1 files changed, 16 insertions, 7 deletions

diff --git a/container-di/src/main/scala/com/yahoo/container/di/ConfigRetriever.scala b/container-di/src/main/scala/com/yahoo/container/di/ConfigRetriever.scala
index 994162695d3..dc94d789f7b 100644
--- a/container-di/src/main/scala/com/yahoo/container/di/ConfigRetriever.scala
+++ b/container-di/src/main/scala/com/yahoo/container/di/ConfigRetriever.scala
@@ -7,7 +7,7 @@ import java.util.logging.{Level, Logger}
 import com.yahoo.config.ConfigInstance
 import com.yahoo.container.di.ConfigRetriever._
 import com.yahoo.container.di.config.Subscriber
-import com.yahoo.log.LogLevel
+import com.yahoo.log.LogLevel.DEBUG
 
 import scala.annotation.tailrec
 import scala.collection.JavaConverters._
@@ -31,7 +31,7 @@ final class ConfigRetriever(bootstrapKeys: Set[ConfigKeyT],
   @tailrec
   final def getConfigs(componentConfigKeys: Set[ConfigKeyT], leastGeneration: Long): ConfigSnapshot = {
     require(componentConfigKeys intersect bootstrapKeys isEmpty)
-    log.log(LogLevel.DEBUG, "getConfigs: " + componentConfigKeys)
+    log.log(DEBUG, "getConfigs: " + componentConfigKeys)
 
     setupComponentSubscriber(componentConfigKeys ++ bootstrapKeys)
 
@@ -43,16 +43,26 @@ final class ConfigRetriever(bootstrapKeys: Set[ConfigKeyT],
 
   private def getConfigsOptional(leastGeneration: Long): Option[ConfigSnapshot] = {
     val newestComponentGeneration = componentSubscriber.waitNextGeneration()
+    log.log(DEBUG, s"getConfigsOptional: new component generation: $newestComponentGeneration")
 
+    // leastGeneration is only used to ensure newer generation when the previous generation was invalidated due to an exception
     if (newestComponentGeneration < leastGeneration) {
       None
     } else if (bootstrapSubscriber.generation < newestComponentGeneration) {
       val newestBootstrapGeneration = bootstrapSubscriber.waitNextGeneration()
+      log.log(DEBUG, s"getConfigsOptional: new bootstrap generation: ${bootstrapSubscriber.generation}")
       bootstrapConfigIfChanged() orElse {
-        if (newestBootstrapGeneration == newestComponentGeneration) componentsConfigIfChanged()
-        else None
+        if (newestBootstrapGeneration == newestComponentGeneration){
+          log.log(DEBUG, s"Got new components configs with unchanged bootstrap configs.")
+          componentsConfigIfChanged()
+        } else {
+          // This should not be a normal case, and hence a warning to allow investigation.
+          log.warning(s"Did not get same generation for bootstrap ($newestBootstrapGeneration) and components configs ($newestComponentGeneration).")
+          None
+        }
       }
     } else {
+      // bootstrapGen==componentGen (happens only when a new component subscriber returns first config after bootstrap)
       componentsConfigIfChanged()
     }
   }
@@ -61,8 +71,7 @@ final class ConfigRetriever(bootstrapKeys: Set[ConfigKeyT],
   private def componentsConfigIfChanged(): Option[ComponentsConfigs] = configIfChanged(componentSubscriber, ComponentsConfigs)
 
   private def configIfChanged[T <: ConfigSnapshot](subscriber: Subscriber,
-                                                   constructor: Map[ConfigKeyT, ConfigInstance] => T ):
-  Option[T] = {
+                                                   constructor: Map[ConfigKeyT, ConfigInstance] => T ): Option[T] = {
     if (subscriber.configChanged) Some(constructor(subscriber.config.asScala.toMap))
     else None
   }
@@ -77,9 +86,9 @@ final class ConfigRetriever(bootstrapKeys: Set[ConfigKeyT],
   private def setupComponentSubscriber(keys: Set[ConfigKeyT]) {
     if (componentSubscriberKeys != keys) {
       componentSubscriber.close()
-
       componentSubscriberKeys = keys
       try {
+        log.log(DEBUG, s"Setting up new component subscriber for keys: $keys")
         componentSubscriber = subscribe(keys)
       } catch {
         case e: Throwable =>