vendor/github.com/opencord/voltha-lib-go/v3/pkg/log/utils.go - voltha-openolt-adapter - Gitiles

 /*
  * Copyright 2018-present Open Networking Foundation

  * 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.
  */

 // File contains utility functions to support Open Tracing in conjunction with
 // Enhanced Logging based on context propagation

 package log

 import (
 	"context"
 	"errors"
 	"github.com/opentracing/opentracing-go"
 	jtracing "github.com/uber/jaeger-client-go"
 	jcfg "github.com/uber/jaeger-client-go/config"
 	"io"
 	"io/ioutil"
 	"os"
 	"strings"
 )

 const (
 	RootSpanNameKey = "op-name"
 )

 // Flag indicating whether to extract Log Fields from Span embedded in the received Context
 var extractLogFieldsFromContext bool = true

 // Flag indicating whether to process Span related operations; to save CPU cycles when disabled
 var processSpanOperations bool = true

 // Jaeger complaint Logger instance to redirect logs to Default Logger
 type traceLogger struct {
 	logger *clogger
 }

 func (tl traceLogger) Error(msg string) {
 	tl.logger.Error(context.Background(), msg)
 }

 func (tl traceLogger) Infof(msg string, args ...interface{}) {
 	// Tracing logs should be performed only at Debug Verbosity
 	tl.logger.Debugf(context.Background(), msg, args...)
 }

 // This method will start the Tracing for a component using Component name injected from the Chart
 // The close() method on returned Closer instance should be called in defer mode to gracefully
 // terminate tracing on component shutdown
 func InitTracingAndLogCorrelation(tracePublishEnabled bool, traceAgentAddress string, logCorrelationEnabled bool) (io.Closer, error) {
 	if !tracePublishEnabled && !logCorrelationEnabled {
 		defaultLogger.Info(context.Background(), "Skipping Global Tracer initialization as both Trace publish and Log correlation are configured as disabled")
 		extractLogFieldsFromContext = false
 		processSpanOperations = false
 		return ioutil.NopCloser(strings.NewReader("")), nil
 	}

 	if !logCorrelationEnabled {
 		defaultLogger.Info(context.Background(), "Disabling Log Fields extraction from context as configured")
 		extractLogFieldsFromContext = false
 	}

 	componentName := os.Getenv("COMPONENT_NAME")
 	if componentName == "" {
 		return nil, errors.New("Unable to retrieve PoD Component Name from Runtime env")
 	}

 	// Use basic configuration to start with; will extend later to support dynamic config updates
 	cfg := jcfg.Configuration{}

 	var err error
 	var jReporterConfig jcfg.ReporterConfig
 	var jReporterCfgOption jtracing.Reporter

 	// Attempt Trace Agent Address only if Trace Publishing is enabled; else directly use Loopback IP
 	if tracePublishEnabled {
 		jReporterConfig = jcfg.ReporterConfig{LocalAgentHostPort: traceAgentAddress, LogSpans: true}
 		jReporterCfgOption, err = jReporterConfig.NewReporter(componentName, jtracing.NewNullMetrics(), traceLogger{logger: defaultLogger})

 		if err != nil {
 			defaultLogger.Errorw(context.Background(), "Unable to create Reporter with given Trace Agent address",
 				Fields{"error": err, "address": traceAgentAddress})
 			// The Reporter initialization may fail due to Invalid Agent address or non-existent Agent (DNS lookup failure).
 			// It is essential for Tracer Instance to still start for correct Span propagation needed for log correlation.
 			// Thus, falback to use loopback IP for Reporter initialization before throwing back any error
 			tracePublishEnabled = false
 		}
 	}

 	if !tracePublishEnabled {
 		jReporterConfig.LocalAgentHostPort = "127.0.0.1:6831"
 		jReporterCfgOption, err = jReporterConfig.NewReporter(componentName, jtracing.NewNullMetrics(), traceLogger{logger: defaultLogger})
 		if err != nil {
 			return nil, errors.New("Failed to initialize Jaeger Tracing due to Reporter creation error : " + err.Error())
 		}
 	}

