refactor: merge go modules

[ernado]

Currently, tetragon is split into 3 modules:

• github.com/cilium/tetragon/pkg/k8s
• github.com/cilium/tetragon/api
• github.com/cilium/tetragon

Also, there is recursive dependency beteen github.com/cilium/tetragon and github.com/cilium/tetragon/api, and none of them are go-gettable because of it.

Moreover, following is invalid:

	github.com/cilium/tetragon/api v0.0.0-00010101000000-000000000000
	github.com/cilium/tetragon/pkg/k8s v0.0.0-00010101000000-000000000000

Because replace-es are working only locally and ignored during go-get, and v0.0.0-00010101000000-000000000000 is not a valid revision.

I propose to merge all three of them, or at least root and /api, because it seems like it is impossible to resolve recursive dependencies.

Why they should be go-gettable

I'm using gRPC client to connect to tetragon and want to use github.com/cilium/tetragon/api for it.

[mtardy]

Hey! I'm not sure to understand your issue here but I'll try to help. It seems that you wanted to use the gRPC client to connect to Tetragon.

1. I had no issue running go get github.com/cilium/tetragon/api/, it returns this in a fresh new module in a fresh 1.20.1 Golang install:

    go: downloading github.com/cilium/tetragon/api v0.0.0-20230221103812-a80c50718487
    go: downloading github.com/cilium/tetragon v0.8.3
    go: added github.com/cilium/tetragon/api v0.0.0-20230221103812-a80c5071848
   

2. Here is a snippet of Go code that uses the gRPC client to interact with Tetragon, assuming it's listening on port 54321:

   package main
   
   import (
       "context"
       "fmt"
       "time"
   
       "github.com/cilium/tetragon/api/v1/tetragon"
       "google.golang.org/grpc"
       "google.golang.org/grpc/credentials/insecure"
   )
   
   func main() {
       // connect and create a gRPC client
       connCtx, connCancel := context.WithTimeout(context.TODO(), 1*time.Second)
       defer connCancel()
       conn, err := grpc.DialContext(connCtx, "localhost:54321", grpc.WithTransportCredentials(insecure.NewCredentials()), grpc.WithBlock())
       if err != nil {
   	    panic(err)
       }
       defer conn.Close()
       client := tetragon.NewFineGuidanceSensorsClient(conn)
   
       // do an arbitrary request and print
       resp, err := client.GetVersion(context.TODO(), &tetragon.GetVersionRequest{})
       if err != nil {
   	    panic(err)
       }
       fmt.Println(resp.String())
   }
   

   Can you try to use this and go mod tidy?

[ernado]

:thinking: that's strange, it worked for me too now.

I'll close this issue for now, probably I messed up with my local setup in some way, thank you.

[smff]

same thing(issue) right now(

[kemingy]

I also ran into this weird error when I was trying to include my project (with a tetragon gRPC client) in a Go workspace. Suddenly, everything stopped working. Removing all the Go workspace related files fixed it.

This can be reproduced by the example provided above: https://github.com/cilium/tetragon/issues/712#issuecomment-1438821340