Fix CrashLoopBackOff in rust-sample

examples/rust-simple/Cargo.toml

@@ -4,4 +4,3 @@ version = "0.1.0"
 
 [dependencies]
 agones = { path = "../../sdks/rust" }
-grpcio = "0.2.2"

examples/rust-simple/src/main.rs

@@ -7,15 +7,25 @@ use std::time::Duration;
 macro_rules! enclose {
     ( ($( $x:ident ),*) $y:expr ) => {
         {
-            $(let $x = $x.clone();)*
+            $(let mut $x = $x.clone();)*
             $y
         }
     };
 }
 
 fn main() {
     println!("Rust Game Server has started!");
-    let _ = run();
+
+    ::std::process::exit(match run() {
+        Ok(_) => {
+            println!("Rust Game Server finished.");
+            0
+        },
+        Err(msg) => {
+            println!("{}", msg);
+            1
+        }
+    });
 }
 
 fn run() -> Result<(), String>{
@@ -25,10 +35,15 @@ fn run() -> Result<(), String>{
 
     let _t = thread::spawn(enclose!{(sdk) move || {
         loop {
-            if sdk.health().is_err() {
-                println!("Health ping failed");
-            } else {
-                println!("Health ping sent");
+            match sdk.health() {
+                (s, Ok(_)) => {
+                    println!("Health ping sent");
+                    sdk = s;
+                },
+                (s, Err(e)) => {
+                    println!("Health ping failed : {:?}", e);
+                    sdk = s;
+                }
             }
             thread::sleep(Duration::from_secs(2));
         }

sdks/rust/src/errors.rs

@@ -3,4 +3,11 @@ error_chain!{
     foreign_links {
         Grpc(::grpcio::Error);
     }
+
+    errors {
+        HealthPingConnectionFailure(t: String) {
+            description("health ping connection failure"),
+            display("health ping connection failure: '{}'", t),
+        }
+    }
 }

sdks/rust/src/sdk.rs

@@ -1,6 +1,7 @@
-use std::sync::Arc;
+use std::sync::{Arc, Mutex};
 use std::time::Duration;
-use grpcio::{ChannelBuilder, EnvBuilder};
+use grpcio;
+use futures::{Future, Sink};
 
 use errors::*;
 use grpc::sdk as sdk;
@@ -12,6 +13,7 @@ const PORT: i32 = 59357;
 /// SDK is an instance of the Agones SDK
 pub struct Sdk {
     client : Arc<sdk_grpc::SdkClient>,
+    health : Arc<Mutex<Option<grpcio::ClientCStreamSender<sdk::Empty>>>>,
 }
 
 impl Sdk {
@@ -21,12 +23,13 @@ impl Sdk {
     /// Times out after 30 seconds.
     pub fn new() -> Result<Sdk> {
         let addr = format!("localhost:{}", PORT);
-        let env = Arc::new(EnvBuilder::new().build());
-        let ch = ChannelBuilder::new(env).keepalive_timeout(Duration::new(30, 0)).connect(&addr);
+        let env = Arc::new(grpcio::EnvBuilder::new().build());
+        let ch = grpcio::ChannelBuilder::new(env).keepalive_timeout(Duration::new(30, 0)).connect(&addr);
         let cli = sdk_grpc::SdkClient::new(ch);
         let req = sdk::Empty::new();
         let _ = cli.ready(&req).map(Box::new)?;
-        Ok(Sdk{client: Arc::new(cli)})
+        let (sender, _) = cli.health()?;
+        Ok(Sdk{client: Arc::new(cli), health: Arc::new(Mutex::new(Some(sender)))})
     }
 
     /// Marks the Game Server as ready to receive connections
@@ -44,16 +47,32 @@ impl Sdk {
     }
 
     /// Sends a ping to the health check to indicate that this server is healthy
-    pub fn health(&self) -> Result<()> {
-        let res = self.client.health().map(|_| ())?;
-        Ok(res)
+    pub fn health(mut self) -> (Self, Result<()>) {
+        // Avoid `cannot move out of borrowed content` compile error for self.health
+        let h = self.health.lock().unwrap().take();
+        if h.is_none() {
+            return (self, Err(ErrorKind::HealthPingConnectionFailure("failed to hold client stream for health ping".to_string()).into()));
+        }
+        let h : grpcio::ClientCStreamSender<sdk::Empty> = h.unwrap().into();
+
+        let req = sdk::Empty::new();
+        match h.send((req, grpcio::WriteFlags::default())).wait() {
+            Ok(h) => {
+                self.health = Arc::new(Mutex::new(Some(h)));
+                (self, Ok(()))
+            },
+            Err(e) => {
+                (self, Err(ErrorKind::Grpc(e).into()))
+            },
+        }
     }
 }
 
 impl Clone for Sdk {
     fn clone(&self) -> Self {
         Self {
             client: Arc::clone(&self.client),
+            health: self.health.clone(),
         }
     }
 }