Enable session clustering in jetty9 non compat. was: Copying session variables between different instances is broken

[johnshunfan]

Currently, session variables stored in MVM instance are not copied over to the other instances. Will this ever be done automatically in the runtime? What are best practices for manually copying session variables around? I was considering generating an ID using secure random and storing it in a cookie, then using the ID as a key for datastore entities storing session variables.
@lesv

[lesv]

An alternative phrasing of this might be: JSESSIONID is unique within an instance, but when you have multiple instances -- you appear to get a new JSESSIONID, what is the best practice for dealing with state for the non-compat runtimes as currently configured?

[ludoch]

This is for non compat, right?

Please be specific. If this is for non compat, it seems that this is in
userland to find the best option.

On Thu, Feb 25, 2016 at 11:56 AM, Les Vogel notifications@github.com
wrote:

An alternative phrasing of this might be: JSESSIONID is unique within an
instance, but when you have multiple instances -- you appear to get a new
JSESSIONID, what is the best practice for dealing with state for the
non-compat runtimes as currently configured?

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#183 (comment)
.

[lesv]

Sorry - Yes - this is for non-compat - and yes - we are seeking advice for how to handle this in userland.

[ludoch]

https://www.eclipse.org/jetty/documentation/current/session-clustering-gcloud-datastore.html
or
https://www.eclipse.org/jetty/documentation/current/session-clustering-infinispan.html
or
https://www.eclipse.org/jetty/documentation/current/session-clustering-mongodb.html
or
https://www.eclipse.org/jetty/documentation/current/session-clustering-jdbc.html
or many other possible solutions

On Thu, Feb 25, 2016 at 1:03 PM, Les Vogel notifications@github.com wrote:

Sorry - Yes - this is for non-compat - and yes - we are seeking advice for
how to handle this in userland.

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#183 (comment)
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[lesv]

Your responses all require configuration that can't be set by our users, if we could use that stuff, we would.

[ludoch]

Maybe we should add an option for the cloud datastore?

On Thu, Feb 25, 2016 at 1:12 PM, Les Vogel notifications@github.com wrote:

Your responses all require configuration that can't be set by our users,
if we could use that stuff, we would.

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#183 (comment)
.

[ludoch]

Extra config might be able to define as xml files in your app. Will check with the Jetty folks.

[lesv]

There is an issue for using Memcache & Cloud Datastore.

An Extra config to enable these things would be a win.

[lesv]

We are trying to do the right thing w/ Jetty, w/o the proper configuration files being enabled. The alternative is something like https://github.com/hazelcast/hazelcast-wm/blob/master/src/main/java/com/hazelcast/web/WebFilter.java (adjusted for our environment)

[gregw]

How about we start by adding an example to the java-docs-samples repository of how to extend this image with configuration for a different session manager (gcloud data store would be the obvious choice).

Once we all look at that , we can see how difficult and/or easy it is and then decide if we need to move a parameterised version of it into the base image.

Note that we will not have full memecache+datastore support until we go to 9.4 and the new session manager that @janbartel has been developing.

[gregw]

as a secondary approach, @janbartel is investigating if the session managers can be entirely configured from within a WEB-INF/jetty-web.xml file, which would allow it all to be within the application... but as that still requires a new image / Dockerfile it may just be simplest to configure normally following the example(s) we develop.

[janbartel]

I've investigated the approach that @gregw mentioned of putting all jars and config into the webapp, and it is not particularly easy to make work. If it was absolutely essential, it could be done, but the cleanest approach is probably the one @gregw first suggested of documenting how to extend the docker image to include a session manager.

[lesv]

Cool - @ludoch should decide on direction.

For now, I've asked @shun-fan to do login and Session handling as Filters (We are working on a Getting Started sample and documentation) and we can change that once things change.

