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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.time.Instant
import com.typesafe.config.Config
import kamon.ReporterRegistry.SpanSink
import kamon.Kamon
import kamon.metric.MetricLookup
import kamon.trace.Span.TagValue
import kamon.trace.SpanContext.SamplingDecision
import kamon.trace.Tracer.SpanBuilder
import kamon.util.{Clock, DynamicAccess}
import org.slf4j.LoggerFactory
import scala.collection.immutable
import scala.util.Try
trait Tracer {
def buildSpan(operationName: String): SpanBuilder
def identityProvider: IdentityProvider
}
object Tracer {
final class Default(metrics: MetricLookup, spanSink: SpanSink, initialConfig: Config, clock: Clock) extends Tracer {
private val logger = LoggerFactory.getLogger(classOf[Tracer])
private[Tracer] val tracerMetrics = new TracerMetrics(metrics)
@volatile private[Tracer] var joinRemoteParentsWithSameSpanID: Boolean = true
@volatile private[Tracer] var scopeSpanMetrics: Boolean = true
@volatile private[Tracer] var _sampler: Sampler = Sampler.Never
@volatile private[Tracer] var _identityProvider: IdentityProvider = IdentityProvider.Default()
reconfigure(initialConfig)
override def buildSpan(operationName: String): SpanBuilder =
new SpanBuilder(operationName, this, spanSink, clock)
override def identityProvider: IdentityProvider =
this._identityProvider
def sampler: Sampler =
_sampler
private[kamon] def reconfigure(config: Config): Unit = synchronized {
Try {
val dynamic = new DynamicAccess(getClass.getClassLoader)
val traceConfig = config.getConfig("kamon.trace")
val newSampler = traceConfig.getString("sampler") match {
case "always" => Sampler.Always
case "never" => Sampler.Never
case "random" => Sampler.random(traceConfig.getDouble("random-sampler.probability"))
case other => sys.error(s"Unexpected sampler name $other.")
}
val newJoinRemoteParentsWithSameSpanID = traceConfig.getBoolean("join-remote-parents-with-same-span-id")
val newScopeSpanMetrics = traceConfig.getBoolean("span-metrics.scope-spans-to-parent")
val newIdentityProvider = dynamic.createInstanceFor[IdentityProvider](
traceConfig.getString("identity-provider"), immutable.Seq.empty[(Class[_], AnyRef)]
).get
_sampler = newSampler
joinRemoteParentsWithSameSpanID = newJoinRemoteParentsWithSameSpanID
scopeSpanMetrics = newScopeSpanMetrics
_identityProvider = newIdentityProvider
}.failed.foreach {
ex => logger.error("Unable to reconfigure Kamon Tracer", ex)
}
}
}
object Default {
def apply(metrics: MetricLookup, spanSink: SpanSink, initialConfig: Config, clock: Clock): Default =
new Default(metrics, spanSink, initialConfig, clock)
}
final class SpanBuilder(operationName: String, tracer: Tracer.Default, spanSink: SpanSink, clock: Clock) {
private var parentSpan: Span = _
private var initialOperationName: String = operationName
private var from: Instant = Instant.EPOCH
private var initialSpanTags = Map.empty[String, Span.TagValue]
private var initialMetricTags = Map.empty[String, String]
private var useParentFromContext = true
private var trackMetrics = true
private var providedTraceID = IdentityProvider.NoIdentifier
def asChildOf(parent: Span): SpanBuilder = {
if(parent != Span.Empty) this.parentSpan = parent
this
}
def withMetricTag(key: String, value: String): SpanBuilder = {
this.initialMetricTags = this.initialMetricTags + (key -> value)
this.initialSpanTags = this.initialSpanTags + (key -> TagValue.String(value))
this
}
def withTag(key: String, value: String): SpanBuilder = {
this.initialSpanTags = this.initialSpanTags + (key -> TagValue.String(value))
this
}
def withTag(key: String, value: Long): SpanBuilder = {
this.initialSpanTags = this.initialSpanTags + (key -> TagValue.Number(value))
this
}
def withTag(key: String, value: Boolean): SpanBuilder = {
val tagValue = if (value) TagValue.True else TagValue.False
this.initialSpanTags = this.initialSpanTags + (key -> tagValue)
this
}
def withFrom(from: Instant): SpanBuilder = {
this.from = from
this
}
def withOperationName(operationName: String): SpanBuilder = {
this.initialOperationName = operationName
this
}
def spanTags: Map[String, Span.TagValue] =
this.initialSpanTags
def metricTags: Map[String, String] =
this.initialMetricTags
def ignoreParentFromContext(): SpanBuilder = {
this.useParentFromContext = false
this
}
def enableMetrics(): SpanBuilder = {
this.trackMetrics = true
this
}
def disableMetrics(): SpanBuilder = {
this.trackMetrics = false
this
}
def withTraceID(identifier: IdentityProvider.Identifier): SpanBuilder = {
this.providedTraceID = identifier
this
}
def start(): Span = {
val spanFrom = if(from == Instant.EPOCH) clock.instant() else from
val parentSpan: Option[Span] = Option(this.parentSpan)
.orElse(if(useParentFromContext) Some(Kamon.currentContext().get(Span.ContextKey)) else None)
.filter(span => span != Span.Empty)
val nonRemoteParent = parentSpan.filter(s => s.isLocal() && s.nonEmpty())
val samplingDecision: SamplingDecision = parentSpan
.map(_.context.samplingDecision)
.filter(_ != SamplingDecision.Unknown)
.getOrElse(tracer.sampler.decide(initialOperationName, initialSpanTags))
val spanContext = parentSpan match {
case Some(parent) => joinParentContext(parent, samplingDecision)
case None => newSpanContext(samplingDecision)
}
tracer.tracerMetrics.createdSpans.increment()
Span.Local(
spanContext,
nonRemoteParent,
initialOperationName,
initialSpanTags,
initialMetricTags,
spanFrom,
spanSink,
trackMetrics,
tracer.scopeSpanMetrics,
clock
)
}
private def joinParentContext(parent: Span, samplingDecision: SamplingDecision): SpanContext =
if(parent.isRemote() && tracer.joinRemoteParentsWithSameSpanID)
parent.context().copy(samplingDecision = samplingDecision)
else
parent.context().createChild(tracer._identityProvider.spanIdGenerator().generate(), samplingDecision)
private def newSpanContext(samplingDecision: SamplingDecision): SpanContext = {
val traceID =
if(providedTraceID != IdentityProvider.NoIdentifier)
providedTraceID
else
tracer._identityProvider.traceIdGenerator().generate()
SpanContext(
traceID,
spanID = tracer._identityProvider.spanIdGenerator().generate(),
parentID = IdentityProvider.NoIdentifier,
samplingDecision = samplingDecision
)
}
}
private final class TracerMetrics(metricLookup: MetricLookup) {
val createdSpans = metricLookup.counter("tracer.spans-created")
}
}
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