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From "Michele Sciabarra" <mich...@sciabarra.com>
Subject Re: Re: A plan to (re) implement OpenWhisk on top of Knative
Date Wed, 03 Jul 2019 17:05:53 GMT
Well.... it  is actually a bit more complex than this.

If we use Tekton for building, it is Tekton the standard, so as long as we define a standard
for input and output, we delegate to a tekton build the preparation  of an image ready for
being served by Knative  Serving,

However the action loop based runtimes rely on a "compilation" script already written in python
that performs the steps, so all I need to do is to adapt the compilation to the Tekton standard.
This is something I already did, at lest for Go, modifying the actionloop codee and I am now
trying to complete the pipeline. 

The way I did for Go was not getting rid of the "init" step but providing an "autoinit" step
that happens at runtime start, executing a binary executable already embedded in the image
and produced by the compilation done by the runtime itself.

All of this is more complex to say  than to do so I hope I can show something soon... hopefully
pretty interesting.

---
Michele Sciabarra
 michele@sciabarra.com

PS the book "learning Apache OpenWhisk" is now on printing!

----- Original message -----
From: Matt Rutkowski <mrutkows@us.ibm.com>
To: dev@openwhisk.apache.org
Subject: Re:  Re: A plan to (re) implement OpenWhisk on top of Knative
Date: Wednesday, July 03, 2019 4:43 PM

Hi Martin, 

It is my belief that Michele, now freshly returned from book editing 
(congrats), was going to implement the same interface for pre/post 
processing requests that we implemented for NodeJS.  This would allow us a 
path to support this across all language runtimes as well as formalize our 
runtime contract that aligns with a Knative Service approach and then also 
allows us to better explore some of the use cases being discussed on 
another thread from Rodric.  I believe that we should look at smaller 
steps towards that alignment like removing the need for the "init" 
entrypoint and allowing access to parameters either by env. vars. or 
function arguments allowing both compat. with 12-factor app approach, as 
well as attempting to encourage a functional programming model where you 
should ideally be unaware of any system environment.

Kind regards,
Matt 




From:   Martin Henke <martin.henke@web.de>
To:     dev@openwhisk.apache.org
Date:   07/03/2019 09:29 AM
Subject:        [EXTERNAL] Re: A plan to (re) implement OpenWhisk on top 
of Knative



Michele,

FYI: Sugandha and myself published a Medium blog article which describes 
to build Nodejs10 images using Tekton and run it on Knative
(based on the work from Priti).
It might be on interest in the context of your Actionloop related Knative 
work.

Link:
https://urldefense.proofpoint.com/v2/url?u=https-3A__medium.com_-40sugandha.agrawal18_build-2Dknative-2Dservice-2Dwith-2Dtekton-2Dand-2Dapache-2Dopenwhisk-2Dnode-2Djs-2Druntime-2Df660bbc3a11e&d=DwIFaQ&c=jf_iaSHvJObTbx-siA1ZOg&r=6zQLM7Gc0Sv1iwayKOKa4_SFxRIxS478q2gZlAJj4Zw&m=bl7bwPaoiSE6fi0fyVHNC9bNUnh1ZUUlfl3lwUZbcH0&s=IQBGPfSTPiAjKhIlsqKDpAjoJBNd7By1YnjxOIx2454&e=



