lwcapi: add test for splitting trace query (#1639)

Ensure trace time series query will get split up into
representative data expressions correctly.

atlas-eval/src/test/scala/com/netflix/atlas/eval/stream/LwcToAggrDatapointSuite.scala

@@ -110,6 +110,30 @@ class LwcToAggrDatapointSuite extends FunSuite {
     assertEquals(countData.map(_.value).toSet, Set(4.0))
   }
 
+  test("eval trace time series") {
+    val styleExpr = "name,cpu,:eq,:avg"
+    val tsExpr = s"app,foo,:eq,$styleExpr,:span-time-series"
+    def subExpr(n: String, e: String): String = {
+      s"""{"id":"$n","expression":"$e","frequency":$step}"""
+    }
+    val expr1 = subExpr("sum", "name,cpu,:eq,:sum")
+    val expr2 = subExpr("count", "name,cpu,:eq,:count")
+    val subv2 =
+      s"""{"type":"subscription-v2","expression":"$tsExpr","exprType":"TRACE_TIME_SERIES","metrics":[$expr1,$expr2]}"""
+    val results = eval(subv2 :: input.tail)
+    assertEquals(results.size, 8)
+
+    val groups = results.groupBy(_.expr)
+    assertEquals(groups.size, 2)
+
+    val sumData = groups(DataExpr.Sum(Query.Equal("name", "cpu")))
+    assertEquals(sumData.map(_.value).toSet, Set(1.0, 2.0, 3.0, 4.0))
+
+    val countData = groups(DataExpr.Count(Query.Equal("name", "cpu")))
+    assertEquals(countData.size, 4)
+    assertEquals(countData.map(_.value).toSet, Set(4.0))
+  }
+
   test("diagnostic messages are logged") {
     logMessages.clear()
     eval(input)

atlas-lwcapi/src/main/scala/com/netflix/atlas/lwcapi/ExpressionSplitter.scala

@@ -21,6 +21,7 @@ import com.netflix.atlas.core.model.EventExpr
 import com.netflix.atlas.core.model.Query
 import com.netflix.atlas.core.model.Query.KeyQuery
 import com.netflix.atlas.core.model.StyleExpr
+import com.netflix.atlas.core.model.TraceQuery
 import com.netflix.atlas.eval.model.ExprType
 import com.netflix.atlas.eval.stream.ExprInterpreter
 import com.netflix.spectator.ipc.ServerGroup
@@ -134,11 +135,23 @@ class ExpressionSplitter(config: Config) {
             val q = intern(compress(e.query))
             DataExprMeta(e.toString, q)
           }
-      case ExprType.TRACE_EVENTS | ExprType.TRACE_TIME_SERIES =>
+      case ExprType.TRACE_EVENTS =>
         parsedExpressions.map { e =>
           // Tracing cannot be scoped to specific infrastructure, always use True
           DataExprMeta(e.toString, Query.True)
         }
+      case ExprType.TRACE_TIME_SERIES =>
+        parsedExpressions
+          .collect {
+            case tq: TraceQuery.SpanTimeSeries =>
+              tq.expr.expr.dataExprs.map(e => tq.copy(expr = StyleExpr(e, Map.empty)))
+          }
+          .flatten
+          .distinct
+          .map { e =>
+            // Tracing cannot be scoped to specific infrastructure, always use True
+            DataExprMeta(e.toString, Query.True)
+          }
     }
   }
 

atlas-lwcapi/src/test/scala/com/netflix/atlas/lwcapi/ExpressionSplitterSuite.scala

@@ -50,6 +50,25 @@ class ExpressionSplitterSuite extends FunSuite {
     assertEquals(actual, expected)
   }
 
+  test("splits compound trace time series expression into data expressions") {
+    def childExpr(e: String): String = {
+      s"nf.app,api,:eq,nf.cluster,skan-test,:eq,:child,$e,:span-time-series"
+    }
+    val expr = s"${childExpr(query1)},${childExpr(query1)}"
+    val actual = splitter.split(expr, ExprType.TRACE_TIME_SERIES, frequency1)
+    val expected = List(
+      Subscription(
+        Query.True,
+        ExpressionMetadata(childExpr(ds1a), ExprType.TRACE_TIME_SERIES, frequency1)
+      ),
+      Subscription(
+        Query.True,
+        ExpressionMetadata(childExpr(ds1b), ExprType.TRACE_TIME_SERIES, frequency1)
+      )
+    ).reverse
+    assertEquals(actual, expected)
+  }
+
   test("throws IAE for invalid expressions") {
     val msg = intercept[IllegalArgumentException] {
       splitter.split("foo", ExprType.TIME_SERIES, frequency1)