Feat: Fügt logging in eine tmp-Datei hinzu.

src/log.rs

@@ -1,7 +1,12 @@
 use std::any::Any;
 use std::fmt::{Display, Formatter};
-use std::io::{IsTerminal, stdout};
-use std::sync::OnceLock;
+use std::io::{IsTerminal, stdout, Write};
+use std::sync::{OnceLock, Mutex};
+use std::fs::{create_dir_all, OpenOptions, File};
+use std::path::PathBuf;
+use std::time::{SystemTime, UNIX_EPOCH};
+use std::{env, process};
+
 use time::{OffsetDateTime, macros::format_description};
 
 #[derive(PartialEq)]
@@ -26,6 +31,8 @@ impl Display for LogLevel {
 static IS_TERMINAL: OnceLock<bool> = OnceLock::new();
 static LOG_LEVEL: LogLevel = LogLevel::Debug; // TODO: LogLevel aus Config laden
 
+static LOG_FILE: OnceLock<Mutex<Option<File>>> = OnceLock::new();
+
 pub fn log(tag: &str, message: &str, log_level: LogLevel) {
     if log_level.type_id() >= LOG_LEVEL.type_id() {
         let message: String = format_message(tag, message, &log_level);
@@ -37,6 +44,14 @@ pub fn log(tag: &str, message: &str, log_level: LogLevel) {
                 println!("{}", message)
             }
         }
+
+        let file_lock = get_or_init_log_file();
+        if let Ok(mut guard) = file_lock.lock() {
+            if let Some(f) = guard.as_mut() {
+                let _ = writeln!(f, "{}", message);
+                let _ = f.flush();
+            }
+        }
     }
 }
 
@@ -71,3 +86,40 @@ fn format_message(tag: &str, message: &str, log_level: &LogLevel) -> String {
         &LogLevel::Debug => format!("{}{}", "🚧", message),
     }
 }
+
+fn get_or_init_log_file() -> &'static Mutex<Option<File>> {
+    LOG_FILE.get_or_init(|| {
+        let file = open_log_file().ok();
+        Mutex::new(file)
+    })
+}
+
+fn open_log_file() -> std::io::Result<File> {
+    let program = program_name();
+    let rand = "13692bbf-a93b-43e9-9cc6-f05f94a8cfb6";
+    let base_dir = format!("/tmp/{}-{}", program, rand);
+
+    let today_fmt = format_description!("[year]-[month]-[day]");
+    let date_str = OffsetDateTime::now_local()
+        .unwrap_or(OffsetDateTime::now_utc())
+        .format(today_fmt)
+        .unwrap_or_else(|_| "0000-00-00".to_string());
+    let file_name = format!("log-{}.log", date_str);
+
+    let mut dir = PathBuf::from(base_dir);
+    create_dir_all(&dir)?;
+    dir.push(file_name);
+
+    OpenOptions::new()
+        .create(true)
+        .append(true)
+        .open(dir)
+}
+
+fn program_name() -> String {
+    env::current_exe()
+        .ok()
+        .and_then(|p| p.file_stem().map(|s| s.to_string_lossy().to_string()))
+        .filter(|s| !s.is_empty())
+        .unwrap_or_else(|| "app".to_string())
+}

src/main.rs

@@ -3,6 +3,8 @@ use crate::log::LogLevel;
 mod log;
 
 fn main() {
+    log::log("main", "========== PROGRAMM START ==========", LogLevel::Info);
+
     log::log("main", "Hello, world!", LogLevel::Error);
     log::log("main", "Hello, world!", LogLevel::Warn);
     log::log("main", "Hello, world!", LogLevel::Info);