Add grpc diagnostic

[josedonizetti]

1. Explain what the PR does

This PR is part of the work to support a v1 for GRPC. This PR implements the diagnostic rpc service. I've tested with -race no data races were found here.

2. Explain how to test it

The below clients can be used to test the GRPC API:

import (
        pb "github.com/aquasecurity/tracee/types/api/v1beta1"
)

func main() {
        var opts []grpc.DialOption
        opts = append(opts, grpc.WithTransportCredentials(insecure.NewCredentials()))

        conn, err := grpc.Dial(":4466", opts...)
        if err != nil {
                log.Fatalf("fail to dial: %v", err)
        }

        client := pb.NewDiagnosticServiceClient(conn)

        changelog := &pb.ChangeLogLevelRequest{
                Level: pb.LogLevel_Info,
        }

        _, err = client.ChangeLogLevel(context.Background(), changelog)
        if err != nil {
                log.Fatal(err)
        }

        fmt.Println("Log level changed to DEBUG")
}

func main() {
	var opts []grpc.DialOption
	opts = append(opts, grpc.WithTransportCredentials(insecure.NewCredentials()))

	conn, err := grpc.Dial(":4466", opts...)
	if err != nil {
		log.Fatalf("fail to dial: %v", err)
	}

	client := pb.NewDiagnosticServiceClient(conn)

	stacktrace, err := client.GetStacktrace(context.Background(), &pb.GetStacktraceRequest{})
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println(string(stacktrace.Stacktrace))
}

func main() {
	var opts []grpc.DialOption
	opts = append(opts, grpc.WithTransportCredentials(insecure.NewCredentials()))

	conn, err := grpc.Dial(":4466", opts...)
	if err != nil {
		log.Fatalf("fail to dial: %v", err)
	}

	client := pb.NewDiagnosticServiceClient(conn)

	metrics, err := client.GetMetrics(context.Background(), &pb.GetMetricsRequest{})
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println("EventCount", metrics.EventCount)
	fmt.Println("EventsFiltered", metrics.EventsFiltered)
	fmt.Println("NetCapCount", metrics.NetCapCount)
	fmt.Println("BPFLogsCount", metrics.BPFLogsCount)
	fmt.Println("ErrorCount", metrics.ErrorCount)
	fmt.Println("LostEvCount", metrics.LostEvCount)
	fmt.Println("LostWrCount", metrics.LostWrCount)
	fmt.Println("LostNtCapCount", metrics.LostNtCapCount)
	fmt.Println("LostBPFLogsCount", metrics.LostBPFLogsCount)
}

3. Other comments

depends on #3395

[josedonizetti]

I don't like this refactoring, but it had to be done because flags create a LoggingConfig, and if this field wasn't exposed it would be nil, generating a panic when you change the log level. But it is weird to allow the user to create a struct but have methods depending on it, we should enforce it by perhaps having these fields private and a constructor function. Nonetheless, I'll create a separate issue to handle this refactor.

[geyslan]

Perhaps, in the future, using a constructor with options pattern.

[geyslan]

LGTM

Tested the new three GPRC services.

For debug ChangeLogLevel I've put a dummy logger.Debugw() and tested changing it to Debug and returning it to Info.

[geyslan]

Perhaps, in the future, using a constructor with options pattern.