 	// To start with, we are using Constant Sampling type
 	samplerParam := 0 // 0: Do not publish span, 1: Publish
 	if tracePublishEnabled {
 		samplerParam = 1
 	}
 	jSamplerConfig := jcfg.SamplerConfig{Type: "const", Param: float64(samplerParam)}
 	jSamplerCfgOption, err := jSamplerConfig.NewSampler(componentName, jtracing.NewNullMetrics())
 	if err != nil {
 		return nil, errors.New("Unable to create Sampler : " + err.Error())
 	}

 	return cfg.InitGlobalTracer(componentName, jcfg.Reporter(jReporterCfgOption), jcfg.Sampler(jSamplerCfgOption))
 }

 func TerminateTracing(c io.Closer) {
 	err := c.Close()
 	if err != nil {
 		defaultLogger.Error(context.Background(), "error-while-closing-jaeger-tracer", Fields{"err": err})
 	}
 }

 // Extracts details of Execution Context as log fields from the Tracing Span injected into the
 // context instance. Following log fields are extracted:
 // 1. Operation Name : key as 'op-name' and value as Span operation name
 // 2. Operation Id : key as 'op-id' and value as 64 bit Span Id in hex digits string
 //
 // Additionally, any tags present in Span are also extracted to use as log fields e.g. device-id.
 //
 // If no Span is found associated with context, blank slice is returned without any log fields
 func ExtractContextAttributes(ctx context.Context) []interface{} {
 	if !extractLogFieldsFromContext {
 		return make([]interface{}, 0)
 	}

 	attrMap := make(map[string]interface{})

 	if ctx != nil {
 		if span := opentracing.SpanFromContext(ctx); span != nil {
 			if jspan, ok := span.(*jtracing.Span); ok {
 				// Add Log fields for operation identified by Root Level Span (Trace)
 				opId := jspan.SpanContext().TraceID().String()
 				opName := jspan.BaggageItem(RootSpanNameKey)

 				taskId := jspan.SpanContext().SpanID().String()
 				taskName := jspan.OperationName()

 				if opName == "" {
 					span.SetBaggageItem(RootSpanNameKey, taskName)
 					opName = taskName
 				}

 				attrMap["op-id"] = opId
 				attrMap["op-name"] = opName

 				// Add Log fields for task identified by Current Span, if it is different
 				// than operation
 				if taskId != opId {
 					attrMap["task-id"] = taskId
 					attrMap["task-name"] = taskName
 				}

 				for k, v := range jspan.Tags() {
 					// Ignore the special tags added by Jaeger, middleware (sampler.type, span.*) present in the span
 					if strings.HasPrefix(k, "sampler.") || strings.HasPrefix(k, "span.") || k == "component" {
 						continue
 					}

 					attrMap[k] = v
 				}
 			}
 		}
 	}

 	return serializeMap(attrMap)
 }

 // Method to inject additional log fields into Span e.g. device-id
 func EnrichSpan(ctx context.Context, keyAndValues ...Fields) {
 	span := opentracing.SpanFromContext(ctx)
 	if span != nil {
 		for _, field := range keyAndValues {
 			for k, v := range field {
 				span.SetTag(k, v)
 			}
 		}
 	}
 }

 // Method to inject Error into the Span in event of any operation failure
 func MarkSpanError(ctx context.Context, err error) {
 	span := opentracing.SpanFromContext(ctx)
 	span.SetTag("error", true)
 	span.SetTag("err", err)
 }

 // Creates a Child Span from Parent Span embedded in passed context. Should be used before starting a new major
 // operation in Synchronous or Asynchronous mode (go routine), such as following:
 // 1. Start of all implemented External API methods unless using a interceptor for auto-injection of Span (Server side impl)
 // 2. Just before calling an Third-Party lib which is invoking a External API (etcd, kafka)
 // 3. In start of a Go Routine responsible for performing a major task involving significant duration
 // 4. Any method which is suspected to be time consuming...
 func CreateChildSpan(ctx context.Context, taskName string, keyAndValues ...Fields) (opentracing.Span, context.Context) {
 	if !processSpanOperations {
 		return opentracing.NoopTracer{}.StartSpan(taskName), ctx
 	}

 	parentSpan := opentracing.SpanFromContext(ctx)
 	childSpan, newCtx := opentracing.StartSpanFromContext(ctx, taskName)

 	if parentSpan == nil || parentSpan.BaggageItem(RootSpanNameKey) == "" {
 		childSpan.SetBaggageItem(RootSpanNameKey, taskName)
 	}