Regards,
Martin


On 2019/05/20 15:00:02, "Michele Sciabarra" <m...@sciabarra.com> wrote: 
> Ok great, I see the discussion is starting to bring ideas.> 
> 
> Yes my goal is basically to run existing actions in Knative, create and 
invoke. And possibile retain the ability of an action to invoke another 
action.> 
> 
> I understand the different way they expose services, so I am rethinking 
the idea of using a "work-alike" path. > 
> 
> If it is needed we can add it with an ingress but it may be not 
necessary in the initial implementation.> 
> 
> Also I checked a bit ML and discussions and I see this Tekton thing that 
should be the preferred way.> 
> 
> Not sure if I understand the relation with the current Build API 
documented in the website. Is Tekton "compatible" or it has a different 
API?> 
> 
> 
> -- > 
>   Michele Sciabarra> 
>   michele@sciabarra.com> 
> 
> ----- Original message -----> 
> From: "Markus Thömmes" <ma...@apache.org>> 
> To: dev@openwhisk.apache.org> 
> Subject: Re: A plan to (re) implement OpenWhisk on top of Knative> 
> Date: Monday, May 20, 2019 4:50 PM> 
> 
> Good discussion, thanks!> 
> 
> Can we try to define what the desired end-goal is here? I'm a bit 
unclear> 
> what resembling the OpenWhisk API actually buys us.> 
> 
> To me, the desired end-state would be to run OpenWhisk actions as-is on 
a> 
> Knative cluster (similar to OpenFaaS' and Azure's integration). There's 
no> 
> good way for us to provide the full API without spinning up a control 
plane> 
> and we can only handle so much via the CLI. So to me, the end-goal 
looks> 
> like:> 
> 
> 1. *wsk action create* actually doing all the pieces necessary to run a> 

> piece of code on Knative.> 
> 2. *wsk action invoke* doing some HTTP call under the hood to "invoke" 
that> 
> action. The action should be reachable via a sensible URL. If we really> 

> want to keep the API surface (as I said, I'm dubious here) we can also 
do> 
> that via ingress level abstractions (like VirtualService).> 
> 
> Cheers,> 
> Markus> 
> 
> Am Mo., 20. Mai 2019 um 15:33 Uhr schrieb Martin Henke 
<martin.henke@web.de> 
> >:> 
> 
> >> 
> > > On 20. May 2019, at 14:55, Michele Sciabarra <mi...@sciabarra.com>>

> > wrote:> 
> > >> 
> > >> Michele,> 
> > >> 
> > >> I like the idea to make the ActionLoop based runtimes to be 
runnable on> 
> > Knative.> 
> > >>> 
> > >> My thoughts on this:> 
> > >> - I second Markus concern to implement the invocation API onto 
Knative> 
> > instead of just using Knative service syntax.> 
> > > Can you elaborate this? I do not understand.> 
> >> 
> > Knative service syntax:    https://<service(in our case => 
> > action)>.<namespace>.<host>/> 
> > OW invocation https://> 
> > <api-host>/api/v1/namespaces/<namespace>/actions/<action>>

> >> 
> > (I personally so no worth in inventing a distinct API for OW images, 
but> 
> > as said I would see that as a valid optional feature)> 
> >> 
> > >> 
> > >> - I would have concerns to make it dependent on Gloo which is kind 
of a> 
> > minority choice for Knative load balancing> 
> > > I do not think it will be hard to setup a test also using Istio, I 
do> 
> > not want to be limited to Gloo.> 
> >> 
> > I just wanted to prevent that Gloo gets a “official” prerequisite for 
an> 
> > “official” OW on Knative flow.> 
> > It is of course free to you to use what ever you want to do in your> 
> > prototype.> 
> >> 
> > > - In my opinion the goal should be to have some uniform behaviour 
for> 
> > ActionLoop based runtimes> 
> > >> and other ones like the adapted NodeJS runtimes demonstrated by 
Matt> 
> > and Priti> 
> > > As much as I can tell the current implementation is just the 
building> 
> > and exposing the "/init" and "/run" but I can be wrong.> 
> > > The build can be of course reused, so it continues the effort. For 
the> 
> > frontend, from the documentation I think Matt wants to add a proxy, 
while I> 
> > would like to implemeent the "invocation" straight in the runtime. 
This is> 
> > open to discussion, but of course it is better to reach an agreement.> 

