Use ratatui instead of tui-rs for the terminal UI (#505)

Author: joshka

.github/workflows/ci.yml

@@ -44,16 +44,22 @@ jobs:
     name: Test ${{ matrix.rust_version }}
     runs-on: ubuntu-latest
     strategy:
+      # 1.70 is the MSRV for the project, which currently does not match the version specified in
+      # the rust-toolchain.toml file as metrics-observer requires 1.74 to build. See
+      # https://github.com/metrics-rs/metrics/pull/505#discussion_r1724092556 for more information.
       matrix:
-        rust_version: ['stable', 'nightly']
+        rust_version: ['stable', 'nightly', '1.70']
+        include:
+          - rust_version: '1.70'
+            exclude-packages: '--exclude metrics-observer'
     steps:
     - uses: actions/checkout@v3
     - name: Install Protobuf Compiler
       run: sudo apt-get install protobuf-compiler
     - name: Install Rust ${{ matrix.rust_version }}
       run: rustup install ${{ matrix.rust_version }}
     - name: Run Tests
-      run: cargo +${{ matrix.rust_version }} test --all-features --workspace
+      run: cargo +${{ matrix.rust_version }} test --all-features --workspace ${{ matrix.exclude-packages }}
   docs:
     runs-on: ubuntu-latest
     env:

metrics-observer/Cargo.toml

@@ -3,7 +3,7 @@ name = "metrics-observer"
 version = "0.4.0"
 authors = ["Toby Lawrence <toby@nuclearfurnace.com>"]
 edition = "2018"
-rust-version = "1.70.0"
+rust-version = "1.74.0"
 
 license = "MIT"
 
@@ -23,8 +23,7 @@ bytes = { version = "1", default-features = false }
 crossbeam-channel = { version = "0.5", default-features = false, features = ["std"] }
 prost = { version = "0.12", default-features = false }
 prost-types = { version = "0.12", default-features = false }
-tui = { version = "0.19", default-features = false, features = ["termion"] }
-termion = { version = "2", default-features = false }
+ratatui = { version = "0.28.0", default-features = false, features = ["crossterm"] }
 chrono = { version = "0.4", default-features = false, features = ["clock"] }
 
 [build-dependencies]

metrics-observer/src/input.rs

@@ -1,37 +1,18 @@
 use std::io;
-use std::thread;
 use std::time::Duration;
 
-use crossbeam_channel::{bounded, Receiver, RecvTimeoutError, TrySendError};
-use termion::event::Key;
-use termion::input::TermRead;
+use ratatui::crossterm::event::{self, Event, KeyEvent, KeyEventKind};
 
-pub struct InputEvents {
-    rx: Receiver<Key>,
-}
+pub struct InputEvents;
 
 impl InputEvents {
-    pub fn new() -> InputEvents {
-        let (tx, rx) = bounded(1);
-        thread::spawn(move || {
-            let stdin = io::stdin();
-            for key in stdin.keys().flatten() {
-                // If our queue is full, we don't care.  The user can just press the key again.
-                if let Err(TrySendError::Disconnected(_)) = tx.try_send(key) {
-                    eprintln!("input event channel disconnected");
-                    return;
-                }
+    pub fn next() -> io::Result<Option<KeyEvent>> {
+        if event::poll(Duration::from_secs(1))? {
+            match event::read()? {
+                Event::Key(key) if key.kind == KeyEventKind::Press => return Ok(Some(key)),
+                _ => {}
             }
-        });
-
-        InputEvents { rx }
-    }
-
-    pub fn next(&mut self) -> Result<Option<Key>, RecvTimeoutError> {
-        match self.rx.recv_timeout(Duration::from_secs(1)) {
-            Ok(key) => Ok(Some(key)),
-            Err(RecvTimeoutError::Timeout) => Ok(None),
-            Err(e) => Err(e),
         }
+        Ok(None)
     }
 }

metrics-observer/src/main.rs

@@ -1,16 +1,20 @@
-use std::fmt;
 use std::num::FpCategory;
 use std::time::Duration;
 use std::{error::Error, io};
+use std::{fmt, io::Stdout};
 
 use chrono::Local;
 use metrics::Unit;
-use termion::{event::Key, input::MouseTerminal, raw::IntoRawMode, screen::IntoAlternateScreen};
-use tui::{
-    backend::TermionBackend,
+use ratatui::{
+    backend::CrosstermBackend,
+    crossterm::{
+        event::KeyCode,
+        execute,
+        terminal::{disable_raw_mode, enable_raw_mode, EnterAlternateScreen, LeaveAlternateScreen},
+    },
     layout::{Constraint, Direction, Layout},
     style::{Color, Modifier, Style},
-    text::{Span, Spans},
+    text::{Line, Span},
     widgets::{Block, Borders, List, ListItem, Paragraph, Wrap},
     Terminal,
 };
@@ -27,23 +31,23 @@ mod selector;
 use self::selector::Selector;
 