 	EnrichSpan(newCtx, keyAndValues...)
 	return childSpan, newCtx
 }

 // Creates a Async Child Span with Follows-From relationship from Parent Span embedded in passed context.
 // Should be used only in scenarios when
 // a) There is dis-continuation in execution and thus result of Child span does not affect the Parent flow at all
 // b) The execution of Child Span is guaranteed to start after the completion of Parent Span
 // In case of any confusion, use CreateChildSpan method
 // Some situations where this method would be suitable includes Kafka Async RPC call, Propagation of Event across
 // a channel etc.
 func CreateAsyncSpan(ctx context.Context, taskName string, keyAndValues ...Fields) (opentracing.Span, context.Context) {
 	if !processSpanOperations {
 		return opentracing.NoopTracer{}.StartSpan(taskName), ctx
 	}

 	var asyncSpan opentracing.Span
 	var newCtx context.Context

 	parentSpan := opentracing.SpanFromContext(ctx)

 	// We should always be creating Aysnc span from a Valid parent span. If not, create a Child span instead
 	if parentSpan == nil {
 		defaultLogger.Warn(context.Background(), "Async span must be created with a Valid parent span only")
 		asyncSpan, newCtx = opentracing.StartSpanFromContext(ctx, taskName)
 	} else {
 		// Use Background context as the base for Follows-from case; else new span is getting both Child and FollowsFrom relationship
 		asyncSpan, newCtx = opentracing.StartSpanFromContext(context.Background(), taskName, opentracing.FollowsFrom(parentSpan.Context()))
 	}

 	if parentSpan == nil || parentSpan.BaggageItem(RootSpanNameKey) == "" {
 		asyncSpan.SetBaggageItem(RootSpanNameKey, taskName)
 	}

 	EnrichSpan(newCtx, keyAndValues...)
 	return asyncSpan, newCtx
 }

 // Extracts the span from Source context and injects into the supplied Target context.
 // This should be used in situations wherein we are calling a time-sensitive operation (etcd update) and hence
 // had a context.Background() used earlier to avoid any cancellation/timeout of operation by passed context.
 // This will allow propagation of span with a different base context (and not the original context)
 func WithSpanFromContext(targetCtx, sourceCtx context.Context) context.Context {
 	span := opentracing.SpanFromContext(sourceCtx)
 	return opentracing.ContextWithSpan(targetCtx, span)
 }

 // Utility method to convert log Fields into array of interfaces expected by zap logger methods
 func serializeMap(fields Fields) []interface{} {
 	data := make([]interface{}, len(fields)*2)
 	i := 0
 	for k, v := range fields {
 		data[i] = k
 		data[i+1] = v
 		i = i + 2
 	}
 	return data
 }
	/*
	* Copyright 2018-present Open Networking Foundation

	* 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.
	*/

	// File contains utility functions to support Open Tracing in conjunction with
	// Enhanced Logging based on context propagation

	package log

	import (
	"context"
	"errors"
	"github.com/opentracing/opentracing-go"
	jtracing "github.com/uber/jaeger-client-go"
	jcfg "github.com/uber/jaeger-client-go/config"
	"io"
	"io/ioutil"
	"os"
	"strings"
	)

	const (
	RootSpanNameKey = "op-name"
	)

	// Flag indicating whether to extract Log Fields from Span embedded in the received Context
	var extractLogFieldsFromContext bool = true

	// Flag indicating whether to process Span related operations; to save CPU cycles when disabled
	var processSpanOperations bool = true

	// Jaeger complaint Logger instance to redirect logs to Default Logger
	type traceLogger struct {
	logger *clogger
	}

	func (tl traceLogger) Error(msg string) {
	tl.logger.Error(context.Background(), msg)
	}

	func (tl traceLogger) Infof(msg string, args ...interface{}) {
	// Tracing logs should be performed only at Debug Verbosity
	tl.logger.Debugf(context.Background(), msg, args...)
	}

	// This method will start the Tracing for a component using Component name injected from the Chart
	// The close() method on returned Closer instance should be called in defer mode to gracefully
	// terminate tracing on component shutdown
	func InitTracingAndLogCorrelation(tracePublishEnabled bool, traceAgentAddress string, logCorrelationEnabled bool) (io.Closer, error) {
	if !tracePublishEnabled && !logCorrelationEnabled {
	defaultLogger.Info(context.Background(), "Skipping Global Tracer initialization as both Trace publish and Log correlation are configured as disabled")
	extractLogFieldsFromContext = false
	processSpanOperations = false
	return ioutil.NopCloser(strings.NewReader("")), nil
	}

	if !logCorrelationEnabled {
	defaultLogger.Info(context.Background(), "Disabling Log Fields extraction from context as configured")
	extractLogFieldsFromContext = false
	}

	componentName := os.Getenv("COMPONENT_NAME")
	if componentName == "" {
	return nil, errors.New("Unable to retrieve PoD Component Name from Runtime env")
	}

