Add --logs to specify custom log file path

README.md

@@ -210,8 +210,13 @@ The cache is are stored in `/var/cache/regreet/cache.toml` (configurable during
 It contains the last authenticated user and the last used session per user, which are automatically selected on next login.
 If the greeter is unable to write to this file, then it reverts to the default behaviour.
 
-The log file is stored in `/var/log/regreet/log` (configurable during installation).
-Once the log file reaches a limit, it is compressed and rotated to `/var/log/regreet/log.X.gz`, where `X` is the index of the log file.
+By default, the logs are stored in `/var/log/regreet/log` (configurable during installation).
+You can use a log file in a different location with the `--logs` argument as follows:
+```sh
+regreet --logs /path/to/custom/regreet/logs
+```
+
+Once the log file reaches a limit, it is compressed and rotated to `log.X.gz` in the same directory, where `X` is the index of the log file.
 The higher the index, the older the log file.
 After reaching a limit, the oldest log file is removed.
 

src/main.rs

@@ -41,6 +41,10 @@ enum LogLevel {
 #[derive(Parser, Debug)]
 #[command(author, version, about)]
 struct Args {
+    /// The path to the log file
+    #[arg(short, long, value_name = "PATH", default_value = LOG_PATH)]
+    logs: PathBuf,
+
     /// The verbosity level of the logs
     #[arg(short, long, value_name = "LEVEL", default_value = "info")]
     log_level: LogLevel,
@@ -65,7 +69,7 @@ struct Args {
 fn main() {
     let args = Args::parse();
     // Keep the guard alive till the end of the function, since logging depends on this.
-    let _guard = init_logging(&args.log_level, args.verbose);
+    let _guard = init_logging(&args.logs, &args.log_level, args.verbose);
 
     let app = relm4::RelmApp::new(APP_ID);
     app.run_async::<Greeter>(GreeterInit {
@@ -76,8 +80,7 @@ fn main() {
 }
 
 /// Initialize the log file with file rotation.
-fn setup_log_file() -> IoResult<FileRotate<AppendCount>> {
-    let log_path = Path::new(LOG_PATH);
+fn setup_log_file(log_path: &Path) -> IoResult<FileRotate<AppendCount>> {
     if !log_path.exists() {
         if let Some(log_dir) = log_path.parent() {
             create_dir_all(log_dir)?;
@@ -102,7 +105,7 @@ fn setup_log_file() -> IoResult<FileRotate<AppendCount>> {
 }
 
 /// Initialize logging with file rotation.
-fn init_logging(log_level: &LogLevel, stdout: bool) -> Vec<WorkerGuard> {
+fn init_logging(log_path: &Path, log_level: &LogLevel, stdout: bool) -> Vec<WorkerGuard> {
     // Parse the log level string.
     let filter = match log_level {
         LogLevel::Off => LevelFilter::OFF,
@@ -125,7 +128,7 @@ fn init_logging(log_level: &LogLevel, stdout: bool) -> Vec<WorkerGuard> {
     // Log in a separate non-blocking thread, then return the guard (otherise the non-blocking
     // writer will immediately stop).
     let mut guards = Vec::new();
-    match setup_log_file() {
+    match setup_log_file(log_path) {
         Ok(file) => {
             let (file, guard) = non_blocking(file);
             guards.push(guard);