Invoking functions using HTTP

[faromero]

Do you have any examples of how to invoke functions using HTTP? Or any guidance on how that can be done?

Thanks!

[shyamjesal]

Once the cluster is up and running like mentioned in this step, you can use knative client to deploy functions.

kn service apply helloworld -f vhive/configs/knative_workloads/helloworld.yaml
Creating service 'helloworld' in namespace 'default':

  0.056s The Route is still working to reflect the latest desired specification.
  0.100s ...
  0.160s Configuration "helloworld" is waiting for a Revision to become ready.
591.046s ...
591.084s Ingress has not yet been reconciled.
591.180s Waiting for load balancer to be ready
591.398s Ready to serve.

Service 'helloworld' created to latest revision 'helloworld-00001' is available at URL:
http://helloworld.default.192.168.1.240.sslip.io

The url on the last line is the HTTP endpoint which can be used to invoke the function.

[faromero]

It's easier to make requests from gg using HTTP than using gRPC. Alternatively, we were thinking of putting a simple proxy HTTP server that simply "translates" the request from gg to gRPC, and from there sends it to vHive as the examples do (and vice-versa).

[ustiugov]

@faromero I see. in this case, I recommend you to use HTTP everywhere (clients and servers) that would not need any modifications in vHive, except slightly different knative yaml files that you would have to use (same as in the Knative examples, to which Shyam gave a link). once you show us your code (best by submitting a PR to this repo), we can see if we want to move from HTTP to gRPC later on.

Adding a HTTP/gRPC translation layer is definitely not a great idea because it would come with measurable overheads and also would be difficult to maintain as an extra vHive component

[niravnshah]

Hi @shyamjesal,
while trying to invoke the function using http, i am getting following error. Any idea what might be going wrong?

nirav@984fee0096e3:~/vhive$ kn service apply myserv -f configs/knative_workloads/pyaes.yaml
Creating service 'myserv' in namespace 'default':

  0.262s The Route is still working to reflect the latest desired specification.
  0.313s ...
  0.364s Configuration "myserv" is waiting for a Revision to become ready.
 10.254s ...
 10.302s Ingress has not yet been reconciled.
 10.413s Waiting for load balancer to be ready
 10.618s Ready to serve.

Service 'myserv' created to latest revision 'myserv-00001' is available at URL:
http://myserv.default.192.168.1.240.sslip.io
nirav@984fee0096e3:~/vhive$ kn service list
NAME           URL                                                  LATEST               AGE    CONDITIONS   READY   REASON
helloworld-0   http://helloworld-0.default.192.168.1.240.sslip.io   helloworld-0-00001   108m   3 OK / 3     True
myserv         http://myserv.default.192.168.1.240.sslip.io         myserv-00001         25s    3 OK / 3     True
nirav@984fee0096e3:~/vhive$ curl http://myserv.default.192.168.1.240.sslip.io
stream error: stream ID 5; INTERNAL_ERROR; received from peer

[ustiugov]

pyaes and other functions in that folder support gRPC only.

[niravnshah]

Found a way to invoke the gRPC function thru command line.

$grpcurl -d '{"name": "Nirav", "vHiveMetadata": "1234"}' -import-path . -proto ./vhive/examples/invoker/helloworld.proto -plaintext helloworld-0.default.192.168.1.240.sslip.io:80 helloworld.Greeter/SayHello
This gives output as...
{ "message": "Hello, Nirav!" }

This helps in determining if the installed services are running fine or not.