Fix span parsing of startTime from OT JSON

Correctly parse startTime from OT JSON if span doesn't contain startTimeNano field

GitOrigin-RevId: 16e8b4fe02f437ef47ca914dc8105afcf85ec9d0

tools/intellij.tools.ide.metrics.collector/src/com/intellij/tools/ide/metrics/collector/telemetry/SpanElement.kt

@@ -8,7 +8,6 @@ import kotlinx.serialization.builtins.serializer
 import kotlinx.serialization.descriptors.SerialDescriptor
 import kotlinx.serialization.encoding.Decoder
 import kotlinx.serialization.encoding.Encoder
-import kotlinx.serialization.json.JsonNames
 import java.time.Instant
 import java.util.concurrent.ConcurrentHashMap
 import kotlin.time.Duration
@@ -43,7 +42,8 @@ internal fun toSpanElement(span: SpanData): SpanElement {
     isWarmup = isWarmup(tags),
     name = span.operationName,
     duration = span.durationNano ?: (span.duration.times(1000)),
-    startTimestamp = span.startTimeNano,
+    startTimestamp = span.startTimeNano ?: span.startTime?.let { Instant.ofEpochMilli(it / 1_000) }
+                     ?: throw IllegalStateException("startTime or startTimeNano should exists"),
     spanId = span.spanID,
     parentSpanId = span.getParentSpanId(),
     tags = tags,
@@ -143,8 +143,8 @@ data class SpanData(
   // see com.intellij.platform.diagnostic.telemetry.exporters.JaegerJsonSpanExporter.export
   @Contextual val duration: Duration,
   @Contextual val durationNano: Duration? = null,
-  @JsonNames("startTime")
-  @Contextual val startTimeNano: Instant,
+  @Contextual val startTimeNano: Instant? = null,
+  @Contextual val startTime: Long? = null,
 
   @JvmField @Serializable(with = CachedReferencesListSerializer::class) val references: List<SpanRef> = emptyList(),
   @JvmField @Serializable(with = CachedTagListSerializer::class) val tags: List<SpanTag> = emptyList(),

tools/intellij.tools.ide.metrics.collector/testSrc/com/intellij/tools/ide/metrics/collector/OpenTelemetrySpanExtractionTest.kt

@@ -1,6 +1,7 @@
 package com.intellij.tools.ide.metrics.collector
 
 import com.intellij.tools.ide.metrics.collector.metrics.PerformanceMetrics.Metric
+import com.intellij.tools.ide.metrics.collector.telemetry.OpentelemetrySpanJsonParser
 import com.intellij.tools.ide.metrics.collector.telemetry.SpanFilter
 import com.intellij.tools.ide.metrics.collector.telemetry.getMetricsBasedOnDiffBetweenSpans
 import com.intellij.tools.ide.metrics.collector.telemetry.getMetricsForStartup
@@ -13,6 +14,7 @@ import org.junit.jupiter.api.Test
 import java.nio.file.FileSystemAlreadyExistsException
 import java.nio.file.FileSystems
 import java.nio.file.Paths
+import java.time.Instant
 import kotlin.io.path.div
 
 internal val openTelemetryReports by lazy {
@@ -29,6 +31,14 @@ internal val openTelemetryReports by lazy {
 
 class OpenTelemetrySpanExtractionTest {
 
+  @Test
+  fun gatewayClientHostMetricsCollected() {
+    val file = (openTelemetryReports / "client-opentelemetry.json")
+    val result = OpentelemetrySpanJsonParser(SpanFilter.nameInList("rdct.station.discovery: scheduled", "rdct.gateway.LinkHandler.reporting.capabilities")).getSpanElements(file)
+    result.filter { it.startTimestamp == Instant.ofEpochMilli(1751546271647270 / 1000) && it.name == "rdct.station.discovery: scheduled" }.shouldHaveSize(1)
+    result.filter { it.startTimestamp == Instant.ofEpochMilli(1751546271719000 / 1000) && it.name == "rdct.gateway.LinkHandler.reporting.capabilities" }.shouldHaveSize(1)
+  }
+
   @Test
   fun startupMetricsCollected() {
     val file = (openTelemetryReports / "startup.json")
@@ -313,13 +323,13 @@ class OpenTelemetrySpanExtractionTest {
                                                     (openTelemetryReports / "opentelemetry_with_warmup_spans.json"),
                                                     "localInspections", "GeneralHighlightingPass")
     assertThat(metrics).containsAll(listOf(
-      Metric.newDuration("semanticHighlighting_1", 33),
-      Metric.newDuration("semanticHighlighting_2", 34),
-      Metric.newDuration("semanticHighlighting_3", 35),
-      Metric.newDuration("semanticHighlighting_4", 45),
-      Metric.newDuration("semanticHighlighting_5", 47),
-      Metric.newDuration("semanticHighlighting", 194),
-      Metric.newDuration("semanticHighlighting#mean_value", 38),
+      Metric.newDuration("semanticHighlighting_1", 347),
+      Metric.newDuration("semanticHighlighting_2", 337),
+      Metric.newDuration("semanticHighlighting_3", 342),
+      Metric.newDuration("semanticHighlighting_4", 349),
+      Metric.newDuration("semanticHighlighting_5", 350),
+      Metric.newDuration("semanticHighlighting", 1725),
+      Metric.newDuration("semanticHighlighting#mean_value", 345),
     ))
     val find = metrics.find { it.id.name == "semanticHighlighting_6" }
     assert(find == null) {