Reserve() SDK implementation #891

markmandel · 2019-07-10T17:32:43Z

This implements Reserve, with an implementation with the Go SDK.

It was also convenience to switch Allocate back to the standard async
implementation here, so that all the SDK commands are consistent in
their concurrency patterns.

Still to come:

e2e tests
sdk conformance test
updates to gameserver lifecycle documentation

agones-bot · 2019-07-10T17:51:43Z

Build Succeeded 👏

Build Id: f7dee006-7775-4d57-8335-04a7139c3966

The following development artifacts have been built, and will exist for the next 30 days:

image: gcr.io/agones-images/agones-controller:0.12.0-2543584
image: gcr.io/agones-images/agones-sdk:0.12.0-2543584
image: gcr.io/agones-images/agones-ping:0.12.0-2543584
Linux C++ SDK (build): agonessdk-0.12.0-2543584-linux-arch_64.tar.gz
SDK Server: agonessdk-server-0.12.0-2543584.zip

A preview of the website (the last 30 builds are retained):

https://2543584-dot-preview-dot-agones-images.appspot.com/

To install this version:

git fetch https://github.com/GoogleCloudPlatform/agones.git pull/891/head:pr_891 && git checkout pr_891
helm install install/helm/agones --namespace agones-system --name agones --set agones.image.tag=0.12.0-2543584

roberthbailey · 2019-07-10T21:18:27Z

Looks like this is part of #660.

markmandel · 2019-07-10T21:27:20Z

Looks like this is part of #660.

Yes! Thanks, forgot to put that on here.

roberthbailey

This is my first long-ish review of Go code in this repository, so feel free to take my comments with a grain of salt. I'm also happy to be told where I'm barking up the wrong tree.

roberthbailey · 2019-07-15T18:55:19Z

sdks/go/sdk.go

@@ -79,6 +79,13 @@ func (s *SDK) Shutdown() error {
 	return errors.Wrapf(err, "could not send Shutdown message")
 }

+// Reserve marks the Game Server as Reserved, for a given duration


This comment seems incomplete, and is missing a matching parentheses.

roberthbailey · 2019-07-15T18:57:52Z

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

+### Reserve(seconds)
+
+With some matchmaking scenarios and systems it is important to be able to ensure that a `GameServer` is unable to be deleted,
+but doesn't trigger a FleetAutoscaler scale up. This is where `Reserver()` is useful.


typo: s/Reserver/Reserve

Also, elsewhere the function is written with the seconds argument, but here it is written as if it has no arguments. Please make them consistent.

roberthbailey · 2019-07-15T18:58:40Z

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

+but doesn't trigger a FleetAutoscaler scale up. This is where `Reserver()` is useful.
+
+`Reserve(seconds)` will move the `GameServer` into the Reserved state for the specified number of seconds (0 is forever), and then it will be
+moved back to `Ready` state. While in `Reserved` state, the `GameServer` cannot be deleted on scale down or `Fleet` update,


s/cannot/will not

roberthbailey · 2019-07-15T18:59:01Z

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

+moved back to `Ready` state. While in `Reserved` state, the `GameServer` cannot be deleted on scale down or `Fleet` update,
+and also cannot be Allocated. 
+
+This is often used wherein a game server process must self register itself with an external system, such as a matchmaker,


s/wherein/when

roberthbailey · 2019-07-15T18:59:29Z

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

+
+This is often used wherein a game server process must self register itself with an external system, such as a matchmaker,
+that requires it to designate itself as available for a game session for a certain period. Once a game session has started,
+it can call `SDK.Allocate` to designate that players are currently active on it.


Should this say must instead of can?

I switched it to should - just because you don't have to, but you should. 👍

roberthbailey · 2019-07-15T19:39:33Z

pkg/sdkserver/sdkserver_test.go

+	// test ready
+	_, err = sc.Reserve(context.Background(), &sdk.Duration{Seconds: 3})
+	assert.NoError(t, err)
+	assertStateChange(v1alpha1.GameServerStateReserved, 2*time.Second, noAdditional)


above the check after calling reserve had an assert, why not do one here too?

