1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
|
/* =========================================================================================
* 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.util.concurrent.ThreadLocalRandom
import scala.collection.JavaConverters._
import io.opentracing.propagation.TextMap
import kamon.util.HexCodec
trait SpanContextCodec[T] {
def inject(spanContext: SpanContext, carrier: T): Unit
def extract(carrier: T, sampler: Sampler): SpanContext
}
object SpanContextCodec {
val TextMap: SpanContextCodec[TextMap] = new TextMapSpanCodec(
traceIDKey = "TRACE_ID",
parentIDKey = "PARENT_ID",
spanIDKey = "SPAN_ID",
sampledKey = "SAMPLED",
baggagePrefix = "BAGGAGE_",
baggageValueEncoder = identity,
baggageValueDecoder = identity
)
val ZipkinB3: SpanContextCodec[TextMap] = new TextMapSpanCodec(
traceIDKey = "X-B3-TraceId",
parentIDKey = "X-B3-ParentSpanId",
spanIDKey = "X-B3-SpanId",
sampledKey = "X-B3-Sampled",
baggagePrefix = "X-B3-Baggage-",
baggageValueEncoder = urlEncode,
baggageValueDecoder = urlDecode
)
private def urlEncode(s: String): String = URLEncoder.encode(s, "UTF-8")
private def urlDecode(s: String): String = URLDecoder.decode(s, "UTF-8")
private class TextMapSpanCodec(traceIDKey: String, parentIDKey: String, spanIDKey: String, sampledKey: String, baggagePrefix: String,
baggageValueEncoder: String => String, baggageValueDecoder: String => String) extends SpanContextCodec[TextMap] {
override def inject(spanContext: SpanContext, carrier: TextMap): Unit = {
carrier.put(traceIDKey, encodeLong(spanContext.traceID))
carrier.put(parentIDKey, encodeLong(spanContext.parentID))
carrier.put(spanIDKey, encodeLong(spanContext.spanID))
spanContext.baggageItems().iterator().asScala.foreach { entry =>
carrier.put(baggagePrefix + entry.getKey, baggageValueEncoder(entry.getValue))
}
}
override def extract(carrier: TextMap, sampler: Sampler): SpanContext = {
var traceID: String = null
var parentID: String = null
var spanID: String = null
var sampled: String = null
var baggage: Map[String, String] = Map.empty
carrier.iterator().asScala.foreach { entry =>
if(entry.getKey.equals(traceIDKey))
traceID = baggageValueDecoder(entry.getValue)
else if(entry.getKey.equals(parentIDKey))
parentID = baggageValueDecoder(entry.getValue)
else if(entry.getKey.equals(spanIDKey))
spanID = baggageValueDecoder(entry.getValue)
else if(entry.getKey.equals(sampledKey))
sampled = entry.getValue
else if(entry.getKey.startsWith(baggagePrefix))
baggage = baggage + (entry.getKey.substring(baggagePrefix.length) -> baggageValueDecoder(entry.getValue))
}
if(traceID != null && spanID != null) {
val actualParent = if(parentID == null) 0L else decodeLong(parentID)
val isSampled = if(sampled == null) sampler.decide(ThreadLocalRandom.current().nextLong()) else sampled.equals("1")
new SpanContext(decodeLong(traceID), decodeLong(spanID), actualParent, isSampled, baggage)
} else null
}
private def decodeLong(input: String): Long =
HexCodec.lowerHexToUnsignedLong(input)
private def encodeLong(input: Long): String =
HexCodec.toLowerHex(input)
}
}
|
