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Truncate action log to avoid json string decoding overflow #8757

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833b707
WIP: truncate action log to max 1000 items per action group
MichaelBuessemeyer Jul 4, 2025
3b289d3
make frontend request action log only in truncated form
MichaelBuessemeyer Jul 7, 2025
3cd88f8
make fetching update action log per default not truncate but truncate…
MichaelBuessemeyer Jul 7, 2025
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3 changes: 2 additions & 1 deletion frontend/javascripts/admin/rest_api.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -777,9 +777,10 @@ export function getUpdateActionLog(
annotationId: string,
oldestVersion?: number,
newestVersion?: number,
truncateActionLog: boolean = false,
): Promise<Array<APIUpdateActionBatch>> {
return doWithToken((token) => {
const params = new URLSearchParams();
const params = new URLSearchParams([["truncate", truncateActionLog.toString()]]);
params.set("token", token);
if (oldestVersion != null) {
params.set("oldestVersion", oldestVersion.toString());
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1 change: 1 addition & 0 deletions frontend/javascripts/viewer/view/version_list.tsx
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Expand Up @@ -168,6 +168,7 @@ async function getUpdateActionLogPage(
annotationId,
oldestVersionInPage,
newestVersionInPage,
true,
);

// The backend won't send the version 0 as that does not exist. The frontend however
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8 changes: 6 additions & 2 deletions ...gstore/app/com/scalableminds/webknossos/tracingstore/annotation/TSAnnotationService.scala
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Expand Up @@ -60,6 +60,8 @@ class TSAnnotationService @Inject()(val remoteWebknossosClient: TSRemoteWebknoss
private lazy val materializedAnnotationWithTracingCache =
AlfuCache[ObjectId, AlfuCache[Long, AnnotationWithTracings]](maxCapacity = 1000)

private val maxUpdateActionLogBatchSize = 1000

private def newInnerCache(implicit ec: ExecutionContext): Fox[AlfuCache[Long, AnnotationWithTracings]] =
Fox.successful(AlfuCache[Long, AnnotationWithTracings](maxCapacity = 2))

Expand Down Expand Up @@ -240,7 +242,7 @@ class TSAnnotationService @Inject()(val remoteWebknossosClient: TSRemoteWebknoss
else
tracingDataStore.annotations.put(annotationId.toString, version, annotationProto)

def updateActionLog(annotationId: ObjectId, newestVersion: Long, oldestVersion: Long)(
def updateActionLog(annotationId: ObjectId, newestVersion: Long, oldestVersion: Long, truncate: Boolean)(
implicit ec: ExecutionContext): Fox[JsValue] = {
def versionedTupleToJson(tuple: (Long, List[UpdateAction])): JsObject =
Json.obj(
Expand All @@ -258,7 +260,9 @@ class TSAnnotationService @Inject()(val remoteWebknossosClient: TSRemoteWebknoss
Some(batchTo),
Some(batchFrom))(fromJsonBytes[List[UpdateAction]])
}
} yield Json.toJson(updateActionBatches.flatten.map(versionedTupleToJson))
truncatedUpdateActionBatches = if (truncate) updateActionBatches.map(_.take(maxUpdateActionLogBatchSize))
else updateActionBatches
} yield Json.toJson(truncatedUpdateActionBatches.flatten.map(versionedTupleToJson))
Comment on lines +263 to +265
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🛠️ Refactor suggestion

Consider total response size in addition to per-batch truncation.

The current implementation truncates each batch to 1000 items but then flattens all batches together. This could still result in very large JSON responses if there are many batches, potentially not fully addressing the JSON decoding overflow issue.