Not sure I understand this one? can you be specific about what is missing? I'm not seeing it.

Here you pass in the noAdditional function as the third argument. Above you did

assertStateChange(v1alpha1.GameServerStateReserved, 2*time.Second, func(status v1alpha1.GameServerStatus) { assert.Equal(t, time.Now().Add(3*time.Second).Round(time.Second), status.ReservedUntil.Time.Round(time.Second)) })

So the first time you verify that the state changed via the callback but in subsequent times you don't.

Oh! I see it now. I figured it might be redundant to test it again, but I see your point. I'll make the change!

roberthbailey · 2019-07-15T19:40:12Z

pkg/sdkserver/sdkserver_test.go

-		m, sc, stop := setup(t, defaultGs.DeepCopy())
-		defer close(stop)
-		done := make(chan struct{}, 10)
+	select {


Is this waiting 4 seconds to verify that the timer has been disabled? Can you just check that directly instead of looking for a side effect?

That's a good point, the timer should be stopped already 👍 . Updated! PTAL!

roberthbailey · 2019-07-15T19:41:49Z

pkg/sdkserver/sdkserver_test.go

-			defer func() {
-				done <- struct{}{}
-			}()
+	// test allocated


Similar to above, make this a full sentence.

roberthbailey · 2019-07-15T19:42:21Z

pkg/sdkserver/sdkserver_test.go

+	case <-time.After(4 * time.Second):
+	}
+
+	// test shutdown


roberthbailey · 2019-07-15T19:43:17Z

pkg/sdkserver/sdkserver_test.go

 	})
+
+	select {
+	case current := <-state:


With 3 test cases all waiting 4+ seconds, this change adds a considerable amount of time to unit tests (which should always be blazingly fast). It would be nice to see if there is a way to do this that completes nearly instantly instead (e.g. my comment about clock manipulation above).

Agreed, they are in parallel though.

This is now removed, as I'm testing the state of the timer directly - so that removes this slowdown at least.

cyriltovena · 2019-07-16T03:45:32Z

Looks very good. Ping me back when you're done.

markmandel · 2019-07-16T03:49:41Z

Thanks for all the comments - will review tomorrow - got lots of time for coding tomorrow 👍

This implements Reserve, with an implementation with the Go SDK. It was also convenience to switch Allocate back to the standard async implementation here, so that all the SDK commands are consistent in their concurrency patterns. Still to come: - e2e tests - sdk conformance test - updates to gameserver lifecycle documentation

markmandel

Just pushed up updates based on the review, and some more comments on others 👍

markmandel · 2019-07-16T16:16:19Z

pkg/sdkserver/sdkserver.go

+			message += fmt.Sprintf(", for %v", s.gsReserveDuration.String())
+		}
+		s.gsUpdateMutex.RUnlock()
+		// unfortunate complexity due to mutex locking, resetReserveAfter has it's own mutex


because the SDK.Allocate() or reserve, etc could change the underlying values while the we are processing.

markmandel · 2019-07-16T16:19:07Z

pkg/sdkserver/sdkserver.go

+	}
+
+	duration := time.Duration(d.Seconds) * time.Second
+	s.gsUpdateMutex.Lock()


Agreed. Good catch 👍

markmandel · 2019-07-16T17:09:48Z

pkg/sdkserver/sdkserver.go

+	})
+}
+
+// stopReserveTimer stops the reserve timer, if it is not nil


Tweaked to: // stopReserveTimer stops the reserve timer. This is a no-op and safe to call if the timer is nil

markmandel · 2019-07-16T17:20:22Z

pkg/sdkserver/sdkserver_test.go

-		_, err := sc.Allocate(context.Background(), &sdk.Empty{})
-		assert.EqualError(t, err, "cannot Allocate a Shutdown GameServer")
+	// wait for the game server to go back to being Ready
+	assertStateChange(v1alpha1.GameServerStateRequestReady, 4*time.Second, func(status v1alpha1.GameServerStatus) {


So usually we do this - but I couldn't find a good way to mock out time.AfterFunc() in this scenario - which was so very useful, as it has both timed functions, and reset capabilities., so this was the best thing I could come up with.

