Installation

In this section, we will gear up your workhorse for developing, deploying and, enjoying smart contracts on Cosmos SDK.

Go

You can setup golang following official documentation (opens new window). The latest versions of wasmd require go version v1.15.

Rust

Assuming you have never worked with rust, you will first need to install some tooling. The standard approach is to use rustup to maintain dependencies and handle updating multiple versions of cargo and rustc, which you will be using.

Installing Rust in Linux and Mac

First, install rustup (opens new window). Once installed, make sure you have the wasm32 target:

Copy rustup default stable cargo version # If this is lower than 1.47.0+, update rustup update stable rustup target list --installed rustup target add wasm32-unknown-unknown

Installing Rust in Windows 10

First, download and execute rustup-init.exe from rustup.rs (opens new window) or rust-lang.org (opens new window).

If requested, manually download and install Visual C++ Build Tools 2019, from https://visualstudio.microsoft.com/visual-cpp-build-tools/ . Make sure "Windows 10 SDK" and "English language pack" are selected.

Continue running rustup-init.exe, and proceed with the installation.

Optionally:

• Download and install gvim (opens new window), and modify the Env vars to add <gvim folder> to the PATH.
• Download and install git for windows (opens new window). Modify the Env vars to add <git folder>\bin to PATH.
• Turn on Developer Mode (Settings -> Update and Security: For Developers) and enable Device Discovery, to be able to access the Windows 10 server through ssh (https://www.ctrl.blog/entry/how-to-win10-ssh-service.html#section-mssshserv-enable).

Install the wasm32 target:

Copy rustup default stable cargo version # If this is lower than 1.47.0, update rustup update stable rustup target list --installed rustup target add wasm32-unknown-unknown

For those new to rust, the stable channel comes out every 6 weeks with a stable release (as of 2020-08-03 it is 1.45.2 - we support 1.44.1+). The nightly channel is the bleeding edge and not only is it a version or two ahead (for testing), but it allows some extra unstable features, whose APIs may change. For compiling wasm, you will want to use stable. We use nightly to compile the runtime for wasmd, which needs it for the singlepass compiler with gas metering and more.

wasmd

wasmd is the backbone of CosmWasm platform. It is the implementation of a Cosmoszone with wasm smart contracts enabled.

This code was forked from the cosmos/gaia repository as a basis and then added x/wasm and cleaned up many gaia-specific files. However, the wasmd binary should function just like gaiad except for the addition of the x/wasm module.

If you intend to develop or edit a contract, you need wasmd.

Copy git clone https://github.com/CosmWasm/wasmd.git cd wasmd # replace the v0.14.0 with the most stable version on https://github.com/CosmWasm/wasmd/releases git checkout v0.14.1 make install # verify the installation wasmd version

If you have any problems here, check your PATH. make install will copy wasmd to $HOME/go/bin by default, please make sure that is set up in your PATH as well, which should be the case in general for building Go code from source.

Using Testnets

Testing network Musselnet (opens new window) is launched to save you of the hassle of running a local network and speed up your development.

Use go 1.15 for compiling wasmd executable

Copy # clone wasmd repo git clone https://github.com/CosmWasm/wasmd.git && cd wasmd # wasmd runs on wasmd v0.14.1 git checkout v0.14.1 # build wasmd executable make install

Further Information on the Cosmos SDK

These represent an instance of a blockchain that utilizes all of the stable features of the Cosmos SDK (opens new window). As such, wasmd have all the same features (plus WASM smart contracts obviously). If you'd like to learn more about accessing those features take a look at the Gaia docs (opens new window). If you'd like to learn more about getting started with the Cosmos SDK in general, take a look at the series of Tutorials (opens new window) that show how to build custom modules for application-specific blockchains.

Setting up your IDE

We will need a good editor to guide us through the experience. We highly recommend plugins that help you learn syntax, especially when just starting rust. There are two free editor environments we recommend, choose the one that is more familiar to you.

If you use VSCode (Download link (opens new window)) you just need to add the rust plugin. This is the best supported environment for RLS (Rust Language Server) and uses the rust compiler to type-check all your code on save. This gives the same error messages as the actual compiler would and highlights along the line of the code, but it can be a bit slow to respond sometime (as it runs the compiler). It is quite good, and if you are used to VSCode, I highly recommend it:

RLS for VSCode (opens new window)

The other option I can recommend it Intellij IDEA Community Edition (Download link (opens new window)), along with the Rust Plugin. This has very nice and quick support for many language features directly inline. In particular, it shows the inferred types along variables, which can be very helpful, especially when working with (nested) generics. It catches most syntax errors very quickly, but not all of them. Which means sometimes you have to look at the compile failures to find the errors. If you are coming from another Intellij product (eg. Goland), I recommend this approach:

RUST for Intellij (opens new window)

There are many more editors out there and some have varying degrees of rust support, at least syntax highlighting, but I would recommend trying one of the two above, especially if you are new to rust. Once you are confident in the language, you can always use another editor and customize it to your liking.