feat: add experiments

- custom logger
- simple mutex example

experiments/go/custom-logger/logger.go

@@ -0,0 +1,85 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"time"
+)
+
+type logWriter struct {
+	level  string
+	writer io.Writer
+}
+
+func (w logWriter) Write(bytes []byte) (int, error) {
+	timestamp := time.Now().UTC().Format(time.RFC3339)
+	return fmt.Fprintf(w.writer, timestamp + " ["+w.level+"]\t"+string(bytes))
+}
+
+type logger struct {
+	infoLogger  *log.Logger
+	errorLogger *log.Logger
+	debugLogger *log.Logger
+}
+
+func newLogger(debug bool) *logger {
+	infoLogWriter := logWriter{
+		level:  "INFO",
+		writer: os.Stdout,
+	}
+	infoLogger := log.New(infoLogWriter, "", 0)
+
+	errorLogWriter := logWriter{
+		level:  "ERROR",
+		writer: os.Stderr,
+	}
+	errorLogger := log.New(errorLogWriter, "", 0)
+
+	var baseDebugWriter io.Writer
+
+	if debug {
+		baseDebugWriter = os.Stdout
+	} else {
+		baseDebugWriter = io.Discard
+	}
+
+	debugLogWriter := logWriter{
+		level:  "DEBUG",
+		writer: baseDebugWriter,
+	}
+	debugLogger := log.New(debugLogWriter, "", log.Lshortfile)
+
+	l := logger{
+		infoLogger:  infoLogger,
+		errorLogger: errorLogger,
+		debugLogger: debugLogger,
+	}
+
+	return &l
+}
+
+func (l *logger) Infoln(v ...interface{}) {
+	l.infoLogger.Println(v...)
+}
+
+func (l *logger) Infof(format string, v ...interface{}) {
+	l.infoLogger.Printf(format, v...)
+}
+
+func (l *logger) Errorln(v ...interface{}) {
+	l.errorLogger.Fatalln(v...)
+}
+
+func (l *logger) Errorf(format string, v ...interface{}) {
+	l.errorLogger.Fatalf(format, v...)
+}
+
+func (l *logger) Debugln(v ...interface{}) {
+	l.debugLogger.Println(v...)
+}
+
+func (l *logger) Debugf(format string, v ...interface{}) {
+	l.debugLogger.Printf(format, v...)
+}

experiments/go/custom-logger/main.go

@@ -0,0 +1,10 @@
+package main
+
+func main() {
+	l := newLogger(true)
+
+	l.Debugln("This is a debug log.")
+	l.Infoln("This is an info log.")
+	l.Infof("Formatting test: Number is %d.", 2)
+	l.Errorln("This is an error message.")
+}

experiments/go/mutex/simple/go.mod

@@ -0,0 +1,3 @@
+module mutex-training/simple
+
+go 1.19

experiments/go/mutex/simple/main.go

@@ -0,0 +1,35 @@
+package main
+
+import (
+	"fmt"
+	"sync"
+)
+
+var x = 0
+
+func main() {
+	var w sync.WaitGroup
+	var m sync.Mutex
+
+	numRunners := 2000
+
+	w.Add(numRunners)
+
+	for i := 0; i < numRunners; i++ {
+		go increment(&w, &m)
+	}
+
+	w.Wait()
+
+	fmt.Println("Final value of x: ", x)
+}
+
+func increment(wg *sync.WaitGroup, m sync.Locker) {
+	m.Lock()
+	{
+		x = x + 1
+	}
+	m.Unlock()
+
+	wg.Done()
+}