Persist node logs (#36)

* Persist node logs

* Fix clippy lints

* Delete the node's db on shutdown but persist logs

* Fix tests

* Separate stdout and stderr and use more consts.

* More consistent handling of open options

* Revert the use of subprocess

* Remove outdated comment

* Flush the log files on drop

* Rename `log_files` -> `logs_file_to_flush`

Author: 0xOmarA

crates/node/src/geth.rs

@@ -2,15 +2,14 @@
 
 use std::{
     collections::HashMap,
-    fs::{File, create_dir_all, remove_dir_all},
+    fs::{File, OpenOptions, create_dir_all, remove_dir_all},
     io::{BufRead, BufReader, Read, Write},
     path::PathBuf,
     process::{Child, Command, Stdio},
     sync::{
         Mutex,
         atomic::{AtomicU32, Ordering},
     },
-    thread,
     time::{Duration, Instant},
 };
 
@@ -28,6 +27,7 @@ use revive_dt_node_interaction::{
     EthereumNode, nonce::fetch_onchain_nonce, trace::trace_transaction,
     transaction::execute_transaction,
 };
+use tracing::Level;
 
 use crate::Node;
 
@@ -45,28 +45,40 @@ pub struct Instance {
     connection_string: String,
     base_directory: PathBuf,
     data_directory: PathBuf,
+    logs_directory: PathBuf,
     geth: PathBuf,
     id: u32,
     handle: Option<Child>,
     network_id: u64,
     start_timeout: u64,
     wallet: EthereumWallet,
     nonces: Mutex<HashMap<Address, u64>>,
+    /// This vector stores [`File`] objects that we use for logging which we want to flush when the
+    /// node object is dropped. We do not store them in a structured fashion at the moment (in
+    /// separate fields) as the logic that we need to apply to them is all the same regardless of
+    /// what it belongs to, we just want to flush them on [`Drop`] of the node.
+    logs_file_to_flush: Vec<File>,
 }
 
 impl Instance {
     const BASE_DIRECTORY: &str = "geth";
     const DATA_DIRECTORY: &str = "data";
+    const LOGS_DIRECTORY: &str = "logs";
 
     const IPC_FILE: &str = "geth.ipc";
     const GENESIS_JSON_FILE: &str = "genesis.json";
 
     const READY_MARKER: &str = "IPC endpoint opened";
     const ERROR_MARKER: &str = "Fatal:";
 
+    const GETH_STDOUT_LOG_FILE_NAME: &str = "node_stdout.log";
+    const GETH_STDERR_LOG_FILE_NAME: &str = "node_stderr.log";
+
     /// Create the node directory and call `geth init` to configure the genesis.
+    #[tracing::instrument(skip_all, fields(geth_node_id = self.id))]
     fn init(&mut self, genesis: String) -> anyhow::Result<&mut Self> {
         create_dir_all(&self.base_directory)?;
+        create_dir_all(&self.logs_directory)?;
 
         let genesis_path = self.base_directory.join(Self::GENESIS_JSON_FILE);
         File::create(&genesis_path)?.write_all(genesis.as_bytes())?;
@@ -96,8 +108,24 @@ impl Instance {
 
