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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.net.{URLDecoder, URLEncoder}
import java.nio.ByteBuffer
import kamon.Kamon
import kamon.context.BinaryPropagation.{ByteStreamReader, ByteStreamWriter}
import kamon.context._
import kamon.context.generated.binary.span.{Span => ColferSpan}
import kamon.context.HttpPropagation.{HeaderReader, HeaderWriter}
import kamon.trace.SpanContext.SamplingDecision
object SpanCodec {
class B3 extends Propagation.EntryReader[HeaderReader] with Propagation.EntryWriter[HeaderWriter] {
import B3.Headers
override def read(reader: HttpPropagation.HeaderReader, context: Context): Context = {
val identityProvider = Kamon.tracer.identityProvider
val traceID = reader.read(Headers.TraceIdentifier)
.map(id => identityProvider.traceIdGenerator().from(urlDecode(id)))
.getOrElse(IdentityProvider.NoIdentifier)
val spanID = reader.read(Headers.SpanIdentifier)
.map(id => identityProvider.spanIdGenerator().from(urlDecode(id)))
.getOrElse(IdentityProvider.NoIdentifier)
if(traceID != IdentityProvider.NoIdentifier && spanID != IdentityProvider.NoIdentifier) {
val parentID = reader.read(Headers.ParentSpanIdentifier)
.map(id => identityProvider.spanIdGenerator().from(urlDecode(id)))
.getOrElse(IdentityProvider.NoIdentifier)
val flags = reader.read(Headers.Flags)
val samplingDecision = flags.orElse(reader.read(Headers.Sampled)) match {
case Some(sampled) if sampled == "1" => SamplingDecision.Sample
case Some(sampled) if sampled == "0" => SamplingDecision.DoNotSample
case _ => SamplingDecision.Unknown
}
context.withKey(Span.ContextKey, Span.Remote(SpanContext(traceID, spanID, parentID, samplingDecision)))
} else context
}
override def write(context: Context, writer: HttpPropagation.HeaderWriter): Unit = {
val span = context.get(Span.ContextKey)
if(span.nonEmpty()) {
val spanContext = span.context()
writer.write(Headers.TraceIdentifier, urlEncode(spanContext.traceID.string))
writer.write(Headers.SpanIdentifier, urlEncode(spanContext.spanID.string))
if(spanContext.parentID != IdentityProvider.NoIdentifier)
writer.write(Headers.ParentSpanIdentifier, urlEncode(spanContext.parentID.string))
encodeSamplingDecision(spanContext.samplingDecision).foreach { samplingDecision =>
writer.write(Headers.Sampled, samplingDecision)
}
}
}
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 B3 {
def apply(): B3 =
new B3()
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"
}
}
class Colfer extends Propagation.EntryReader[ByteStreamReader] with Propagation.EntryWriter[ByteStreamWriter] {
val emptyBuffer = ByteBuffer.allocate(0)
override def read(medium: ByteStreamReader, context: Context): Context = {
if(medium.available() == 0)
context
else {
val identityProvider = Kamon.tracer.identityProvider
val colferSpan = new ColferSpan()
colferSpan.unmarshal(medium.readAll(), 0)
val spanContext = SpanContext(
traceID = identityProvider.traceIdGenerator().from(colferSpan.traceID),
spanID = identityProvider.spanIdGenerator().from(colferSpan.spanID),
parentID = identityProvider.spanIdGenerator().from(colferSpan.parentID),
samplingDecision = byteToSamplingDecision(colferSpan.samplingDecision)
)
context.withKey(Span.ContextKey, Span.Remote(spanContext))
}
}
override def write(context: Context, medium: ByteStreamWriter): Unit = {
val span = context.get(Span.ContextKey)
if(span.nonEmpty()) {
val marshalBuffer = Colfer.codecBuffer.get()
val colferSpan = new ColferSpan()
val spanContext = span.context()
colferSpan.setTraceID(spanContext.traceID.bytes)
colferSpan.setSpanID(spanContext.spanID.bytes)
colferSpan.setParentID(spanContext.parentID.bytes)
colferSpan.setSamplingDecision(samplingDecisionToByte(spanContext.samplingDecision))
val marshalledSize = colferSpan.marshal(marshalBuffer, 0)
medium.write(marshalBuffer, 0, marshalledSize)
}
}
private def samplingDecisionToByte(samplingDecision: SamplingDecision): Byte = samplingDecision match {
case SamplingDecision.Sample => 1
case SamplingDecision.DoNotSample => 2
case SamplingDecision.Unknown => 3
}
private def byteToSamplingDecision(byte: Byte): SamplingDecision = byte match {
case 1 => SamplingDecision.Sample
case 2 => SamplingDecision.DoNotSample
case _ => SamplingDecision.Unknown
}
}
object Colfer {
private val codecBuffer = new ThreadLocal[Array[Byte]] {
override def initialValue(): Array[Byte] = Array.ofDim[Byte](256)
}
}
}
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