 fn main() -> Result<(), Box<dyn Error>> {
-    let stdout = io::stdout().into_raw_mode()?;
-    let stdout = MouseTerminal::from(stdout).into_alternate_screen()?;
-    let backend = TermionBackend::new(stdout);
-    let mut terminal = Terminal::new(backend)?;
+    let terminal = init_terminal()?;
+    let result = run(terminal);
+    restore_terminal()?;
+    result
+}
 
-    let mut events = InputEvents::new();
+fn run(mut terminal: Terminal<CrosstermBackend<Stdout>>) -> Result<(), Box<dyn Error>> {
     let address = std::env::args().nth(1).unwrap_or_else(|| "127.0.0.1:5000".to_owned());
     let client = metrics_inner::Client::new(address);
     let mut selector = Selector::new();
-
     loop {
         terminal.draw(|f| {
             let chunks = Layout::default()
                 .direction(Direction::Vertical)
                 .margin(1)
                 .constraints([Constraint::Length(4), Constraint::Percentage(90)].as_ref())
-                .split(f.size());
+                .split(f.area());
 
             let current_dt = Local::now().format(" (%Y/%m/%d %I:%M:%S %p)").to_string();
             let client_state = match client.state() {
@@ -58,9 +62,9 @@ fn main() -> Result<(), Box<dyn Error>> {
                         spans.push(Span::raw(s));
                     }
 
-                    Spans::from(spans)
+                    Line::from(spans)
                 }
-                ClientState::Connected => Spans::from(vec![
+                ClientState::Connected => Line::from(vec![
                     Span::raw("state: "),
                     Span::styled("connected", Style::default().fg(Color::Green)),
                 ]),
@@ -75,7 +79,7 @@ fn main() -> Result<(), Box<dyn Error>> {
 
             let text = vec![
                 client_state,
-                Spans::from(vec![
+                Line::from(vec![
                     Span::styled("controls: ", Style::default().add_modifier(Modifier::BOLD)),
                     Span::raw("up/down = scroll, q = quit"),
                 ]),
@@ -149,21 +153,31 @@ fn main() -> Result<(), Box<dyn Error>> {
 
         // Poll the event queue for input events.  `next` will only block for 1 second,
         // so our screen is never stale by more than 1 second.
-        if let Some(input) = events.next()? {
-            match input {
-                Key::Char('q') => break,
-                Key::Up => selector.previous(),
-                Key::Down => selector.next(),
-                Key::PageUp => selector.top(),
-                Key::PageDown => selector.bottom(),
+        if let Some(input) = InputEvents::next()? {
+            match input.code {
+                KeyCode::Char('q') => break,
+                KeyCode::Up => selector.previous(),
+                KeyCode::Down => selector.next(),
+                KeyCode::PageUp => selector.top(),
+                KeyCode::PageDown => selector.bottom(),
                 _ => {}
             }
         }
     }
-
     Ok(())
 }
 
+fn init_terminal() -> io::Result<Terminal<CrosstermBackend<Stdout>>> {
+    enable_raw_mode()?;
+    execute!(io::stdout(), EnterAlternateScreen)?;
+    Terminal::new(CrosstermBackend::new(io::stdout()))
+}
+
+fn restore_terminal() -> io::Result<()> {
+    disable_raw_mode()?;
+    execute!(io::stdout(), LeaveAlternateScreen)
+}
+
 fn u64_to_displayable(value: u64, unit: Option<Unit>) -> String {
     let unit = match unit {
         None => return value.to_string(),

metrics-observer/src/selector.rs

@@ -1,4 +1,4 @@
-use tui::widgets::ListState;
+use ratatui::widgets::ListState;
 
 pub struct Selector(usize, ListState);
 

metrics/src/common.rs

@@ -276,7 +276,7 @@ macro_rules! into_f64 {
     };
 }
 
-pub(self) use into_f64;
+use into_f64;
 
 #[cfg(test)]
 mod tests {

rust-toolchain.toml

@@ -1,2 +1,5 @@
 [toolchain]
-channel = "1.70.0"
+# Note that this is greater than the MSRV of the workspace (1.70) due to metrics-observer needing
+# 1.74, while all the other crates only require 1.70. See
+# https://github.com/metrics-rs/metrics/pull/505#discussion_r1724092556 for more information.
+channel = "1.74.0"