JPERF-1435: Reduce JS overhead

For every resource (navigation, XHR, JS, CSS, image), it would send a
new HTTP request to parse headers.

The resource URI was not taken into account in the synthetic request,
so it could not infer original HTTP headers. Especially since the new
request can have different response headers than the original requests.
And even if they had the same, then it means we assume sticky session.
So we might read node id once just as well.

Supposedly, the synthetic request was being read from a cache,
but apparently it's still too much overhead.

We'll have to read the node id from `Server-Timing` header,
which is automatically captured by the browser
and it's the same way we obtain the response thread id.

CHANGELOG.md

@@ -31,6 +31,9 @@ Dropping a requirement of a major version of a dependency is a new contract.
   - formalize the dependency on `Server-Timing`s convention (e.g. `response-thread-plugin` public behavioral API)
   - encapsulate a specific `ActionMetric.drilldown` analysis (e.g. navigations are not the only backend interactions)
 
+### Fixed
+- Reduce overhead of `JavascriptW3cPerformanceTimeline`.
+
 ## [3.25.0] - 2023-11-09
 [3.25.0]: https://github.com/atlassian/jira-actions/compare/release-3.24.0...release-3.25.0
 

src/main/kotlin/com/atlassian/performance/tools/jiraactions/w3c/harvesters/JsNavigations.kt

@@ -6,28 +6,26 @@ import org.openqa.selenium.JavascriptExecutor
 
 internal fun getJsNavigationsPerformance(jsExecutor: JavascriptExecutor): List<PerformanceNavigationTiming> {
     val jsNavigations = jsExecutor.executeScript("return window.performance.getEntriesByType(\"navigation\");")
-    return parseNavigations(jsNavigations, jsExecutor)
+    return parseNavigations(jsNavigations)
 }
 
 private fun parseNavigations(
-    jsNavigations: Any?,
-    jsExecutor: JavascriptExecutor
+    jsNavigations: Any?
 ): List<PerformanceNavigationTiming> {
     if (jsNavigations !is List<*>) {
         throw Exception("Unexpected non-list JavaScript value: $jsNavigations")
     }
-    return jsNavigations.map { parsePerformanceNavigationTiming(it, jsExecutor) }
+    return jsNavigations.map { parsePerformanceNavigationTiming(it) }
 }
 
 private fun parsePerformanceNavigationTiming(
-    map: Any?,
-    jsExecutor: JavascriptExecutor
+    map: Any?
 ): PerformanceNavigationTiming {
     if (map !is Map<*, *>) {
         throw Exception("Unexpected non-map JavaScript value: $map")
     }
     return PerformanceNavigationTiming(
-        resource = parsePerformanceResourceTiming(map, jsExecutor),
+        resource = parsePerformanceResourceTiming(map),
         unloadEventStart = parseTimestamp(map["unloadEventStart"]),
         unloadEventEnd = parseTimestamp(map["unloadEventEnd"]),
         domInteractive = parseTimestamp(map["domInteractive"]),

src/main/kotlin/com/atlassian/performance/tools/jiraactions/w3c/harvesters/JsResources.kt

@@ -4,26 +4,23 @@ import com.atlassian.performance.tools.jiraactions.api.w3c.PerformanceEntry
 import com.atlassian.performance.tools.jiraactions.api.w3c.PerformanceResourceTiming
 import com.atlassian.performance.tools.jiraactions.api.w3c.PerformanceServerTiming
 import org.openqa.selenium.JavascriptExecutor
-import java.time.Duration
 
 internal fun getJsResourcesPerformance(jsExecutor: JavascriptExecutor): List<PerformanceResourceTiming> {
     val jsResources = jsExecutor.executeScript("return window.performance.getEntriesByType(\"resource\");")
-    return parseResources(jsResources, jsExecutor)
+    return parseResources(jsResources)
 }
 
 private fun parseResources(
-    jsResources: Any,
-    jsExecutor: JavascriptExecutor
+    jsResources: Any
 ): List<PerformanceResourceTiming> {
     if (jsResources !is List<*>) {
         throw Exception("Unexpected non-list JavaScript value: $jsResources")
     }
-    return jsResources.map { parsePerformanceResourceTiming(it, jsExecutor) }
+    return jsResources.map { parsePerformanceResourceTiming(it) }
 }
 
 internal fun parsePerformanceResourceTiming(
-    map: Any?,
-    jsExecutor: JavascriptExecutor
+    map: Any?
 ): PerformanceResourceTiming {
     if (map !is Map<*, *>) {
         throw Exception("Unexpected non-map JavaScript value: $map")
@@ -47,7 +44,7 @@ internal fun parsePerformanceResourceTiming(
         transferSize = map["transferSize"] as Long,
         encodedBodySize = map["encodedBodySize"] as Long,
         decodedBodySize = map["decodedBodySize"] as Long,
-        serverTiming = map["serverTiming"]?.let { parseServerTimings(it, jsExecutor) }
+        serverTiming = map["serverTiming"]?.let { parseServerTimings(it) }
     )
 }
 
@@ -66,29 +63,12 @@ private fun parsePerformanceEntry(
 }
 
 private fun parseServerTimings(
-    jsServerTimings: Any,
-    jsExecutor: JavascriptExecutor
+    jsServerTimings: Any
 ): List<PerformanceServerTiming> {
     if (jsServerTimings !is List<*>) {
         throw Exception("Unexpected non-list JavaScript value: $jsServerTimings")
     }
-    val result = jsServerTimings.map { parseServerTiming(it) }.toMutableList()
-    val responseHeaders = getResponseHeaders(jsExecutor)
-    val nodeId = responseHeaders["x-anodeid"]
-    addAttribute(result, "nodeId", nodeId)
-    return result
-}
-
-private fun addAttribute(result: MutableList<PerformanceServerTiming>, attributeName: String, attributeValue: String?) {
-    if (attributeValue != null) {
-        result.add(
-            PerformanceServerTiming(
-                name = attributeName,
-                duration = Duration.ZERO,
-                description = attributeValue
-            )
-        )
-    }
+    return jsServerTimings.map { parseServerTiming(it) }.toMutableList()
 }
 
 private fun parseServerTiming(
@@ -103,25 +83,3 @@ private fun parseServerTiming(
         description = map["description"] as String
     )
 }
-
-private fun getResponseHeaders(jsExecutor: JavascriptExecutor): Map<String, String?> {
-    val jsResult = jsExecutor.executeScript(
-        """
-                var r = new XMLHttpRequest();
-                r.open('HEAD', window.location, false);
-                r.send(null);
-                var headersString = r.getAllResponseHeaders();
-                const arr = headersString.trim().split(/[\r\n]+/);
-                const headerMap = {};
-                arr.forEach((line) => {
-                  const parts = line.split(": ");
-                  const header = parts.shift();
-                  const value = parts.join(": ");
-                  headerMap[header] = value;
-                });
-                return headerMap;
-        """.trimIndent()
-    )
-    @Suppress("UNCHECKED_CAST")
-    return (jsResult as Map<String, String>).mapKeys { it.key.toLowerCase() }
-}