = "sample"
version = "0.1.0"
edition = "2021"

[dependencies]
odra = { version = "2.9.0", features = [], default-features = false }

[dev-dependencies]
odra-test = { version = "2.9.0", features = [], default-features = false }

[build-dependencies]
odra-build = { version = "2.9.0", features = [], default-features = false }

[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
odra-build = { version = "2.9.0", features = [], default-features = false }
odra-cli = { version = "2.9.0", features = [], default-features = false }

[[bin]]
name = "sample_build_contract"
path = "bin/build_contract.rs"
test = false

[[bin]]
name = "sample_build_schema"
path = "bin/build_schema.rs"
test = false

[[bin]]
name = "sample_cli"
path = "bin/cli.rs"
test = false

[profile.release]
codegen-units = 1
lto = true

[profile.dev.package."*"]
opt-level = 3

By default, your project will use the latest odra version available at crates.io. For testing purposes, odra-test is also added as a dev dependency. The cfg(not(target_arch = "wasm32")) section holds the dependencies that are only needed off-chain - the build helpers and the Odra CLI - so they are not compiled into your wasm.

Odra.toml

This is the file that holds information about contracts that will be generated when running cargo odra build and cargo odra test:

[[contracts]]
fqn = "flipper::Flipper"

As we can see, we have a single contract. Its fqn (Fully Qualified Name) is the Rust path to the contract module - here the Flipper struct in the flipper module, which lives in src/flipper.rs. More contracts can be added here by hand, or by using cargo odra generate command.

src/

This is the folder where your smart contract files live.

build.rs

A small build script that Odra uses to set up code generation. You don't need to touch it.

bin/

This is the folder where scripts that will be used to generate code or schemas live. build_contract.rs and build_schema.rs are generated by cargo odra new and are used by cargo odra build, cargo odra test and cargo odra schema - you don't need to modify those. cli.rs is different: it is a starting point for your own deployment and interaction commands, and it is meant to be edited. See Odra CLI.

target/

Files generated by cargo during the build process are put here.

wasm/

WASM files generated by cargo odra build and cargo odra test are put here. You can grab those WASM files and deploy them on the blockchain.

What's next

Now, let's take a look at one of the files mentioned above in more detail, namely the Odra.toml file.