Configure dotenv

.env.example

@@ -0,0 +1,3 @@
+STYLUS_PROGRAM_ADDRESS=<the onchain address of your deployed program>
+PRIV_KEY_PATH=<the file path for your priv key to transact with>
+RPC_URL=https://stylus-testnet.arbitrum.io/rpc

.gitignore

@@ -1 +1,2 @@
 /target
+.env

Cargo.toml

@@ -14,6 +14,7 @@ alloy-sol-types = "0.3.1"
 stylus-sdk = "0.3.0"
 hex = "0.4.3"
 wee_alloc = "0.4.5"
+dotenv = "0.15.0"
 
 [dev-dependencies]
 tokio = { version = "1.12.0", features = ["full"] } 

README.md

@@ -168,8 +168,12 @@ let num = counter.number().call().await;
 println!("New counter number value = {:?}", num);
 ```
 
-To run it, set the following env vars or place them in a `.env` file this project, then:
+To run it, set your env vars or in a `.env` file:
+```bash
+cp .env.example .env
+```
 
+Now update `.env`:
 ```
 STYLUS_PROGRAM_ADDRESS=<the onchain address of your deployed program>
 PRIV_KEY_PATH=<the file path for your priv key to transact with>

examples/counter.rs

@@ -3,6 +3,7 @@
 //! Then, it attempts to check the current counter value, increment it via a tx,
 //! and check the value again. The deployed program is fully written in Rust and compiled to WASM
 //! but with Stylus, it is accessible just as a normal Solidity smart contract is via an ABI.
+use dotenv::dotenv;
 use ethers::{
     middleware::SignerMiddleware,
     prelude::abigen,
@@ -24,7 +25,10 @@ const ENV_PROGRAM_ADDRESS: &str = "STYLUS_PROGRAM_ADDRESS";
 
 #[tokio::main]
 async fn main() -> eyre::Result<()> {
-    let priv_key_path = std::env::var(ENV_PRIV_KEY_PATH)
+    // Read env vars from .env file
+    dotenv().ok();
+
+    let priv_key_path = std::eanv::var(ENV_PRIV_KEY_PATH)
         .map_err(|_| eyre!("No {} env var set", ENV_PRIV_KEY_PATH))?;
     let rpc_url =
         std::env::var(ENV_RPC_URL).map_err(|_| eyre!("No {} env var set", ENV_RPC_URL))?;