	// Use basic configuration to start with; will extend later to support dynamic config updates
	cfg := jcfg.Configuration{}

	var err error
	var jReporterConfig jcfg.ReporterConfig
	var jReporterCfgOption jtracing.Reporter

	// Attempt Trace Agent Address only if Trace Publishing is enabled; else directly use Loopback IP
	if tracePublishEnabled {
	jReporterConfig = jcfg.ReporterConfig{LocalAgentHostPort: traceAgentAddress, LogSpans: true}
	jReporterCfgOption, err = jReporterConfig.NewReporter(componentName, jtracing.NewNullMetrics(), traceLogger{logger: defaultLogger})

	if err != nil {
	defaultLogger.Errorw(context.Background(), "Unable to create Reporter with given Trace Agent address",
	Fields{"error": err, "address": traceAgentAddress})
	// The Reporter initialization may fail due to Invalid Agent address or non-existent Agent (DNS lookup failure).
	// It is essential for Tracer Instance to still start for correct Span propagation needed for log correlation.
	// Thus, falback to use loopback IP for Reporter initialization before throwing back any error
	tracePublishEnabled = false
	}
	}

	if !tracePublishEnabled {
	jReporterConfig.LocalAgentHostPort = "127.0.0.1:6831"
	jReporterCfgOption, err = jReporterConfig.NewReporter(componentName, jtracing.NewNullMetrics(), traceLogger{logger: defaultLogger})
	if err != nil {
	return nil, errors.New("Failed to initialize Jaeger Tracing due to Reporter creation error : " + err.Error())
	}
	}

	// To start with, we are using Constant Sampling type
	samplerParam := 0 // 0: Do not publish span, 1: Publish
	if tracePublishEnabled {
	samplerParam = 1
	}
	jSamplerConfig := jcfg.SamplerConfig{Type: "const", Param: float64(samplerParam)}
	jSamplerCfgOption, err := jSamplerConfig.NewSampler(componentName, jtracing.NewNullMetrics())
	if err != nil {
	return nil, errors.New("Unable to create Sampler : " + err.Error())
	}

	return cfg.InitGlobalTracer(componentName, jcfg.Reporter(jReporterCfgOption), jcfg.Sampler(jSamplerCfgOption))
	}

	func TerminateTracing(c io.Closer) {
	err := c.Close()
	if err != nil {
	defaultLogger.Error(context.Background(), "error-while-closing-jaeger-tracer", Fields{"err": err})
	}
	}

	// Extracts details of Execution Context as log fields from the Tracing Span injected into the
	// context instance. Following log fields are extracted:
	// 1. Operation Name : key as 'op-name' and value as Span operation name
	// 2. Operation Id : key as 'op-id' and value as 64 bit Span Id in hex digits string
	//
	// Additionally, any tags present in Span are also extracted to use as log fields e.g. device-id.
	//
	// If no Span is found associated with context, blank slice is returned without any log fields
	func ExtractContextAttributes(ctx context.Context) []interface{} {
	if !extractLogFieldsFromContext {
	return make([]interface{}, 0)
	}

	attrMap := make(map[string]interface{})

	if ctx != nil {
	if span := opentracing.SpanFromContext(ctx); span != nil {
	if jspan, ok := span.(*jtracing.Span); ok {
	// Add Log fields for operation identified by Root Level Span (Trace)
	opId := jspan.SpanContext().TraceID().String()
	opName := jspan.BaggageItem(RootSpanNameKey)

	taskId := jspan.SpanContext().SpanID().String()
	taskName := jspan.OperationName()

	if opName == "" {
	span.SetBaggageItem(RootSpanNameKey, taskName)
	opName = taskName
	}

	attrMap["op-id"] = opId
	attrMap["op-name"] = opName

	// Add Log fields for task identified by Current Span, if it is different
	// than operation
	if taskId != opId {
	attrMap["task-id"] = taskId
	attrMap["task-name"] = taskName
	}

	for k, v := range jspan.Tags() {
	// Ignore the special tags added by Jaeger, middleware (sampler.type, span.*) present in the span
	if strings.HasPrefix(k, "sampler.") \|\| strings.HasPrefix(k, "span.") \|\| k == "component" {
	continue
	}

	attrMap[k] = v
	}
	}
	}
	}

	return serializeMap(attrMap)
	}

	// Method to inject additional log fields into Span e.g. device-id
	func EnrichSpan(ctx context.Context, keyAndValues ...Fields) {
	span := opentracing.SpanFromContext(ctx)
	if span != nil {
	for _, field := range keyAndValues {
	for k, v := range field {
	span.SetTag(k, v)
	}
	}
	}
	}

