Implement block on connect with Rust SDK

- Uses a simple polling mechanism to confirm the connection is live
- Add `ready` to the SDK documentation.

- Implements and documents a sdk.connect() function

- Tweaks the conformance tests to add a random delay to ensure future
  testing of SDK blocking.

Fixes googleforgames#938

build/includes/sdk.mk

@@ -122,15 +122,17 @@ run-sdk-conformance-local: ensure-agones-sdk-image
 	 -e "TEST=$(TESTS)" -e "TIMEOUT=$(TIMEOUT)" $(sidecar_tag)
 
 # Run SDK conformance test, previously built, for a specific SDK_FOLDER
+# Sleeps the start of the sidecar to test that the SDK blocks on connection correctly
 run-sdk-conformance-no-build: TIMEOUT ?= 30
+run-sdk-conformance-no-build: RANDOM := $(shell bash -c 'echo $$RANDOM')
+run-sdk-conformance-no-build: DELAY ?= $(shell bash -c "echo $$[ ($(RANDOM) % 5 ) + 1 ]s")
 run-sdk-conformance-no-build: TESTS ?= ready,allocate,setlabel,setannotation,gameserver,health,shutdown,watch
 run-sdk-conformance-no-build: ensure-agones-sdk-image
 run-sdk-conformance-no-build: ensure-build-sdk-image
-	sleep 2s && DOCKER_RUN_ARGS="--network=host $(DOCKER_RUN_ARGS)" COMMAND=sdktest $(MAKE) run-sdk-command & \
-	docker run -p 59357:59357 -e "ADDRESS=" \
+	DOCKER_RUN_ARGS="--network=host $(DOCKER_RUN_ARGS)" COMMAND=sdktest $(MAKE) run-sdk-command & \
+	sleep $(DELAY) && docker run -p 59357:59357 -e "ADDRESS=" \
 	 -e "TEST=$(TESTS)" -e "TIMEOUT=$(TIMEOUT)" --net=host  $(sidecar_tag)
 
-
 # Run SDK conformance test for a specific SDK_FOLDER
 run-sdk-conformance-test:
 	$(MAKE) run-sdk-command COMMAND=build-sdk-test

sdks/nodejs/spec/agonesSDK.spec.js

@@ -26,6 +26,31 @@ describe('agones', () => {
 		agonesSDK = new AgonesSDK();
 	});
 
+	describe('connect', () => {
+		it('calls the server and handles success', async () => {
+			spyOn(agonesSDK.client, 'waitForReady').and.callFake((deadline, callback) => {
+				let result = new messages.Empty();
+				callback(undefined, result);
+			});
+			let result = await agonesSDK.connect();
+			expect(agonesSDK.client.waitForReady).toHaveBeenCalled();
+			expect(result).toEqual(undefined);
+		});
+
+		it('calls the server and handles failure', async () => {
+			spyOn(agonesSDK.client, 'waitForReady').and.callFake((deadline, callback) => {
+				callback('error', undefined);
+			});
+			try {
+				await agonesSDK.connect();
+				fail();
+			} catch (error) {
+				expect(agonesSDK.client.waitForReady).toHaveBeenCalled();
+				expect(error).toEqual('error');
+			}
+		});
+	});
+
 	describe('allocate', () => {
 		it('calls the server and handles success', async () => {
 			spyOn(agonesSDK.client, 'allocate').and.callFake((request, callback) => {

sdks/nodejs/src/agonesSDK.js

@@ -24,8 +24,20 @@ class AgonesSDK {
 		this.emitters = [];
 	}
 
+	async connect() {
+		return new Promise((resolve, reject) => {
+			this.client.waitForReady(Date.now() + 30000, (error) => {
+				if (error) {
+					reject(error);
+				} else {
+					resolve();
+				}
+			})
+		});
+	}
+
 	async close() {
-		if (this.healthStream !== undefined) {
+		if (this.healthStream !== undefined){
 			this.healthStream.destroy();
 		}
 		this.emitters.forEach(emitter => emitter.call.cancel());

sdks/rust/src/sdk.rs

@@ -12,15 +12,18 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use futures::{Future, Sink, Stream};
-use grpcio;
 use std::sync::{Arc, Mutex};
+use std::thread::sleep;
 use std::time::Duration;
 
