openwhisk-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Carlos Santana <>
Subject Re: A proposal for a more efficient implementation of Go actions
Date Sat, 10 Feb 2018 15:47:38 GMT
Hi Michele

I’m not super familiar with go, but I think it goes inline with what we do

So If I understand correctly your proposal is for the use case that user
provide and precompiled the executable.
One approach is for the web server that implements /init on port 8080 to
run the go executable the go executable in turn be a another web server
that implement the /run endpoint

One problem I see is the /run running on port 8080 there will be a port
There could be different options
To avoid having use another port like 8081 this will required changes in
the invoker to know about.
I will try to avoid changes on the invoker to start

Another option is for the executable that implements the /run to tell the
server on /init to shutdown to release the port and then bind the web
server to port 8080 then from this point all the invokes will hit the /run
on the users executable action implementing the webserver.

This can be documented as the standard api for anyone to write this web
server executable.

This approach can be also be applicable to other compile languages like
Swift which I’m currently working which I’m currently implementing for
Swift 4.

I agree providing a user land library/package like you mentioned will be an
improvement if user want an easy way to implement the executable
implementing the webserver for the /run endpoint.

This is a good experiment and can be implemented today in user land using
docker action and quickly iterate and get feedback.

This approach can be implemented with modifications to the python proxy to
handle the /init but not the /run

Something that can be use for Swift to improve the mode of passing params
via stdin and last line of stdout and have memory with state and
connections and preserved improving performance.

Similar as the go library can be offer for Swift to implement the web
server wrapper.
And other languages :-)

I will let others shine in their point of view and other alternatives

Thank you for your interested in helping with Go support

— Carlos
On Sat, Feb 10, 2018 at 9:52 AM Michele Sciabarra <>

> # How Go Action are currently implemented
> Currently, Go Action are implemented using the generic docker support.
> I investigated the implementation and I found there is a python based
> server, listening for /init and /run requests. The /init will collect an
> executable and place in the current folder, while the /run will invoke the
> executable with popen, feeding the input and returning the output as log,
> and the last line as the result as a serialized json.
> The problem is spawning a new process for each request sound like a
> revival of the CGI.  I made some investigation and it is certainly not the
> most efficient implementation.  Basically everyone moved from CGI executing
> processes to servers listening  fro requests since many many years ago.
> Also I investigated how AWS Lambda supports go, and as I suspected it is a
> completely different story: they implements a server in Go listening and
> serving requests.
> The problem here is Python and Node are dynamic scripting languages, while
> Go is a compiled language.
> I checked also how Node and Python runtimes work: they are all servers,
> they receive the code of the function, “eval" the code and then execute it
> for serving requests.
> Go, generating an executable, cannot afford to do that. We cannot “eval”
> precompiled code. But it is also inefficient to spawn a new process for
> each function invocation.
> The solution here is to exec only once, when the runtime receive the
> executable of the function, at the /init time. Then you should replace the
> main executable and  serve the /run requests directly in the replaced
> executable. Of course this means that the replaced executable should be
> able to serve the /init requests too. All of this should go in a library
> # My proposal.
> Support for Go should look like to the following (very similar to Lambda
> support, I admit it):
> package main
> import (
>         “"
> )
> func hello() (string, error) {
>         return "Hello Whisk!", nil
> }
> func main() {
>         openwhisk.Start(hello)
> }
> The magic will be inside the library.
> The Start function will start a web server listening for two requests.
> Posts to /run will invoke some deserialisation code and then invoke the
> function.
> Posts to /init will receive an executable, unzip it, look for an "exec"
> file and then exec to it (expecting of course the server itself is
> implemented using the same library).
> A new Go specific runtime will built easily using the same library. Maybe
> with a default action retuning an error.
> If the proposal sounds acceptable I volunteer to implement it.
> --
>   Michele Sciabarra

  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message