Probe revamped to provide for a new WrappedError struct to wrap probes as error interface

This convenience was necessary to be used for golang library functions like io.Copy and io.Pipe
where we shouldn't be writing proxies and alternatives returning *probe.Error

This change also brings more changes across code base for clear separation regarding where an error
interface should be passed encapsulating *probe.Error and where it should be used as is.

pkg/server/minhttp/net.go

@@ -82,7 +82,7 @@ func (n *minNet) getInheritedListeners() *probe.Error {
 		}
 		count, err := strconv.Atoi(countStr)
 		if err != nil {
-			retErr = probe.New(fmt.Errorf("found invalid count value: %s=%s", envCountKey, countStr))
+			retErr = probe.NewError(fmt.Errorf("found invalid count value: %s=%s", envCountKey, countStr))
 			return
 		}
 
@@ -92,18 +92,18 @@ func (n *minNet) getInheritedListeners() *probe.Error {
 			l, err := net.FileListener(file)
 			if err != nil {
 				file.Close()
-				retErr = probe.New(err)
+				retErr = probe.NewError(err)
 				return
 			}
 			if err := file.Close(); err != nil {
-				retErr = probe.New(err)
+				retErr = probe.NewError(err)
 				return
 			}
 			n.inheritedListeners = append(n.inheritedListeners, l)
 		}
 	})
 	if retErr != nil {
-		return probe.New(retErr)
+		return retErr.Trace()
 	}
 	return nil
 }
@@ -115,17 +115,17 @@ func (n *minNet) getInheritedListeners() *probe.Error {
 func (n *minNet) Listen(nett, laddr string) (net.Listener, *probe.Error) {
 	switch nett {
 	default:
-		return nil, probe.New(net.UnknownNetworkError(nett))
+		return nil, probe.NewError(net.UnknownNetworkError(nett))
 	case "tcp", "tcp4", "tcp6":
 		addr, err := net.ResolveTCPAddr(nett, laddr)
 		if err != nil {
-			return nil, probe.New(err)
+			return nil, probe.NewError(err)
 		}
 		return n.ListenTCP(nett, addr)
 	case "unix", "unixpacket":
 		addr, err := net.ResolveUnixAddr(nett, laddr)
 		if err != nil {
-			return nil, probe.New(err)
+			return nil, probe.NewError(err)
 		}
 		return n.ListenUnix(nett, addr)
 	}
@@ -158,7 +158,7 @@ func (n *minNet) ListenTCP(nett string, laddr *net.TCPAddr) (net.Listener, *prob
 	// make a fresh listener
 	l, err := net.ListenTCP(nett, laddr)
 	if err != nil {
-		return nil, probe.New(err)
+		return nil, probe.NewError(err)
 	}
 	n.activeListeners = append(n.activeListeners, rateLimitedListener(l, n.connLimit))
 	return l, nil
@@ -191,7 +191,7 @@ func (n *minNet) ListenUnix(nett string, laddr *net.UnixAddr) (net.Listener, *pr
 	// make a fresh listener
 	l, err := net.ListenUnix(nett, laddr)
 	if err != nil {
-		return nil, probe.New(err)
+		return nil, probe.NewError(err)
 	}
 	n.activeListeners = append(n.activeListeners, rateLimitedListener(l, n.connLimit))
 	return l, nil
@@ -240,7 +240,7 @@ func (n *minNet) StartProcess() (int, *probe.Error) {
 		var err error
 		files[i], err = l.(fileListener).File()
 		if err != nil {
-			return 0, probe.New(err)
+			return 0, probe.NewError(err)
 		}
 		defer files[i].Close()
 	}
@@ -249,7 +249,7 @@ func (n *minNet) StartProcess() (int, *probe.Error) {
 	// the file it points to has been changed we will use the updated symlink.
 	argv0, err := exec.LookPath(os.Args[0])
 	if err != nil {
-		return 0, probe.New(err)
+		return 0, probe.NewError(err)
 	}
 
 	// Pass on the environment and replace the old count key with the new one.
@@ -268,7 +268,7 @@ func (n *minNet) StartProcess() (int, *probe.Error) {
 		Files: allFiles,
 	})
 	if err != nil {
-		return 0, probe.New(err)
+		return 0, probe.NewError(err)
 	}
 	return process.Pid, nil
 }