Interestingly, https://godoc.org/github.com/facebookgo/clock#Mock.AfterFunc, and a couple of other clock mocks has an AfterFunc mock, but the one we use (from apimachinery, which is handy because we are on k8s), does not.

Maybe we should move to another clock interface?

markmandel · 2019-07-16T17:34:34Z

pkg/sdkserver/sdkserver_test.go

-	t.Run("contention on first build", func(t *testing.T) {
-		m, sc, stop := setup(t, defaultGs.DeepCopy())
-		defer close(stop)
+	sc, err := NewSDKServer("test", "default", m.KubeClient, m.AgonesClient)


Good catch.

markmandel · 2019-07-16T17:55:03Z

pkg/sdkserver/sdkserver_test.go

+	// test ready
+	_, err = sc.Reserve(context.Background(), &sdk.Duration{Seconds: 3})
+	assert.NoError(t, err)
+	assertStateChange(v1alpha1.GameServerStateReserved, 2*time.Second, noAdditional)


Not sure I understand this one? can you be specific about what is missing? I'm not seeing it.

markmandel · 2019-07-16T17:55:49Z

pkg/sdkserver/sdkserver_test.go

 	})
+
+	select {
+	case current := <-state:


This is now removed, as I'm testing the state of the timer directly - so that removes this slowdown at least.

markmandel · 2019-07-16T18:09:59Z

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

+
+This is often used wherein a game server process must self register itself with an external system, such as a matchmaker,
+that requires it to designate itself as available for a game session for a certain period. Once a game session has started,
+it can call `SDK.Allocate` to designate that players are currently active on it.


I switched it to should - just because you don't have to, but you should. 👍

markmandel · 2019-07-16T18:24:37Z

pkg/sdkserver/sdkserver.go

+			message += fmt.Sprintf(", for %v", s.gsReserveDuration.String())
+		}
+		s.gsUpdateMutex.RUnlock()
+		// unfortunate complexity due to mutex locking, resetReserveAfter has it's own mutex


I've cleaned this up, much simpler locking now. PTAL.

markmandel · 2019-07-16T18:36:57Z

pkg/sdkserver/sdkserver.go

+		s.gsUpdateMutex.RLock()
+		hasDuration := s.gsReserveDuration != nil
+		if hasDuration {
+			message += fmt.Sprintf(", for %v", s.gsReserveDuration.String())


Also you can drop the .String(), %v use the Stringer interface if implemented which is your case.

Done!

The final message will be SDK state change, for 10m. I also think it lacks of information even though the reason is Reserved. I would prefer SDK state change to Reserved for ... or even better SDK state change to Reserved until utc date since when looking at the event you might not know if it is gone.

To give an example of the full event output, that might help with context on this:

Events: Type Reason Age From Message ---- ------ ---- ---- ------- Normal PortAllocation 53s gameserver-controller Port allocated Normal Creating 53s gameserver-controller Pod simple-udp-567rr created Normal Scheduled 53s gameserver-controller Address and port populated Normal RequestReady 47s gameserver-sidecar SDK state change Normal Reserved 10s gameserver-sidecar SDK state change, for 10s Normal Ready 0s (x2 over 47s) gameserver-controller SDK.Ready() complete

So you can see the State in the Reason column, so I figure it's redundant to include it again in the Message.

I would also leave the time period as for 10s - reason being, from the Age column, you can actually see how long its been since the Reserved state was set, and therefore know what the difference is going to be, and can calculate the time left.

