Merge pull request #3 from cabify/colega/context-logging-with-baggage-values

Context logging with baggage values & go mod

Author: colega

baggage.go

@@ -0,0 +1,73 @@
+package log
+
+import (
+	"context"
+	"crypto/md5"
+	"fmt"
+	"math/rand"
+	"strconv"
+
+	"github.com/cabify/go-logging/internal"
+)
+
+const loggerRequestIDLength = 7
+
+// WithBaggageValue returns a context with the added key value pair in the baggage store.
+func WithBaggageValue(ctx context.Context, key, value string) context.Context {
+	oldBaggage, ok := ctx.Value(internal.BaggageContextKey).(internal.Baggage)
+
+	if !ok {
+		return context.WithValue(ctx, internal.BaggageContextKey, internal.Baggage{key: value})
+	}
+
+	newBaggage := make(internal.Baggage, len(oldBaggage)+1)
+	for oldKey, oldValue := range oldBaggage {
+		newBaggage[oldKey] = oldValue
+	}
+	newBaggage[key] = value
+
+	return context.WithValue(ctx, internal.BaggageContextKey, newBaggage)
+}
+
+// WithBaggageValues returns a context with all key value pairs added to the baggage store.
+func WithBaggageValues(ctx context.Context, keyValue map[string]string) context.Context {
+	oldBaggage, ok := ctx.Value(internal.BaggageContextKey).(internal.Baggage)
+	if !ok {
+		return context.WithValue(ctx, internal.BaggageContextKey, internal.Baggage(keyValue))
+	}
+
+	newBaggage := make(internal.Baggage, len(oldBaggage)+len(keyValue))
+	for oldKey, oldValue := range oldBaggage {
+		newBaggage[oldKey] = oldValue
+	}
+
+	for newKey, newValue := range keyValue {
+		newBaggage[newKey] = newValue
+	}
+
+	return context.WithValue(ctx, internal.BaggageContextKey, newBaggage)
+}
+
+// NewContextWithBaggageFrom returns a new context with baggage values obtained from another context
+func NewContextWithBaggageFrom(ctx context.Context) context.Context {
+	oldBaggage, ok := ctx.Value(internal.BaggageContextKey).(internal.Baggage)
+	if !ok {
+		return context.Background()
+	}
+	return context.WithValue(context.Background(), internal.BaggageContextKey, oldBaggage)
+}
+
+// NewContextFromWithValue creates a new context with baggage values from ctx plus the provided one
+// it's just a shorthand for the composition of NewContextWithBaggageFrom and WithBaggageValue
+func NewContextFromWithValue(ctx context.Context, k, v string) context.Context {
+	return NewContextWithBaggageFrom(
+		WithBaggageValue(ctx, k, v),
+	)
+}
+
+// NewID returns a random id to follow the log traces
+func NewID() string {
+	data := rand.Int63()
+	encoded := md5.Sum([]byte(strconv.FormatInt(data, 16)))
+	return fmt.Sprintf("%x", encoded)[:loggerRequestIDLength]
+}

baggage_test.go

@@ -0,0 +1,13 @@
+package log
+
+import (
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestNewID(t *testing.T) {
+	t.Run("has correct length", func(t *testing.T) {
+		id := NewID()
+		assert.Equal(t, loggerRequestIDLength, len(id))
+	})
+}

