feat: add tracing crate (#236)

crates/tracing/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "reth-tracing"
+version = "0.1.0"
+edition = "2021"
+license = "MIT OR Apache-2.0"
+repository = "https://github.com/foundry-rs/reth"
+readme = "README.md"
+description = "tracing helpers"
+
+[dependencies]
+tracing = { version = "0.1", default-features = false }
+tracing-subscriber = { version = "0.3", default-features = false, features = ["env-filter", "fmt"] }

crates/tracing/src/lib.rs

@@ -0,0 +1,22 @@
+#![warn(missing_docs, unreachable_pub)]
+#![deny(unused_must_use, rust_2018_idioms)]
+#![doc(test(
+    no_crate_inject,
+    attr(deny(warnings, rust_2018_idioms), allow(dead_code, unused_variables))
+))]
+
+//! reth-tracing
+
+// re-export tracing crates.
+pub use tracing;
+pub use tracing_subscriber;
+
+/// Initialises a tracing subscriber via `RUST_LOG` environment variable filter.
+///
+/// Note: This ignores any error and should be used for testing.
+pub fn init_tracing() {
+    let _ = tracing_subscriber::fmt()
+        .with_env_filter(tracing_subscriber::EnvFilter::from_default_env())
+        .with_writer(std::io::stderr)
+        .try_init();
+}