Automatically determine chain id through web3 (#1416)

instead of having to specify it on the command line.

For the contract using the chain id instead of network id is what was
intended anyway and for the gas station it doesn't matter whether we
match on network id or chain id because they are the same for mainnet
and rinkeby.

Based on Felix' suggestion.

### Test Plan
Added a debug print to the gas station to see which chain id is used and tried it with mainnet and rinkeby node url.

driver/src/main.rs

@@ -51,11 +51,6 @@ struct Options {
     #[structopt(short, long, env = "ETHEREUM_NODE_URL")]
     node_url: Url,
 
-    /// The network ID used for signing transactions (e.g. 1 for mainnet, 4 for
-    /// rinkeby, 5777 for ganache).
-    #[structopt(short = "i", long, env = "NETWORK_ID")]
-    network_id: u64,
-
     /// Which style of solver to use. Can be one of:
     /// 'NaiveSolver' for the naive solver;
     /// 'StandardSolver' for mixed integer programming solver;
@@ -256,11 +251,11 @@ fn main() {
 
     // Set up shared HTTP client and HTTP services.
     let http_factory = HttpFactory::new(options.http_timeout, http_metrics);
-    let (web3, gas_station) = setup_http_services(&http_factory, &options);
+    let (web3, gas_station) = setup_http_services(&http_factory, &options).wait();
 
     // Set up connection to exchange contract
     let contract = Arc::new(
-        StableXContractImpl::new(&web3, options.private_key.clone(), options.network_id)
+        StableXContractImpl::new(&web3, options.private_key.clone())
             .wait()
             .unwrap(),
     );
@@ -362,13 +357,14 @@ fn setup_monitoring() -> (
     (stablex_metrics, http_metrics, solver_metrics, health)
 }
 
-fn setup_http_services(
+async fn setup_http_services(
     http_factory: &HttpFactory,
     options: &Options,
 ) -> (Web3, Arc<dyn GasPriceEstimating + Send + Sync>) {
     let web3 = web3_provider(http_factory, options.node_url.as_str(), options.rpc_timeout).unwrap();
-    let gas_station =
-        gas_price::create_estimator(options.network_id, &http_factory, &web3).unwrap();
+    let gas_station = gas_price::create_estimator(&http_factory, &web3)
+        .await
+        .unwrap();
     (web3, gas_station)
 }
 

price-estimator/src/main.rs

@@ -55,11 +55,6 @@ struct Options {
     #[structopt(long, env = "ETHEREUM_NODE_URL")]
     node_url: Url,
 
-    /// The network ID used for gas estimations.
-    /// For example 1 for mainnet, 4 for rinkeby.
-    #[structopt(long, env = "NETWORK_ID", default_value = "1")]
-    network_id: u64,
-
     /// The timeout in seconds of web3 JSON RPC calls.
     #[structopt(
         long,
@@ -154,13 +149,10 @@ fn main() {
     let web3 = web3_provider(&http_factory, options.node_url.as_str(), options.timeout).unwrap();
     // The private key is not actually used but StableXContractImpl requires it.
     let private_key = PrivateKey::from_raw([1u8; 32]).unwrap();
-    let contract = Arc::new(
-        StableXContractImpl::new(&web3, private_key, 0)
-            .wait()
-            .unwrap(),
-    );
-    let gas_station =
-        gas_price::create_estimator(options.network_id, &http_factory, &web3).unwrap();
+    let contract = Arc::new(StableXContractImpl::new(&web3, private_key).wait().unwrap());
+    let gas_station = gas_price::create_estimator(&http_factory, &web3)
+        .wait()
+        .unwrap();
 
     let cache: HashMap<_, _> = options.token_data.clone().into();
     let token_info = TokenInfoCache::with_cache(contract.clone(), cache);

services-core/src/contracts.rs

@@ -17,8 +17,8 @@ pub fn web3_provider(http_factory: &HttpFactory, url: &str, timeout: Duration) -
     Ok(web3)
 }
 
