reimpl Gautham's additions

cargo-espflash/src/main.rs

@@ -357,6 +357,7 @@ fn flash(args: FlashArgs, config: &Config) -> Result<()> {
             pid,
             args.flash_args.monitor_baud.unwrap_or(default_baud),
             args.flash_args.log_format,
+            args.flash_args.log_output,
             true,
         )
     } else {

espflash/Cargo.toml

@@ -26,6 +26,7 @@ required-features = ["cli", "serialport"]
 addr2line = { version = "0.21.0", optional = true }
 base64 = "0.22.0"
 bytemuck = { version = "1.14.3", features = ["derive"] }
+chrono = "0.4.38"
 clap = { version = "4.5.2", features = [
     "derive",
     "env",

espflash/src/bin/espflash.rs

@@ -294,6 +294,7 @@ fn flash(args: FlashArgs, config: &Config) -> Result<()> {
             pid,
             args.flash_args.monitor_baud.unwrap_or(default_baud),
             args.flash_args.log_format,
+            args.flash_args.log_output,
             true,
         )
     } else {

espflash/src/cli/mod.rs

@@ -136,6 +136,9 @@ pub struct FlashArgs {
     /// Logging format.
     #[arg(long, short = 'L', default_value = "serial", requires = "monitor")]
     pub log_format: LogFormat,
+    /// Logging format.
+    #[arg(long, short = 'O', requires = "monitor")]
+    pub log_output: Option<String>,
     /// Minimum chip revision supported by image, in format: major.minor
     #[arg(long, default_value = "0.0", value_parser = parse_chip_rev)]
     pub min_chip_rev: u16,
@@ -261,6 +264,9 @@ pub struct MonitorArgs {
     /// Logging format.
     #[arg(long, short = 'L', default_value = "serial", requires = "elf")]
     pub log_format: LogFormat,
+    /// Logging format.
+    #[arg(long, short = 'O')]
+    pub log_output: Option<String>,
 }
 
 #[derive(Debug, Args)]
@@ -445,6 +451,7 @@ pub fn serial_monitor(args: MonitorArgs, config: &Config) -> Result<()> {
         pid,
         args.connect_args.baud.unwrap_or(default_baud),
         args.log_format,
+        args.log_output,
         !args.non_interactive,
     )
 }

espflash/src/cli/monitor/mod.rs

@@ -10,11 +10,15 @@
 //! call are not displayed until `println!()` is subsequently called, where as
 //! in our monitor the output is displayed immediately upon reading.
 
+use regex::Regex;
 use std::{
-    io::{stdout, ErrorKind, Read, Write},
+    fs::{File, OpenOptions},
+    io::{stdout, BufWriter, ErrorKind, Read, Write},
     time::Duration,
 };
 
+use chrono::Local;
+
 use crossterm::{
     event::{poll, read, Event, KeyCode, KeyEvent, KeyModifiers},
     terminal::{disable_raw_mode, enable_raw_mode},
@@ -71,6 +75,7 @@ pub fn monitor(
     pid: u16,
     baud: u32,
     log_format: LogFormat,
+    log_path: Option<String>,
     interactive_mode: bool,
 ) -> miette::Result<()> {
     if interactive_mode {
@@ -101,9 +106,30 @@ pub fn monitor(
     };
 
     let mut buff = [0; 1024];
+    let mut log_file: Option<BufWriter<File>> = if let Some(log_path) = log_path.as_ref() {
+        let log_file_obj = OpenOptions::new().create(true).append(true).open(log_path);
+        if let Err(err) = log_file_obj.as_ref() {
+            println!("error opening log_file: {:?}", err);
+        }
+        log_file_obj.map(BufWriter::new).ok()
+    } else {
+        None
+    };
+
     loop {
         let read_count = match serial.read(&mut buff) {
-            Ok(count) => Ok(count),
+            Ok(count) => {
+                if let Some(log_file) = log_file.as_mut() {
+                    let line = String::from_utf8(buff.to_vec()).unwrap();
+                    if let Err(err) = log_file
+                        .write_all(strip_ansi_formatting_and_apply_timestamp(&line).as_bytes())
+                    {
+                        println!("could not write line {} to log file: {}", line, err);
+                    }
+                    log_file.write_all(b"\n").ok();
+                }
+                Ok(count)
+            }
             Err(e) if e.kind() == ErrorKind::TimedOut => Ok(0),
             Err(e) if e.kind() == ErrorKind::Interrupted => continue,
             err => err.into_diagnostic(),
@@ -112,6 +138,9 @@ pub fn monitor(
         parser.feed(&buff[0..read_count], &mut stdout);
 
         // Don't forget to flush the writer!
+        if let Some(log_file) = log_file.as_mut() {
+            log_file.flush().ok();
+        }
         stdout.flush().ok();
 
         if interactive_mode && poll(Duration::from_secs(0)).into_diagnostic()? {
@@ -138,6 +167,15 @@ pub fn monitor(
     Ok(())
 }
 
+fn strip_ansi_formatting_and_apply_timestamp(line_str: &str) -> String {
+    let re = Regex::new(r"\x1b\[[0-9;]*m").unwrap();
+    let line_str = re.replace_all(line_str, "").to_string();
+    let re = Regex::new(r";[0-9]*m").unwrap();
+    let line_str = re.replace_all(&line_str, "").to_string();
+    let current_time = Local::now().format("%+");
+    format!("{current_time} - {line_str}")
+}
+
 // Converts key events from crossterm into appropriate character/escape
 // sequences which are then sent over the serial connection.
 //