> >> 
> > Also in the work of Priti and Matt the invocation goes directly to 
the> 
> > runtime. The action code is either passed with the call (not yet 
tested by> 
> > me) or set via environment variable in the docker build.> 
> >> 
> > >> 
> > >> - As Knative Build seems be on a dead end I would propose to 
target> 
> > Tekton as the build system (which developed as kind of >successor out 
of> 
> > Knative)> 
> > >> 
> > > If Knative build is dead then it would be a bit unfair that they 
change> 
> > it as the scope of the Knative project!> 
> > > It looks like the goal is  to setup some standards! And I would be 
very> 
> > disappointed to know that.> 
> >> 
> > Tekton evolved out of Knative Build (or more correct out of Knative> 
> > Pipelines) but is very similar to the Knative build.> 
> > Flows can easily be ported from one to the other,> 
> > If we target Tekton build we would target the platform were the 
Knative> 
> > build team is focusing on.> 
> > But again feel free to use whatever platform for your prototype work.> 

> >> 
> > > At this stage the build is the more interesting thing, and it could 
be> 
> > even imported in main openwhisk to speed up deployment.> 
> > > I have already baked it in the ActionLoop runtimes (with 
precompilation).> 
> > > Also if we use Tekton, where is the Knative standard then? What is 
the> 
> > point? We can build our own system instead of "Knativizing" it...> 
> > >> 
> > >> Maybe it would be a good solution to tackle two things 
independently.> 
> > >> 1) Design and implement a common protocol of building, running and>


> > calling OW runtimes on Knative> 
> > >> 2) Implement the OW invocation API on top of Knative as an 
additional> 
> > option for those who have the need to expose it.> 
> > >> 
> > > On this, for my personal approach at building things, I want 
something> 
> > that works and it is complete and useful. A "MVP”.> 
> >> 
> > Cool. Just go on.> 
> >> 
> > > So I do not plan to split the effort. Version 0.1 must be a minimal> 

> > working subset of OpenWhisk on Knative.> 
> > > Because otherwise there will be incomplete useless inusable pieces> 
> > around (see for example kwsk).> 
> > >> 
> > > It does not mean that things cannot be modular, nor that everyone 
must> 
> > but to me "openwhisk-knative" must be a single repo with all the 
pieces to> 
> > make something where you can download is and deploy in a kubernetes 
cluster> 
> > and be able to deploy simple actions. When this works, we can improve> 

> > incrementally and split it but keeping it working.> 
> > >> 
> > >> I would looking forward to work with you on the first work item.> 
> > > Great  but I see now more details to discuss before we can start. 
Most> 
> > notably I need to understand how I can build on top of Mark and Priti 
work> 
> > and continue their work. ANd I can even probably recover some of the 
code> 
> > of kwsk as they implemented some openwhisk api, that I want now in 
the> 
> > runtime.> 
> > >> 
> >> 
> > I do not want to stop you in any way. My hope is that the action loop> 

> > runtimes and the “other ones” do expose the same behaviour when being> 

> > called. So that the users is not surprised when calling different 
actions> 
> > in different languages.> 
> > And behaving the same way might also mean to adapt the “other 
languages”> 
> > to the same behaviour as the action loop based ones.> 
> > They just should be uniform to be used.> 
> >> 
> > When your prototype is accessible it would be a good point of time to> 

> > discuss this.> 
> >> 
> > As said I very much like your effort.> 
> >> 
> > >> 
> > >> On 20. May 2019, at 08:55, Michele Sciabarra <mi...@sciabarra.com>>


> > wrote:> 
> > >>> 
> > >>> 
> > >>>> I have an idea for implementing a prototype of OpenWhisk on top

of> 
> > Knative.> 
> > >>>> My basic ideas are: do not use any proxy, forwarding or adapter:>


> > extend> 
> > >>>> the runtime to support the REST call and expose them as ingress.

