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/* =========================================================================================
* Copyright © 2013-2017 the kamon project <http://kamon.io/>
*
* 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 kamon.trace
import java.lang.StringBuilder
import java.net.{URLDecoder, URLEncoder}
import java.nio.ByteBuffer
import kamon.trace.SpanContext.{Baggage, SamplingDecision, Source}
import scala.collection.mutable
trait SpanContextCodec[T] {
def inject(spanContext: SpanContext, carrier: T): T
def inject(spanContext: SpanContext): T
def extract(carrier: T): Option[SpanContext]
}
object SpanContextCodec {
sealed trait Format[C]
object Format {
case object TextMap extends Format[TextMap]
case object HttpHeaders extends Format[TextMap]
case object Binary extends Format[ByteBuffer]
}
class ExtendedB3(identityProvider: IdentityProvider) extends SpanContextCodec[TextMap] {
import ExtendedB3.Headers
override def inject(spanContext: SpanContext, carrier: TextMap): TextMap = {
if(spanContext != SpanContext.EmptySpanContext) {
carrier.put(Headers.TraceIdentifier, urlEncode(spanContext.traceID.string))
carrier.put(Headers.SpanIdentifier, urlEncode(spanContext.spanID.string))
carrier.put(Headers.ParentSpanIdentifier, urlEncode(spanContext.parentID.string))
carrier.put(Headers.Baggage, encodeBaggage(spanContext.baggage))
encodeSamplingDecision(spanContext.samplingDecision).foreach { samplingDecision =>
carrier.put(Headers.Sampled, samplingDecision)
}
spanContext.baggage.get(Headers.Flags).foreach { flags =>
carrier.put(Headers.Flags, flags)
}
}
carrier
}
override def inject(spanContext: SpanContext): TextMap =
inject(spanContext, TextMap.Default())
override def extract(carrier: TextMap): Option[SpanContext] = {
val traceID = carrier.get(Headers.TraceIdentifier)
.map(id => identityProvider.traceIdentifierGenerator().from(urlDecode(id)))
.getOrElse(IdentityProvider.NoIdentifier)
val spanID = carrier.get(Headers.SpanIdentifier)
.map(id => identityProvider.spanIdentifierGenerator().from(urlDecode(id)))
.getOrElse(IdentityProvider.NoIdentifier)
if(traceID != IdentityProvider.NoIdentifier && spanID != IdentityProvider.NoIdentifier) {
val parentID = carrier.get(Headers.ParentSpanIdentifier)
.map(id => identityProvider.spanIdentifierGenerator().from(urlDecode(id)))
.getOrElse(IdentityProvider.NoIdentifier)
val baggage = decodeBaggage(carrier.get(Headers.Baggage))
val flags = carrier.get(Headers.Flags)
flags.foreach { flags =>
baggage.add(Headers.Flags, flags)
}
val samplingDecision = flags.orElse(carrier.get(Headers.Sampled)) match {
case Some(sampled) if sampled == "1" => SamplingDecision.Sample
case Some(sampled) if sampled == "0" => SamplingDecision.DoNotSample
case _ => SamplingDecision.Unknown
}
Some(SpanContext(traceID, spanID, parentID, samplingDecision, baggage, Source.Remote))
} else None
}
private def encodeBaggage(baggage: Baggage): String = {
if(baggage.getAll().nonEmpty) {
val encodedBaggage = new StringBuilder()
baggage.getAll().foreach {
case (key, value) =>
if(key != Headers.Flags) {
if (encodedBaggage.length() > 0)
encodedBaggage.append(';')
encodedBaggage
.append(urlEncode(key))
.append('=')
.append(urlEncode(value))
}
}
encodedBaggage.toString()
} else ""
}
private def decodeBaggage(encodedBaggage: Option[String]): Baggage = {
val baggage = Baggage()
encodedBaggage.foreach { baggageString =>
baggageString.split(";").foreach { group =>
val pair = group.split("=")
if(pair.length >= 2 && pair(0).nonEmpty) {
baggage.add(urlDecode(pair(0)), urlDecode(pair(1)))
}
}
}
baggage
}
private def encodeSamplingDecision(samplingDecision: SamplingDecision): Option[String] = samplingDecision match {
case SamplingDecision.Sample => Some("1")
case SamplingDecision.DoNotSample => Some("0")
case SamplingDecision.Unknown => None
}
private def urlEncode(s: String): String = URLEncoder.encode(s, "UTF-8")
private def urlDecode(s: String): String = URLDecoder.decode(s, "UTF-8")
}
object ExtendedB3 {
def apply(identityProvider: IdentityProvider): ExtendedB3 =
new ExtendedB3(identityProvider)
object Headers {
val TraceIdentifier = "X-B3-TraceId"
val ParentSpanIdentifier = "X-B3-ParentSpanId"
val SpanIdentifier = "X-B3-SpanId"
val Sampled = "X-B3-Sampled"
val Flags = "X-B3-Flags"
val Baggage = "X-B3-Extra-Baggage"
}
}
}
trait TextMap {
def get(key: String): Option[String]
def put(key: String, value: String): Unit
def values: Iterator[(String, String)]
}
object TextMap {
class Default extends TextMap {
private val storage = mutable.Map.empty[String, String]
override def get(key: String): Option[String] = storage.get(key)
override def put(key: String, value: String): Unit = storage.put(key, value)
override def values: Iterator[(String, String)] = storage.toIterator
}
object Default {
def apply(): Default = new Default()
}
}
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