Anchor Example: Escrow Program

See this doc for more implementation details

Overview

Since this program is extended from the original Escrow Program, I assumed you have gone through the original blog post at least once.

However, there is one major difference between this exmaple and the original Escrow program: Instead of letting initializer create a token account to be reset to a PDA authority, we create Vault Authority(PDA)'s associated token account (ATA) directly without transferring authority.

Initialize

Initializer can send a transaction to the escrow program to initialize the Vault. In this transaction, two new accounts: Vault Authority's ATA and Escrow State, will be created and tokens (Token A) to be exchanged will be transferred from Initializer to Vault(short for vault authority's ATA).

Cancel

Initializer can also send a transaction to the escrow program to cancel the demand of escrow. The tokens will be transferred back to the Initializer and both Vault and Escrow State will be closed in this case.

Exchange

Taker can send a transaction to the escrow to exchange Token B for Token A. First, tokens (Token B) will be transferred from Taker to Initializer. Afterward, the tokens (Token A) kept in the Vault will be transferred to Taker. Finally, both Vault and Escrow State will be closed.

Install, Build, Deploy and Test

Let's run the test once to see what happens.

Install anchor

First, make sure that anchor is installed:

Install avm:

$ cargo install --git https://github.com/coral-xyz/anchor avm --locked --force
...

Install latest anchor version:

$ avm install 0.27.0
...
$ avm use 0.27.0
...

If you haven't installed cargo, please refer to this doc for installation steps.

Extra Dependencies on Linux (Optional)

You may have to install some extra dependencies on Linux (ex. Ubuntu):

$ sudo apt-get update && sudo apt-get upgrade && sudo apt-get install -y pkg-config build-essential libudev-dev
...

Verify the Installation

Check if Anchor is successfully installed:

$ anchor --version
anchor-cli 0.27.0

Install Dependencies

Next, install dependencies:

$ yarn

Build anchor-escrow

Update program_id

Get the public key of the deploy key. This keypair is generated automatically so a different key is exptected:

$ anchor keys list
anchor_escrow: Fg6PaFpoGXkYsidMpWTK6W2BeZ7FEfcYkg476zPFsLnS

Replace the default value of program_id with this new value:

# Anchor.toml

[programs.localnet]
anchor_escrow = "Fg6PaFpoGXkYsidMpWTK6W2BeZ7FEfcYkg476zPFsLnS"

...

// lib.rs

...

declare_id!("Fg6PaFpoGXkYsidMpWTK6W2BeZ7FEfcYkg476zPFsLnS");

...

Build the program:

$ anchor build

Deploy anchor-escrow

Let's deploy the program. Notice that anchor-escrow will be deployed on a mainnet-fork test validator run by Dappio:

$ solana config set --url localhost
...

$ anchor deploy
...

Program Id: Fg6PaFpoGXkYsidMpWTK6W2BeZ7FEfcYkg476zPFsLnS

Deploy success

Finally, run the test:

$ anchor test --skip-deploy --skip-build --skip-local-validator