feat: improve python related errors

crates/pathfinder/src/bin/pathfinder.rs

@@ -20,16 +20,16 @@ async fn main() -> anyhow::Result<()> {
         .init();
 
     let config =
-        config::Configuration::parse_cmd_line_and_cfg_file().expect("Configuration failed");
+        config::Configuration::parse_cmd_line_and_cfg_file().context("Parsing configuration")?;
 
     info!("🏁 Starting node.");
     let eth_transport = ethereum_transport(config.ethereum)
         .await
-        .context("Create Ethereum transport")?;
+        .context("Creating Ethereum transport")?;
 
     let network_chain = ethereum::chain(&eth_transport)
         .await
-        .context("Determine Ethereum chain")?;
+        .context("Determining Ethereum chain")?;
 
     let database_path = match network_chain {
         ethereum::Chain::Mainnet => "mainnet.sqlite",
@@ -54,13 +54,13 @@ async fn main() -> anyhow::Result<()> {
         futures::future::pending(),
     )
     .await
-    .context("Create python process for call handling")?;
+    .context("Creating python process for call handling. Have you setup and activate the python `VIRTUAL_ENV` in the `py` directory?")?;
 
     let api =
         rpc::api::RpcApi::new(storage, sequencer, network_chain).with_call_handling(call_handle);
 
     let (_rpc_handle, local_addr) =
-        rpc::run_server(config.http_rpc_addr, api).context("Start the RPC server")?;
+        rpc::run_server(config.http_rpc_addr, api).context("Starting the RPC server")?;
     info!("📡 HTTP-RPC server started on: {}", local_addr);
     let () = std::future::pending().await;
 
@@ -80,11 +80,11 @@ async fn ethereum_transport(config: EthereumConfig) -> anyhow::Result<Web3<Http>
         None => client,
     }
     .build()
-    .context("Create HTTP client")?;
+    .context("Creating HTTP client")?;
 
     let mut url = config.url;
     url.set_password(config.password.as_deref())
-        .map_err(|_| anyhow::anyhow!("Set password"))?;
+        .map_err(|_| anyhow::anyhow!("Setting password"))?;
 
     let client = Http::with_client(client, url);
 

crates/pathfinder/src/cairo/ext_py/service.rs

@@ -57,17 +57,17 @@ pub async fn start(
                     // good, now we can launch the other processes requested later
                 },
                 SubProcessEvent::CommandHandled(..) => {
-                    unreachable!("first message must not be CommandHandled");
+                    unreachable!("First message must not be CommandHandled");
                 },
             }
         },
         Some(res) = &mut joinhandles.next() => {
             match res {
-                Ok(Ok(t)) => unreachable!("first subprocess should not have exited successfully: {:?}", t),
+                Ok(Ok(t)) => unreachable!("First subprocess should not have exited successfully: {:?}", t),
                 // this is the failure to start
                 Ok(Err(e)) => return Err(e),
                 // this is the failure to join, panic or cancellation
-                Err(e) => return Err(e).context("Launch first python executor"),
+                Err(e) => return Err(e).context("Launching first python executor"),
             }
         }
     };

crates/pathfinder/src/cairo/ext_py/sub_process.rs

@@ -164,8 +164,7 @@ async fn spawn(
     database_path: PathBuf,
 ) -> anyhow::Result<(Child, u32, ChildStdin, BufReader<ChildStdout>, String)> {
     // there is not intentionally any std::fs::exists calls to avoid bringing any TOCTOU issues.
-    let virtual_env = std::env::var_os("VIRTUAL_ENV")
-        .context("VIRTUAL_ENV is not defined; has the user activated virtual environment")?;
+    let virtual_env = std::env::var_os("VIRTUAL_ENV").context("VIRTUAL_ENV is not defined")?;
 
     // FIXME: use choom, add something over /proc/self/oom_score_adj ?
     let mut python_exe = PathBuf::from(&virtual_env);
@@ -246,7 +245,7 @@ async fn spawn(
     anyhow::ensure!(
         // buffer will contain the newline, which doesn't bother serde_json
         buffer.trim() == "ready",
-        "failed to read ready from python process, read: {buffer:?}"
+        "Failed to read 'ready' from python process, read: {buffer:?}"
     );
     buffer.clear();