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/api/logging-handlers.go

@@ -24,7 +24,6 @@ import (
 	"os"
 	"time"
 
-	"github.com/minio/minio/pkg/probe"
 	"github.com/minio/minio/pkg/utils/log"
 )
 
@@ -99,12 +98,12 @@ func fileLogger(filename string) (chan<- []byte, error) {
 	ch := make(chan []byte)
 	file, err := os.OpenFile(filename, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0600)
 	if err != nil {
-		return nil, probe.New(err)
+		return nil, err
 	}
 	go func() {
 		for message := range ch {
 			if _, err := io.Copy(file, bytes.NewBuffer(message)); err != nil {
-				log.Errorln(probe.New(err))
+				log.Errorln(err)
 			}
 		}
 	}()

pkg/server/api/range.go

@@ -41,7 +41,7 @@ func (r *httpRange) String() string {
 }
 
 // Grab new range from request header
-func getRequestedRange(hrange string, size int64) (*httpRange, error) {
+func getRequestedRange(hrange string, size int64) (*httpRange, *probe.Error) {
 	r := &httpRange{
 		start:  0,
 		length: 0,
@@ -51,16 +51,16 @@ func getRequestedRange(hrange string, size int64) (*httpRange, error) {
 	if hrange != "" {
 		err := r.parseRange(hrange)
 		if err != nil {
-			return nil, probe.New(err)
+			return nil, err.Trace()
 		}
 	}
 	return r, nil
 }
 
-func (r *httpRange) parse(ra string) error {
+func (r *httpRange) parse(ra string) *probe.Error {
 	i := strings.Index(ra, "-")
 	if i < 0 {
-		return probe.New(donut.InvalidRange{})
+		return probe.NewError(donut.InvalidRange{})
 	}
 	start, end := strings.TrimSpace(ra[:i]), strings.TrimSpace(ra[i+1:])
 	if start == "" {
@@ -68,7 +68,7 @@ func (r *httpRange) parse(ra string) error {
 		// range start relative to the end of the file.
 		i, err := strconv.ParseInt(end, 10, 64)
 		if err != nil {
-			return probe.New(donut.InvalidRange{})
+			return probe.NewError(donut.InvalidRange{})
 		}
 		if i > r.size {
 			i = r.size
@@ -78,7 +78,7 @@ func (r *httpRange) parse(ra string) error {
 	} else {
 		i, err := strconv.ParseInt(start, 10, 64)
 		if err != nil || i > r.size || i < 0 {
-			return probe.New(donut.InvalidRange{})
+			return probe.NewError(donut.InvalidRange{})
 		}
 		r.start = i
 		if end == "" {
@@ -87,7 +87,7 @@ func (r *httpRange) parse(ra string) error {
 		} else {
 			i, err := strconv.ParseInt(end, 10, 64)
 			if err != nil || r.start > i {
-				return probe.New(donut.InvalidRange{})
+				return probe.NewError(donut.InvalidRange{})
 			}
 			if i >= r.size {
 				i = r.size - 1
@@ -99,26 +99,26 @@ func (r *httpRange) parse(ra string) error {
 }
 
 // parseRange parses a Range header string as per RFC 2616.
-func (r *httpRange) parseRange(s string) error {
+func (r *httpRange) parseRange(s string) *probe.Error {
 	if s == "" {
-		return probe.New(errors.New("header not present"))
+		return probe.NewError(errors.New("header not present"))
 	}
 	if !strings.HasPrefix(s, b) {
-		return probe.New(donut.InvalidRange{})
+		return probe.NewError(donut.InvalidRange{})
 	}
 
 	ras := strings.Split(s[len(b):], ",")
 	if len(ras) == 0 {
-		return probe.New(errors.New("invalid request"))
+		return probe.NewError(errors.New("invalid request"))
 	}
 	// Just pick the first one and ignore the rest, we only support one range per object
 	if len(ras) > 1 {
-		return probe.New(errors.New("multiple ranges specified"))
+		return probe.NewError(errors.New("multiple ranges specified"))
 	}
 
 	ra := strings.TrimSpace(ras[0])
 	if ra == "" {
-		return probe.New(donut.InvalidRange{})
+		return probe.NewError(donut.InvalidRange{})
 	}
 	return r.parse(ra)
 }

pkg/server/api/signature.go

@@ -72,7 +72,7 @@ func InitSignatureV4(req *http.Request) (*donut.Signature, *probe.Error) {
 		var err error
 		accessKeyID, err = StripAccessKeyID(ah)
 		if err != nil {
-			return nil, probe.New(err)
+			return nil, probe.NewError(err)
 		}
 	}
 	authConfig, err := auth.LoadConfig()
@@ -80,7 +80,7 @@ func InitSignatureV4(req *http.Request) (*donut.Signature, *probe.Error) {
 		return nil, err.Trace()
 	}
 	if _, ok := authConfig.Users[accessKeyID]; !ok {
-		return nil, probe.New(errors.New("AccessID not found"))
+		return nil, probe.NewError(errors.New("AccessID not found"))
 	}
 	signature := &donut.Signature{
 		AccessKeyID:     authConfig.Users[accessKeyID].AccessKeyID,

