Add tracing.

Cargo.lock

@@ -188,6 +188,8 @@ dependencies = [
  "reqwest",
  "serde",
  "tokio",
+ "tracing",
+ "tracing-subscriber",
 ]
 
 [[package]]
@@ -936,6 +938,16 @@ dependencies = [
  "tempfile",
 ]
 
+[[package]]
+name = "nu-ansi-term"
+version = "0.46.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77a8165726e8236064dbb45459242600304b42a5ea24ee2948e18e023bf7ba84"
+dependencies = [
+ "overload",
+ "winapi",
+]
+
 [[package]]
 name = "num-integer"
 version = "0.1.45"
@@ -1041,6 +1053,12 @@ version = "6.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ceedf44fb00f2d1984b0bc98102627ce622e083e49a5bacdb3e514fa4238e267"
 
+[[package]]
+name = "overload"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b15813163c1d831bf4a13c3610c05c0d03b39feb07f7e09fa234dac9b15aaf39"
+
 [[package]]
 name = "owo-colors"
 version = "3.5.0"
@@ -1628,9 +1646,21 @@ dependencies = [
  "cfg-if",
  "log",
  "pin-project-lite",
+ "tracing-attributes",
  "tracing-core",
 ]
 
+[[package]]
+name = "tracing-attributes"
+version = "0.1.24"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0f57e3ca2a01450b1a921183a9c9cbfda207fd822cef4ccb00a65402cbba7a74"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "tracing-core"
 version = "0.1.31"
@@ -1651,15 +1681,42 @@ dependencies = [
  "tracing-subscriber",
 ]
 
+[[package]]
+name = "tracing-log"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "78ddad33d2d10b1ed7eb9d1f518a5674713876e97e5bb9b7345a7984fbb4f922"
+dependencies = [
+ "lazy_static",
+ "log",
+ "tracing-core",
+]
+
+[[package]]
+name = "tracing-serde"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bc6b213177105856957181934e4920de57730fc69bf42c37ee5bb664d406d9e1"
+dependencies = [
+ "serde",
+ "tracing-core",
+]
+
 [[package]]
 name = "tracing-subscriber"
 version = "0.3.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "30a651bc37f915e81f087d86e62a18eec5f79550c7faff886f7090b4ea757c77"
 dependencies = [
+ "nu-ansi-term",
+ "serde",
+ "serde_json",
  "sharded-slab",
+ "smallvec",
  "thread_local",
  "tracing-core",
+ "tracing-log",
+ "tracing-serde",
 ]
 
 [[package]]

Cargo.toml

@@ -13,5 +13,7 @@ pretty-hex = "0.3"
 reqwest = { version = "0.11", features = ["json"] }
 serde = { version = "1", features = ["derive"] }
 tokio = { version = "1", features = ["full"] }
+tracing = "0.1"
+tracing-subscriber = { version = "0.3", features = ["json"] }
 
 [dev-dependencies]

src/main.rs

@@ -1,3 +1,5 @@
+use std::str::FromStr;
+
 use axum::{
     body::BoxBody,
     http::header,
@@ -7,12 +9,25 @@ use axum::{
 };
 use reqwest::StatusCode;
 use serde::Deserialize;
+use tracing::{info, Level};
+use tracing_subscriber::{filter::Targets, layer::SubscriberExt, util::SubscriberInitExt};
 
 #[tokio::main]
 async fn main() {
+    let filter = Targets::from_str(std::env::var("RUST_LOG").as_deref().unwrap_or("info"))
+        .expect("RUST_LOG should be a valid tracing filter");
+    tracing_subscriber::fmt()
+        .with_max_level(Level::TRACE)
+        .json()
+        .finish()
+        .with(filter)
+        .init();
+
     let app = Router::new().route("/", get(root_get));
 
-    axum::Server::bind(&"0.0.0.0:8080".parse().unwrap())
+    let addr = "0.0.0.0:8080".parse().unwrap();
+    info!("Listening on {addr}");
+    axum::Server::bind(&addr)
         .serve(app.into_make_service())
         .await
         .unwrap();