Rearrange pipeline injector to a vec of filters

src/command.rs

@@ -1,8 +1,10 @@
-use crate::progress::BackupEvent;
-use std::io;
 use std::io::Read;
-use std::sync::mpsc::Sender;
-use std::time::{Duration, Instant};
+
+/// A trait for filters that can be applied to the output of a command before
+/// it is piped to another command.
+pub trait Filter {
+    fn filter(&self, reader: Box<dyn Read>) -> Box<dyn Read>;
+}
 
 pub fn exec_command(command: &Vec<&str>) -> Result<String, String> {
     if command.is_empty() {
@@ -25,48 +27,10 @@ pub fn exec_command(command: &Vec<&str>) -> Result<String, String> {
     Ok(output_str)
 }
 
-struct CountingReader<R: Read> {
-    inner: R,
-    sender: Sender<BackupEvent>,
-    bytes: u64,
-    last_send: Instant,
-    total: Option<u64>,
-}
-
-impl<R: Read> Read for CountingReader<R> {
-    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
-        let n = self.inner.read(buf)?;
-        self.bytes += n as u64;
-        if self.last_send.elapsed().as_millis() >= 100 {
-            self.sender
-                .send(BackupEvent::BytesTransferred {
-                    bytes: self.bytes,
-                    estimated_total: self.total,
-                })
-                .ok();
-            self.last_send = Instant::now();
-        }
-        Ok(n)
-    }
-}
-
-impl<R: Read> CountingReader<R> {
-    fn new(inner: R, sender: Sender<BackupEvent>, total: Option<u64>) -> Self {
-        Self {
-            inner,
-            sender,
-            total,
-            bytes: 0,
-            last_send: Instant::now() - Duration::from_secs(1),
-        }
-    }
-}
-
 pub fn exec_piped_commands(
     source: &Vec<&str>,
     dest: &Vec<&str>,
-    sender: Option<Sender<BackupEvent>>,
-    total: Option<u64>,
+    filters: Vec<Box<dyn Filter>>,
 ) -> Result<(), String> {
     if source.is_empty() || dest.is_empty() {
         return Err("Source or destination command is empty".to_string());
@@ -93,10 +57,11 @@ pub fn exec_piped_commands(
     let send_stdout = send_process.stdout.take().unwrap();
     let mut receive_stdin = receive_process.stdin.take().unwrap();
 
-    let mut reader: Box<dyn Read> = match sender {
-        Some(s) => Box::new(CountingReader::new(send_stdout, s, total)),
-        None => Box::new(send_stdout),
-    };
+    let mut reader: Box<dyn Read> = Box::new(send_stdout);
+    for filter in filters {
+        reader = filter.filter(reader);
+    }
+
     std::io::copy(&mut reader, &mut receive_stdin).map_err(|e| e.to_string())?;
 
     let receive_status = receive_process.wait().map_err(|e| e.to_string())?;

src/job.rs

@@ -1,5 +1,6 @@
 use crate::command;
 use crate::progress::BackupEvent;
+use crate::progress::filter;
 use chrono::{Local, NaiveDateTime};
 use std::collections::HashSet;
 use std::sync::mpsc::Sender;
@@ -192,7 +193,11 @@ impl Job {
 
         let mut receive_cmd = self.get_side_command(JobSide::Destination);
         receive_cmd.extend(["receive", "-F", dest]);
-        command::exec_piped_commands(&send_cmd, &receive_cmd, self.sender.clone(), total)?;
+        let filters = match self.sender.as_ref() {
+            Some(sender) => vec![filter::CountingReaderBuilder::build(sender.clone(), total)],
+            None => vec![],
+        };
+        command::exec_piped_commands(&send_cmd, &receive_cmd, filters)?;
         self.send_event(BackupEvent::DatasetCompleted(source.to_string()));
         Ok(())
     }

src/main.rs

@@ -1,11 +1,11 @@
 use clap::Parser;
 
 use std::error::Error;
+use std::io::IsTerminal;
 use std::sync::mpsc::channel;
 use std::thread;
 use zfsbackup::job::JobBuilder;
-use zfsbackup::progress::Progressor;
-use zfsbackup::progress::terminal;
+use zfsbackup::progress::{Progressor, log, terminal};
 
 #[derive(Parser)]
 #[command(version, about, long_about = None)]
@@ -51,7 +51,11 @@ fn main() -> Result<(), Box<dyn Error>> {
     }
 
     let (tx, rx) = channel();
-    let mut pr: Box<dyn Progressor> = Box::new(terminal::Progressor::new(rx));
+    let mut pr: Box<dyn Progressor> = if std::io::stdout().is_terminal() {
+        Box::new(terminal::Progressor::new(rx))
+    } else {
+        Box::new(log::Progressor::new(rx))
+    };
     thread::spawn(move || pr.run());
 
     builder = builder.sender(tx);

src/progress/filter.rs

@@ -0,0 +1,59 @@
+use super::BackupEvent;
+use crate::command::Filter;
+use std::io::{self, Read};
+use std::sync::mpsc::Sender;
+use std::time::{Duration, Instant};
+
+struct CountingReader<R: Read> {
+    inner: R,
+    sender: Sender<BackupEvent>,
+    bytes: u64,
+    last_send: Instant,
+    total: Option<u64>,
+}
+
+impl<R: Read> Read for CountingReader<R> {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let n = self.inner.read(buf)?;
+        self.bytes += n as u64;
+        if self.last_send.elapsed().as_millis() >= 100 {
+            self.sender
+                .send(BackupEvent::BytesTransferred {
+                    bytes: self.bytes,
+                    estimated_total: self.total,
+                })
+                .ok();
+            self.last_send = Instant::now();
+        }
+        Ok(n)
+    }
+}
+
+impl<R: Read> CountingReader<R> {
+    fn new(inner: R, sender: Sender<BackupEvent>, total: Option<u64>) -> Self {
+        Self {
+            inner,
+            sender,
+            total,
+            bytes: 0,
+            last_send: Instant::now() - Duration::from_secs(1),
+        }
+    }
+}
+
+pub struct CountingReaderBuilder {
+    sender: Sender<BackupEvent>,
+    total: Option<u64>,
+}
+
+impl Filter for CountingReaderBuilder {
+    fn filter(&self, reader: Box<dyn Read>) -> Box<dyn Read> {
+        Box::new(CountingReader::new(reader, self.sender.clone(), self.total))
+    }
+}
+
+impl CountingReaderBuilder {
+    pub fn build(sender: Sender<BackupEvent>, total: Option<u64>) -> Box<dyn Filter> {
+        Box::new(Self { sender, total })
+    }
+}

src/progress/mod.rs

@@ -1,3 +1,4 @@
+pub mod filter;
 pub mod log;
 pub mod terminal;