dump logrus and roll our own logger instead

logger/datastructures.go

@@ -0,0 +1,86 @@
+package logger
+
+import (
+	"context"
+	"fmt"
+	"github.com/pkg/errors"
+	"time"
+)
+
+type Level int
+
+const (
+	Debug Level = iota
+	Info
+	Warn
+	Error
+)
+
+func (l Level) Short() string {
+	switch l {
+	case Debug:
+		return "DEBG"
+	case Info:
+		return "INFO"
+	case Warn:
+		return "WARN"
+	case Error:
+		return "ERRO"
+	default:
+		return fmt.Sprintf("%s", l)
+	}
+}
+
+func (l Level) String() string {
+	switch l {
+	case Debug:
+		return "debug"
+	case Info:
+		return "info"
+	case Warn:
+		return "warn"
+	case Error:
+		return "error"
+	default:
+		return fmt.Sprintf("%s", l)
+	}
+}
+
+func ParseLevel(s string) (l Level, err error) {
+	for _, l := range AllLevels {
+		if s == l.String() {
+			return l, nil
+		}
+	}
+	return -1, errors.Errorf("unknown level '%s'", s)
+}
+
+// Levels ordered least severe to most severe
+var AllLevels []Level = []Level{Debug, Info, Warn, Error}
+
+type Fields map[string]interface{}
+
+type Entry struct {
+	Level   Level
+	Message string
+	Time    time.Time
+	Fields  Fields
+}
+
+type Outlet interface {
+	// Note: os.Stderr is also used by logger.Logger for reporting errors returned by outlets
+	//       => you probably don't want to log there
+	WriteEntry(ctx context.Context, entry Entry) error
+}
+
+type Outlets map[Level][]Outlet
+
+func NewOutlets() Outlets {
+	return make(Outlets, len(AllLevels))
+}
+
+func (os Outlets) Add(outlet Outlet, minLevel Level) {
+	for _, l := range AllLevels[minLevel:] {
+		os[l] = append(os[l], outlet)
+	}
+}

logger/logger.go

@@ -0,0 +1,124 @@
+package logger
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"runtime/debug"
+	"sync"
+	"time"
+)
+
+const (
+	// The field set by WithError function
+	FieldError = "err"
+)
+
+const DefaultUserFieldCapacity = 5
+const InternalErrorPrefix = "github.com/zrepl/zrepl/logger: "
+
+type Logger struct {
+	fields        Fields
+	outlets       Outlets
+	outletTimeout time.Duration
+
+	mtx *sync.Mutex
+}
+
+func NewLogger(outlets Outlets, outletTimeout time.Duration) *Logger {
+	return &Logger{
+		make(Fields, DefaultUserFieldCapacity),
+		outlets,
+		outletTimeout,
+		&sync.Mutex{},
+	}
+}
+
+func (l *Logger) log(level Level, msg string) {
+
+	l.mtx.Lock()
+	defer l.mtx.Unlock()
+
+	entry := Entry{level, msg, time.Now(), l.fields}
+
+	ctx, _ := context.WithDeadline(context.Background(), time.Now().Add(l.outletTimeout))
+	ech := make(chan error)
+
+	louts := l.outlets[level]
+	for i := range louts {
+		go func(ctx context.Context, outlet Outlet, entry Entry) {
+			ech <- outlet.WriteEntry(ctx, entry)
+		}(ctx, louts[i], entry)
+	}
+
+	for fin := 0; fin < len(louts); fin++ {
+		select {
+		case err := <-ech:
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "%s outlet error: %s\n", InternalErrorPrefix, err)
+			}
+		case <-ctx.Done():
+			if ctx.Err() == context.DeadlineExceeded {
+				fmt.Fprintf(os.Stderr, "%s outlets exceeded deadline, keep waiting anyways", InternalErrorPrefix)
+			}
+		}
+	}
+
+}
+
+func (l *Logger) WithField(field string, val interface{}) *Logger {
+
+	l.mtx.Lock()
+	defer l.mtx.Unlock()
+
+	if _, ok := l.fields[field]; ok {
+		fmt.Fprintf(os.Stderr, "%s caller overwrites field '%s'. Stack:\n%s\n", InternalErrorPrefix, string(debug.Stack()))
+	}
+
+	child := &Logger{
+		fields:        make(Fields, len(l.fields)+1),
+		outlets:       l.outlets, // cannot be changed after logger initialized
+		outletTimeout: l.outletTimeout,
+		mtx:           l.mtx,
+	}
+	for k, v := range l.fields {
+		child.fields[k] = v
+	}
+	child.fields[field] = val
+
+	return child
+
+}
+
+func (l *Logger) WithFields(fields Fields) (ret *Logger) {
+	// TODO optimize
+	ret = l
+	for field, value := range fields {
+		ret = l.WithField(field, value)
+	}
+	return ret
+}
+
+func (l *Logger) WithError(err error) *Logger {
+	return l.WithField(FieldError, err.Error())
+}
+
+func (l *Logger) Debug(msg string) {
+	l.log(Debug, msg)
+}
+
+func (l *Logger) Info(msg string) {
+	l.log(Info, msg)
+}
+
+func (l *Logger) Warn(msg string) {
+	l.log(Warn, msg)
+}
+
+func (l *Logger) Error(msg string) {
+	l.log(Error, msg)
+}
+
+func (l *Logger) Printf(format string, args ...interface{}) {
+	l.log(Error, fmt.Sprintf(format, args...))
+}

logger/logger_test.go

@@ -0,0 +1,47 @@
+package logger_test
+
+import (
+	"context"
+	"fmt"
+	"github.com/kr/pretty"
+	"github.com/zrepl/zrepl/logger"
+	"testing"
+	"time"
+)
+
+type TestOutlet struct {
+	Record []logger.Entry
+}
+
+func (o *TestOutlet) WriteEntry(ctx context.Context, entry logger.Entry) error {
+	o.Record = append(o.Record, entry)
+	return nil
+}
+
+func NewTestOutlet() *TestOutlet {
+	return &TestOutlet{make([]logger.Entry, 0)}
+}
+
+func TestLogger_Basic(t *testing.T) {
+
+	outlet_arr := []logger.Outlet{
+		NewTestOutlet(),
+		NewTestOutlet(),
+	}
+
+	outlets := logger.NewOutlets()
+	for _, o := range outlet_arr {
+		outlets.Add(o, logger.Debug)
+	}
+
+	l := logger.NewLogger(outlets, 1*time.Second)
+
+	l.Info("foobar")
+
+	l.WithField("fieldname", "fieldval").Info("log with field")
+
+	l.WithError(fmt.Errorf("fooerror")).Error("error")
+
+	t.Log(pretty.Sprint(outlet_arr))
+
+}