Add logging

Cargo.lock

@@ -474,6 +474,12 @@ version = "1.70.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7943c866cc5cd64cbc25b2e01621d07fa8eb2a1a23160ee81ce38704e97b8ecf"
 
+[[package]]
+name = "lazy_static"
+version = "1.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bbd2bcb4c963f2ddae06a2efc7e9f3591312473c50c6685e1f298068316e66fe"
+
 [[package]]
 name = "lettre"
 version = "0.11.17"
@@ -496,6 +502,7 @@ dependencies = [
  "quoted_printable",
  "socket2",
  "tokio",
+ "tracing",
  "url",
 ]
 
@@ -529,6 +536,8 @@ version = "0.1.0"
 dependencies = [
  "clap",
  "lettre",
+ "tracing",
+ "tracing-subscriber",
 ]
 
 [[package]]
@@ -589,6 +598,16 @@ dependencies = [
  "memchr",
 ]
 
+[[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 = "object"
 version = "0.36.7"
@@ -654,6 +673,12 @@ dependencies = [
  "vcpkg",
 ]
 
+[[package]]
+name = "overload"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b15813163c1d831bf4a13c3610c05c0d03b39feb07f7e09fa234dac9b15aaf39"
+
 [[package]]
 name = "percent-encoding"
 version = "2.3.1"
@@ -797,6 +822,15 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "sharded-slab"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f40ca3c46823713e0d4209592e8d6e826aa57e928f09752619fc696c499637f6"
+dependencies = [
+ "lazy_static",
+]
+
 [[package]]
 name = "shlex"
 version = "1.3.0"
@@ -885,6 +919,15 @@ dependencies = [
  "windows-sys 0.59.0",
 ]
 
+[[package]]
+name = "thread_local"
+version = "1.1.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f60246a4944f24f6e018aa17cdeffb7818b76356965d03b07d6a9886e8962185"
+dependencies = [
+ "cfg-if",
+]
+
 [[package]]
 name = "tinystr"
 version = "0.8.1"
@@ -911,6 +954,63 @@ dependencies = [
  "windows-sys 0.52.0",
 ]
 
+[[package]]
+name = "tracing"
+version = "0.1.41"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "784e0ac535deb450455cbfa28a6f0df145ea1bb7ae51b821cf5e7927fdcfbdd0"
+dependencies = [
+ "pin-project-lite",
+ "tracing-attributes",
+ "tracing-core",
+]
+
+[[package]]
+name = "tracing-attributes"
+version = "0.1.30"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "81383ab64e72a7a8b8e13130c49e3dab29def6d0c7d76a03087b3cf71c5c6903"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "tracing-core"
+version = "0.1.34"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b9d12581f227e93f094d3af2ae690a574abb8a2b9b7a96e7cfe9647b2b617678"
+dependencies = [
+ "once_cell",
+ "valuable",
+]
+
+[[package]]
+name = "tracing-log"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ee855f1f400bd0e5c02d150ae5de3840039a3f54b025156404e34c23c03f47c3"
+dependencies = [
+ "log",
+ "once_cell",
+ "tracing-core",
+]
+
+[[package]]
+name = "tracing-subscriber"
+version = "0.3.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e8189decb5ac0fa7bc8b96b7cb9b2701d60d48805aca84a238004d665fcc4008"
+dependencies = [
+ "nu-ansi-term",
+ "sharded-slab",
+ "smallvec",
+ "thread_local",
+ "tracing-core",
+ "tracing-log",
+]
+
 [[package]]
 name = "unicode-ident"
 version = "1.0.18"
@@ -940,6 +1040,12 @@ version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "06abde3611657adf66d383f00b093d7faecc7fa57071cce2578660c9f1010821"
 
+[[package]]
+name = "valuable"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ba73ea9cf16a25df0c8caa16c51acb937d5712a8429db78a3ee29d5dcacd3a65"
+
 [[package]]
 name = "vcpkg"
 version = "0.2.15"
@@ -967,6 +1073,28 @@ dependencies = [
  "wit-bindgen-rt",
 ]
 
+[[package]]
+name = "winapi"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c839a674fcd7a98952e593242ea400abe93992746761e38641405d28b00f419"
+dependencies = [
+ "winapi-i686-pc-windows-gnu",
+ "winapi-x86_64-pc-windows-gnu",
+]
+
+[[package]]
+name = "winapi-i686-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
+
+[[package]]
+name = "winapi-x86_64-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
+
 [[package]]
 name = "windows-link"
 version = "0.1.3"

Cargo.toml

@@ -5,4 +5,6 @@ edition = "2024"
 
 [dependencies]
 clap = { version = "4.5.40", features = ["derive"] }
-lettre = "0.11.17"
+lettre = { version = "0.11.17", features = ["tracing"] }
+tracing = "0.1"
+tracing-subscriber = "0.3.19"

src/main.rs

@@ -4,6 +4,8 @@ use lettre::message::header::ContentType;
 use lettre::transport::smtp::authentication::Credentials;
 use lettre::transport::smtp::extension::ClientId;
 use lettre::{Message, SmtpTransport, Transport};
+use tracing::Level;
+use tracing_subscriber::FmtSubscriber;
 
 /// Simple mail sender
 #[derive(Parser, Debug)]
@@ -69,6 +71,18 @@ struct Args {
 fn main() {
     let args = Args::parse();
 
+    // a builder for `FmtSubscriber`.
+    let subscriber = FmtSubscriber::builder()
+        // all spans/events with a level higher than TRACE (e.g, debug, info, warn, etc.)
+        // will be written to stdout.
+        .with_max_level(Level::TRACE)
+        // completes the builder.
+        .finish();
+
+    tracing::subscriber::set_global_default(subscriber)
+        .expect("setting default subscriber failed");
+
+
     let mut builder = Message::builder();
     builder = builder.from(Mailbox::new(
         args.from_name,