And> 
> > use a> 
> > >>>> wrapper on top of `kubectl` to generate all the needed 
components.> 
> > >>> 
> > >>> Does this tie into the work that Matt was doing to the runtimes to

make> 
> > >>> them runnable on Knative? Is this lined up with that at all?> 
> > >> Actually yes. He suggested I can investigate how to migrate 
ActionLoop> 
> > to port many other languages to Knative.> 
> > >> Also he recommended I add my idea and this is what I am doing. 
Current> 
> > code is, if I am not wrong, a Knative build of the nodejs runtime.> 
> > >>> 
> > >> There has been a number of attempts and proposal to move forward> 
> > OpenWhisk. My idea that to succeed we need something small but that 
just> 
> > works. This is my idea to be able to implement in the shorter time 
frame> 
> > possible an actual subset of OpenWhisk that works and it is truly 
built on> 
> > top of Knative. So I am putting the thing a bit further than Matt 
work.> 
> > >>> 
> > >>> 
> > >>>> My goal is to have a functional work-alike of OpenWhisk built on

top> 
> > of> 
> > >>>> Knative, using ActionLoop as a foundation. I will extend 
ActionLoop to> 
> > >>>> support the required REST calls of OpenWhisk.> 
> > >>>> 
> > >>>> I also want to create tool, I will call `wskn`. This tool will>

> > initially> 
> > >>>> just a python script, a wrapper on top of `kubectl` as it will>

> > generate> 
> > >>>> kubernetes descriptors.> 
> > >>> Why not build this into "wsk" itself? The Azure Functions CLI as 
an> 
> > example> 
> > >>> supports multiple deployment types like this in one CLI.> 
> > >>> 
> > >> When it will works, yes, of course. But to start, what I really 
need is> 
> > a prototype that can generate kubernetes descripttors to feed to 
kubectl,> 
> > so a  simplee, quick and ditry, separate tool (that I will keep 
together> 
> > the runtime) is all I need for now.> 
> > >>> 
> > >>>>> 
> > >>>> It will support initially just the the action creation and>

> > invocation, and> 
> > >>>> only synchronous (blocking) behaviour, as all the request will

go> 
> > straight> 
> > >>>> to the runtimes. Hopefully also a subset of `package` and> 
> > `activation`.> 
> > >>>> Again triggers, rules, asynchronous for later.> 
> > >>>>> 
> > >>>> The idea is that you will be able to create actions and web 
actions> 
> > that> 
> > >>>> can run existing OpenWhisk actions, at least those with blocking>


> > behaviour> 
> > >>>> that run with ActionLoop (Go, Java, Python, PHP, Swift, Rust, 
Ruby,> 
> > >>>> Crystal...)> 
> > >>>>> 
> > >>>> Implementation.> 
> > >>>> ==============> 
> > >>>>> 
> > >>>> This is how I plan to implement it.> 
> > >>>>> 
> > >>>> At this stage I want to use just Knative Serving and Knative 
Build,> 
> > using> 
> > >>>> Gloo for the ingress part. I also plan to install a local Docker>


> > registry> 
> > >>>> Kubernetes registry, so we do not have to use DockerHub for>

> > everything. All> 
> > >>>> of this can be done with existing command line tools in a few 
minutes> 
> > in> 
> > >>>> any running Kubernetes deployment.> 
> > >>>>> 
> > >>> 
> > >>> Why specifying Gloo here? Do you need anything specific from Gloo>


> > itself?> 
> > >>> If not I'd propose to just keep it on a Knative Serving API 
surface> 
> > level.> 
> > >> I want to build it on top of Knative serving, full stop. 
Currently,> 
> > installing Gloo is pretty easy and is more  lightweight than Istio so 
I> 
> > will use it for my  first implementation.> 
> > >>> 
> > >>>>> 
> > >>>> When I create an action, it will use Knative build that will 
work> 
> > roughly> 
> > >>>> in this way:> 
> > >>>>> 
> > >>>> - create a configmap with the action code> 
> > >>>> - build the actin using ActionLoop precompilation feature that

will> 
> > return> 
> > >>>> a zip file including all the needed to run the action> 
> > >>>> - create a new docker image extending the runtime with the new

