How to use NoErr method of is Package

...47	}48	// Connection is closed49	if s == 0 {50		log.Println("Connection closed")51		return TERMMSG, syserror.NoErr52	}53	// Read returns an error (we test this only as a second test since s=0 means socket closed,54	// which returns also EOF as an error but we want to handle it as normal termination, not an error case55	if err != nil {56		log.Println("ERROR:", err.Error())57		return INVALID, syserror.ErrFatal58	}59	if s > 0 && s != 4 {60		log.Println("ERROR Cannot recv header")61		return INVALID, syserror.NoErr62	}63	// Disconnect request64	if string(hdr[:s]) == TERMMSG {65		log.Println("Recv'd disconnect request")66		return TERMMSG, syserror.NoErr67	}68	if string(hdr[:s]) == CONNREQ {69		log.Println("Recv'd connection request")70		return CONNREQ, syserror.NoErr71	}72	if string(hdr[:s]) == CONNACK {73		log.Println("Recv'd connection ACK")74		return CONNACK, syserror.NoErr75	}76	log.Println("Invalid msg header")77	return INVALID, syserror.ErrFatal78}79func (p *PeerInfo) getPayloadSize() (uint64, syserror.SysError) {80	if p == nil || p.conn == nil {81		return 0, syserror.ErrNotAvailable82	}83	ps := make([]byte, 8) // Payload size is always 8 bytes84	s, myerr := p.conn.Read(ps)85	if s != 8 || myerr != nil {86		log.Println("ERROR: expecting 8 bytes but received", s)87		return 0, syserror.ErrFatal88	}89	return binary.LittleEndian.Uint64(ps), syserror.NoErr90}91func (p *PeerInfo) getPayload(size uint64) ([]byte, syserror.SysError) {92	if p == nil || p.conn == nil {93		return nil, syserror.ErrNotAvailable94	}95	payload := make([]byte, size)96	s, myerr := p.conn.Read(payload)97	if uint64(s) != size || myerr != nil {98		log.Println("ERROR: expecting ", size, "but received", s)99		return nil, syserror.ErrFatal100	}101	return payload, syserror.NoErr102}103func (p *PeerInfo) handleConnReq(size uint64, payload []byte) syserror.SysError {104	if p == nil {105		log.Println("ERROR: local server is not initialized")106		return syserror.ErrFatal107	}108	// Send CONNACK with the payload109	log.Println("Sending CONNACK...")110	err := p.SendMsg(CONNACK, payload)111	if err != syserror.NoErr {112		return err113	}114	return syserror.NoErr115}116// HandleHandshake receives and handles a CONNREQ message, i.e., a client trying to connect117func (p *PeerInfo) HandleHandshake() syserror.SysError {118	/* Handle the CONNREQ message */119	msgtype, payload_size, payload, err := p.RecvMsg()120	if err != syserror.NoErr {121		return syserror.ErrFatal122	}123	if msgtype == CONNREQ {124		err := p.handleConnReq(payload_size, payload)125		if err != syserror.NoErr {126			return err127		}128	} else {129		return syserror.NoErr // We did not get the expected CONNREQ msg130	}131	return syserror.NoErr132}133func (p *PeerInfo) sendMsgType(msgType string) syserror.SysError {134	if p.conn == nil {135		return syserror.ErrFatal136	}137	s, err := p.conn.Write([]byte(msgType))138	if s == 0 || err != nil {139		return syserror.ErrFatal140	}141	return syserror.NoErr142}143// SendMsg sends a basic message144func (p *PeerInfo) SendMsg(msgType string, payload []byte) syserror.SysError {145	if p.conn == nil {146		return syserror.ErrFatal147	}148	hdrerr := p.sendMsgType(msgType)149	if hdrerr != syserror.NoErr {150		return hdrerr151	}152	if payload != nil {153		syserr := p.sendUint64(uint64(len(payload)))154		if syserr != syserror.NoErr {155			return syserr156		}157		s, err := p.conn.Write(payload)158		if s != len(payload) || err != nil {159			log.Println("[ERROR] write operation failed")160			return syserror.ErrFatal161		}162	} else {163		syserr := p.sendUint64(uint64(0))164		if syserr != syserror.NoErr {165			return syserr166		}167	}168	return syserror.NoErr169}170func (p *PeerInfo) sendUint64(value uint64) syserror.SysError {171	if p == nil || p.conn == nil {172		return syserror.ErrFatal173	}174	buff := make([]byte, 8)175	if buff == nil {176		return syserror.ErrOutOfRes177	}178	binary.LittleEndian.PutUint64(buff, value)179	s, myerr := p.conn.Write(buff)180	if myerr != nil {181		log.Println(myerr.Error())182	}183	if myerr == nil && s != 8 {184		log.Println("Received ", s, "bytes, instead of 8")185	}186	if s != 8 || myerr != nil {187		return syserror.ErrFatal188	}189	return syserror.NoErr190}191// RecvMsg receives a basic message192func (p *PeerInfo) RecvMsg() (string, uint64, []byte, syserror.SysError) {193	if p == nil || p.conn == nil {194		return "", 0, nil, syserror.ErrFatal195	}196	msgtype, err := p.GetHeader()197	// Messages without payload198	if msgtype == "TERM" || msgtype == "INVA" || err != syserror.NoErr {199		return msgtype, 0, nil, syserror.ErrFatal200	}201	// Get the payload size202	payload_size, err := p.getPayloadSize()203	if err != syserror.NoErr {204		return msgtype, 0, nil, syserror.ErrFatal205	}206	if payload_size == 0 {207		return msgtype, 0, nil, syserror.NoErr208	}209	// Get the payload210	buff, err := p.getPayload(payload_size)211	if err != syserror.NoErr {212		return msgtype, payload_size, buff, syserror.NoErr213	}214	return msgtype, payload_size, buff, syserror.NoErr215}216// ConnectHandshake initiates a connection handshake217func (p *PeerInfo) ConnectHandshake() syserror.SysError {218	err := p.SendMsg(CONNREQ, nil)219	if err != syserror.NoErr {220		return err221	}222	// Receive the CONNACK, the payload is the block_sizw223	msgtype, size, _, recverr := p.RecvMsg()224	if recverr != syserror.NoErr || msgtype != CONNACK || size < 0 {225		return syserror.ErrFatal226	}227	// todo: handle payload228	return syserror.NoErr229}230func (p *PeerInfo) connectHandshake() syserror.SysError {231	err := p.SendMsg(CONNREQ, nil)232	if err != syserror.NoErr {233		return err234	}235	// Receive the CONNACK, the payload is the block_sizw236	msgtype, s, _, err := p.RecvMsg()237	if err != syserror.NoErr || msgtype != CONNACK || s < 0 {238		return syserror.ErrFatal239	}240	return syserror.NoErr241}242func (p *PeerInfo) Connect() syserror.SysError {243	retry := 0244	if p == nil {245		return syserror.ErrFatal246	}247	var err error248Retry:249	p.conn, err = net.Dial("tcp", p.URL)250	if err != nil {251		log.Printf("Dial failed: %s", err.Error())252		if retry < 5 {253			retry++254			log.Printf("Retrying after %d seconds\n", retry)255			time.Sleep(time.Duration(retry) * time.Second)256			goto Retry257		}258		return syserror.ErrOutOfRes259	}260	syserr := p.connectHandshake()261	if syserr != syserror.NoErr {262		return syserror.ErrFatal263	}264	return syserror.NoErr265}266func (info *PeerInfo) doServer() syserror.SysError {267	done := 0268	syserr := info.HandleHandshake()269	if syserr != syserror.NoErr {270		log.Printf("[ERROR] handshake with client failed: %s", syserr.Error())271	}272	for done != 1 {273		// Handle the message header274		msgtype, syserr := info.GetHeader()275		if syserr != syserror.NoErr {276			done = 1277		}278		if msgtype == "INVA" || msgtype == "TERM" {279			done = 1280		}281		//  Handle the paylaod size282		payload_size, pserr := info.getPayloadSize()283		if pserr != syserror.NoErr {284			done = 1285		}286		// Handle the payload when necessary287		var payload []byte = nil288		if payload_size != 0 {289			payload, syserr = info.getPayload(payload_size)290		}291		if payload_size != 0 && payload != nil {292			return syserror.ErrFatal293		}294	}295	info.conn.Close()296	log.Printf("Go routine for peer %s done\n", info.URL)297	return syserror.NoErr298}299func (info *PeerInfo) CreateEmbeddedServer() syserror.SysError {300	if info == nil {301		return syserror.ErrFatal302	}303	log.Println("Creating embedded server...")304	listener, err := net.Listen("tcp", info.URL)305	if err != nil {306		return syserror.ErrFatal307	}308	log.Println("Server created on", info.URL)309	var conn net.Conn310	for {311		conn, err = listener.Accept()312		log.Println("Connection accepted")313		var newPeer PeerInfo314		newPeer.conn = conn315		if err != nil {316			log.Println("[ERROR] ", err.Error())317		}318		log.Println("Creating new Go routine for new peer...")319		go newPeer.doServer()320	}321	// todo: fix termination322	//return syserror.NoErr323}324func (info *PeerInfo) CreateServer() (PeerInfo, syserror.SysError) {325	var newPeer PeerInfo326	if info == nil {327		return newPeer, syserror.ErrFatal328	}329	listener, err := net.Listen("tcp", info.URL)330	if err != nil {331		log.Printf("failed to listen on socket: %s", err)332		return newPeer, syserror.ErrFatal333	}334	if info.timeout > 0 {335		listener.(*net.TCPListener).SetDeadline(time.Now().Add(time.Duration(info.timeout) * time.Second))336	}337	newPeer.conn, err = listener.Accept()338	if err != nil {339		return newPeer, syserror.ErrFatal340	}341	return newPeer, syserror.NoErr342}...

