feature(kratactl): rework cli to use subcommands (#268)

crates/ctl/src/cli/zone/watch.rs

@@ -0,0 +1,63 @@
+use anyhow::Result;
+use clap::{Parser, ValueEnum};
+use krata::{
+    events::EventStream,
+    v1::{common::Zone, control::watch_events_reply::Event},
+};
+use prost_reflect::ReflectMessage;
+use serde_json::Value;
+
+use crate::format::{kv2line, proto2dynamic, proto2kv, zone_simple_line};
+
+#[derive(ValueEnum, Clone, Debug, PartialEq, Eq)]
+enum ZoneWatchFormat {
+    Simple,
+    Json,
+    KeyValue,
+}
+
+#[derive(Parser)]
+#[command(about = "Watch for zone changes")]
+pub struct ZoneWatchCommand {
+    #[arg(short, long, default_value = "simple", help = "Output format")]
+    format: ZoneWatchFormat,
+}
+
+impl ZoneWatchCommand {
+    pub async fn run(self, events: EventStream) -> Result<()> {
+        let mut stream = events.subscribe();
+        loop {
+            let event = stream.recv().await?;
+
+            let Event::ZoneChanged(changed) = event;
+            let zone = changed.zone.clone();
+            self.print_event("zone.changed", changed, zone)?;
+        }
+    }
+
+    fn print_event(&self, typ: &str, event: impl ReflectMessage, zone: Option<Zone>) -> Result<()> {
+        match self.format {
+            ZoneWatchFormat::Simple => {
+                if let Some(zone) = zone {
+                    println!("{}", zone_simple_line(&zone));
+                }
+            }
+
+            ZoneWatchFormat::Json => {
+                let message = proto2dynamic(event)?;
+                let mut value = serde_json::to_value(&message)?;
+                if let Value::Object(ref mut map) = value {
+                    map.insert("event.type".to_string(), Value::String(typ.to_string()));
+                }
+                println!("{}", serde_json::to_string(&value)?);
+            }
+
+            ZoneWatchFormat::KeyValue => {
+                let mut map = proto2kv(event)?;
+                map.insert("event.type".to_string(), typ.to_string());
+                println!("{}", kv2line(map),);
+            }
+        }
+        Ok(())
+    }
+}