fix: examples (#2153)

* fix: abigen example

* fix: gas oracle example

* fix: call override example

examples/contracts/examples/abigen.rs

@@ -32,10 +32,12 @@ async fn main() -> Result<()> {
 }
 
 fn rust_file_generation() -> Result<()> {
-    let base_dir = "./examples/contracts/examples/abi";
-    Abigen::new("IERC20", format!("{base_dir}/IERC20.json"))?
-        .generate()?
-        .write_to_file(format!("{base_dir}/ierc20.rs"))?;
+    let abi_source = "./examples/contracts/examples/abi/IERC20.json";
+    let out_file = std::env::temp_dir().join("ierc20.rs");
+    if out_file.exists() {
+        std::fs::remove_file(&out_file)?;
+    }
+    Abigen::new("IERC20", abi_source)?.generate()?.write_to_file(out_file)?;
     Ok(())
 }
 

examples/middleware/examples/gas_oracle.rs

@@ -39,13 +39,18 @@ async fn blocknative() {
 
 async fn etherscan() {
     let chain = Chain::Mainnet;
-    let api_key: String = std::env::var("ETHERSCAN_API_KEY_ETHEREUM").expect("Provide an API key");
-    if let Ok(client) = Client::new(chain, api_key) {
-        let oracle = Etherscan::new(client).category(GasCategory::Fast);
-        match oracle.fetch().await {
-            Ok(gas_price) => println!("[Etherscan]: Gas price is {gas_price:?}"),
-            Err(e) => panic!("[Etherscan]: Cannot estimate gas: {e:?}"),
-        }
+    let client = match Client::new_from_env(chain) {
+        Ok(client) => client,
+        Err(_) => Client::builder()
+            .chain(chain)
+            .expect("Mainnet is valid")
+            .build()
+            .expect("Mainnet is valid"),
+    };
+    let oracle = Etherscan::new(client).category(GasCategory::Fast);
+    match oracle.fetch().await {
+        Ok(gas_price) => println!("[Etherscan]: Gas price is {gas_price:?}"),
+        Err(e) => panic!("[Etherscan]: Cannot estimate gas: {e:?}"),
     }
 }
 

examples/transactions/examples/call_override.rs

@@ -10,12 +10,27 @@ use ethers::{
     },
 };
 use eyre::Result;
-use std::sync::Arc;
+use std::{
+    process::{Command, Stdio},
+    sync::Arc,
+};
 
 abigen!(Greeter, "ethers-contract/tests/solidity-contracts/greeter.json",);
 
 #[tokio::main]
 async fn main() -> Result<()> {
+    match geth_version() {
+        e @ Ok(false) | e @ Err(_) => {
+            eprint!("Error spawning geth, skipping example");
+            if let Err(e) = e {
+                eprint!(": {e}");
+            }
+            eprintln!();
+            return Ok(())
+        }
+        Ok(true) => {}
+    }
+
     let geth = Geth::new().spawn();
     let provider = Provider::<Http>::try_from(geth.endpoint()).unwrap();
     let client = Arc::new(provider);
@@ -75,3 +90,13 @@ fn encode_string_for_storage(s: &str) -> H256 {
     bytes.push(len as u8 * 2);
     H256::from_slice(&bytes)
 }
+
+fn geth_version() -> Result<bool> {
+    Command::new("geth")
+        .arg("version")
+        .stdout(Stdio::null())
+        .stderr(Stdio::null())
+        .status()
+        .map(|s| s.success())
+        .map_err(Into::into)
+}