Append to log files instead of overwriting

Cargo.toml

@@ -11,6 +11,7 @@ eyre = "0.6.12"
 [dev-dependencies]
 assert_cmd = "2.0.16"
 pretty_assertions = "1.4.1"
+tempfile = "3.12.0"
 
 [lints.clippy]
 all = "deny"

src/lib.rs

@@ -5,7 +5,7 @@ use core::panic;
 use crossbeam::channel::{bounded, select, Receiver, TrySendError};
 use eyre::{eyre, Result};
 use std::{
- fs::File,
+ fs::OpenOptions,
  io::{stderr, stdin, stdout, Read, Write},
  path::Path,
  process::{Command, Stdio},
@@ -18,7 +18,7 @@ fn io_streams<W: Write + Send + 'static>(
 ) -> Result<(Stdio, Vec<Box<dyn Write + Send>>)> {
  match log_path {
  Some(path) => {
- let file = File::create(path)?;
+ let file = OpenOptions::new().create(true).append(true).open(path)?;
  Ok((Stdio::piped(), vec![Box::new(writer), Box::new(file)]))
  }
  None => Ok((Stdio::inherit(), vec![Box::new(writer)])),
@@ -53,7 +53,10 @@ pub fn run(
 
  match child.stdin.take() {
  Some(child_in) => {
- let in_file = File::create(stdin_log_path.unwrap())?;
+ let in_file = OpenOptions::new()
+ .create(true)
+ .append(true)
+ .open(stdin_log_path.unwrap())?;
  let mut in_writers: Vec<Box<dyn Write + Send>> =
  vec![Box::new(child_in), Box::new(in_file)];
 

tests/integration_test.rs

@@ -1,15 +1,90 @@
 use assert_cmd::Command;
+use eyre::{eyre, Result};
+use pretty_assertions::assert_eq;
+use std::{
+ fs::File,
+ io::{Read, Write},
+ path::Path,
+};
+use tempfile::tempdir;
 
 #[test]
-fn child_exit() {
- let mut runner = Command::cargo_bin("runner").unwrap();
- let assert = runner.args(["--", "echo", "hello"]).assert();
- assert.success().stdout("hello\n");
+fn child_exit() -> Result<()> {
+ Command::cargo_bin("runner")?
+ .args(["--", "echo", "hello"])
+ .assert()
+ .success()
+ .stdout("hello\n");
+ Ok(())
 }
 
 #[test]
-fn stdin_close() {
+fn stdin_close() -> Result<()> {
+ Command::cargo_bin("runner")?
+ .args(["--", "cat"])
+ .write_stdin("hello")
+ .assert()
+ .success()
+ .stdout("hello");
+ Ok(())
+}
+
+const TEMP_HEADER: &str = "Temporary File Header";
+
+#[test]
+fn child_exit_with_files() -> Result<()> {
  let mut runner = Command::cargo_bin("runner").unwrap();
- let assert = runner.args(["--", "cat"]).write_stdin("hello").assert();
- assert.success().stdout("hello");
+ let dir = tempdir()?;
+
+ let in_file_path = dir.path().join("in.log");
+ let out_file_path = dir.path().join("out.log");
+ let err_file_path = dir.path().join("err.log");
+
+ [&in_file_path, &out_file_path, &err_file_path]
+ .into_iter()
+ .try_for_each(|p| create_temp_data_in_file(p))
+ .unwrap();
+
+ runner
+ .args([
+ "--in-file",
+ in_file_path
+ .to_str()
+ .ok_or_else(|| eyre!("invalid in-file path"))?,
+ "--out-file",
+ out_file_path
+ .to_str()
+ .ok_or_else(|| eyre!("invalid out-file path"))?,
+ "--err-file",
+ err_file_path
+ .to_str()
+ .ok_or_else(|| eyre!("invalid err-file path"))?,
+ "--",
+ "cat",
+ ])
+ .write_stdin("hello world\n")
+ .assert()
+ .success()
+ .stdout("hello world\n");
+
+ let in_contents = read_file(&in_file_path)?;
+ let out_contents = read_file(&out_file_path)?;
+ let err_contents = read_file(&err_file_path)?;
+
+ assert_eq!(in_contents, format!("{TEMP_HEADER}\nhello world\n"));
+ assert_eq!(out_contents, format!("{TEMP_HEADER}\nhello world\n"));
+ assert_eq!(err_contents, format!("{TEMP_HEADER}\n"));
+ Ok(())
+}
+
+fn read_file(path: &Path) -> Result<String> {
+ let mut out = String::new();
+ File::open(path)?.read_to_string(&mut out)?;
+ Ok(out)
+}
+
+fn create_temp_data_in_file(path: &Path) -> Result<()> {
+ let mut f = File::create_new(path)?;
+ writeln!(f, "{TEMP_HEADER}")?;
+ Ok(())
 }