Golang Logrus Enable Opentelemetry Trace ID and Span ID in all Application Logs

Question

I am trying to enable Trace ID and Span ID for every application log. I am using opentelemtry APIs to inject and logrus labrary for logging. Below is an example code where i am able to enable trace/span entried to all logs but the trace and span id values are always 0's.

#Server.go#

package main

import (
    log "github.com/sirupsen/logrus"
    "fmt"
    "context"
    "os"
    "net/http"
    "go.opentelemetry.io/otel/trace"
     stdout "go.opentelemetry.io/otel/exporters/stdout/stdouttrace"
     sdktrace "go.opentelemetry.io/otel/sdk/trace"
     "go.opentelemetry.io/otel/sdk/resource"
     semconv "go.opentelemetry.io/otel/semconv/v1.10.0"
     "go.opentelemetry.io/otel"
     "go.opentelemetry.io/contrib/propagators/b3"
     "go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
)

func init() {
  log.SetFormatter(customLogger{
                formatter:    log.JSONFormatter{FieldMap: log.FieldMap{
                "msg": "message",
                }},
        })
  log.SetOutput(os.Stdout)
  log.SetLevel(log.InfoLevel)
}


func initTracer() (*sdktrace.TracerProvider, error) {
        exporter, err := stdout.New(stdout.WithPrettyPrint())
        if err != nil {
                return nil, err
        }

        tp := sdktrace.NewTracerProvider(
                sdktrace.WithSampler(sdktrace.AlwaysSample()),
                sdktrace.WithBatcher(exporter),
                sdktrace.WithResource(resource.NewWithAttributes(semconv.SchemaURL, semconv.ServiceNameKey.String("PreferencesService"))),
        )
        otel.SetTracerProvider(tp)
        b3 := b3.New()
        otel.SetTextMapPropagator(b3)
        return tp, err
}


func main() {
    ctx := context.Background()
    tp, err := initTracer()
    if err != nil {
           log.Error(err)
    }
    defer func() {
           if err := tp.Shutdown(ctx); err != nil {
                  log.Error("Error shutting down tracer provider: %v", err)
           }
    }()

    otelHandler := otelhttp.NewHandler(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
        log.Info("About End Point Printning...")
        fmt.Fprintln(w, "about page")
    }),"About")
    http.Handle("/about", otelHandler)
    log.Info("Listening...")
    log.Fatal(http.ListenAndServe(":8080", nil))
}

type customLogger struct {
        formatter    log.JSONFormatter
}

func (l customLogger) Format(entry *log.Entry) ([]byte, error) {
        span := trace.SpanFromContext(entry.Context)
        entry.Data["trace_id"] = span.SpanContext().TraceID().String()
        entry.Data["span_id"] = span.SpanContext().SpanID().String()
        //Below injection is Just to understand what Context has
        entry.Data["Context"] = span.SpanContext()
        return l.formatter.Format(entry)
}

#Client.go#

package main

import (
    "fmt"
    "io/ioutil"
    "log"
    "net/http"
)

func main() {

    resp, err := http.Get("http://localhost:8080/about")

    if err != nil {
        log.Fatal(err)
    }

    defer resp.Body.Close()

    body, err := ioutil.ReadAll(resp.Body)

    if err != nil {
        log.Fatal(err)
    }

    fmt.Println(string(body))
}

#Output :#

{"Context":{"TraceID":"00000000000000000000000000000000","SpanID":"0000000000000000","TraceFlags":"00","TraceState":"","Remote":false},"level":"info","message":"Listening...","span_id":"0000000000000000","time":"2022-06-30T12:34:21+05:30","trace_id":"00000000000000000000000000000000"}
{"Context":


**Below Line Should have Proper Trace ID and Span ID**
{"TraceID":"00000000000000000000000000000000","SpanID":"0000000000000000","TraceFlags":"00","TraceState":"","Remote":false},"level":"info","message":"About End Point Printning...","span_id":"0000000000000000","time":"2022-06-30T12:34:28+05:30","trace_id":"00000000000000000000000000000000"}




