API endpoint and associated RPC changes to resolve VMs IP's (#188)

* API endpoint and associated RPC changes to resolve VMs IP's

* Fix "Missing expected argument '<name>'" error when doing "tart set"

* Implement TestIPEndpoint() and IP() method in controller HTTP client

internal/controller/rendezvous/rendezvous.go

@@ -0,0 +1,48 @@
+package rendezvous
+
+import (
+	"context"
+	"errors"
+	"github.com/cirruslabs/orchard/internal/concurrentmap"
+)
+
+var ErrInvalidToken = errors.New("invalid rendezvous token")
+
+type Rendezvous[T any] struct {
+	sessions *concurrentmap.ConcurrentMap[*TokenSlot[T]]
+}
+
+type TokenSlot[T any] struct {
+	ctx context.Context
+	ch  chan T
+}
+
+func New[T any]() *Rendezvous[T] {
+	return &Rendezvous[T]{
+		sessions: concurrentmap.NewConcurrentMap[*TokenSlot[T]](),
+	}
+}
+
+func (rendezvous *Rendezvous[T]) Request(ctx context.Context, session string) (chan T, func()) {
+	tokenSlot := &TokenSlot[T]{
+		ctx: ctx,
+		ch:  make(chan T),
+	}
+
+	rendezvous.sessions.Store(session, tokenSlot)
+
+	return tokenSlot.ch, func() {
+		rendezvous.sessions.Delete(session)
+	}
+}
+
+func (rendezvous *Rendezvous[T]) Respond(session string, conn T) (context.Context, error) {
+	tokenSlot, ok := rendezvous.sessions.Load(session)
+	if !ok {
+		return nil, ErrInvalidToken
+	}
+
+	tokenSlot.ch <- conn
+
+	return tokenSlot.ctx, nil
+}

internal/controller/rendezvous/rendezvous_test.go

@@ -0,0 +1,39 @@
+package rendezvous_test
+
+import (
+	"context"
+	"github.com/cirruslabs/orchard/internal/controller/rendezvous"
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/require"
+	"net"
+	"sync"
+	"testing"
+)
+
+func TestProxy(t *testing.T) {
+	ctx := context.Background()
+
+	expectedConn, _ := net.Pipe()
+
+	proxy := rendezvous.New[net.Conn]()
+
+	token := uuid.New().String()
+
+	connCh, cancel := proxy.Request(ctx, token)
+	defer cancel()
+
+	var wg sync.WaitGroup
+	wg.Add(1)
+
+	go func() {
+		_, err := proxy.Respond(token, expectedConn)
+		require.NoError(t, err)
+
+		wg.Done()
+	}()
+
+	actualConn := <-connCh
+	require.Equal(t, expectedConn, actualConn)
+
+	wg.Wait()
+}