Add watch example.

Author: davidli2010

examples/kv.rs

@@ -46,14 +46,14 @@ async fn main() -> Result<(), Error> {
     println!("put kv: {:?}", chris);
     println!();
 
-    // get bob
+    // get kv
     let resp = client.get(bob.key(), None).await?;
     if let Some(kv) = resp.kvs().first() {
         println!("Get kv: {{{}: {}}}", kv.key_str()?, kv.value_str()?);
         println!();
     }
 
-    // get all key-value pairs
+    // get all kv pairs
     println!("Get all users:");
     let resp = client
         .get("", Some(GetOptions::new().with_from_key()))
@@ -63,7 +63,7 @@ async fn main() -> Result<(), Error> {
     }
     println!();
 
-    // delete chris
+    // delete kv
     let resp = client
         .delete(chris.key(), Some(DeleteOptions::new().with_prev_key()))
         .await?;

examples/watch.rs

@@ -0,0 +1,42 @@
+//! Watch example
+
+use etcdv3::*;
+
+#[tokio::main]
+async fn main() -> Result<(), Error> {
+    let mut client = Client::connect(["localhost:2379"]).await?;
+
+    client.put("foo", "bar", None).await?;
+    println!("put kv: {{foo: bar}}");
+
+    let (mut watcher, mut stream) = client.watch("foo", None).await?;
+    println!("create watcher {}", watcher.watch_id());
+    println!();
+
+    client.put("foo", "bar2", None).await?;
+    client.delete("foo", None).await?;
+
+    while let Some(resp) = stream.message().await? {
+        println!("receive watch response");
+
+        if resp.canceled() {
+            println!("watch canceled!");
+            break;
+        }
+
+        for event in resp.events() {
+            println!("event type: {:?}", event.event_type());
+            if let Some(kv) = event.kv() {
+                println!("kv: {{{}: {}}}", kv.key_str()?, kv.value_str()?);
+            }
+
+            if EventType::Delete == event.event_type() {
+                watcher.cancel().await?;
+            }
+        }
+
+        println!();
+    }
+
+    Ok(())
+}