	// Method to inject Error into the Span in event of any operation failure
	func MarkSpanError(ctx context.Context, err error) {
	span := opentracing.SpanFromContext(ctx)
	span.SetTag("error", true)
	span.SetTag("err", err)
	}

	// Creates a Child Span from Parent Span embedded in passed context. Should be used before starting a new major
	// operation in Synchronous or Asynchronous mode (go routine), such as following:
	// 1. Start of all implemented External API methods unless using a interceptor for auto-injection of Span (Server side impl)
	// 2. Just before calling an Third-Party lib which is invoking a External API (etcd, kafka)
	// 3. In start of a Go Routine responsible for performing a major task involving significant duration
	// 4. Any method which is suspected to be time consuming...
	func CreateChildSpan(ctx context.Context, taskName string, keyAndValues ...Fields) (opentracing.Span, context.Context) {
	if !processSpanOperations {
	return opentracing.NoopTracer{}.StartSpan(taskName), ctx
	}

	parentSpan := opentracing.SpanFromContext(ctx)
	childSpan, newCtx := opentracing.StartSpanFromContext(ctx, taskName)

	if parentSpan == nil \|\| parentSpan.BaggageItem(RootSpanNameKey) == "" {
	childSpan.SetBaggageItem(RootSpanNameKey, taskName)
	}

	EnrichSpan(newCtx, keyAndValues...)
	return childSpan, newCtx
	}

	// Creates a Async Child Span with Follows-From relationship from Parent Span embedded in passed context.
	// Should be used only in scenarios when
	// a) There is dis-continuation in execution and thus result of Child span does not affect the Parent flow at all
	// b) The execution of Child Span is guaranteed to start after the completion of Parent Span
	// In case of any confusion, use CreateChildSpan method
	// Some situations where this method would be suitable includes Kafka Async RPC call, Propagation of Event across
	// a channel etc.
	func CreateAsyncSpan(ctx context.Context, taskName string, keyAndValues ...Fields) (opentracing.Span, context.Context) {
	if !processSpanOperations {
	return opentracing.NoopTracer{}.StartSpan(taskName), ctx
	}

	var asyncSpan opentracing.Span
	var newCtx context.Context

	parentSpan := opentracing.SpanFromContext(ctx)

	// We should always be creating Aysnc span from a Valid parent span. If not, create a Child span instead
	if parentSpan == nil {
	defaultLogger.Warn(context.Background(), "Async span must be created with a Valid parent span only")
	asyncSpan, newCtx = opentracing.StartSpanFromContext(ctx, taskName)
	} else {
	// Use Background context as the base for Follows-from case; else new span is getting both Child and FollowsFrom relationship
	asyncSpan, newCtx = opentracing.StartSpanFromContext(context.Background(), taskName, opentracing.FollowsFrom(parentSpan.Context()))
	}

	if parentSpan == nil \|\| parentSpan.BaggageItem(RootSpanNameKey) == "" {
	asyncSpan.SetBaggageItem(RootSpanNameKey, taskName)
	}

	EnrichSpan(newCtx, keyAndValues...)
	return asyncSpan, newCtx
	}

	// Extracts the span from Source context and injects into the supplied Target context.
	// This should be used in situations wherein we are calling a time-sensitive operation (etcd update) and hence
	// had a context.Background() used earlier to avoid any cancellation/timeout of operation by passed context.
	// This will allow propagation of span with a different base context (and not the original context)
	func WithSpanFromContext(targetCtx, sourceCtx context.Context) context.Context {
	span := opentracing.SpanFromContext(sourceCtx)
	return opentracing.ContextWithSpan(targetCtx, span)
	}

	// Utility method to convert log Fields into array of interfaces expected by zap logger methods
	func serializeMap(fields Fields) []interface{} {
	data := make([]interface{}, len(fields)*2)
	i := 0
	for k, v := range fields {
	data[i] = k
	data[i+1] = v
	i = i + 2
	}
	return data
	}