-fn method_defaults(key: PrivateKey, network_id: u64) -> Result<MethodDefaults> {
-    let account = Account::Offline(key, Some(network_id));
+fn method_defaults(key: PrivateKey, chain_id: u64) -> Result<MethodDefaults> {
+    let account = Account::Offline(key, Some(chain_id));
     let defaults = MethodDefaults {
         from: Some(account),
         gas: None,

services-core/src/contracts/stablex_contract.rs

@@ -15,7 +15,11 @@ use ethcontract::{
     transaction::{confirm::ConfirmParams, Account, GasPrice, ResolveCondition, TransactionResult},
     Address, BlockNumber, PrivateKey, U256,
 };
-use futures::future::{BoxFuture, FutureExt as _};
+use futures::{
+    compat::Future01CompatExt as _,
+    future::{BoxFuture, FutureExt as _},
+};
+
 use lazy_static::lazy_static;
 use std::collections::HashMap;
 use std::time::Duration;
@@ -33,8 +37,9 @@ pub struct StableXContractImpl {
 }
 
 impl StableXContractImpl {
-    pub async fn new(web3: &contracts::Web3, key: PrivateKey, network_id: u64) -> Result<Self> {
-        let defaults = contracts::method_defaults(key, network_id)?;
+    pub async fn new(web3: &contracts::Web3, key: PrivateKey) -> Result<Self> {
+        let chain_id = web3.eth().chain_id().compat().await?.as_u64();
+        let defaults = contracts::method_defaults(key, chain_id)?;
 
         let viewer = BatchExchangeViewer::deployed(&web3).await?;
         let mut instance = BatchExchange::deployed(&web3).await?;
@@ -324,8 +329,6 @@ impl StableXContract for StableXContractImpl {
     }
 
     async fn get_transaction_count(&self) -> Result<U256> {
-        use futures::compat::Future01CompatExt as _;
-
         let web3 = self.instance.raw_instance().web3();
         let account = self.account().ok_or_else(|| anyhow!("no account"))?;
         let address = account.address();

services-core/src/gas_price.rs

@@ -5,6 +5,7 @@ pub use self::gas_station::GnosisSafeGasStation;
 use crate::{contracts::Web3, http::HttpFactory};
 use anyhow::Result;
 use ethcontract::U256;
+use futures::compat::Future01CompatExt as _;
 use std::sync::Arc;
 
 #[cfg_attr(test, mockall::automock)]
@@ -15,12 +16,12 @@ pub trait GasPriceEstimating {
 }
 
 /// Creates the default gas price estimator for the given network.
-pub fn create_estimator(
-    network_id: u64,
+pub async fn create_estimator(
     http_factory: &HttpFactory,
     web3: &Web3,
 ) -> Result<Arc<dyn GasPriceEstimating + Send + Sync>> {
-    Ok(match gas_station::api_url_from_network_id(network_id) {
+    let network_id = web3.net().version().compat().await?;
+    Ok(match gas_station::api_url_from_network_id(&network_id) {
         Some(url) => Arc::new(GnosisSafeGasStation::new(http_factory, url)?),
         None => Arc::new(web3.clone()),
     })

services-core/src/gas_price/gas_station.rs

@@ -12,10 +12,10 @@ use uint::FromDecStrErr;
 const DEFAULT_MAINNET_URI: &str = "https://safe-relay.gnosis.io/api/v1/gas-station/";
 const DEFAULT_RINKEBY_URI: &str = "https://safe-relay.rinkeby.gnosis.io/api/v1/gas-station/";
 
-pub fn api_url_from_network_id(network_id: u64) -> Option<&'static str> {
+pub fn api_url_from_network_id(network_id: &str) -> Option<&'static str> {
     match network_id {
-        1 => Some(DEFAULT_MAINNET_URI),
-        4 => Some(DEFAULT_RINKEBY_URI),
+        "1" => Some(DEFAULT_MAINNET_URI),
+        "4" => Some(DEFAULT_RINKEBY_URI),
         _ => None,
     }
 }

services-core/src/token_info/onchain.rs

@@ -44,7 +44,6 @@ mod tests {
                 "0x0102030405060708091011121314151617181920212223242526272829303132",
             )
             .expect("Invalid private key"),
-            1,
         )
         .wait()
         .expect("Error creating contract")