# ########## injection.py
from opentelemetry import trace

class CustomDatadogLogProcessor(object):
    def __call__(self, logger, method_name, event_dict):
        # Datadog 形式のトレースコンテキストのログへの追加例
        # from: https://github.com/open-telemetry/opentelemetry-python-contrib/blob/b53b9a012f76c4fc883c3c245fddc29142706d0d/exporter/opentelemetry-exporter-datadog/src/opentelemetry/exporter/datadog/propagator.py#L122-L129 
        current_span = trace.get_current_span()

        if current_span is not None:
            event_dict['dd.trace_id'] = str(current_span.context.trace_id & 0xFFFFFFFFFFFFFFFF)
            event_dict['dd.span_id'] = str(current_span.context.span_id)

        return event_dict        
# ##########

# ########## app.py
import .injection
import logging
import structlog
# カスタム形式を追加して、Datadog 形式のトレース ID をログに挿入
structlog.configure(
    processors=[
        injection.CustomDatadogLogProcessor(),
        structlog.processors.JSONRenderer(sort_keys=True)
    ],
)

log = structlog.getLogger()

log.info("Example log line with trace correlation info")

// ########## logger.js

// 以下で dd に変換します。
// https://github.com/DataDog/dd-trace-js/blob/master/packages/dd-trace/src/id.js
const opentelemetry = require('@opentelemetry/api');
const winston = require('winston')

const tracingFormat = function () {
  return winston.format(info => {
    const span = opentelemetry.trace.getSpan(opentelemetry.context.active());
    if (span) {
      const { spanId, traceId } = span.spanContext();
      const traceIdEnd = traceId.slice(traceId.length / 2);
      info['dd.trace_id'] = BigInt(`0x${traceIdEnd}`).toString();
      info['dd.span_id'] = BigInt(`0x${spanId}`).toString();
    }
    return info;
  })();
}

module.exports = winston.createLogger({
  transports: [new winston.transports.Console],
  format: winston.format.combine(tracingFormat(), winston.format.json())
});

// ##########

// ########## index.js
//
// ...
// トレーサーを初期化します
// ...
// 
const logger = require('./logger') 
//
// アプリケーションでロガーを使用します
logger.info("Example log line with trace correlation info")

logger = Logger.new(STDOUT)
logger.progname = 'multivac'
original_formatter = Logger::Formatter.new
logger.formatter  = proc do |severity, datetime, progname, msg|
  current_span = OpenTelemetry::Trace.current_span(OpenTelemetry::Context.current).context

  dd_trace_id = current_span.trace_id.unpack1('H*')[16, 16].to_i(16).to_s
  dd_span_id = current_span.span_id.unpack1('H*').to_i(16).to_s

  if current_span
    "#{{datetime: datetime, progname: progname, severity: severity, msg: msg, 'dd.trace_id': dd_trace_id, 'dd.span_id': dd_span_id}.to_json}\n"
  else
    "#{{datetime: datetime, progname: progname, severity: severity, msg: msg}.to_json}\n"
  end
end

logger.info("Example log line with trace correlation info")

String traceIdValue = Span.current().getSpanContext().getTraceId();
String traceIdHexString = traceIdValue.substring(traceIdValue.length() - 16 );
long datadogTraceId = Long.parseUnsignedLong(traceIdHexString, 16);
String datadogTraceIdString = Long.toUnsignedString(datadogTraceId);

String spanIdHexString = Span.current().getSpanContext().getSpanId();
long datadogSpanId = Long.parseUnsignedLong(spanIdHexString, 16);
String datadogSpanIdString = Long.toUnsignedString(datadogSpanId);

logging.pattern.console = %d{yyyy-MM-dd HH:mm:ss} - %logger{36} - %msg dd.trace_id=%X{datadogTraceIdString} dd.span_id=%X{datadogSpanIdString} %n

package main

import (
    "context"
    log "github.com/sirupsen/logrus"
    "go.opentelemetry.io/otel"
    "strconv"
)

func main() {
    ctx := context.Background()
    tracer := otel.Tracer("example/main")
    ctx, span := tracer.Start(ctx, "example")
    defer span.End()

    log.SetFormatter(&log.JSONFormatter{})

    standardFields := log.Fields{
        "dd.trace_id": convertTraceID(span.SpanContext().TraceID().String()),
        "dd.span_id":  convertTraceID(span.SpanContext().SpanID().String()),
        "dd.service":  "serviceName",
        "dd.env":      "serviceEnv",
        "dd.version":  "serviceVersion",
    }

    log.WithFields(standardFields).WithContext(ctx).Info("hello world")
}

func convertTraceID(id string) string {
    if len(id) < 16 {
        return ""
    }
    if len(id) > 16 {
        id = id[16:]
    }
    intValue, err := strconv.ParseUint(id, 16, 64)
    if err != nil {
        return ""
    }
    return strconv.FormatUint(intValue, 10)
}

var stringTraceId = Activity.Current.TraceId.ToString();
var stringSpanId = Activity.Current.SpanId.ToString();

var ddTraceId = Convert.ToUInt64(stringTraceId.Substring(16), 16).ToString();
var ddSpanId = Convert.ToUInt64(stringSpanId, 16).ToString();

using (LogContext.PushProperty("dd.trace_id", ddTraceId))
using (LogContext.PushProperty("dd.span_id", ddSpanId))
{
    Serilog.Log.Logger.Information("Example log line with trace correlation info");
}