How to use Write method of log Package

Best Syzkaller code snippet using log.Write

handler.go

Source:handler.go

...21	Order_Name string `json:"ordername"`22	Quantity   string `json:"quantity"`23	UserID     string `json:"id"`24}25func (h *Handler) CreateUser(w http.ResponseWriter, r *http.Request) {26	user := User{}27	dbConn, err := db.CreatConnection()28	if err != nil {29		h.Log.Error(err.Error())30		w.Write([]byte(err.Error()))31		w.WriteHeader(http.StatusInternalServerError)32	}33	defer dbConn.Close()34	if err := json.NewDecoder(r.Body).Decode(&user); err != nil {35		h.Log.Error(err.Error())36		w.Write([]byte("Cannot Decode request"))37		w.WriteHeader(http.StatusBadRequest)38	}39	insForm, err := dbConn.Prepare("INSERT INTO User(id, name, email, number) VALUES(?,?,?,?)")40	if err != nil {41		h.Log.Error(err.Error())42		w.Write([]byte("Cannot insert data"))43		w.WriteHeader(http.StatusInternalServerError)44	}45	_, err = insForm.Exec(user.Id, user.Name, user.Email, user.Phone_Number)46	if err != nil {47		h.Log.Error(err.Error())48		w.Write([]byte("Cannot insert data"))49		w.WriteHeader(http.StatusInternalServerError)50	}51}52func (h *Handler) FetchUser(w http.ResponseWriter, r *http.Request) {53	dbConn, err := db.CreatConnection()54	if err != nil {55		h.Log.Error(err.Error())56		w.Write([]byte(err.Error()))57		w.WriteHeader(http.StatusInternalServerError)58	}59	defer dbConn.Close()60	value := strings.Split(r.URL.Path, "/")[3]61	result, err := dbConn.Query("SELECT * FROM User WHERE id=?", value)62	if err != nil {63		h.Log.Error(err.Error())64		w.Write([]byte(err.Error()))65		w.WriteHeader(http.StatusInternalServerError)66	}67	user := User{}68	for result.Next() {69		var id, name, email, number string70		err = result.Scan(&id, &name, &email, &number)71		if err != nil {72			h.Log.Error(err.Error())73			w.Write([]byte("Cannot read user data"))74			w.WriteHeader(http.StatusInternalServerError)75		}76		user.Id = id77		user.Name = name78		user.Email = email79		user.Phone_Number = number80	}81	jData, err := json.Marshal(user)82	if err != nil {83		h.Log.Error(err.Error())84		w.Write([]byte("Cannot unmarshal data fetched for user"))85		w.WriteHeader(http.StatusInternalServerError)86	}87	w.Header().Set("Content-Type", "application/json")88	w.Write(jData)89}90func (h *Handler) UpdateUser(w http.ResponseWriter, r *http.Request) {91	user := User{}92	if err := json.NewDecoder(r.Body).Decode(&user); err != nil {93		h.Log.Error(err.Error())94		w.Write([]byte("Cannot Decode request"))95		w.WriteHeader(http.StatusBadRequest)96	}97	var queryString = "UPDATE User SET "98	if user.Name != "" {99		queryString += "name=?"100	}101	if user.Email != "" {102		if user.Name != "" {103			queryString += ", "104		}105		queryString += "email=?"106	}107	if user.Phone_Number != "" {108		if user.Name != "" || user.Email != "" {109			queryString += ", "110		}111		queryString += "number=?"112	}113	queryString += " WHERE id=?"114	dbConn, err := db.CreatConnection()115	if err != nil {116		h.Log.Error(err.Error())117		w.Write([]byte(err.Error()))118		w.WriteHeader(http.StatusInternalServerError)119	}120	defer dbConn.Close()121	value := strings.Split(r.URL.Path, "/")[3]122	insForm, err := dbConn.Prepare(queryString)123	if err != nil {124		h.Log.Error(err.Error())125		w.Write([]byte("Cannot update user data"))126		w.WriteHeader(http.StatusInternalServerError)127	}128	if user.Name != "" && user.Email != "" && user.Phone_Number != "" {129		_, err = insForm.Exec(user.Name, user.Email, user.Phone_Number, value)130	} else if user.Name != "" && user.Email != "" {131		_, err = insForm.Exec(user.Name, user.Email, value)132	} else if user.Name != "" && user.Phone_Number != "" {133		_, err = insForm.Exec(user.Name, user.Phone_Number, value)134	} else if user.Email != "" && user.Phone_Number != "" {135		_, err = insForm.Exec(user.Email, user.Phone_Number, value)136	} else if user.Name != "" {137		_, err = insForm.Exec(user.Name, value)138	} else if user.Email != "" {139		_, err = insForm.Exec(user.Email, value)140	} else {141		_, err = insForm.Exec(user.Phone_Number, value)142	}143	if err != nil {144		h.Log.Error(err.Error())145		w.Write([]byte(err.Error()))146		w.WriteHeader(http.StatusInternalServerError)147	}148	w.WriteHeader(http.StatusOK)149}150func (h *Handler) FetchAllUsers(w http.ResponseWriter, r *http.Request) {151	user := User{}152	dbConn, err := db.CreatConnection()153	if err != nil {154		h.Log.Error(err.Error())155		w.Write([]byte(err.Error()))156		w.WriteHeader(http.StatusInternalServerError)157	}158	defer dbConn.Close()159	result, err := dbConn.Query("SELECT * FROM User ")160	if err != nil {161		h.Log.Error(err.Error())162		w.Write([]byte(err.Error()))163		w.WriteHeader(http.StatusInternalServerError)164	}165	for result.Next() {166		var id, name, email, number string167		err = result.Scan(&id, &name, &email, &number)168		if err != nil {169			h.Log.Error(err.Error())170			log.Fatal(err.Error())171			w.Write([]byte(err.Error()))172			w.WriteHeader(http.StatusInternalServerError)173		}174		user.Id = id175		user.Name = name176		user.Email = email177		user.Phone_Number = number178		jData, err := json.Marshal(user)179		if err != nil {180			h.Log.Error(err.Error())181			w.Write([]byte(err.Error()))182			w.WriteHeader(http.StatusInternalServerError)183		}184		w.Write(jData)185	}186}187func (h *Handler) CreateOrder(w http.ResponseWriter, r *http.Request) {188	order := Order{}189	dbConn, err := db.CreatConnection()190	if err != nil {191		h.Log.Error(err.Error())192		w.Write([]byte(err.Error()))193		w.WriteHeader(http.StatusInternalServerError)194	}195	defer dbConn.Close()196	if err := json.NewDecoder(r.Body).Decode(&order); err != nil {197		h.Log.Error(err.Error())198		w.Write([]byte("Cannot Decode request"))199		w.WriteHeader(http.StatusBadRequest)200	}201	insForm, err := dbConn.Prepare("INSERT INTO Order_inv(orderid, ordername, quantity, id) VALUES(?,?,?,?)")202	if err != nil {203		h.Log.Error(err.Error())204		w.Write([]byte(err.Error()))205		w.WriteHeader(http.StatusInternalServerError)206	}207	_, err = insForm.Exec(order.Order_Id, order.Order_Name, order.Quantity, order.UserID)208	if err != nil {209		h.Log.Error(err.Error())210		w.Write([]byte(err.Error()))211		w.WriteHeader(http.StatusInternalServerError)212	}213}214func (h *Handler) CancelOrder(w http.ResponseWriter, r *http.Request) {215	value := strings.Split(r.URL.Path, "/")[3]216	dbConn, err := db.CreatConnection()217	if err != nil {218		h.Log.Error(err.Error())219		w.Write([]byte(err.Error()))220		w.WriteHeader(http.StatusInternalServerError)221	}222	_, err = dbConn.Query("Delete FROM Order_inv WHERE orderid=?", value)223	if err != nil {224		h.Log.Error(err.Error())225		w.Write([]byte(err.Error()))226		w.WriteHeader(http.StatusInternalServerError)227	}228}229func (h *Handler) FetchAllOrders(w http.ResponseWriter, r *http.Request) {230	value := strings.Split(r.URL.Path, "/")[3]231	dbConn, err := db.CreatConnection()232	if err != nil {233		h.Log.Error(err.Error())234		w.Write([]byte(err.Error()))235		w.WriteHeader(http.StatusInternalServerError)236	}237	defer dbConn.Close()238	result, err := dbConn.Query("SELECT * FROM Order_inv WHERE id=?", value)239	if err != nil {240		h.Log.Error(err.Error())241		w.Write([]byte(err.Error()))242		w.WriteHeader(http.StatusInternalServerError)243	}244	for result.Next() {245		order := Order{}246		var orderid, ordername, quantity, id string247		err = result.Scan(&orderid, &ordername, &quantity, &id)248		if err != nil {249			panic(err.Error())250		}251		order.Order_Id = orderid252		order.Order_Name = ordername253		order.Quantity = quantity254		order.UserID = id255		jData, err := json.Marshal(order)256		if err != nil {257			h.Log.Error(err.Error())258			w.Write([]byte(err.Error()))259			w.WriteHeader(http.StatusInternalServerError)260		}261		w.Write(jData)262	}263}...

