lock: Return message text on success

Since the lock API is intended to be used from command-line utilities
and shell scripts, we should return a helpful message when successful.

src/lock.rs

@@ -119,7 +119,7 @@ async fn wait_lease(client: Client, name: &str) -> Result<(), kube::Error> {
 pub async fn lock_v1(
     lockheader: Result<LockRequestHeader, InvalidHeader>,
     data: rocket::form::Result<'_, Form<LockRequest>>,
-) -> Result<(), LockError> {
+) -> Result<String, LockError> {
     lockheader?;
     let data = data?;
     let client = Client::try_default().await.inspect_err(|e| {
@@ -159,7 +159,10 @@ pub async fn lock_v1(
             Err(e) => return Err(e.into()),
         }
     }
-    Ok(())
+    Ok(format!(
+        "Acquired reboot lock for group {}, host {}\n",
+        data.group, data.hostname
+    ))
 }
 
 #[rocket::post("/api/v1/unlock", data = "<data>")]

tests/integration/lock.rs

@@ -43,7 +43,12 @@ async fn test_lock_v1_success() {
         .dispatch()
         .await;
     assert_eq!(response.status(), Status::Ok);
-    assert_eq!(response.into_string().await, None);
+    assert_eq!(
+        response.into_string().await.as_deref(),
+        Some(
+            "Acquired reboot lock for group default, host test1.example.org\n"
+        )
+    );
     let lease = get_lease("reboot-lock-default").await.unwrap();
     assert_eq!(
         lease.spec.unwrap().holder_identity.as_deref(),
@@ -65,7 +70,12 @@ async fn test_lock_v1_custom_group() {
         .dispatch()
         .await;
     assert_eq!(response.status(), Status::Ok);
-    assert_eq!(response.into_string().await, None);
+    assert_eq!(
+        response.into_string().await.as_deref(),
+        Some(
+            "Acquired reboot lock for group testgroup, host test1.example.org\n"
+        )
+    );
     let lease = get_lease("reboot-lock-testgroup").await.unwrap();
     assert_eq!(
         lease.spec.unwrap().holder_identity.as_deref(),
@@ -88,7 +98,12 @@ async fn test_lock_v1_conflict() {
         .dispatch()
         .await;
     assert_eq!(response.status(), Status::Ok);
-    assert_eq!(response.into_string().await, None);
+    assert_eq!(
+        response.into_string().await.as_deref(),
+        Some(
+            "Acquired reboot lock for group default, host test1.example.org\n"
+        )
+    );
     let response = client
         .post("/api/v1/lock")
         .header(Header::new("K8s-Reboot-Lock", "lock"))
@@ -129,7 +144,12 @@ async fn test_lock_v1_conflict_wait() {
         .dispatch()
         .await;
     assert_eq!(response.status(), Status::Ok);
-    assert_eq!(response.into_string().await, None);
+    assert_eq!(
+        response.into_string().await.as_deref(),
+        Some(
+            "Acquired reboot lock for group default, host test1.example.org\n"
+        )
+    );
     let lease = get_lease("reboot-lock-default").await.unwrap();
     assert_eq!(
         lease.spec.unwrap().holder_identity.as_deref(),
@@ -153,7 +173,12 @@ async fn test_lock_v1_conflict_wait() {
         .dispatch()
         .await;
     assert_eq!(response.status(), Status::Ok);
-    assert_eq!(response.into_string().await, None);
+    assert_eq!(
+        response.into_string().await.as_deref(),
+        Some(
+            "Acquired reboot lock for group default, host test2.example.org\n"
+        )
+    );
     let duration = timer.elapsed().as_millis();
     assert!(duration > 1000 && duration < 2000);
     let lease = get_lease("reboot-lock-default").await.unwrap();
@@ -213,7 +238,6 @@ async fn test_unlock_v1_success() {
         .dispatch()
         .await;
     assert_eq!(response.status(), Status::Ok);
-    assert_eq!(response.into_string().await, None);
     let lease = get_lease("reboot-lock-default").await.unwrap();
     assert_eq!(
         lease.spec.unwrap().holder_identity.as_deref(),
@@ -269,7 +293,6 @@ async fn test_unlock_v1_not_mine() {
         .dispatch()
         .await;
     assert_eq!(response.status(), Status::Ok);
-    assert_eq!(response.into_string().await, None);
     let lease = get_lease("reboot-lock-default").await.unwrap();
     assert_eq!(
         lease.spec.unwrap().holder_identity.as_deref(),