feat: initial commit

reach/discovery/discovery.go

@@ -0,0 +1,56 @@
+package discovery
+
+import (
+	"context"
+	"net"
+	"sync"
+
+	"github.com/grandcat/zeroconf"
+)
+
+// Service is a ReachRS service discovered via MDNS-SD
+type Service struct {
+	Name   string
+	AddrV4 *net.IP
+	Port   int
+}
+
+// Discover tries to discover ReachRS services on the local network via mDNS-SD
+func Discover(ctx context.Context) ([]Service, error) {
+	var wg sync.WaitGroup
+
+	wg.Add(1)
+
+	resolver, err := zeroconf.NewResolver()
+	if err != nil {
+		return nil, err
+	}
+
+	services := make([]Service, 0)
+	entries := make(chan *zeroconf.ServiceEntry)
+
+	go func() {
+		for e := range entries {
+			var addr *net.IP
+			if len(e.AddrIPv4) > 0 {
+				addr = &e.AddrIPv4[0]
+			}
+			srv := Service{
+				Name:   e.Instance,
+				AddrV4: addr,
+				Port:   e.Port,
+			}
+			services = append(services, srv)
+		}
+		wg.Done()
+	}()
+
+	if err = resolver.Browse(ctx, "_reach._tcp", ".local", entries); err != nil {
+		return nil, err
+	}
+
+	wg.Wait()
+
+	return services, nil
+
+}

reach/discovery/discovery_test.go

@@ -0,0 +1,53 @@
+package discovery
+
+import (
+	"context"
+	"regexp"
+	"testing"
+	"time"
+
+	"forge.cadoles.com/cadoles/go-emlid/reach"
+)
+
+func TestDiscovery(t *testing.T) {
+	reach.AssertIntegrationTests(t)
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	services, err := Discover(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if g, e := len(services), 1; g < e {
+		t.Fatalf("len(services): got '%d', expected > %d", g, e)
+	}
+
+	t.Logf("Found %d services", len(services))
+
+	patterns := []string{"reach", "Reach", "^RS.*"}
+
+	for i, s := range services {
+		t.Logf("Service #%d: %s - %s:%d", i, s.Name, s.AddrV4.String(), s.Port)
+
+		matched := false
+
+		for _, p := range patterns {
+			re, err := regexp.Compile(p)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			if re.Match([]byte(s.Name)) {
+				matched = true
+				break
+			}
+		}
+
+		if !matched {
+			t.Errorf("services[%d].Name ('%s') to match on of '%v'", i, s.Name, patterns)
+		}
+	}
+
+}