     /// Spawn the go-ethereum node child process.
     ///
-    /// [Instance::init] must be called priorly.
+    /// [Instance::init] must be called prior.
+    #[tracing::instrument(skip_all, fields(geth_node_id = self.id))]
     fn spawn_process(&mut self) -> anyhow::Result<&mut Self> {
+        // This is the `OpenOptions` that we wish to use for all of the log files that we will be
+        // opening in this method. We need to construct it in this way to:
+        // 1. Be consistent
+        // 2. Less verbose and more dry
+        // 3. Because the builder pattern uses mutable references so we need to get around that.
+        let open_options = {
+            let mut options = OpenOptions::new();
+            options.create(true).truncate(true).write(true);
+            options
+        };
+
+        let stdout_logs_file = open_options
+            .clone()
+            .open(self.geth_stdout_log_file_path())?;
+        let stderr_logs_file = open_options.open(self.geth_stderr_log_file_path())?;
         self.handle = Command::new(&self.geth)
             .arg("--dev")
             .arg("--datadir")
@@ -109,49 +137,67 @@ impl Instance {
             .arg("--nodiscover")
             .arg("--maxpeers")
             .arg("0")
-            .stderr(Stdio::piped())
-            .stdout(Stdio::null())
+            .stderr(stderr_logs_file.try_clone()?)
+            .stdout(stdout_logs_file.try_clone()?)
             .spawn()?
             .into();
+
+        if let Err(error) = self.wait_ready() {
+            tracing::error!(?error, "Failed to start geth, shutting down gracefully");
+            self.shutdown()?;
+            return Err(error);
+        }
+
+        self.logs_file_to_flush
+            .extend([stderr_logs_file, stdout_logs_file]);
+
         Ok(self)
     }
 
     /// Wait for the g-ethereum node child process getting ready.
     ///
     /// [Instance::spawn_process] must be called priorly.
+    #[tracing::instrument(skip_all, fields(geth_node_id = self.id))]
     fn wait_ready(&mut self) -> anyhow::Result<&mut Self> {
-        // Thanks clippy but geth is a server; we don't `wait` but eventually kill it.
-        #[allow(clippy::zombie_processes)]
-        let mut child = self.handle.take().expect("should be spawned");
         let start_time = Instant::now();
-        let maximum_wait_time = Duration::from_millis(self.start_timeout);
-        let mut stderr = BufReader::new(child.stderr.take().expect("should be piped")).lines();
-        let error = loop {
-            let Some(Ok(line)) = stderr.next() else {
-                break "child process stderr reading error".to_string();
-            };
-            if line.contains(Self::ERROR_MARKER) {
-                break line;
-            }
-            if line.contains(Self::READY_MARKER) {
-                // Keep stderr alive
-                // https://github.com/alloy-rs/alloy/issues/2091#issuecomment-2676134147
-                thread::spawn(move || for _ in stderr.by_ref() {});
 
-                self.handle = child.into();
-                return Ok(self);
+        let logs_file = OpenOptions::new()
+            .read(true)
+            .write(false)
+            .append(false)
+            .truncate(false)
+            .open(self.geth_stderr_log_file_path())?;
+
+        let maximum_wait_time = Duration::from_millis(self.start_timeout);
+        let mut stderr = BufReader::new(logs_file).lines();
+        loop {
+            if let Some(Ok(line)) = stderr.next() {
+                if line.contains(Self::ERROR_MARKER) {
+                    anyhow::bail!("Failed to start geth {line}");
+                }
+                if line.contains(Self::READY_MARKER) {
+                    return Ok(self);
+                }
             }
             if Instant::now().duration_since(start_time) > maximum_wait_time {
-                break "spawn timeout".to_string();
+                anyhow::bail!("Timeout in starting geth");
             }
-        };
+        }
+    }
 
-        let _ = child.kill();
-        anyhow::bail!("geth node #{} spawn error: {error}", self.id)
+    #[tracing::instrument(skip_all, fields(geth_node_id = self.id), level = Level::TRACE)]
+    fn geth_stdout_log_file_path(&self) -> PathBuf {
+        self.logs_directory.join(Self::GETH_STDOUT_LOG_FILE_NAME)
+    }
+
+    #[tracing::instrument(skip_all, fields(geth_node_id = self.id), level = Level::TRACE)]
+    fn geth_stderr_log_file_path(&self) -> PathBuf {
+        self.logs_directory.join(Self::GETH_STDERR_LOG_FILE_NAME)
     }
 }
 
 impl EthereumNode for Instance {
+    #[tracing::instrument(skip_all, fields(geth_node_id = self.id))]
     fn execute_transaction(
         &self,
         transaction: TransactionRequest,
@@ -241,6 +287,7 @@ impl EthereumNode for Instance {
         }))
     }
 
