Add tracing logging

Cargo.toml

@@ -58,6 +58,8 @@ portpicker = "0.1.1"
 tokio = { version = "1.23.0", features = ["full"] }
 async-trait = "0.1.59"
 semver = "1.0.14"
+tracing = "0.1.37"
+tracing-subscriber = "0.3.17"
 
 [dev-dependencies]
 dotenv-parser = "0.1.3"

src/lib.rs

@@ -41,6 +41,7 @@ use providers::{
     rust::RustProvider, scala::ScalaProvider, staticfile::StaticfileProvider, swift::SwiftProvider,
     zig::ZigProvider, Provider,
 };
+use tracing::info;
 
 mod chain;
 #[macro_use]
@@ -118,7 +119,7 @@ pub async fn create_docker_image(
 
     if let Ok(subdir) = app.source.strip_prefix(orig_path) {
         if subdir != std::path::Path::new("") {
-            println!("Using subdirectory \"{}\"", subdir.to_str().unwrap());
+            info!("Using subdirectory \"{}\"", subdir.to_str().unwrap());
         }
     }
 
@@ -127,19 +128,19 @@ pub async fn create_docker_image(
 
     let phase_count = plan.phases.clone().map_or(0, |phases| phases.len());
     if phase_count > 0 {
-        println!("{}", plan.get_build_string()?);
+        info!("Build plan has {} phases", phase_count);
 
         let start = plan.start_phase.clone().unwrap_or_default();
         if start.cmd.is_none() && !build_options.no_error_without_start {
             bail!("No start command could be found")
         }
     } else {
-        println!("\nNixpacks was unable to generate a build plan for this app.\nPlease check the documentation for supported languages: https://nixpacks.com");
-        println!("\nThe contents of the app directory are:\n");
+        info!("\nNixpacks was unable to generate a build plan for this app.\nPlease check the documentation for supported languages: https://nixpacks.com");
+        info!("\nThe contents of the app directory are:\n");
 
         for file in &app.paths {
             let path = app.strip_source_path(file.as_path())?;
-            println!(
+            info!(
                 "  {}{}",
                 path.display(),
                 if file.is_dir() { "/" } else { "" }

src/main.rs

@@ -19,6 +19,7 @@ use std::{
     ops::Deref,
     string::ToString,
 };
+use tracing::info;
 
 /// The build plan config file format to use.
 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, ValueEnum)]
@@ -156,6 +157,8 @@ enum Commands {
 
 #[tokio::main]
 async fn main() -> Result<()> {
+    tracing_subscriber::fmt::init();
+
     let args = Args::parse();
 
     let pkgs = args
@@ -213,12 +216,12 @@ async fn main() -> Result<()> {
                 PlanFormat::Toml => plan.to_toml()?,
             };
 
-            println!("{plan_s}");
+            info!("Generated build plan: {}", plan_s);
         }
-        // Detect which providers should be used to build a project and print them to stdout.
+        // Detect which providers should be used to build a project and print them.
         Commands::Detect { path } => {
             let providers = get_plan_providers(&path, env, &options)?;
-            println!("{}", providers.join(", "));
+            info!("Detected providers: {}", providers.join(", "));
         }
         // Generate a Dockerfile and builds a container, using any specified build options.
         Commands::Build {