switch from .env to .toml config file instead

Author: alxiong

.env.example

@@ -36,7 +36,3 @@ __pycache__/
 # Rust bindings for smart contracts
 timeboost-contract/src/bindings
 foundry.lock
-
-# env var files that may contains secrets
-.env*
-!.env*.example

.gitignore

@@ -92,6 +92,7 @@ tokio = { version = "1", default-features = false, features = ["full"] }
 tokio-stream = "0.1.17"
 tokio-tungstenite = { version = "0.27.0", features = ["rustls-tls-webpki-roots", "url"] }
 tokio-util = "0.7.15"
+toml = "0.8"
 tonic = "0.14.1"
 tonic-prost = "0.14.1"
 tonic-prost-build = "0.14.1"

Cargo.lock

@@ -0,0 +1,3 @@
+[wallet]
+mnemonic = "test test test test test test test test test test test junk"
+index = 0

Cargo.toml

@@ -8,10 +8,11 @@ rust-version.workspace = true
 [dependencies]
 alloy = { workspace = true }
 anyhow = { workspace = true }
-dotenvy = "0.15"
 rand = { workspace = true }
 tracing = { workspace = true }
+serde = { workspace = true }
 tokio = { workspace = true }
+toml = { workspace = true }
 
 [build-dependencies]
 alloy = { workspace = true }

test-configs/keymanager.toml

@@ -8,6 +8,7 @@ use alloy::{
     transports::http::reqwest::Url,
 };
 use anyhow::Result;
+use serde::Deserialize;
 
 // Include the generated contract bindings
 // The build script auto-detects contracts and generates bindings in src/bindings/
@@ -19,14 +20,28 @@ mod sol_types;
 use provider::{HttpProviderWithWallet, TestProviderWithWallet, build_provider};
 pub use sol_types::*;
 
+/// Config type for the key manager who has the permission to update the KeyManager contract
+/// See `test-configs/keymanager.toml` for an example
+#[derive(Deserialize)]
+struct KeyManagerConfig {
+    wallet: LocalWalletConfig,
+}
+
+#[derive(Deserialize)]
+struct LocalWalletConfig {
+    mnemonic: String,
+    index: u32,
+}
+
 /// Connect to a real blockchain, deploy the KeyManager contract, set the
 /// `TIMEBOOST_KEY_MANAGER_MNEMONIC` as the manager.
 /// Returns the (wallet provider, KeyManager address).
 pub async fn init_chain(chain: Url) -> Result<(HttpProviderWithWallet, Address)> {
-    dotenvy::dotenv()?;
+    let config =
+        toml::from_str::<KeyManagerConfig>(include_str!("../../test-configs/keymanager.toml"))?;
 
-    let mnemonic = dotenvy::var("TIMEBOOST_KEY_MANAGER_MNEMONIC")?;
-    let account_idx = dotenvy::var("TIMEBOOST_KEY_ACCOUNT_INDEX")?.parse::<u32>()?;
+    let mnemonic = config.wallet.mnemonic;
+    let account_idx = config.wallet.index;
     let provider = build_provider(mnemonic, account_idx, chain);
 
     let km_addr =