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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.util.concurrent.ThreadLocalRandom
import com.typesafe.config.Config
import io.opentracing.propagation.{Format, TextMap}
import io.opentracing.propagation.Format.Builtin.{BINARY, HTTP_HEADERS, TEXT_MAP}
import io.opentracing.util.ThreadLocalActiveSpanSource
import kamon.ReporterRegistryImpl
import kamon.metric.MetricLookup
import kamon.util.Clock
import org.slf4j.LoggerFactory
class Tracer(metrics: MetricLookup, reporterRegistry: ReporterRegistryImpl, initialConfig: Config)
extends ThreadLocalActiveSpanSource with io.opentracing.Tracer {
private val logger = LoggerFactory.getLogger(classOf[Tracer])
private val tracerMetrics = new TracerMetrics(metrics)
@volatile private var configuredSampler: Sampler = Sampler.never
@volatile private var textMapSpanContextCodec = SpanContextCodec.TextMap
@volatile private var httpHeaderSpanContextCodec = SpanContextCodec.ZipkinB3
reconfigure(initialConfig)
override def buildSpan(operationName: String): io.opentracing.Tracer.SpanBuilder =
new SpanBuilder(operationName)
override def extract[C](format: Format[C], carrier: C): io.opentracing.SpanContext = format match {
case HTTP_HEADERS => httpHeaderSpanContextCodec.extract(carrier.asInstanceOf[TextMap], configuredSampler)
case TEXT_MAP => textMapSpanContextCodec.extract(carrier.asInstanceOf[TextMap], configuredSampler)
case BINARY => null // TODO: Implement Binary Encoding
case _ => null
}
override def inject[C](spanContext: io.opentracing.SpanContext, format: Format[C], carrier: C): Unit = format match {
case HTTP_HEADERS => httpHeaderSpanContextCodec.inject(spanContext.asInstanceOf[SpanContext], carrier.asInstanceOf[TextMap])
case TEXT_MAP => textMapSpanContextCodec.inject(spanContext.asInstanceOf[SpanContext], carrier.asInstanceOf[TextMap])
case BINARY =>
case _ =>
}
def sampler: Sampler =
configuredSampler
def setTextMapSpanContextCodec(codec: SpanContextCodec[TextMap]): Unit =
this.textMapSpanContextCodec = codec
def setHttpHeaderSpanContextCodec(codec: SpanContextCodec[TextMap]): Unit =
this.httpHeaderSpanContextCodec = codec
private class SpanBuilder(operationName: String) extends io.opentracing.Tracer.SpanBuilder {
private var parentContext: SpanContext = _
private var startTimestamp = 0L
private var initialTags = Map.empty[String, String]
private var useActiveSpanAsParent = true
override def asChildOf(parent: io.opentracing.SpanContext): io.opentracing.Tracer.SpanBuilder = parent match {
case spanContext: kamon.trace.SpanContext =>
this.parentContext = spanContext
this
case null => this
case _ => logger.error("Can't extract the parent ID from a non-Kamon SpanContext"); this
}
override def asChildOf(parent: io.opentracing.BaseSpan[_]): io.opentracing.Tracer.SpanBuilder =
asChildOf(parent.context())
override def addReference(referenceType: String, referencedContext: io.opentracing.SpanContext): io.opentracing.Tracer.SpanBuilder = {
if(referenceType != null && referenceType.equals(io.opentracing.References.CHILD_OF)) {
asChildOf(referencedContext)
} else this
}
override def withTag(key: String, value: String): io.opentracing.Tracer.SpanBuilder = {
this.initialTags = this.initialTags + (key -> value)
this
}
override def withTag(key: String, value: Boolean): io.opentracing.Tracer.SpanBuilder = {
this.initialTags = this.initialTags + (key -> value.toString)
this
}
override def withTag(key: String, value: Number): io.opentracing.Tracer.SpanBuilder = {
this.initialTags = this.initialTags + (key -> value.toString)
this
}
override def withStartTimestamp(microseconds: Long): io.opentracing.Tracer.SpanBuilder = {
this.startTimestamp = microseconds
this
}
override def ignoreActiveSpan(): io.opentracing.Tracer.SpanBuilder = {
this.useActiveSpanAsParent = false
this
}
override def start(): io.opentracing.Span =
startManual()
override def startActive(): io.opentracing.ActiveSpan =
makeActive(startManual())
override def startManual(): Span = {
val startTimestampMicros = if(startTimestamp != 0L) startTimestamp else Clock.microTimestamp()
if(parentContext == null && useActiveSpanAsParent) {
val possibleParent = activeSpan()
if(possibleParent != null)
parentContext = possibleParent.context().asInstanceOf[SpanContext]
}
val spanContext =
if(parentContext != null)
new SpanContext(parentContext.traceID, createID(), parentContext.spanID, parentContext.sampled, parentContext.baggageMap)
else {
val traceID = createID()
new SpanContext(traceID, traceID, 0L, configuredSampler.decide(traceID), Map.empty)
}
tracerMetrics.createdSpans.increment()
new Span(spanContext, operationName, initialTags, startTimestampMicros, reporterRegistry)
}
private def createID(): Long =
ThreadLocalRandom.current().nextLong()
}
private[kamon] def reconfigure(config: Config): Unit = synchronized {
val traceConfig = config.getConfig("kamon.trace")
configuredSampler = traceConfig.getString("sampler") match {
case "always" => Sampler.always
case "never" => Sampler.never
case "random" => Sampler.random(traceConfig.getDouble("sampler-random.chance"))
case other => sys.error(s"Unexpected sampler name $other.")
}
}
private final class TracerMetrics(metricLookup: MetricLookup) {
val createdSpans = metricLookup.counter("tracer.spans-created")
}
}
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