...11	_ = createTestBucket(testPutBucketName)12	const path = "TestClientXAPIObject/test"13	// check non-existed object14	_, err := svc.XDeleteObjectFromPath(ctx, testPutBucketName, path)15	is.NoErr(err)16	ok, err := svc.XExistObject(ctx, testPutBucketName, path)17	is.NoErr(err)18	is.Equal(ok, false)19	resGet, err := svc.XGetObjectFromPath(ctx, testPutBucketName, path)20	is.NoErr(err)21	is.Equal(resGet.Exists, false)22	// check existed object23	resPut, err := svc.XPutObjectToPath(ctx, testPutBucketName, path, []byte("001"))24	is.NoErr(err)25	is.True(resPut.ETag != "") // ETag must be set26	ok, err = svc.XExistObject(ctx, testPutBucketName, path)27	is.NoErr(err)28	is.True(ok)29	resGet, err = svc.XGetObjectFromPath(ctx, testPutBucketName, path)30	is.NoErr(err)31	is.Equal(resGet.ETag, resPut.ETag) // ETag must be same32	byt, err := resGet.ToBytes()33	is.NoErr(err)34	is.Equal(byt, []byte("001")) // content must be updated35	// update existed object36	resPut, err = svc.XPutObjectToPath(ctx, testPutBucketName, path, []byte("002"))37	is.NoErr(err)38	is.True(resPut.ETag != "") // ETag must be set39	resGet, err = svc.XGetObjectFromPath(ctx, testPutBucketName, path)40	is.NoErr(err)41	is.Equal(resGet.ETag, resPut.ETag) // ETag must be same42	byt, err = resGet.ToBytes()43	is.NoErr(err)44	is.Equal(byt, []byte("002")) // content must be updated45	// check deleted object46	_, err = svc.XDeleteObjectFromPath(ctx, testPutBucketName, path)47	is.NoErr(err)48	ok, err = svc.XExistObject(ctx, testPutBucketName, path)49	is.NoErr(err)50	is.Equal(ok, false)51	resGet, err = svc.XGetObjectFromPath(ctx, testPutBucketName, path)52	is.NoErr(err)53	is.Equal(resGet.Exists, false)54	_, err = svc.XDeleteObjectFromPath(ctx, testPutBucketName, path)55	is.NoErr(err)56}...

