feature: add context log (#21)

* feature: add context log

Signed-off-by: 1046102779 <seachen@tencent.com>

* feature: add context log

Signed-off-by: 1046102779 <seachen@tencent.com>

* feature: add context log

Signed-off-by: 1046102779 <seachen@tencent.com>

* feature: add context log

Signed-off-by: 1046102779 <seachen@tencent.com>

* feature: add context log

Signed-off-by: 1046102779 <seachen@tencent.com>

Signed-off-by: 1046102779 <seachen@tencent.com>

logger/default.go

@@ -0,0 +1,75 @@
+/*
+Copyright 2022 The Dapr Authors
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+        http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package logger
+
+import "io"
+
+type nopLogger struct{}
+
+// EnableJSONOutput enables JSON formatted output log.
+func (n *nopLogger) EnableJSONOutput(dnabled bool) {}
+
+// SetAppID sets dapr_id field in the log. nopLogger value is empty string.
+func (n *nopLogger) SetAppID(id string) {}
+
+// SetOutputLevel sets log output level.
+func (n *nopLogger) SetOutputLevel(outputLevel LogLevel) {}
+
+// SetOutput sets the destination for the logs
+func (n *nopLogger) SetOutput(dst io.Writer) {}
+
+// IsOutputLevelEnabled returns true if the logger will output this LogLevel.
+func (n *nopLogger) IsOutputLevelEnabled(level LogLevel) bool { return true }
+
+// WithLogType specify the log_type field in log. nopLogger value is LogTypeLog.
+func (n *nopLogger) WithLogType(logType string) Logger {
+	return n
+}
+
+// WithFields returns a logger with the added structured fields.
+func (n *nopLogger) WithFields(fields map[string]any) Logger {
+	return n
+}
+
+// Info logs a message at level Info.
+func (n *nopLogger) Info(args ...interface{}) {}
+
+// Infof logs a message at level Info.
+func (n *nopLogger) Infof(format string, args ...interface{}) {}
+
+// Debug logs a message at level Debug.
+func (n *nopLogger) Debug(args ...interface{}) {}
+
+// Debugf logs a message at level Debug.
+func (n *nopLogger) Debugf(format string, args ...interface{}) {}
+
+// Warn logs a message at level Warn.
+func (n *nopLogger) Warn(args ...interface{}) {}
+
+// Warnf logs a message at level Warn.
+func (n *nopLogger) Warnf(format string, args ...interface{}) {}
+
+// Error logs a message at level Error.
+func (n *nopLogger) Error(args ...interface{}) {}
+
+// Errorf logs a message at level Error.
+func (n *nopLogger) Errorf(format string, args ...interface{}) {}
+
+// Fatal logs a message at level Fatal then the process will exit with status set to 1.
+func (n *nopLogger) Fatal(args ...interface{}) {}
+
+// Fatalf logs a message at level Fatal then the process will exit with status set to 1.
+func (n *nopLogger) Fatalf(format string, args ...interface{}) {}

logger/logger.go

@@ -14,6 +14,7 @@ limitations under the License.
 package logger
 
 import (
+	"context"
 	"io"
 	"strings"
 	"sync"
@@ -36,6 +37,11 @@ const (
 	logFieldAppID     = "app_id"
 )
 
+type logContextKeyType struct{}
+
+// logContextKey is how we find Loggers in a context.Context
+var logContextKey = logContextKeyType{}
+
 // LogLevel is Dapr Logger Level type.
 type LogLevel string
 
@@ -60,6 +66,7 @@ const (
 var (
 	globalLoggers     = map[string]Logger{}
 	globalLoggersLock = sync.RWMutex{}
+	defaultOpLogger   = &nopLogger{}
 )
 
 // Logger includes the logging api sets.
@@ -150,3 +157,19 @@ func getLoggers() map[string]Logger {
 
 	return l
 }
+
+// NewContext returns a new Context, derived from ctx, which carries the
+// provided Logger.
+func NewContext(ctx context.Context, logger Logger) context.Context {
+	return context.WithValue(ctx, logContextKey, logger)
+}
+
+// FromContextOrDiscard returns a Logger from ctx.  If no Logger is found, this
+// returns a Logger that discards all log messages.
+func FromContextOrDefault(ctx context.Context) Logger {
+	if v, ok := ctx.Value(logContextKey).(Logger); ok {
+		return v
+	}
+
+	return defaultOpLogger
+}

logger/logger_test.go

@@ -14,6 +14,7 @@ limitations under the License.
 package logger
 
 import (
+	"context"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -74,3 +75,27 @@ func TestToLogLevel(t *testing.T) {
 		assert.Equal(t, UndefinedLevel, toLogLevel("undefined"))
 	})
 }
+
+func TestNewContext(t *testing.T) {
+	t.Run("input nil logger", func(t *testing.T) {
+		ctx := NewContext(context.Background(), nil)
+		assert.NotNil(t, ctx, "ctx is not nil")
+
+		logger := FromContextOrDefault(ctx)
+		assert.NotNil(t, logger, "logger is not nil")
+		assert.Equal(t, logger, defaultOpLogger)
+	})
+
+	t.Run("input non-nil logger", func(t *testing.T) {
+		testLoggerName := "dapr.test"
+		logger := NewLogger(testLoggerName)
+		assert.NotNil(t, logger)
+
+		ctx := NewContext(context.Background(), logger)
+		assert.NotNil(t, ctx, "ctx is not nil")
+		logger2 := FromContextOrDefault(ctx)
+		assert.NotNil(t, logger2)
+		assert.Equal(t, logger2, logger)
+		assert.NotEqual(t, logger2, defaultOpLogger)
+	})
+}