zip,> 
> > using> 
> > >>>> Kaanico> 
> > >>>> - push the image in the local registry> 
> > >>> This feels like a fairly heavyweight process, we should be able 
to> 
> > come up> 
> > >>> with a way to circumvent zipping entirely. Maybe the runtime can 
detect> 
> > >>> that the unzipped content is already there and skip the unzip 
step?> 
> > >>> 
> > >> Actually this is my first idea of how to use Knative build. And is 
not> 
> > complicated: when I create the action, a run a build that includes 
Kanico.> 
> > I generate a Dockerfile on the fly. The docker file uses the action 
runtime> 
> > that already know how to compile a script. And then I save an image. 
I> 
> > already implemented un "autoinit" so just launching the image will 
give a> 
> > runtime ready to run that execute an action already compiled.> 
> > >>> 
> > >>> 
> > >>> I'm fairly hesitant on the usage of a ConfigMap for storing the 
action> 
> > >>> code. It's all stored in the in-cluster etcd instance and it has 
a> 
> > limit of> 
> > >>> 1M. This is at most a stop-gap solution to provide a PoC I think. 
Any> 
> > ideas> 
> > >>> on how to "productize" this?> 
> > >>> 
> > >> ConfigMap can be mounted as files, so it is an easy way  to feed 
an> 
> > action to a build. It is just an easy way to feed the action code to 
the> 
> > Build.> 
> > >>> 
> > >> My initial constraint is that I want just to generate Kubernetes> 
> > descriptors to feed to kubectl.> 
> > >> Of course in the long run I can add some "file upload" storage.> 
> > >>> 
> > >> If I could to this file upload when invoking a build it could ideal 
as> 
> > I do not have to store anything anywhere, just process the code and> 
> > generate a single layer to execute actions to be store in the 
registry.> 
> > >> I will investigate better this area, I understand your concern.> 
> > >>> 
> > >>>> 
> > >>>> At this point you can run the action. ActionLoop will be extended

to> 
> > >>>> support invocations in the format> 
> > >>>> "/v1/namespaces/namespace/actions/package/action".> 
> > >>> Why bother reimplementing this exact path? To obtain API 
compatibility> 
> > with> 
> > >>> OpenWhisk as it is today?> 
> > >>> 
> > >> I want to implement a subset of the OpenWhisk API on top of 
Knative> 
> > serving.> 
> > >> Knative serving already does the scaling and routing, so what we 
need> 
> > are the "endpoints" to invoke actions.> 
> > >>> 
> > >> Since I do not want to add additional components, not at the first>


> > stage. Just knative serve and build, the runtime and a controller 
script,> 
> > the runtime is the natural place where to "handle" the API 
invocations,> 
> > since Knative only generates the URL but not anything else.  If I> 
> > understood well, Matt is adding a proxy. I do not want to add a proxy, 
just> 
> > add to the runtime the ability to respond to "API like" calls, at 
least> 
> > those regarding action invocation.> 
> > >>> 
> > >>>> It will do all the decoding required to invoke the action with

the> 
> > >>>> expected paramenters (straight invocation thrhoug the actinloop>

> > protocol,> 
> > >>>> not proxies).> 
> > >>> Does this mean moving all of the Controller's "smartness" about>

> > incoming> 
> > >>> and outgoing HTTP requests (see the whole WebActions for 
example)?> 
> > >>> 
> > >> At least decoding web actions in the runtime, yes. Knative serving>


> > already has routing and proxying.> 
> > >> So a true implementation on top of Knative requires IHMO this> 
> > sacrifice. Unless there is a way to keep the controller in a 
"Knative"> 
> > compatible way. Open to suggestions here.> 
> > >>> 
> > >>> Each action will then be exposed using an ingress with its 
specific> 
> > >>> invocation path.> 
> > >>>> 
> > >>> If the community agrees with this plan, I would create a repo> 
> > >>> `incubator-openwhisk-knative` to work on it.> 
> > >>>> 
> > >>> Thoughts?> 
> >> 
> >> 
>

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