context_logger.go

@@ -0,0 +1,124 @@
+package log
+
+import (
+	"context"
+
+	"github.com/cabify/go-logging/internal"
+)
+
+type baggageLogger struct {
+	Logger
+	ctx context.Context
+}
+
+func newBaggageLogger(ctx context.Context, base Logger) baggageLogger {
+	return baggageLogger{
+		Logger: base,
+		ctx:    ctx,
+	}
+}
+
+func (l baggageLogger) getContextString() string {
+	baggage, ok := l.ctx.Value(internal.BaggageContextKey).(internal.Baggage)
+	if !ok {
+		return ""
+	}
+
+	return baggage.String() + ": "
+}
+
+func (l baggageLogger) Fatal(args ...interface{}) {
+	l.Logger.Fatal(append([]interface{}{l.getContextString()}, args...)...)
+}
+
+func (l baggageLogger) Fatalf(format string, args ...interface{}) {
+	l.Logger.Fatalf(l.getContextString()+format, args...)
+}
+
+func (l baggageLogger) Fatalln(args ...interface{}) {
+	l.Logger.Fatalln(append([]interface{}{l.getContextString()}, args...)...)
+}
+
+func (l baggageLogger) Panic(args ...interface{}) {
+	l.Logger.Panic(append([]interface{}{l.getContextString()}, args...)...)
+}
+
+func (l baggageLogger) Panicf(format string, args ...interface{}) {
+	l.Logger.Panicf(l.getContextString()+format, args...)
+}
+
+func (l baggageLogger) Panicln(args ...interface{}) {
+	l.Logger.Panicln(append([]interface{}{l.getContextString()}, args...)...)
+}
+
+func (l baggageLogger) Critical(args ...interface{}) {
+	l.Logger.Critical(append([]interface{}{l.getContextString()}, args...)...)
+}
+
+func (l baggageLogger) Criticalf(format string, args ...interface{}) {
+	l.Logger.Criticalf(l.getContextString()+format, args...)
+}
+
+func (l baggageLogger) Criticalln(args ...interface{}) {
+	l.Logger.Criticalln(append([]interface{}{l.getContextString()}, args...)...)
+}
+
+func (l baggageLogger) Error(args ...interface{}) {
+	l.Logger.Error(append([]interface{}{l.getContextString()}, args...)...)
+}
+
+func (l baggageLogger) Errorf(format string, args ...interface{}) {
+	l.Logger.Errorf(l.getContextString()+format, args...)
+}
+
+func (l baggageLogger) Errorln(args ...interface{}) {
+	l.Logger.Errorln(append([]interface{}{l.getContextString()}, args...)...)
+}
+
+func (l baggageLogger) Warning(args ...interface{}) {
+	l.Logger.Warning(append([]interface{}{l.getContextString()}, args...)...)
+}
+
+func (l baggageLogger) Warningf(format string, args ...interface{}) {
+	l.Logger.Warningf(l.getContextString()+format, args...)
+}
+
+func (l baggageLogger) Warningln(args ...interface{}) {
+	l.Logger.Warningln(append([]interface{}{l.getContextString()}, args...)...)
+}
+
+func (l baggageLogger) Notice(args ...interface{}) {
+	l.Logger.Notice(append([]interface{}{l.getContextString()}, args...)...)
+}
+
+func (l baggageLogger) Noticef(format string, args ...interface{}) {
+	l.Logger.Noticef(l.getContextString()+format, args...)
+}
+
+func (l baggageLogger) Noticeln(args ...interface{}) {
+	l.Logger.Noticeln(append([]interface{}{l.getContextString()}, args...)...)
+}
+
+func (l baggageLogger) Info(args ...interface{}) {
+	l.Logger.Info(append([]interface{}{l.getContextString()}, args...)...)
+}
+
+func (l baggageLogger) Infof(format string, args ...interface{}) {
+	l.Logger.Infof(l.getContextString()+format, args...)
+}
+
+func (l baggageLogger) Infoln(args ...interface{}) {
+	l.Logger.Infoln(append([]interface{}{l.getContextString()}, args...)...)
+}
+
+func (l baggageLogger) Debug(args ...interface{}) {
+	l.Logger.Debug(append([]interface{}{l.getContextString()}, args...)...)
+}
+
+func (l baggageLogger) Debugf(format string, args ...interface{}) {
+	l.Logger.Debugf(l.getContextString()+format, args...)
+}
+
+func (l baggageLogger) Debugln(args ...interface{}) {
+	l.Logger.Debugln(append([]interface{}{l.getContextString()}, args...)...)
+}