...12		bits = 3213		rate = 4410014	)15	f, err := ioutil.TempFile("", "wavPkgtest")16	is.NoErr(err)17	testFname := f.Name()18	meta := File{19		Channels:        1,20		SampleRate:      rate,21		SignificantBits: bits,22	}23	writer, err := meta.NewWriter(f)24	is.NoErr(err)25	var freq float6426	freq = 0.000127	// one second28	for n := 0; n < rate; n++ {29		y := int32(0.8 * math.Pow(2, bits-1) * math.Sin(freq*float64(n)))30		freq += 0.00000231		err = writer.WriteInt32(y)32		if err != nil {33			t.Fatal(err)34		}35	}36	err = writer.Close()37	is.NoErr(err)38	f, err = os.Open(testFname)39	is.NoErr(err)40	stat, err := f.Stat()41	is.NoErr(err)42	_, err = NewReader(f, stat.Size())43	is.NoErr(err)44	is.NoErr(os.Remove(testFname))45}46func TestWriteRead_Sample(t *testing.T) {47	is := is.New(t)48	const (49		bits = 1650		rate = 4410051	)52	f, err := ioutil.TempFile("", "wavPkgtest")53	is.NoErr(err)54	testFname := f.Name()55	meta := File{56		Channels:        1,57		SampleRate:      rate,58		SignificantBits: bits,59	}60	writer, err := meta.NewWriter(f)61	is.NoErr(err)62	var freq float6463	freq = 0.000164	var s = make([]byte, 2)65	// one second66	for n := 0; n < rate; n++ {67		y := int32(0.8 * math.Pow(2, bits-1) * math.Sin(freq*float64(n)))68		freq += 0.00000269		// s[3] = byte((y >> 24) & 0xFF)70		// s[2] = byte((y >> 16) & 0xFF)71		s[1] = byte((y >> 8) & 0xFF)72		s[0] = byte(y & 0xFF)73		err = writer.WriteSample(s)74		if err != nil {75			t.Fatal(err)76		}77	}78	err = writer.Close()79	is.NoErr(err)80	f, err = os.Open(testFname)81	is.NoErr(err)82	stat, err := f.Stat()83	is.NoErr(err)84	_, err = NewReader(f, stat.Size())85	is.NoErr(err)86	is.NoErr(os.Remove(testFname))87}...

1import "fmt"2func main() {3	fmt.Println("Hello, playground")4}5import "fmt"6func main() {7	fmt.Println("Hello, playground")8}9import "fmt"10func main() {11	fmt.Println("Hello, playground")12}13import "fmt"14func main() {15	fmt.Println("Hello, playground")16}17import "fmt"18func main() {19	fmt.Println("Hello, playground")20}21import "fmt"22func main() {23	fmt.Println("Hello, playground")24}25import "fmt"26func main() {27	fmt.Println("Hello, playground")28}29import "fmt"30func main() {31	fmt.Println("Hello, playground")32}33import "fmt"34func main() {35	fmt.Println("Hello, playground")36}37import "fmt"38func main() {39	fmt.Println("Hello, playground")40}41import "fmt"42func main() {43	fmt.Println("Hello, playground")44}45import "fmt"46func main() {47	fmt.Println("Hello, playground")48}49import "fmt"50func main() {51	fmt.Println("Hello, playground")52}53import "fmt"54func main() {55	fmt.Println("Hello, playground

1import (2func main() {3	f, err := os.Open("notfound.txt")4	if err != nil {5		fmt.Println(err)6	}7	fmt.Println(f.Name(), "opened successfully")8}9import (10func main() {11	f, err := os.Open("notfound.txt")12	if err != nil {13		if os.IsNotExist(err) {14			fmt.Println("File does not exist")15		}16	}17	fmt.Println(f.Name(), "opened successfully")18}19import (20func main() {21	f, err := os.Open("notfound.txt")22	if err != nil {23		if os.IsPermission(err) {24			fmt.Println("Permission denied")25		}26	}27	fmt.Println(f.Name(), "opened successfully")28}29import (30func main() {31	f, err := os.Open("notfound.txt")32	if err != nil {33		if os.IsTimeout(err) {34			fmt.Println("Timeout")35		}36	}37	fmt.Println(f.Name(), "opened successfully")38}39import (40func main() {41	f, err := os.Open("notfound.txt")42	if err != nil {43		if os.IsExist(err) {44			fmt.Println("File already exists")45		}46	}47	fmt.Println(f.Name(), "opened successfully")48}49import (50func main() {51	f, err := os.Open("notfound.txt")52	if err != nil {53		if os.IsPathSeparator(err) {54			fmt.Println("Path separator")55		}56	}57	fmt.Println(f.Name(), "opened successfully")58}

1import (2type Config struct {3}4func main() {5	err := envconfig.Process("app", &c)6	if err != nil {7		fmt.Println("error")8	}9	fmt.Println(c.Port)10}11import (12type Config struct {13}14func main() {15	err := envconfig.Process("app", &c)16	if err != nil {17		fmt.Println("error")18	}19	fmt.Println(c.Port)20}21import (22type Config struct {23}24func main() {25	err := envconfig.Process("app", &c)26	if err != nil {27		fmt.Println("error")28	}29	fmt.Println(c.Port)30}31import (32type Config struct {33}34func main() {35	err := envconfig.Process("app", &c)36	if err != nil {37		fmt.Println("error")38	}39	fmt.Println(c.Port)40}41import (42type Config struct {43}44func main() {