feat: add initial implementation of osiris, the TLS terminator for Anubis

Signed-off-by: Xe Iaso <me@xeiaso.net>

cmd/osiris/internal/config/bind.go

@@ -0,0 +1,48 @@
+package config
+
+import (
+	"errors"
+	"fmt"
+	"net"
+)
+
+var (
+	ErrCantBindToPort = errors.New("bind: can't bind to host:port")
+)
+
+type Bind struct {
+	HTTP    string `hcl:"http"`
+	HTTPS   string `hcl:"https"`
+	Metrics string `hcl:"metrics"`
+}
+
+func (b *Bind) Valid() error {
+	var errs []error
+
+	ln, err := net.Listen("tcp", b.HTTP)
+	if err != nil {
+		errs = append(errs, fmt.Errorf("%w %q: %w", ErrCantBindToPort, b.HTTP, err))
+	} else {
+		defer ln.Close()
+	}
+
+	ln, err = net.Listen("tcp", b.HTTPS)
+	if err != nil {
+		errs = append(errs, fmt.Errorf("%w %q: %w", ErrCantBindToPort, b.HTTPS, err))
+	} else {
+		defer ln.Close()
+	}
+
+	ln, err = net.Listen("tcp", b.Metrics)
+	if err != nil {
+		errs = append(errs, fmt.Errorf("%w %q: %w", ErrCantBindToPort, b.Metrics, err))
+	} else {
+		defer ln.Close()
+	}
+
+	if len(errs) != 0 {
+		return errors.Join(errs...)
+	}
+
+	return nil
+}