As for the Datastore plugin, unless you've rev'd it recently, I suspect it's not based on the correct API set. (https://github.com/GoogleCloudPlatform/gcloud-java)

I'm not sure if extending the image is easiest approach for our users. It tends to get messy and difficult to maintain. (I've done it a few times).

[janbartel]

@lesv looks like gcloud-java is up to rev 0.1.4. Jetty is at 0.0.8. On a quick compile attempt, looks like there is some incompatibility in the api. I'll work on updating to 0.1.4. I'll see if I can get it into a jetty 9.3.8.RC1 release or not (we just did RC0).

[gregw]

@lesv I'm a bit unsure how applications are going to deployed on this image (the non -compat Jetty9 image). I thought creating a new image in the normal docker way was the intended path to use this image! Is there another path that does need a new image? If so, can you point me to it?
light bulb moment Is it just a normal gcloud:deploy but in a non-compat mode?

If so, then perhaps we should come up with a simple way for such deployments to activate additional jetty modules and to add either properties and/or XML configuration?

We should also provide and example app for this (or is there one already?)

[lesv]

Yep - it's a normal "mvn gcloud:deploy" -- hence my grumpiness at Ludo
earlier. What ever turns it on should be easy to do.

On Sat, Feb 27, 2016 at 9:54 AM, Greg Wilkins notifications@github.com
wrote:

@lesv https://github.com/lesv I'm a bit unsure how applications are
going to deployed on this image (the non -compat Jetty9 image). I thought
creating a new image in the normal docker way was the intended path to use
this image! Is there another path that does need a new image? If so, can
you point me to it?

light bulb moment
http://images.clipartpanda.com/idea-light-bulb-clip-art-black-and-white-MTLEnkBTa.jpeg
Is it just a normal gcloud:deploy but in a non-compat mode?

If so, then perhaps we should come up with a simple way for such
deployments to activate additional jetty modules and to add either
properties and/or XML configuration?

We should also provide and example app for this (or is there one already?)

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#183 (comment)
.

• • *Les Vogel
• • *Cloud Developer Relations
• • *lesv@google.com
• • *+1-4 <%2B1-650-338-7103>08-676-7023

[lesv]

I should point out that it is both mvn gcloud:deploy and mvn jetty:run (running locally) that we promote. Ideally we should find a solution that can work in both cases.

[gregw]

@lesv Ah I'm understanding the scenario now. I had not realised the jetty9 image was intended for use by the SDK for apps that do not need to compat level.

Having discussed this with @janbartel, we have a little bit of a challenge to make this nice. The jetty-maven-plugin predates the module system used by jetty's start.jar, thus to configure the server for jetty:run you pass it custom XML. To configure the server for a gcloud:deploy, it would be best to pass it a list of modules & parameters (and only custom XML for very special config).

So I think module/param based configuration is a good feature to add to jetty:run, but I will defer to @janbartel if that can be done in the 9.3.x or will it need a bit more drastic re factoring of our distribution artefacts in 9.4.x so that the modules can be made available to the plugin.

Meanwhile, we will have a look at how we can best pass modules and configuration for a gcloud:deploy usage. Do you (@lesv ) have an example app we can look at? Is it just that you use a Dockerfile that names the instance or is there something in the appengine-web.xml ?

[lesv]

@gregw @janbartel The way we document your work is:
https://cloud.google.com/appengine/docs/managed-vms/java/hello-world
Pure Jetty: https://cloud.google.com/appengine/docs/managed-vms/java/dev-jetty9
Compat: https://cloud.google.com/appengine/docs/managed-vms/java/dev-jetty9-and-apis

The code that @shun-fan is working on: https://github.com/GoogleCloudPlatform/getting-started-java/tree/master/bookshelf

[janbartel]

Just want to document that I've begun the IP clearance process at Eclipse to allow jetty to update to gcloud-datastore version 0.2.0.

[gregw]

An example non compat session clustering example has been prepared at GoogleCloudPlatform/java-docs-samples#123, but some more work is needed

[gregw]

Closing as a duplicate of #167