Setup server logging to file using standard XDG directory (#334)

Co-authored-by: joshuadavidthomas <[email protected]>
Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: Josh Thomas <[email protected]>

Author: Copilot

CHANGELOG.md

@@ -29,6 +29,7 @@ and this project attempts to adhere to [Semantic Versioning](https://semver.org/
 ### Changed
 
 - Changed user configuration directory paths to use application name only, removing organization identifiers
+- Changed log directory to use XDG cache directories (e.g., `~/.cache/djls` on Linux) with `/tmp` fallback
 - **Internal**: Refactored workspace to use domain types (`FileKind`) instead of LSP types (`LanguageId`)
 - **Internal**: Added client detection for LSP-specific workarounds (e.g., Sublime Text's `html` language ID handling)
 

crates/djls-conf/src/lib.rs

@@ -3,7 +3,9 @@ pub mod tagspecs;
 use std::fs;
 use std::path::Path;
 
+use anyhow::Context;
 use camino::Utf8Path;
+use camino::Utf8PathBuf;
 use config::Config;
 use config::ConfigError as ExternalConfigError;
 use config::File;
@@ -19,6 +21,28 @@ pub use crate::tagspecs::SimpleArgTypeDef;
 pub use crate::tagspecs::TagArgDef;
 pub use crate::tagspecs::TagSpecDef;
 
+pub(crate) fn project_dirs() -> Option<ProjectDirs> {
+    ProjectDirs::from("", "", "djls")
+}
+
+/// Get the log directory for the application and ensure it exists.
+///
+/// Returns the XDG cache directory (e.g., ~/.cache/djls on Linux) if available,
+/// otherwise falls back to /tmp. Creates the directory if it doesn't exist.
+///
+/// # Errors
+///
+/// Returns an error if the directory cannot be created.
+pub fn log_dir() -> anyhow::Result<Utf8PathBuf> {
+    let dir = project_dirs()
+        .and_then(|proj_dirs| Utf8PathBuf::from_path_buf(proj_dirs.cache_dir().to_path_buf()).ok())
+        .unwrap_or_else(|| Utf8PathBuf::from("/tmp"));
+
+    fs::create_dir_all(&dir).with_context(|| format!("Failed to create log directory: {dir}"))?;
+
+    Ok(dir)
+}
+
 #[derive(Error, Debug)]
 pub enum ConfigError {
     #[error("Configuration build/deserialize error")]
@@ -45,8 +69,8 @@ pub struct Settings {
 
 impl Settings {
     pub fn new(project_root: &Utf8Path, overrides: Option<Settings>) -> Result<Self, ConfigError> {
-        let user_config_file = ProjectDirs::from("", "", "djls")
-            .map(|proj_dirs| proj_dirs.config_dir().join("djls.toml"));
+        let user_config_file =
+            project_dirs().map(|proj_dirs| proj_dirs.config_dir().join("djls.toml"));
 
         let mut settings = Self::load_from_paths(project_root, user_config_file.as_deref())?;
 

crates/djls-server/src/lib.rs

@@ -15,6 +15,7 @@ use tower_lsp_server::Server;
 pub use crate::server::DjangoLanguageServer;
 pub use crate::session::Session;
 
+/// Run the Django language server.
 pub fn run() -> Result<()> {
     if std::io::stdin().is_terminal() {
         eprintln!(

crates/djls-server/src/logging.rs

@@ -105,20 +105,32 @@ where
 /// Initialize the dual-layer tracing subscriber.
 ///
 /// Sets up:
-/// - File layer: writes to /tmp/djls.log with daily rotation
+/// - File layer: writes to XDG cache directory (e.g., ~/.cache/djls/djls.log on Linux) with daily rotation.
+///   Falls back to /tmp/djls.log if XDG cache directory is not available.
+///   If file logging cannot be initialized, falls back to stderr.
 /// - LSP layer: forwards INFO+ messages to the client
 /// - `EnvFilter`: respects `RUST_LOG` env var, defaults to "info"
 ///
-/// Returns a `WorkerGuard` that must be kept alive for the file logging to work.
+/// Returns a `WorkerGuard` that must be kept alive for the logging to work.
 pub fn init_tracing<F>(send_message: F) -> WorkerGuard
 where
     F: Fn(lsp_types::MessageType, String) + Send + Sync + 'static,
 {
-    let file_appender = tracing_appender::rolling::daily("/tmp", "djls.log");
-    let (non_blocking, guard) = tracing_appender::non_blocking(file_appender);
-
     let env_filter = EnvFilter::try_from_default_env().unwrap_or_else(|_| EnvFilter::new("info"));
-    let file_layer = fmt::layer()
+
+    let (non_blocking, guard) = match djls_conf::log_dir() {
+        Ok(log_dir) => {
+            let file_appender = tracing_appender::rolling::daily(log_dir.as_std_path(), "djls.log");
+            tracing_appender::non_blocking(file_appender)
+        }
+        Err(e) => {
+            eprintln!("Warning: Failed to initialize file logging: {e}");
+            eprintln!("Falling back to stderr logging...");
+            tracing_appender::non_blocking(std::io::stderr())
+        }
+    };
+
+    let log_layer = fmt::layer()
         .with_writer(non_blocking)
         .with_ansi(false)
         .with_thread_ids(true)
@@ -131,7 +143,7 @@ where
     let lsp_layer =
         LspLayer::new(send_message).with_filter(tracing_subscriber::filter::LevelFilter::INFO);
 
-    Registry::default().with(file_layer).with(lsp_layer).init();
+    Registry::default().with(log_layer).with(lsp_layer).init();
 
     guard
 }