feat: basic kratactl top command (#72)

* feat: basic kratactl top command

* fix: use magic bytes 0xff 0xff in idm to improve reliability

crates/ctl/src/cli/mod.rs

@@ -6,6 +6,7 @@ pub mod list;
 pub mod logs;
 pub mod metrics;
 pub mod resolve;
+pub mod top;
 pub mod watch;
 
 use anyhow::{anyhow, Result};
@@ -20,7 +21,7 @@ use tonic::{transport::Channel, Request};
 use self::{
     attach::AttachCommand, destroy::DestroyCommand, idm_snoop::IdmSnoopCommand,
     launch::LauchCommand, list::ListCommand, logs::LogsCommand, metrics::MetricsCommand,
-    resolve::ResolveCommand, watch::WatchCommand,
+    resolve::ResolveCommand, top::TopCommand, watch::WatchCommand,
 };
 
 #[derive(Parser)]
@@ -52,6 +53,7 @@ pub enum Commands {
     Resolve(ResolveCommand),
     Metrics(MetricsCommand),
     IdmSnoop(IdmSnoopCommand),
+    Top(TopCommand),
 }
 
 impl ControlCommand {
@@ -95,6 +97,10 @@ impl ControlCommand {
             Commands::IdmSnoop(snoop) => {
                 snoop.run(client, events).await?;
             }
+
+            Commands::Top(top) => {
+                top.run(client, events).await?;
+            }
         }
         Ok(())
     }

crates/ctl/src/cli/top.rs

@@ -0,0 +1,215 @@
+use anyhow::Result;
+use clap::Parser;
+use krata::{events::EventStream, v1::control::control_service_client::ControlServiceClient};
+use std::{
+    io::{self, stdout, Stdout},
+    time::Duration,
+};
+use tokio::select;
+use tokio_stream::StreamExt;
+use tonic::transport::Channel;
+
+use crossterm::{
+    event::{Event, KeyCode, KeyEvent, KeyEventKind},
+    execute,
+    terminal::*,
+};
+use ratatui::{
+    prelude::*,
+    symbols::border,
+    widgets::{
+        block::{Position, Title},
+        Block, Borders, Row, Table, TableState,
+    },
+};
+
+use crate::{
+    format::guest_status_text,
+    metrics::{
+        lookup_metric_value, MultiMetricCollector, MultiMetricCollectorHandle, MultiMetricState,
+    },
+};
+
+#[derive(Parser)]
+#[command(about = "Dashboard for running guests")]
+pub struct TopCommand {}
+
+pub type Tui = Terminal<CrosstermBackend<Stdout>>;
+
+impl TopCommand {
+    pub async fn run(
+        self,
+        client: ControlServiceClient<Channel>,
+        events: EventStream,
+    ) -> Result<()> {
+        let collector = MultiMetricCollector::new(client, events, Duration::from_millis(200))?;
+        let collector = collector.launch().await?;
+        let mut tui = TopCommand::init()?;
+        let mut app = TopApp {
+            metrics: MultiMetricState { guests: vec![] },
+            exit: false,
+            table: TableState::new(),
+        };
+        app.run(collector, &mut tui).await?;
+        TopCommand::restore()?;
+        Ok(())
+    }
+
+    pub fn init() -> io::Result<Tui> {
+        execute!(stdout(), EnterAlternateScreen)?;
+        enable_raw_mode()?;
+        Terminal::new(CrosstermBackend::new(stdout()))
+    }
+
+    pub fn restore() -> io::Result<()> {
+        execute!(stdout(), LeaveAlternateScreen)?;
+        disable_raw_mode()?;
+        Ok(())
+    }
+}
+
+pub struct TopApp {
+    table: TableState,
+    metrics: MultiMetricState,
+    exit: bool,
+}
+
+impl TopApp {
+    pub async fn run(
+        &mut self,
+        mut collector: MultiMetricCollectorHandle,
+        terminal: &mut Tui,
+    ) -> Result<()> {
+        let mut events = crossterm::event::EventStream::new();
+
+        while !self.exit {
+            terminal.draw(|frame| self.render_frame(frame))?;
+
+            select! {
+                x = collector.receiver.recv() => match x {
+                    Some(state) => {
+                        self.metrics = state;
+                    },
+
+                    None => {
+                        break;
+                    }
+                },
+
+                x = events.next() => match x {
+                    Some(event) => {
+                        let event = event?;
+                        self.handle_event(event)?;
+                    },
+
+                    None => {
+                        break;
+                    }
+                }
+            };
+        }
+        Ok(())
+    }
+
+    fn render_frame(&mut self, frame: &mut Frame) {
+        frame.render_widget(self, frame.size());
+    }
+
+    fn handle_event(&mut self, event: Event) -> io::Result<()> {
+        match event {
+            Event::Key(key_event) if key_event.kind == KeyEventKind::Press => {
+                self.handle_key_event(key_event)
+            }
+            _ => {}
+        };
+        Ok(())
+    }
+
+    fn exit(&mut self) {
+        self.exit = true;
+    }
+
+    fn handle_key_event(&mut self, key_event: KeyEvent) {
+        if let KeyCode::Char('q') = key_event.code {
+            self.exit()
+        }
+    }
+}
+
+impl Widget for &mut TopApp {
+    fn render(self, area: Rect, buf: &mut Buffer) {
+        let title = Title::from(" krata hypervisor ".bold());
+        let instructions = Title::from(vec![" Quit ".into(), "<Q> ".blue().bold()]);
+        let block = Block::default()
+            .title(title.alignment(Alignment::Center))
+            .title(
+                instructions
+                    .alignment(Alignment::Center)
+                    .position(Position::Bottom),
+            )
+            .borders(Borders::ALL)
+            .border_set(border::THICK);
+
+        let mut rows = vec![];
+
+        for ms in &self.metrics.guests {
+            let Some(ref spec) = ms.guest.spec else {
+                continue;
+            };
+
+            let Some(ref state) = ms.guest.state else {
+                continue;
+            };
+
+            let memory_total = ms
+                .root
+                .as_ref()
+                .and_then(|root| lookup_metric_value(root, "system/memory/total"));
+            let memory_used = ms
+                .root
+                .as_ref()
+                .and_then(|root| lookup_metric_value(root, "system/memory/used"));
+            let memory_free = ms
+                .root
+                .as_ref()
+                .and_then(|root| lookup_metric_value(root, "system/memory/free"));
+
+            let row = Row::new(vec![
+                spec.name.clone(),
+                ms.guest.id.clone(),
+                guest_status_text(state.status()),
+                memory_total.unwrap_or_default(),
+                memory_used.unwrap_or_default(),
+                memory_free.unwrap_or_default(),
+            ]);
+            rows.push(row);
+        }
+
+        let widths = [
+            Constraint::Min(8),
+            Constraint::Min(8),
+            Constraint::Min(8),
+            Constraint::Min(8),
+            Constraint::Min(8),
+            Constraint::Min(8),
+        ];
+
+        let table = Table::new(rows, widths)
+            .header(
+                Row::new(vec![
+                    "name",
+                    "id",
+                    "status",
+                    "total memory",
+                    "used memory",
+                    "free memory",
+                ])
+                .style(Style::new().bold())
+                .bottom_margin(1),
+            )
+            .column_spacing(1)
+            .block(block);
+
+        StatefulWidget::render(table, area, buf, &mut self.table);
+    }
+}