move alignment and duration utilities to the companion object

3 files changed, 60 insertions, 9 deletions

diff --git a/kamon-core-tests/src/test/scala/kamon/util/ClockSpec.scala b/kamon-core-tests/src/test/scala/kamon/util/ClockSpec.scala
new file mode 100644
index 00000000..5f83d22c
--- /dev/null
+++ b/kamon-core-tests/src/test/scala/kamon/util/ClockSpec.scala
@@ -0,0 +1,39 @@
+package kamon.util
+
+import java.time.{Duration, Instant}
+
+import kamon.util
+import org.scalatest.{Matchers, WordSpec}
+
+class ClockSpec extends WordSpec with Matchers {
+  "the Clock" should {
+    "generate nanosecond precision Instants" in {
+      newClock().instant().getNano() % MicrosInSecond shouldNot be(0)
+    }
+
+    "turn Instants into micros" in {
+      Clock.toEpochMicros(Instant.parse("2017-12-18T08:39:59.000000000Z")) shouldBe 1513586399000000L
+      Clock.toEpochMicros(Instant.parse("2017-12-18T08:39:59.000000010Z")) shouldBe 1513586399000000L
+      Clock.toEpochMicros(Instant.parse("2017-12-18T08:39:59.987654321Z")) shouldBe 1513586399987654L
+      Clock.toEpochMicros(Instant.parse("2017-12-18T08:39:59.987000000Z")) shouldBe 1513586399987000L
+    }
+
+    "calculate nanos between two Instants" in {
+      Clock.nanosBetween(Instant.parse("2017-12-18T08:39:59.987654321Z"), Instant.parse("2017-12-18T08:39:59.987654322Z")) shouldBe 1
+      Clock.nanosBetween(Instant.parse("2017-12-18T08:39:59.987654322Z"), Instant.parse("2017-12-18T08:39:59.987654321Z")) shouldBe -1
+      Clock.nanosBetween(Instant.parse("2017-12-18T08:39:59.987Z"), Instant.parse("2017-12-18T08:39:59.988Z")) shouldBe 1000000
+      Clock.nanosBetween(Instant.parse("2017-12-18T08:39:59.987654Z"), Instant.parse("2017-12-18T08:39:59.987Z")) shouldBe -654000
+    }
+
+    "calculate ticks aligned to rounded boundaries" in {
+      Clock.nextTick(Instant.parse("2017-12-18T08:39:59.999Z"), Duration.ofSeconds(10)).toString shouldBe "2017-12-18T08:40:00Z"
+      Clock.nextTick(Instant.parse("2017-12-18T08:40:00.000Z"), Duration.ofSeconds(10)).toString shouldBe "2017-12-18T08:40:10Z"
+      Clock.nextTick(Instant.parse("2017-12-18T08:39:14.906Z"), Duration.ofSeconds(10)).toString shouldBe "2017-12-18T08:39:20Z"
+    }
+  }
+
+  val MicrosInSecond = 1000000
+
+  def newClock(): Clock =
+    new util.Clock.Default()
+}
diff --git a/kamon-core/src/main/scala/kamon/trace/Span.scala b/kamon-core/src/main/scala/kamon/trace/Span.scala
index d773d46e..690efeb4 100644
--- a/kamon-core/src/main/scala/kamon/trace/Span.scala
+++ b/kamon-core/src/main/scala/kamon/trace/Span.scala
@@ -201,7 +201,7 @@ object Span {
       Span.FinishedSpan(spanContext, operationName, from, to, spanTags, marks)
 
     private def recordSpanMetrics(to: Instant): Unit = {
-      val elapsedTime = clock.nanosBetween(from, to)
+      val elapsedTime = Clock.nanosBetween(from, to)
       val isErrorText = if(hasError) TagValue.True.text else TagValue.False.text
 
       if(scopeSpanMetrics)
diff --git a/kamon-core/src/main/scala/kamon/util/Clock.scala b/kamon-core/src/main/scala/kamon/util/Clock.scala
index 48a88968..8c00ecc6 100644
--- a/kamon-core/src/main/scala/kamon/util/Clock.scala
+++ b/kamon-core/src/main/scala/kamon/util/Clock.scala
@@ -15,17 +15,17 @@
 
 package kamon.util
 
-import java.time.{Instant, ZoneId, Clock => JavaClock}
+import java.time.{Duration, Instant, ZoneId, Clock => JavaClock}
 
 abstract class Clock extends JavaClock {
   def nanos(): Long
-  def nanosBetween(left: Instant, right: Instant): Long
   def toInstant(nanos: Long): Instant
 }
 
 object Clock {
 
   private val MillisInSecond = 1000L
+  private val NanosInMicro = 1000L
   private val MicrosInSecond = 1000000L
   private val NanosInSecond = 1000000000L
 
@@ -74,16 +74,28 @@ object Clock {
     override def instant(): Instant =
       toInstant(System.nanoTime())
 
-    override def nanosBetween(left: Instant, right: Instant): Long = {
-      val secsDiff = Math.subtractExact(right.getEpochSecond, left.getEpochSecond)
-      val totalNanos = Math.multiplyExact(secsDiff, NanosInSecond)
-      return Math.addExact(totalNanos, right.getNano - left.getNano)
-    }
-
     override def withZone(zone: ZoneId): JavaClock =
       systemClock.withZone(zone)
 
     override def getZone: ZoneId =
       systemClock.getZone()
   }
+
+  def nanosBetween(left: Instant, right: Instant): Long = {
+    val secsDiff = Math.subtractExact(right.getEpochSecond, left.getEpochSecond)
+    val totalNanos = Math.multiplyExact(secsDiff, NanosInSecond)
+    return Math.addExact(totalNanos, right.getNano - left.getNano)
+  }
+
+  def toEpochMicros(instant: Instant): Long = {
+    Math.multiplyExact(instant.getEpochSecond, MicrosInSecond) + Math.floorDiv(instant.getNano, NanosInMicro)
+  }
+
+  def nextTick(from: Instant, expectedDuration: Duration): Instant = {
+    val fromMillis = from.toEpochMilli()
+    val intervalCount = Math.floorDiv(fromMillis, expectedDuration.toMillis)
+    val nextTickMillis = expectedDuration.toMillis * (intervalCount + 1)
+
+    Instant.ofEpochMilli(nextTickMillis)
+  }
 }
\ No newline at end of file