feat: Add logging with tracing

Cargo.toml

@@ -60,6 +60,10 @@ is-terminal = "0.4"
 path-absolutize = "3.1.0"
 human-sort = "0.2.2"
 regex = "1.10"
+tracing = "0.1.40"
+tracing-subscriber = { version = "0.3.18", features = ["env-filter", "serde", "serde_json"] }
+tracing-error = "0.2.0"
+directories = "5.0.1"
 
 [target.'cfg(windows)'.dependencies]
 windows = { version = "0.58.0", features = ["Win32_Foundation", "Win32_UI_Shell", "Win32_Security", "Win32_System_JobObjects", "Win32_System_Console", "Win32_System_Threading", "Services_Store", "Foundation", "Foundation_Collections", "Web_Http", "Web_Http_Headers", "Storage_Streams", "Management_Deployment"] }

src/utils.rs

@@ -1,8 +1,77 @@
 use anyhow::{anyhow, bail, Context, Result};
 use semver::{BuildMetadata, Version};
 use std::path::PathBuf;
+use tracing_error::ErrorLayer;
+use tracing_subscriber::{
+    self, prelude::__tracing_subscriber_SubscriberExt, util::SubscriberInitExt,
+};
 use url::Url;
 
+/// Returns the project directories.
+/// Uses the `ProjectDirs` struct from the `directories` crate to define a directory
+/// structure for the project with "org" as the organization, "julialang" as the application,
+/// and "install" as the qualifier. This is a standard approach for determining data storage paths.
+fn project_dirs() -> Option<directories::ProjectDirs> {
+    directories::ProjectDirs::from("org", "julialang", "install")
+}
+
+/// Returns the default data directory for the application.
+/// First, it checks the environment variable `JULIAUP_DATA_HOME`.
+/// If the environment variable is not set, it falls back to the data directory
+/// provided by `project_dirs`, which is typically platform-specific.
+/// If both fail, it defaults to a `.data` directory in the current working directory.
+pub fn default_data_dir() -> PathBuf {
+    std::env::var("JULIAUP_DATA_HOME")
+        .map(PathBuf::from)
+        .or_else(|_| {
+            project_dirs()
+                .map(|dirs| dirs.data_local_dir().to_path_buf())
+                .ok_or(())
+        })
+        .unwrap_or(PathBuf::from(".").join(".data"))
+}
+
+/// Initializes logging for the application.
+/// Creates the default data directory if it doesn't already exist.
+/// A log file named after the package is created in this directory.
+/// The `tracing_subscriber` library is then used to configure logging to the file,
+/// including file and line numbers in log entries, while disabling ANSI coloring.
+/// The log level for specific libraries (`tokio_util`, `hyper`, `reqwest`) is turned off.
+pub fn init_logging() -> Result<()> {
+    // Get the default data directory
+    let directory = default_data_dir();
+
+    // Create the directory (and any missing parent directories) if it doesn't exist
+    std::fs::create_dir_all(directory.clone())?;
+
+    // Create a log file named after the package
+    let log_file = format!("{}.log", env!("CARGO_PKG_NAME"));
+    let log_path = directory.join(log_file);
+    let log_file = std::fs::File::create(log_path)?;
+
+    // Set up a logging subscriber that writes to the log file, with specific configurations
+    let file_subscriber = tracing_subscriber::fmt::layer()
+        .with_file(true) // Include source file name in logs
+        .with_line_number(true) // Include line number in logs
+        .with_writer(log_file) // Log to the created file
+        .with_target(false) // Disable logging target (e.g., module paths)
+        .with_ansi(false); // Disable ANSI color codes
+
+    // Initialize the tracing subscriber with filters for specific libraries
+    tracing_subscriber::registry()
+        .with(file_subscriber)
+        .with(ErrorLayer::default()) // Add error handling layer
+        .with(
+            tracing_subscriber::filter::EnvFilter::from_default_env()
+                .add_directive("tokio_util=off".parse().unwrap()) // Disable logging for `tokio_util`
+                .add_directive("hyper=off".parse().unwrap()) // Disable logging for `hyper`
+                .add_directive("reqwest=off".parse().unwrap()), // Disable logging for `reqwest`
+        )
+        .init();
+
+    Ok(())
+}
+
 pub fn get_juliaserver_base_url() -> Result<Url> {
     let base_url = if let Ok(val) = std::env::var("JULIAUP_SERVER") {
         if val.ends_with('/') {