syslog.go

Source:syslog.go

...61	LOG_LOCAL562	LOG_LOCAL663	LOG_LOCAL764)65// A Writer is a connection to a syslog server.66type Writer struct {67	priority Priority68	tag      string69	hostname string70	network  string71	raddr    string72	mu   sync.Mutex // guards conn73	conn serverConn74}75// This interface and the separate syslog_unix.go file exist for76// Solaris support as implemented by gccgo.  On Solaris you can not77// simply open a TCP connection to the syslog daemon.  The gccgo78// sources have a syslog_solaris.go file that implements unixSyslog to79// return a type that satisfies this interface and simply calls the C80// library syslog function.81type serverConn interface {82	writeString(p Priority, hostname, tag, s, nl string) error83	close() error84}85type netConn struct {86	local bool87	conn  net.Conn88}89// New establishes a new connection to the system log daemon.  Each90// write to the returned writer sends a log message with the given91// priority and prefix.92func New(priority Priority, tag string) (w *Writer, err error) {93	return Dial("", "", priority, tag)94}95// Dial establishes a connection to a log daemon by connecting to96// address raddr on the specified network.  Each write to the returned97// writer sends a log message with the given facility, severity and98// tag.99// If network is empty, Dial will connect to the local syslog server.100func Dial(network, raddr string, priority Priority, tag string) (*Writer, error) {101	if priority < 0 || priority > LOG_LOCAL7|LOG_DEBUG {102		return nil, errors.New("log/syslog: invalid priority")103	}104	if tag == "" {105		tag = os.Args[0]106	}107	hostname, _ := os.Hostname()108	w := &Writer{109		priority: priority,110		tag:      tag,111		hostname: hostname,112		network:  network,113		raddr:    raddr,114	}115	w.mu.Lock()116	defer w.mu.Unlock()117	err := w.connect()118	if err != nil {119		return nil, err120	}121	return w, err122}123// connect makes a connection to the syslog server.124// It must be called with w.mu held.125func (w *Writer) connect() (err error) {126	if w.conn != nil {127		// ignore err from close, it makes sense to continue anyway128		w.conn.close()129		w.conn = nil130	}131	if w.network == "" {132		w.conn, err = unixSyslog()133		if w.hostname == "" {134			w.hostname = "localhost"135		}136	} else {137		var c net.Conn138		c, err = net.Dial(w.network, w.raddr)139		if err == nil {140			w.conn = &netConn{conn: c}141			if w.hostname == "" {142				w.hostname = c.LocalAddr().String()143			}144		}145	}146	return147}148// Write sends a log message to the syslog daemon.149func (w *Writer) Write(b []byte) (int, error) {150	return w.writeAndRetry(w.priority, string(b))151}152// Close closes a connection to the syslog daemon.153func (w *Writer) Close() error {154	w.mu.Lock()155	defer w.mu.Unlock()156	if w.conn != nil {157		err := w.conn.close()158		w.conn = nil159		return err160	}161	return nil162}163// Emerg logs a message with severity LOG_EMERG, ignoring the severity164// passed to New.165func (w *Writer) Emerg(m string) (err error) {166	_, err = w.writeAndRetry(LOG_EMERG, m)167	return err168}169// Alert logs a message with severity LOG_ALERT, ignoring the severity170// passed to New.171func (w *Writer) Alert(m string) (err error) {172	_, err = w.writeAndRetry(LOG_ALERT, m)173	return err174}175// Crit logs a message with severity LOG_CRIT, ignoring the severity176// passed to New.177func (w *Writer) Crit(m string) (err error) {178	_, err = w.writeAndRetry(LOG_CRIT, m)179	return err180}181// Err logs a message with severity LOG_ERR, ignoring the severity182// passed to New.183func (w *Writer) Err(m string) (err error) {184	_, err = w.writeAndRetry(LOG_ERR, m)185	return err186}187// Warning logs a message with severity LOG_WARNING, ignoring the188// severity passed to New.189func (w *Writer) Warning(m string) (err error) {190	_, err = w.writeAndRetry(LOG_WARNING, m)191	return err192}193// Notice logs a message with severity LOG_NOTICE, ignoring the194// severity passed to New.195func (w *Writer) Notice(m string) (err error) {196	_, err = w.writeAndRetry(LOG_NOTICE, m)197	return err198}199// Info logs a message with severity LOG_INFO, ignoring the severity200// passed to New.201func (w *Writer) Info(m string) (err error) {202	_, err = w.writeAndRetry(LOG_INFO, m)203	return err204}205// Debug logs a message with severity LOG_DEBUG, ignoring the severity206// passed to New.207func (w *Writer) Debug(m string) (err error) {208	_, err = w.writeAndRetry(LOG_DEBUG, m)209	return err210}211func (w *Writer) writeAndRetry(p Priority, s string) (int, error) {212	pr := (w.priority & facilityMask) | (p & severityMask)213	w.mu.Lock()214	defer w.mu.Unlock()215	if w.conn != nil {216		if n, err := w.write(pr, s); err == nil {217			return n, err218		}219	}220	if err := w.connect(); err != nil {221		return 0, err222	}223	return w.write(pr, s)224}225// write generates and writes a syslog formatted string. The226// format is as follows: <PRI>TIMESTAMP HOSTNAME TAG[PID]: MSG227func (w *Writer) write(p Priority, msg string) (int, error) {228	// ensure it ends in a \n229	nl := ""230	if !strings.HasSuffix(msg, "\n") {231		nl = "\n"232	}233	err := w.conn.writeString(p, w.hostname, w.tag, msg, nl)234	if err != nil {235		return 0, err236	}237	// Note: return the length of the input, not the number of238	// bytes printed by Fprintf, because this must behave like239	// an io.Writer.240	return len(msg), nil241}242func (n *netConn) writeString(p Priority, hostname, tag, msg, nl string) error {243	if n.local {244		// Compared to the network form below, the changes are:245		//	1. Use time.Stamp instead of time.RFC3339.246		//	2. Drop the hostname field from the Fprintf.247		timestamp := time.Now().Format(time.Stamp)248		_, err := fmt.Fprintf(n.conn, "<%d>%s %s[%d]: %s%s",249			p, timestamp,250			tag, os.Getpid(), msg, nl)251		return err252	}253	timestamp := time.Now().Format(time.RFC3339)...