factory.go

@@ -0,0 +1,29 @@
+package log
+
+import (
+	"context"
+
+)
+
+// Factory provides context aware loggers.
+type Factory struct {
+	baseLogger Logger
+}
+
+// NewFactory instantiates a factory with the default logger.
+func NewFactory() Factory {
+	return Factory{
+		baseLogger: DefaultLogger,
+	}
+}
+
+// For provides a logger which is aware of the passed context and will prepend the context baggage values.
+func (f Factory) For(ctx context.Context) Logger {
+	return newBaggageLogger(ctx, f.baseLogger)
+}
+
+// For provides a logger which is aware of the passed context and will prepend
+// the context baggage values, using DefaultLogger as base logger.
+func For(ctx context.Context) Logger {
+	return newBaggageLogger(ctx, DefaultLogger)
+}

go.mod

@@ -0,0 +1,8 @@
+module github.com/cabify/go-logging
+
+require (
+	github.com/hashicorp/go-multierror v1.0.0
+	github.com/mattn/go-isatty v0.0.4
+	github.com/stretchr/testify v1.3.0
+	golang.org/x/sys v0.0.0-20190219092855-153ac476189d // indirect
+)

go.sum

@@ -0,0 +1,15 @@
+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/hashicorp/errwrap v1.0.0 h1:hLrqtEDnRye3+sgx6z4qVLNuviH3MR5aQ0ykNJa/UYA=
+github.com/hashicorp/errwrap v1.0.0/go.mod h1:YH+1FKiLXxHSkmPseP+kNlulaMuP3n2brvKWEqk/Jc4=
+github.com/hashicorp/go-multierror v1.0.0 h1:iVjPR7a6H0tWELX5NxNe7bYopibicUzc7uPribsnS6o=
+github.com/hashicorp/go-multierror v1.0.0/go.mod h1:dHtQlpGsu+cZNNAkkCN/P3hoUDHhCYQXV3UM06sGGrk=
+github.com/mattn/go-isatty v0.0.4 h1:bnP0vzxcAdeI1zdubAl5PjU6zsERjGZb7raWodagDYs=
+github.com/mattn/go-isatty v0.0.4/go.mod h1:M+lRXTBqGeGNdLjl/ufCoiOlB5xdOkqRJdNxMWT7Zi4=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0Q=
+github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
+golang.org/x/sys v0.0.0-20190219092855-153ac476189d h1:Z0Ahzd7HltpJtjAHHxX8QFP3j1yYgiuvjbjRzDj/KH0=
+golang.org/x/sys v0.0.0-20190219092855-153ac476189d/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=

internal/baggage.go

@@ -0,0 +1,28 @@
+package internal
+
+import (
+	"sort"
+	"strings"
+)
+
+// BaggageContextKey is the key to be used for the Baggage map in
+// context.*Value.
+const BaggageContextKey ContextKey = "baggage"
+
+// ContextKey is the type of BaggageContextKey.
+type ContextKey string
+
+// Baggage is the type of the value associated with BaggageContextKey.
+type Baggage map[string]string
+
+// String returns baggages contents as a string of key value pairs ordered alphabetically.
+func (b Baggage) String() string {
+	var kvPairs []string
+	for key, value := range b {
+		kvPairs = append(kvPairs, key+":"+value)
+	}
+
+	sort.Strings(kvPairs)
+
+	return strings.Join(kvPairs, ": ")
+}

logtest/baggage.go

@@ -0,0 +1,19 @@
+/*
+Package logtest is intended to be used by tests for checking that baggage values have been correctly set
+ */
+package logtest
+
+import (
+	"context"
+
+	"github.com/cabify/go-logging/internal"
+)
+
+// HasBaggageValue returns whether the context contains a baggage value.
+func HasBaggageValue(ctx context.Context, key, value string) bool {
+	baggage, ok := ctx.Value(internal.BaggageContextKey).(internal.Baggage)
+	if !ok {
+		return false
+	}
+	return baggage[key] == value
+}