fix(solver/setup): update setup & docs

bin/onlyswaps-solver/README.md

@@ -49,3 +49,39 @@ It is also possible to configure the solver with an external omnievent endpoint
 [omnievent]
 endpoint = "https://omnievent:3284"
 ```
+
+## Initial setup
+The current version of the solver relies on [Uniswap's permit2 contract](https://docs.uniswap.org/contracts/permit2/overview) for EIP-712 (i.e., gasless) token approvals for any ERC20 tokens.
+This requires a one-time setup which consists of giving an unlimited token approval to the permit2 contract for each configured tokens.
+Given that the contracts have been audited (see [here](https://github.com/Uniswap/permit2/tree/main/audits)), and have undergone public scrutiny for several years, the risk of an unlimited approval to permit2 is very low.
+
+The initial setup can be done with the following command:
+```bash
+> cargo run -p onlyswaps-solver -- --config ./path/to/my/config.toml --private-key $PRIV setup
+Loading app config from ./path/to/my/config.toml
+The following allowances are required:
+Chain      Token Address                                Permit2
+------------------------------------------------------------------------------------------
+56         0x55d398326f99059fF775485246999027B3197955   Default
+314        0x80B98d3aa09ffff255c3ba4A241111Ff1262F045   Custom (0x1Ea2dBcB20263a969A017022E8B1C1dc13BD2470)
+43114      0x1b0F6cF6f3185872a581BD2B5a738EB52CCd4d76   Default
+
+Proceed? [y/n]: y
+Sending txs...
+> [Chain 56] sending approve for 0x55d398326f99059fF775485246999027B3197955...
+> [Chain 314] sending approve for 0x80B98d3aa09ffff255c3ba4A241111Ff1262F045...
+> [Chain 43114] sending approve for 0x1b0F6cF6f3185872a581BD2B5a738EB52CCd4d76...
+> [Chain 56] approval for 0x55d398326f99059fF775485246999027B3197955 sent successfully
+> [Chain 43114] approval for 0x1b0F6cF6f3185872a581BD2B5a738EB52CCd4d76 sent successfully
+> [Chain 314] approval for 0x80B98d3aa09ffff255c3ba4A241111Ff1262F045 sent successfully
+
+Transaction results:
+Chain      Token Address                                Result
+------------------------------------------------------------------------------------------
+56         0x55d398326f99059fF775485246999027B3197955   mined in 0xc1fc22d51f3130574da2c2501ed10aca986ab5e3a388b9f9d57717d630374d1c
+314        0x80B98d3aa09ffff255c3ba4A241111Ff1262F045   mined in 0xf2f206ed3439b80a43c08bfd042da99596f689cdc155243bea187e47f5cbeb5f
+43114      0x1b0F6cF6f3185872a581BD2B5a738EB52CCd4d76   mined in 0x4044eadc976bdd4546649e41e573eca30786593969b1ca4582d713892a1e4134
+```
+
+After executing the command, the binary first checks which chain / token pairs require an approval, and ask for confirmation.
+Upon acceptance, a transaction per chain / token pair is sent, and the result is displayed.

bin/onlyswaps-solver/src/setup.rs

@@ -1,8 +1,9 @@
 use crate::network::Network;
 use alloy::primitives::{Address, U160, U256, address};
-use alloy::providers::{DynProvider, Provider};
+use alloy::providers::{DynProvider, Provider, ProviderBuilder};
 use anyhow::Context;
 use futures::TryFutureExt;
+use generated::onlyswaps::ierc20::IERC20::IERC20Instance;
 use onlyswaps_client::client::OnlySwapsClient;
 use std::collections::HashMap;
 use std::io::{Write, stdin};
@@ -25,11 +26,21 @@ pub async fn setup_allowances(
             .get(&chain_id)
             .context("tried setting allowance for unknown chain??")?;
 
+        // all tokens on a network share the same provider
+        let Some(provider) = net.tokens.first().map(|t| t.provider()) else {
+            continue;
+        };
+        let provider = ProviderBuilder::new()
+            .disable_recommended_fillers()
+            .with_cached_nonce_management() // ensure the provider uses a cached nonce for concurrency
+            .connect_provider(provider);
+
         for (amount, token) in details
             .current_allowances
             .into_iter()
             .zip(net.tokens.iter())
         {
+            let token_address = *token.address();
             if amount > U256::from(U160::MAX) {
                 // we consider anything up to 2**160 a max allowance
                 continue;
@@ -43,9 +54,14 @@ pub async fn setup_allowances(
 
             println!(
                 "{chain_id:<10} {:<44} {permit2_display}",
-                token.address().to_string(),
+                token_address.to_string(),
             );
-            calls.push((chain_id, token, details.permit2_address));
+            calls.push((
+                chain_id,
+                IERC20Instance::new(token_address, provider.clone()),
+                details.permit2_address,
+                net.own_addr,
+            ));
         }
     }
 
@@ -65,12 +81,13 @@ pub async fn setup_allowances(
 
     println!("Sending txs...");
     let results = futures::future::join_all(calls.into_iter().map(
-        async move |(chain_id, token, permit2_address)| {
+        async move |(chain_id, token, permit2_address, own_addr)| {
             println!(
                 "> [Chain {chain_id}] sending approve for {}...",
                 token.address()
             );
-            let approve = token.approve(permit2_address, U256::MAX);
+
+            let approve = token.approve(permit2_address, U256::MAX).from(own_addr);
             let res = approve
                 .send()
                 .and_then(async move |tx_watch| Ok(tx_watch.watch().await?))