write_err_android.go

Source:write_err_android.go

...35			logger = legacy36			initLegacy()37		}38	}39	// Write to stderr for command-line programs.40	write(2, unsafe.Pointer(&b[0]), int32(len(b)))41	// Log format: "<header>\x00<message m bytes>\x00"42	//43	// <header>44	//   In legacy mode: "<priority 1 byte><tag n bytes>".45	//   In logd mode: "<android_log_header_t 11 bytes><priority 1 byte><tag n bytes>"46	//47	// The entire log needs to be delivered in a single syscall (the NDK48	// does this with writev). Each log is its own line, so we need to49	// buffer writes until we see a newline.50	var hlen int51	switch logger {52	case logd:53		hlen = writeLogdHeader()54	case legacy:55		hlen = len(writeHeader)56	}57	dst := writeBuf[hlen:]58	for _, v := range b {59		if v == 0 { // android logging won't print a zero byte60			v = '0'61		}62		dst[writePos] = v63		writePos++64		if v == '\n' || writePos == len(dst)-1 {65			dst[writePos] = 066			write(writeFD, unsafe.Pointer(&writeBuf[0]), int32(hlen+writePos))67			for i := range dst {68				dst[i] = 069			}70			writePos = 071		}72	}73}74func initLegacy() {75	// In legacy mode, logs are written to /dev/log/main76	writeFD = uintptr(open(&writePath[0], 0x1 /* O_WRONLY */, 0))77	if writeFD == 0 {78		// It is hard to do anything here. Write to stderr just79		// in case user has root on device and has run80		//	adb shell setprop log.redirect-stdio true81		msg := []byte("runtime: cannot open /dev/log/main\x00")82		write(2, unsafe.Pointer(&msg[0]), int32(len(msg)))83		exit(2)84	}85	// Prepopulate the invariant header part.86	copy(writeBuf[:len(writeHeader)], writeHeader)87}88// used in initLogdWrite but defined here to avoid heap allocation.89var logdAddr sockaddr_un90func initLogd() {91	// In logd mode, logs are sent to the logd via a unix domain socket.92	logdAddr.family = _AF_UNIX93	copy(logdAddr.path[:], writeLogd)94	// We are not using non-blocking I/O because writes taking this path95	// are most likely triggered by panic, we cannot think of the advantage of96	// non-blocking I/O for panic but see disadvantage (dropping panic message),97	// and blocking I/O simplifies the code a lot.98	fd := socket(_AF_UNIX, _SOCK_DGRAM|_O_CLOEXEC, 0)99	if fd < 0 {100		msg := []byte("runtime: cannot create a socket for logging\x00")101		write(2, unsafe.Pointer(&msg[0]), int32(len(msg)))102		exit(2)...

Automation Testing Tutorials

Learn to execute automation testing from scratch with LambdaTest Learning Hub. Right from setting up the prerequisites to run your first automation test, to following best practices and diving deeper into advanced test scenarios. LambdaTest Learning Hubs compile a list of step-by-step guides to help you be proficient with different test automation frameworks i.e. Selenium, Cypress, TestNG etc.