+use futures::{Future, Sink, Stream};
+use grpcio;
+use grpcio::CallOption;
+use protobuf::Message;
+
 use errors::*;
 use grpc::sdk;
 use grpc::sdk_grpc;
-use protobuf::Message;
 use types::*;
 
 const PORT: i32 = 59357;
@@ -34,7 +37,7 @@ pub struct Sdk {
 impl Sdk {
     /// Starts a new SDK instance, and connects to localhost on port 59357.
     /// Blocks until connection and handshake are made.
-    /// Times out after 30 seconds.
+    /// Times out after ~30 seconds.
     pub fn new() -> Result<Sdk> {
         let addr = format!("localhost:{}", PORT);
         let env = Arc::new(grpcio::EnvBuilder::new().build());
@@ -43,7 +46,24 @@ impl Sdk {
             .connect(&addr);
         let cli = sdk_grpc::SdkClient::new(ch);
         let req = sdk::Empty::new();
-        let _ = cli.ready(&req).map(Box::new)?;
+
+        // Unfortunately there isn't a native way to block until connected
+        // so we had to roll our own.
+        let mut counter = 0;
+        loop {
+            counter += 1;
+            match cli.get_game_server(&req) {
+                Ok(_) => break,
+                Err(e) => {
+                    if counter > 30 {
+                        return Err(ErrorKind::Grpc(e).into());
+                    }
+                    sleep(Duration::from_secs(1));
+                    continue;
+                }
+            }
+        }
+
         let (sender, _) = cli.health()?;
         Ok(Sdk {
             client: Arc::new(cli),
@@ -58,15 +78,13 @@ impl Sdk {
         Ok(res)
     }
 
-
-    /// Allocate the Game Server 
+    /// Allocate the Game Server
     pub fn allocate(&self) -> Result<()> {
         let req = sdk::Empty::default_instance();
         let res = self.client.allocate(req).map(|_| ())?;
         Ok(res)
     }
 
-
     /// Marks the Game Server as ready to shutdown
     pub fn shutdown(&self) -> Result<()> {
         let req = sdk::Empty::default_instance();

site/content/en/docs/Guides/Client SDKs/nodejs.md

@@ -28,14 +28,24 @@ Add the agones dependency to `package.json`, replacing with the download locatio
 }
 ```
 
-To begin working with the SDK, create an instance of it. This will open a connection to the SDK server.
+To begin working with the SDK, create an instance of it. {{< feature expiryVersion="0.12.0" >}}This will open a connection to the SDK server.{{< /feature >}}
 
 ```javascript
 const AgonesSDK = require('agones');
 
 let agonesSDK = new AgonesSDK();
 ```
 
+{{% feature publishVersion="0.12.0" %}}
+
+To connect to the SDK server, either local or when running on Agones, run the `async` method `sdk.connect()`, which will
+`resolve` once connected or `reject` on error or if no connection can be made after 30 seconds.
+
+```javascript
+await agonesSDK.connect();
+```
+{{% /feature %}}
+
 To send a [health check]({{< relref "_index.md#health" >}}) ping call `health()`.
 
 ```javascript

site/content/en/docs/Guides/Client SDKs/rust.md

@@ -46,6 +46,15 @@ if sdk.health().is_ok() {
 }
 ```
 
+{{% feature publishVersion="0.12.0" %}}
+
+To mark the [game session as ready]({{< relref "_index.md#ready" >}}) call `sdk.ready()`.
+
+```rust
+sdk.ready()?;
+```
+{{% /feature %}}
+
 To mark that the [game session is completed]({{< relref "_index.md#shutdown" >}}) and the game server should be shut down call `sdk.shutdown()`. 
 
 ```rust

test/sdk/nodejs/testSDKClient.js

@@ -18,6 +18,9 @@ const agonesSDK = new AgonesSDK();
 const connect = async function() {
   var UID = ""
   try {
+    console.log("attempting to connect");
+    await agonesSDK.connect();
+    console.log("connected!");
     var once = true;
     agonesSDK.watchGameServer((result) => {
         console.log("watch", result);

test/sdk/rust/.gitignore

@@ -0,0 +1,16 @@
+# Copyright 2019 Google LLC All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+/target/
+Cargo.lock

test/sdk/rust/src/main.rs

@@ -111,7 +111,7 @@ fn run() -> Result<(), String> {
         thread::sleep(Duration::from_secs(5));
     }
 
-    println!("Shutting down after 20 seconds...");
+    println!("Shutting down...");
     sdk.shutdown()
         .map_err(|e| format!("Could not run Shutdown: {}. Exiting!", e))?;
     println!("...marked for Shutdown");