refactor: move metrics endpoint to node cmd (#505)

* refactor: move metrics endpoint to node cmd

* feat: value names

* refactor: simplify db path parsing

bin/reth/src/cli.rs

@@ -1,8 +1,6 @@
 //! CLI definition and entrypoint to executable
 
 use clap::{ArgAction, Parser, Subcommand};
-use metrics_exporter_prometheus::PrometheusBuilder;
-use metrics_util::layers::{PrefixLayer, Stack};
 use tracing_subscriber::util::SubscriberInitExt;
 
 use crate::{
@@ -13,20 +11,8 @@ use crate::{
 /// main function that parses cli and runs command
 pub async fn run() -> eyre::Result<()> {
     let opt = Cli::parse();
-
-    let tracing = if opt.silent { TracingMode::Silent } else { TracingMode::All };
-
-    reth_tracing::build_subscriber(tracing).init();
-
-    if opt.metrics {
-        let (recorder, exporter) =
-            PrometheusBuilder::new().build().expect("couldn't build Prometheus");
-        tokio::task::spawn(exporter);
-        Stack::new(recorder)
-            .push(PrefixLayer::new("reth"))
-            .install()
-            .expect("couldn't install metrics recorder");
-    }
+    reth_tracing::build_subscriber(if opt.silent { TracingMode::Silent } else { TracingMode::All })
+        .init();
 
     match opt.command {
         Commands::Node(command) => command.execute().await,
@@ -63,7 +49,4 @@ struct Cli {
     /// Silence all output
     #[clap(long, global = true)]
     silent: bool,
-
-    #[clap(long, global = true)]
-    metrics: bool,
 }

bin/reth/src/db/mod.rs

@@ -1,5 +1,6 @@
 //! Database debugging tool
 
+use crate::util::parse_path;
 use clap::{Parser, Subcommand};
 use eyre::{Result, WrapErr};
 use reth_db::{
@@ -11,15 +12,16 @@ use reth_db::{
 };
 use reth_interfaces::test_utils::generators::random_block_range;
 use reth_provider::insert_canonical_block;
-use std::path::Path;
+use std::path::PathBuf;
 use tracing::info;
 
 /// `reth db` command
 #[derive(Debug, Parser)]
 pub struct Command {
-    /// Path to database folder
-    #[arg(long, default_value = "~/.reth/db")]
-    db: String,
+    /// The path to the database folder.
+    // TODO: This should use dirs-next
+    #[arg(long, value_name = "PATH", default_value = "~/.reth/db", value_parser = parse_path)]
+    db: PathBuf,
 
     #[clap(subcommand)]
     command: Subcommands,
@@ -58,13 +60,11 @@ pub struct ListArgs {
 impl Command {
     /// Execute `db` command
     pub async fn execute(&self) -> eyre::Result<()> {
-        let path = shellexpand::full(&self.db)?.into_owned();
-        let expanded_db_path = Path::new(&path);
-        std::fs::create_dir_all(expanded_db_path)?;
+        std::fs::create_dir_all(&self.db)?;
 
         // TODO: Auto-impl for Database trait
         let db = reth_db::mdbx::Env::<reth_db::mdbx::WriteMap>::open(
-            expanded_db_path,
+            &self.db,
             reth_db::mdbx::EnvKind::RW,
         )?;
 

bin/reth/src/node/mod.rs

@@ -1,8 +1,11 @@
 //! Main node command
 //!
 //! Starts the client
-use crate::util::chainspec::Genesis;
+use crate::util::{chainspec::Genesis, parse_path};
 use clap::{crate_version, Parser};
+use eyre::WrapErr;
+use metrics_exporter_prometheus::PrometheusBuilder;
+use metrics_util::layers::{PrefixLayer, Stack};
 use reth_consensus::EthConsensus;
 use reth_db::{
     cursor::DbCursorRO,
@@ -22,6 +25,7 @@ use reth_primitives::{hex_literal::hex, Account, Header, H256};
 use reth_provider::{db_provider::ProviderImpl, BlockProvider, HeaderProvider};
 use reth_stages::stages::{bodies::BodyStage, headers::HeaderStage, senders::SendersStage};
 use std::{
+    net::SocketAddr,
     path::{Path, PathBuf},
     sync::Arc,
 };
@@ -35,8 +39,14 @@ const MAINNET_GENESIS: &str = include_str!("../../res/chainspec/mainnet.json");
 pub struct Command {
     /// The path to the database folder.
     // TODO: This should use dirs-next
-    #[arg(long, default_value = "~/.reth/db")]
-    db: String,
+    #[arg(long, value_name = "PATH", default_value = "~/.reth/db", value_parser = parse_path)]
+    db: PathBuf,
+
+    /// Enable Prometheus metrics.
+    ///
+    /// The metrics will be served at the given interface and port.
+    #[clap(long, value_name = "SOCKET")]
+    metrics: Option<SocketAddr>,
 }
 
 impl Command {
@@ -45,11 +55,23 @@ impl Command {
     pub async fn execute(&self) -> eyre::Result<()> {
         info!("reth {} starting", crate_version!());
 
-        let db_path = PathBuf::from(shellexpand::full(&self.db)?.into_owned());
-        info!("Opening database at {}", db_path.display());
-        let db = Arc::new(init_db(db_path)?);
+        info!("Opening database at {}", &self.db.display());
+        let db = Arc::new(init_db(&self.db)?);
         info!("Database open");
 
+        if let Some(listen_addr) = self.metrics {
+            info!("Starting metrics endpoint at {}", listen_addr);
+            let (recorder, exporter) = PrometheusBuilder::new()
+                .with_http_listener(listen_addr)
+                .build()
+                .wrap_err("Could not build Prometheus endpoint.")?;
+            tokio::task::spawn(exporter);
+            Stack::new(recorder)
+                .push(PrefixLayer::new("reth"))
+                .install()
+                .wrap_err("Couldn't set metrics recorder.")?;
+        }
+
         // TODO: More info from chainspec (chain ID etc.)
         let consensus = Arc::new(EthConsensus::new(consensus_config()));
         let genesis_hash =

bin/reth/src/util/mod.rs

@@ -1,11 +1,14 @@
 //! Utility functions.
-
-use std::path::{Path, PathBuf};
+use std::{
+    env::VarError,
+    path::{Path, PathBuf},
+};
 use walkdir::{DirEntry, WalkDir};
 
 /// Utilities for parsing chainspecs
 pub mod chainspec;
 
+/// Finds all files in a directory with a given postfix.
 pub(crate) fn find_all_files_with_postfix(path: &Path, postfix: &str) -> Vec<PathBuf> {
     WalkDir::new(path)
         .into_iter()
@@ -15,6 +18,12 @@ pub(crate) fn find_all_files_with_postfix(path: &Path, postfix: &str) -> Vec<Pat
         .collect::<Vec<PathBuf>>()
 }
 
+/// Parses a user-specified path with support for environment variables and common shorthands (e.g.
+/// ~ for the user's home directory).
+pub(crate) fn parse_path(value: &str) -> Result<PathBuf, shellexpand::LookupError<VarError>> {
+    shellexpand::full(value).map(|path| PathBuf::from(path.into_owned()))
+}
+
 /// Tracing utility
 pub mod reth_tracing {
     use tracing::Subscriber;