+    #[tracing::instrument(skip_all, fields(geth_node_id = self.id))]
     fn trace_transaction(
         &self,
         transaction: TransactionReceipt,
@@ -263,6 +310,7 @@ impl EthereumNode for Instance {
         }))
     }
 
+    #[tracing::instrument(skip_all, fields(geth_node_id = self.id))]
     fn state_diff(
         &self,
         transaction: alloy::rpc::types::TransactionReceipt,
@@ -276,6 +324,7 @@ impl EthereumNode for Instance {
         }
     }
 
+    #[tracing::instrument(skip_all, fields(geth_node_id = self.id))]
     fn fetch_add_nonce(&self, address: Address) -> anyhow::Result<u64> {
         let connection_string = self.connection_string.clone();
         let wallet = self.wallet.clone();
@@ -299,6 +348,7 @@ impl Node for Instance {
         Self {
             connection_string: base_directory.join(Self::IPC_FILE).display().to_string(),
             data_directory: base_directory.join(Self::DATA_DIRECTORY),
+            logs_directory: base_directory.join(Self::LOGS_DIRECTORY),
             base_directory,
             geth: config.geth.clone(),
             id,
@@ -307,22 +357,46 @@ impl Node for Instance {
             start_timeout: config.geth_start_timeout,
             wallet: config.wallet(),
             nonces: Mutex::new(HashMap::new()),
+            // We know that we only need to be storing 2 files so we can specify that when creating
+            // the vector. It's the stdout and stderr of the geth node.
+            logs_file_to_flush: Vec::with_capacity(2),
         }
     }
 
+    #[tracing::instrument(skip_all, fields(geth_node_id = self.id))]
     fn connection_string(&self) -> String {
         self.connection_string.clone()
     }
 
-    fn shutdown(self) -> anyhow::Result<()> {
+    #[tracing::instrument(skip_all, fields(geth_node_id = self.id))]
+    fn shutdown(&mut self) -> anyhow::Result<()> {
+        // Terminate the processes in a graceful manner to allow for the output to be flushed.
+        if let Some(mut child) = self.handle.take() {
+            child
+                .kill()
+                .map_err(|error| anyhow::anyhow!("Failed to kill the geth process: {error:?}"))?;
+        }
+
+        // Flushing the files that we're using for keeping the logs before shutdown.
+        for file in self.logs_file_to_flush.iter_mut() {
+            file.flush()?
+        }
+
+        // Remove the node's database so that subsequent runs do not run on the same database. We
+        // ignore the error just in case the directory didn't exist in the first place and therefore
+        // there's nothing to be deleted.
+        let _ = remove_dir_all(self.base_directory.join(Self::DATA_DIRECTORY));
+
         Ok(())
     }
 
+    #[tracing::instrument(skip_all, fields(geth_node_id = self.id))]
     fn spawn(&mut self, genesis: String) -> anyhow::Result<()> {
-        self.init(genesis)?.spawn_process()?.wait_ready()?;
+        self.init(genesis)?.spawn_process()?;
         Ok(())
     }
 
+    #[tracing::instrument(skip_all, fields(geth_node_id = self.id))]
     fn version(&self) -> anyhow::Result<String> {
         let output = Command::new(&self.geth)
             .arg("--version")
@@ -337,14 +411,9 @@ impl Node for Instance {
 }
 
 impl Drop for Instance {
+    #[tracing::instrument(skip_all, fields(geth_node_id = self.id))]
     fn drop(&mut self) {
-        tracing::info!(id = self.id, "Dropping node");
-        if let Some(child) = self.handle.as_mut() {
-            let _ = child.kill();
-        }
-        if self.base_directory.exists() {
-            let _ = remove_dir_all(&self.base_directory);
-        }
+        self.shutdown().expect("Failed to shutdown")
     }
 }