pkg/server/api_donut_cache_test.go

@@ -52,8 +52,8 @@ func (s *MyAPIDonutCacheSuite) SetUpSuite(c *C) {
 	conf.Version = "0.0.1"
 	conf.MaxSize = 100000
 	donut.SetDonutConfigPath(filepath.Join(root, "donut.json"))
-	err = donut.SaveConfig(conf)
-	c.Assert(err, IsNil)
+	perr := donut.SaveConfig(conf)
+	c.Assert(perr, IsNil)
 
 	httpHandler, minioAPI := getAPIHandler(api.Config{RateLimit: 16})
 	go startTM(minioAPI)

pkg/server/api_donut_test.go

@@ -71,8 +71,8 @@ func (s *MyAPIDonutSuite) SetUpSuite(c *C) {
 	conf.NodeDiskMap = createTestNodeDiskMap(root)
 	conf.MaxSize = 100000
 	donut.SetDonutConfigPath(filepath.Join(root, "donut.json"))
-	err = donut.SaveConfig(conf)
-	c.Assert(err, IsNil)
+	perr := donut.SaveConfig(conf)
+	c.Assert(perr, IsNil)
 
 	httpHandler, minioAPI := getAPIHandler(api.Config{RateLimit: 16})
 	go startTM(minioAPI)

pkg/server/api_signature_v4_test.go

@@ -60,13 +60,13 @@ func (s *MyAPISignatureV4Suite) SetUpSuite(c *C) {
 	conf.NodeDiskMap = createTestNodeDiskMap(root)
 	conf.MaxSize = 100000
 	donut.SetDonutConfigPath(filepath.Join(root, "donut.json"))
-	err = donut.SaveConfig(conf)
-	c.Assert(err, IsNil)
+	perr := donut.SaveConfig(conf)
+	c.Assert(perr, IsNil)
 
-	accessKeyID, err := auth.GenerateAccessKeyID()
-	c.Assert(err, IsNil)
-	secretAccessKey, err := auth.GenerateSecretAccessKey()
-	c.Assert(err, IsNil)
+	accessKeyID, perr := auth.GenerateAccessKeyID()
+	c.Assert(perr, IsNil)
+	secretAccessKey, perr := auth.GenerateSecretAccessKey()
+	c.Assert(perr, IsNil)
 
 	authConf := &auth.Config{}
 	authConf.Users = make(map[string]*auth.User)
@@ -79,8 +79,8 @@ func (s *MyAPISignatureV4Suite) SetUpSuite(c *C) {
 	s.secretAccessKey = string(secretAccessKey)
 
 	auth.SetAuthConfigPath(filepath.Join(root, "users.json"))
-	err = auth.SaveConfig(authConf)
-	c.Assert(err, IsNil)
+	perr = auth.SaveConfig(authConf)
+	c.Assert(perr, IsNil)
 
 	httpHandler, minioAPI := getAPIHandler(api.Config{RateLimit: 16})
 	go startTM(minioAPI)

pkg/server/minhttp/http.go

@@ -41,7 +41,7 @@ type app struct {
 	listeners []net.Listener
 	sds       []httpdown.Server
 	net       *minNet
-	errors    chan error
+	errors    chan *probe.Error
 }
 
 // listen initailize listeners
@@ -79,7 +79,7 @@ func (a *app) wait() {
 		go func(s httpdown.Server) {
 			defer wg.Done()
 			if err := s.Wait(); err != nil {
-				a.errors <- probe.New(err)
+				a.errors <- probe.NewError(err)
 			}
 		}(s)
 	}
@@ -101,7 +101,7 @@ func (a *app) trapSignal(wg *sync.WaitGroup) {
 				go func(s httpdown.Server) {
 					defer wg.Done()
 					if err := s.Stop(); err != nil {
-						a.errors <- probe.New(err)
+						a.errors <- probe.NewError(err)
 					}
 				}(s)
 			}
@@ -112,7 +112,7 @@ func (a *app) trapSignal(wg *sync.WaitGroup) {
 			// we only return here if there's an error, otherwise the new process
 			// will send us a TERM when it's ready to trigger the actual shutdown.
 			if _, err := a.net.StartProcess(); err != nil {
-				a.errors <- probe.New(err)
+				a.errors <- err.Trace()
 			}
 		}
 	}
@@ -129,7 +129,7 @@ func ListenAndServe(servers ...*http.Server) *probe.Error {
 		listeners: make([]net.Listener, 0, len(servers)),
 		sds:       make([]httpdown.Server, 0, len(servers)),
 		net:       &minNet{},
-		errors:    make(chan error, 1+(len(servers)*2)),
+		errors:    make(chan *probe.Error, 1+(len(servers)*2)),
 	}
 