How do you both feel about this now?

agones-bot · 2019-07-16T19:13:34Z

Build Succeeded 👏

Build Id: b0fbce8e-fed5-4c79-9135-084b8edd7b91

The following development artifacts have been built, and will exist for the next 30 days:

image: gcr.io/agones-images/agones-controller:0.12.0-7d4f05f
image: gcr.io/agones-images/agones-sdk:0.12.0-7d4f05f
image: gcr.io/agones-images/agones-ping:0.12.0-7d4f05f
Linux C++ SDK (build): agonessdk-0.12.0-7d4f05f-linux-arch_64.tar.gz
SDK Server: agonessdk-server-0.12.0-7d4f05f.zip

A preview of the website (the last 30 builds are retained):

https://7d4f05f-dot-preview-dot-agones-images.appspot.com/

To install this version:

git fetch https://github.com/GoogleCloudPlatform/agones.git pull/891/head:pr_891 && git checkout pr_891
helm install install/helm/agones --namespace agones-system --name agones --set agones.image.tag=0.12.0-7d4f05f

roberthbailey · 2019-07-16T20:01:10Z

pkg/sdkserver/sdkserver.go

 	// 0 is forever.
-	if d.Seconds == 0 {
-		return e, nil
+	if d.Seconds > 0 {


This check actually means that 0 or a negative value means forever.

Yeah, that was deliberate. I wanted to handle the error condition in a sane way.

Do you feel I should change the docs?

agones-bot · 2019-07-16T20:23:12Z

Build Succeeded 👏

Build Id: 042262d8-afd6-47ee-af34-cad3f010d07a

The following development artifacts have been built, and will exist for the next 30 days:

image: gcr.io/agones-images/agones-controller:0.12.0-c278ea1
image: gcr.io/agones-images/agones-sdk:0.12.0-c278ea1
image: gcr.io/agones-images/agones-ping:0.12.0-c278ea1
Linux C++ SDK (build): agonessdk-0.12.0-c278ea1-linux-arch_64.tar.gz
SDK Server: agonessdk-server-0.12.0-c278ea1.zip

A preview of the website (the last 30 builds are retained):

https://c278ea1-dot-preview-dot-agones-images.appspot.com/

To install this version:

git fetch https://github.com/GoogleCloudPlatform/agones.git pull/891/head:pr_891 && git checkout pr_891
helm install install/helm/agones --namespace agones-system --name agones --set agones.image.tag=0.12.0-c278ea1

markmandel · 2019-07-16T20:31:07Z

Going to push this through, as I know you are waiting on it for some other PRs. @roberthbailey if you think I should change the docs, I'll do so in a separate PR.

Reserve() SDK implementation (googleforgames#891)

markmandel added kind/feature New features for Agones area/user-experience Pertaining to developers trying to use Agones, e.g. SDK, installation, etc kind/breaking Breaking change labels Jul 10, 2019

roberthbailey reviewed Jul 15, 2019

View reviewed changes

markmandel force-pushed the feature/reserve-sdk-impl branch from 2543584 to 7d4f05f Compare July 16, 2019 18:38

markmandel commented Jul 16, 2019

View reviewed changes

roberthbailey mentioned this pull request Jul 16, 2019

Approver access for @roberthbailey #914

Closed

5 tasks

Code review updates.

c278ea1

markmandel force-pushed the feature/reserve-sdk-impl branch from 7d4f05f to c278ea1 Compare July 16, 2019 19:50

roberthbailey approved these changes Jul 16, 2019

View reviewed changes

markmandel merged commit 3430d34 into googleforgames:master Jul 16, 2019

markmandel deleted the feature/reserve-sdk-impl branch July 16, 2019 20:31

markmandel added this to the 0.12.0 milestone Jul 16, 2019

pjayara-g added a commit to pjayara-g/agones that referenced this pull request Jul 16, 2019

Merge pull request #3 from googleforgames/master

67e3c86

Reserve() SDK implementation (googleforgames#891)

markmandel removed the kind/breaking Breaking change label Aug 1, 2019

Reserve() SDK implementation #891

Reserve() SDK implementation #891

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markmandel commented Jul 10, 2019

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