Consider also limiting the total number of batches or implementing a global response size limit to ensure the final JSON stays within frontend decoding limits.

 truncatedUpdateActionBatches = if (truncate) updateActionBatches.map(_.take(maxUpdateActionLogBatchSize))
 else updateActionBatches
+// Consider also limiting total response size:
+finalBatches = if (truncate) truncatedUpdateActionBatches.take(maxBatchCount) else truncatedUpdateActionBatches
-} yield Json.toJson(truncatedUpdateActionBatches.flatten.map(versionedTupleToJson))
+} yield Json.toJson(finalBatches.flatten.map(versionedTupleToJson))

Committable suggestion skipped: line range outside the PR's diff.

🤖 Prompt for AI Agents 
In
webknossos-tracingstore/app/com/scalableminds/webknossos/tracingstore/annotation/TSAnnotationService.scala
around lines 263 to 265, the code truncates each batch to a maximum size but
then flattens all batches, which can still produce an excessively large JSON
response. To fix this, implement an additional limit on the total number of
batches or the overall size of the combined response before converting to JSON,
ensuring the final output stays within frontend decoding limits.

}

def findEditableMappingInfo(annotationId: ObjectId, tracingId: String, version: Option[Long] = None)(
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6 changes: 4 additions & 2 deletions ...re/app/com/scalableminds/webknossos/tracingstore/controllers/TSAnnotationController.scala
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Expand Up @@ -78,14 +78,16 @@ class TSAnnotationController @Inject()(

def updateActionLog(annotationId: ObjectId,
newestVersion: Option[Long] = None,
oldestVersion: Option[Long] = None): Action[AnyContent] = Action.async { implicit request =>
oldestVersion: Option[Long] = None,
truncate: Option[Boolean] = None): Action[AnyContent] = Action.async { implicit request =>
log() {
accessTokenService.validateAccessFromTokenContext(UserAccessRequest.readAnnotation(annotationId)) {
for {
newestMaterializableVersion <- annotationService.currentMaterializableVersion(annotationId)
updateLog <- annotationService.updateActionLog(annotationId,
newestVersion.getOrElse(newestMaterializableVersion),
oldestVersion.getOrElse(0))
oldestVersion.getOrElse(0),
truncate.getOrElse(false))
} yield Ok(updateLog)
}
}
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2 changes: 1 addition & 1 deletion webknossos-tracingstore/conf/tracingstore.latest.routes
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Expand Up @@ -7,7 +7,7 @@ GET /health
POST /annotation/save @com.scalableminds.webknossos.tracingstore.controllers.TSAnnotationController.save(annotationId: ObjectId)
GET /annotation/:annotationId @com.scalableminds.webknossos.tracingstore.controllers.TSAnnotationController.get(annotationId: ObjectId, version: Option[Long])
POST /annotation/:annotationId/update @com.scalableminds.webknossos.tracingstore.controllers.TSAnnotationController.update(annotationId: ObjectId)
GET /annotation/:annotationId/updateActionLog @com.scalableminds.webknossos.tracingstore.controllers.TSAnnotationController.updateActionLog(annotationId: ObjectId, newestVersion: Option[Long], oldestVersion: Option[Long])
GET /annotation/:annotationId/updateActionLog @com.scalableminds.webknossos.tracingstore.controllers.TSAnnotationController.updateActionLog(annotationId: ObjectId, newestVersion: Option[Long], oldestVersion: Option[Long], truncate: Option[Boolean])
GET /annotation/:annotationId/newestVersion @com.scalableminds.webknossos.tracingstore.controllers.TSAnnotationController.newestVersion(annotationId: ObjectId)
POST /annotation/:annotationId/duplicate @com.scalableminds.webknossos.tracingstore.controllers.TSAnnotationController.duplicate(annotationId: ObjectId, newAnnotationId: ObjectId, ownerId: ObjectId, requestingUserId: ObjectId, version: Option[Long], isFromTask: Boolean, datasetBoundingBox: Option[String])
POST /annotation/:annotationId/resetToBase @com.scalableminds.webknossos.tracingstore.controllers.TSAnnotationController.resetToBase(annotationId: ObjectId)
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