 	// Acquire Listeners
@@ -143,7 +143,7 @@ func ListenAndServe(servers ...*http.Server) *probe.Error {
 	// Close the parent if we inherited and it wasn't init that started us.
 	if os.Getenv("LISTEN_FDS") != "" && ppid != 1 {
 		if err := syscall.Kill(ppid, syscall.SIGTERM); err != nil {
-			return probe.New(err)
+			return probe.NewError(err)
 		}
 	}
 
@@ -160,7 +160,7 @@ func ListenAndServe(servers ...*http.Server) *probe.Error {
 		if err == nil {
 			panic("unexpected nil error")
 		}
-		return probe.New(err)
+		return err.Trace()
 	case <-waitdone:
 		return nil
 	}
@@ -176,7 +176,7 @@ func ListenAndServeLimited(connLimit int, servers ...*http.Server) *probe.Error
 		listeners: make([]net.Listener, 0, len(servers)),
 		sds:       make([]httpdown.Server, 0, len(servers)),
 		net:       &minNet{connLimit: connLimit},
-		errors:    make(chan error, 1+(len(servers)*2)),
+		errors:    make(chan *probe.Error, 1+(len(servers)*2)),
 	}
 
 	// Acquire Listeners
@@ -190,7 +190,7 @@ func ListenAndServeLimited(connLimit int, servers ...*http.Server) *probe.Error
 	// Close the parent if we inherited and it wasn't init that started us.
 	if os.Getenv("LISTEN_FDS") != "" && ppid != 1 {
 		if err := syscall.Kill(ppid, syscall.SIGTERM); err != nil {
-			return probe.New(err)
+			return probe.NewError(err)
 		}
 	}
 
@@ -207,7 +207,7 @@ func ListenAndServeLimited(connLimit int, servers ...*http.Server) *probe.Error
 		if err == nil {
 			panic("unexpected nil error")
 		}
-		return probe.New(err)
+		return err.Trace()
 	case <-waitdone:
 		return nil
 	}

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
 }

pkg/server/rpc/auth.go

@@ -49,7 +49,7 @@ func getAuth(reply *AuthReply) *probe.Error {
 // Get auth keys
 func (s *AuthService) Get(r *http.Request, args *Args, reply *AuthReply) error {
 	if err := getAuth(reply); err != nil {
-		return err
+		return probe.NewWrappedError(err)
 	}
 	return nil
 }

pkg/server/rpc/donut.go

@@ -56,5 +56,8 @@ func setDonut(args *DonutArgs, reply *Reply) *probe.Error {
 
 // Set method
 func (s *DonutService) Set(r *http.Request, args *DonutArgs, reply *Reply) error {
-	return setDonut(args, reply)
+	if err := setDonut(args, reply); err != nil {
+		return probe.NewWrappedError(err)
+	}
+	return nil
 }

pkg/server/rpc/sysinfo.go

@@ -55,7 +55,7 @@ func setSysInfoReply(sis *SysInfoReply) *probe.Error {
 	var err error
 	sis.Hostname, err = os.Hostname()
 	if err != nil {
-		return probe.New(err)
+		return probe.NewError(err)
 	}
 	return nil
 }
@@ -70,7 +70,7 @@ func setMemStatsReply(sis *MemStatsReply) *probe.Error {
 // Get method
 func (s *SysInfoService) Get(r *http.Request, args *Args, reply *SysInfoReply) error {
 	if err := setSysInfoReply(reply); err != nil {
-		return err
+		return probe.NewWrappedError(err)
 	}
 	return nil
 }
@@ -78,7 +78,7 @@ func (s *SysInfoService) Get(r *http.Request, args *Args, reply *SysInfoReply) e
 // Get method
 func (s *MemStatsService) Get(r *http.Request, args *Args, reply *MemStatsReply) error {
 	if err := setMemStatsReply(reply); err != nil {
-		return err
+		return probe.NewWrappedError(err)
 	}
 	return nil
 }

pkg/server/server.go

@@ -44,13 +44,13 @@ func getAPIServer(conf api.Config, apiHandler http.Handler) (*http.Server, *prob
 		httpServer.TLSConfig.Certificates = make([]tls.Certificate, 1)
 		httpServer.TLSConfig.Certificates[0], err = tls.LoadX509KeyPair(conf.CertFile, conf.KeyFile)
 		if err != nil {
-			return nil, probe.New(err)
+			return nil, probe.NewError(err)
 		}
 	}
 
 	host, port, err := net.SplitHostPort(conf.Address)
 	if err != nil {
-		return nil, probe.New(err)
+		return nil, probe.NewError(err)
 	}
 
 	var hosts []string
@@ -60,7 +60,7 @@ func getAPIServer(conf api.Config, apiHandler http.Handler) (*http.Server, *prob
 	default:
 		addrs, err := net.InterfaceAddrs()
 		if err != nil {
-			return nil, probe.New(err)
+			return nil, probe.NewError(err)
 		}
 		for _, addr := range addrs {
 			if addr.Network() == "ip+net" {