Add a header to log files

Cargo.toml

@@ -4,6 +4,7 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
+chrono = "0.4.38"
 clap = { version = "4.5.17", features = ["derive", "env"] }
 crossbeam = "0.8.4"
 eyre = "0.6.12"

src/lib.rs

@@ -1,24 +1,30 @@
 mod flat_map_err;
+mod log_file;
 
 use crate::flat_map_err::FlatMapErr;
+use chrono::Utc;
 use core::panic;
 use crossbeam::channel::{bounded, select, Receiver, TrySendError};
 use eyre::{eyre, Result};
 use std::{
- fs::OpenOptions,
  io::{stderr, stdin, stdout, Read, Write},
  path::Path,
  process::{Command, Stdio},
  thread::{self, Scope},
 };
 
+fn default_header(name: &str) -> String {
+ format!("[{}]: Begin runner log of {name}", Utc::now())
+}
+
 fn io_streams<W: Write + Send + 'static>(
+ header: Option<&str>,
  writer: W,
  log_path: Option<&Path>,
 ) -> Result<(Stdio, Vec<Box<dyn Write + Send>>)> {
  match log_path {
  Some(path) => {
- let file = OpenOptions::new().create(true).append(true).open(path)?;
+ let file = log_file::new(header, path)?;
  Ok((Stdio::piped(), vec![Box::new(writer), Box::new(file)]))
  }
  None => Ok((Stdio::inherit(), vec![Box::new(writer)])),
@@ -36,13 +42,23 @@ fn io_streams<W: Write + Send + 'static>(
 pub fn run(
  cmd: &str,
  args: &[&str],
+ no_header: bool,
  stdin_log_path: Option<&Path>,
  stdout_log_path: Option<&Path>,
  stderr_log_path: Option<&Path>,
 ) -> Result<i32> {
  let in_io = stdout_log_path.map_or(Stdio::inherit(), |_| Stdio::piped());
- let (out_io, mut out_writers) = io_streams(stdout(), stdout_log_path)?;
- let (err_io, mut err_writers) = io_streams(stderr(), stderr_log_path)?;
+
+ let (out_header, err_header) = if no_header {
+ (None, None)
+ } else {
+ (
+ Some(default_header("stdout")),
+ Some(default_header("stderr")),
+ )
+ };
+ let (out_io, mut out_writers) = io_streams(out_header.as_deref(), stdout(), stdout_log_path)?;
+ let (err_io, mut err_writers) = io_streams(err_header.as_deref(), stderr(), stderr_log_path)?;
 
  let mut child = Command::new(cmd)
  .args(args)
@@ -53,10 +69,12 @@ pub fn run(
 
  match child.stdin.take() {
  Some(child_in) => {
- let in_file = OpenOptions::new()
- .create(true)
- .append(true)
- .open(stdin_log_path.unwrap())?;
+ let header = if no_header {
+ None
+ } else {
+ Some(default_header("stdin"))
+ };
+ let in_file = log_file::new(header.as_deref(), stdin_log_path.unwrap())?;
  let mut in_writers: Vec<Box<dyn Write + Send>> =
  vec![Box::new(child_in), Box::new(in_file)];
 

src/log_file.rs

@@ -0,0 +1,13 @@
+use std::{
+ fs::{File, OpenOptions},
+ io::{Result, Write},
+ path::Path,
+};
+
+pub(crate) fn new(header: Option<&str>, path: &Path) -> Result<File> {
+ let mut file = OpenOptions::new().create(true).append(true).open(path)?;
+ if let Some(header) = header {
+ writeln!(file, "{header}")?;
+ }
+ Ok(file)
+}