{
        "Name": "About",
        "SpanContext": {
                "TraceID": "cb4dc4953a633fbe9b41c19a0870e9d6",
                "SpanID": "b7346b7aba15e074",
                "TraceFlags": "01",
                "TraceState": "",
                "Remote": false
        },
        "Parent": {
                "TraceID": "00000000000000000000000000000000",
                "SpanID": "0000000000000000",
                "TraceFlags": "00",
                "TraceState": "",
                "Remote": false
        },
        "SpanKind": 2,
        "StartTime": "2022-06-30T12:34:28.838523497+05:30",
        "EndTime": "2022-06-30T12:34:28.838858989+05:30",
        "Attributes": [
                {
                        "Key": "net.transport",
                        "Value": {
                                "Type": "STRING",
                                "Value": "ip_tcp"
                        }
                },
                {
                        "Key": "net.peer.ip",
                        "Value": {
                                "Type": "STRING",
                                "Value": "127.0.0.1"
                        }
                },
                {
                        "Key": "net.peer.port",
                        "Value": {
                                "Type": "INT64",
                                "Value": 41900
                        }
                },
                {
                        "Key": "net.host.name",
                        "Value": {
                                "Type": "STRING",
                                "Value": "localhost"
                        }
                },
                {
                        "Key": "net.host.port",
                        "Value": {
                                "Type": "INT64",
                                "Value": 8080
                        }
                },
                {
                        "Key": "http.method",
                        "Value": {
                                "Type": "STRING",
                                "Value": "GET"
                        }
                },
                {
                        "Key": "http.target",
                        "Value": {
                                "Type": "STRING",
                                "Value": "/about"
                        }
                },
                {
                        "Key": "http.server_name",
                        "Value": {
                                "Type": "STRING",
                                "Value": "About"
                        }
                },
                {
                        "Key": "http.user_agent",
                        "Value": {
                                "Type": "STRING",
                                "Value": "Go-http-client/1.1"
                        }
                },
                {
                        "Key": "http.scheme",
                        "Value": {
                                "Type": "STRING",
                                "Value": "http"
                        }
                },
                {
                        "Key": "http.host",
                        "Value": {
                                "Type": "STRING",
                                "Value": "localhost:8080"
                        }
                },
                {
                        "Key": "http.flavor",
                        "Value": {
                                "Type": "STRING",
                                "Value": "1.1"
                        }
                },
                {
                        "Key": "http.wrote_bytes",
                        "Value": {
                                "Type": "INT64",
                                "Value": 11
                        }
                },
                {
                        "Key": "http.status_code",
                        "Value": {
                                "Type": "INT64",
                                "Value": 200
                        }
                }
        ],
        "Events": null,
        "Links": null,
        "Status": {
                "Code": "Unset",
                "Description": ""
        },
        "DroppedAttributes": 0,
        "DroppedEvents": 0,
        "DroppedLinks": 0,
        "ChildSpanCount": 0,
        "Resource": [
                {
                        "Key": "service.name",
                        "Value": {
                                "Type": "STRING",
                                "Value": "PreferencesService"
                        }
                }
        ],
        "InstrumentationLibrary": {
                "Name": "go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp",
                "Version": "semver:0.32.0",
                "SchemaURL": ""
        }
}

Not Sure where/what is the mistake but it will be helpful if someone route me to the right direction, how i can inject Trace ID and Span ID to all logs..

Note: I don't want to pass request context to all the functions. Looking for other options

Answer 1

the problem is span := trace.SpanFromContext(entry.Context) can not get span context.

maybe you should inject req.Context() to logrus then print log

    otelHandler := otelhttp.NewHandler(http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
        //log.Info("About End Point Printning...")
        // inject req.Context
        log.WithContext(req.Context()).Info("About End Point Printning...")
        fmt.Fprintln(w, "about page")
    }), "About")

run the server.go, and then run client.go, the output is

{"Context":{"TraceID":"00000000000000000000000000000000","SpanID":"0000000000000000","TraceFlags":"00","TraceState":"","Remote":false},"level":"info","message":"Listening...","span_id":"0000000000000000","time":"2022-07-02T21:39:49+08:00","trace_id":"00000000000000000000000000000000"}
{"Context":{"TraceID":"7cab2739ea2c5b2d3e6a08cfb57858a9","SpanID":"ec5ba151b6823658","TraceFlags":"01","TraceState":"","Remote":false},"level":"info","message":"About End Point Printning...","span_id":"ec5ba151b6823658","time":"2022-07-02T21:39:54+08:00","trace_id":"7cab2739ea2c5b2d3e6a08cfb57858a9"}

notice: the first line not print traceId is because there is no request

hope it is helpful for you.