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
├── .builder_casper/
├── src/
│   ├── flipper.rs
│   └── lib.rs
├── target/
└── wasm/

Cargo.toml

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

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

[dependencies]
odra = { version = "0.3.1", default-features = false }

[features]
default = ["mock-vm"]
mock-vm = ["odra/mock-vm"]
casper = ["odra/casper"]

By default, your project will use the latest odra version available at crates.io. We are using two features:

• odra/mock-vm - it is responsible for running tests on Odra's MockVM
• odra/casper - backend implementation of Casper blockchain More backends will be released as features that will be possible to enable here.

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]]
name = "flipper"
fqn = "sample::Flipper"

As we can see, we have a single contract, its fqn (Fully Qualified Name) corresponds to the contract is located in src/flipper.rs. More contracts can be added here by hand, or by using cargo odra generate command.

.builder_* folders

Those folders will be created and managed automatically by Cargo Odra. They contain project files necessary for building wasm files and running them against blockchain VMs. As it is not necessary to modify files in those folders in any way, by default they are hidden (hence the . at the beginning of the folder name).

src/

This is the folder where your smart contract files live.

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 of your choosing.

What's next

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