# ThreadContext loses headers between threads
**URL:** https://discuss.elastic.co/t/threadcontext-loses-headers-between-threads/166741
**Category:** Elasticsearch
**Created:** [February 1, 2019, 1:43pm UTC](https://discuss.elastic.co/t/threadcontext-loses-headers-between-threads/166741 "2019-02-01T13:43:58Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Sergey\_Ivanov](https://discuss.elastic.co/u/Sergey_Ivanov)
#### Post date: [February 1, 2019, 1:43pm UTC](https://discuss.elastic.co/t/threadcontext-loses-headers-between-threads/166741/1 "2019-02-01T13:43:59Z")
Hello,
We're using our custom plugin for Elasticsearch and we faced the following problem after upgrade from ES 5.6.6 to 6.5.0:
Looks like `ThreadContext` loses headers between `http_server_worker` and `updateTask` threads.
For example, we store custom header in `RestHandler` like:
```
@Override
public void handleRequest(RestRequest restRequest, RestChannel restChannel, NodeClient nodeClient)
throws Exception {
try {
threadContext.putHeader("user", "test");
......
```
and then we try to get this header in `IndexEventListener` implementation:
```
@Override
public void afterIndexCreated(IndexService indexService) {
final String user = threadContext.getHeader("user");
....
```
But headers are empty.
Could you please help, is it expected behavior? I didn't find any information about these changes in change-log for update to 6.5.0 but it worked fine on ES 5.6.6.
---
### Author:  [@Sergey\_Ivanov](https://discuss.elastic.co/u/Sergey_Ivanov)
#### Post date: [February 12, 2019, 8:56am UTC](https://discuss.elastic.co/t/threadcontext-loses-headers-between-threads/166741/2 "2019-02-12T08:56:44Z")
In addition, we found the issue which probably affected this behavior:
[Use system context for cluster state update tasks (#31241)](https://github.com/elastic/elasticsearch/commit/02a4ef38a7960895b4e26111167676ec49302cba#diff-162074b704aa51c938206a14de3aa227R733)
and specifically here is this code:
```
final Supplier supplier = threadContext.newRestorableContext(false);
try (ThreadContext.StoredContext ignore = threadContext.stashContext()) {
threadContext.markAsSystemContext();
List safeTasks = tasks.entrySet().stream()
.map(e -> taskBatcher.new UpdateTask(config.priority(), source, e.getKey(), safe(e.getValue()), executor))
.map(e -> taskBatcher.new UpdateTask(config.priority(), source, e.getKey(), safe(e.getValue(), supplier), executor))
.collect(Collectors.toList());
taskBatcher.submitTasks(safeTasks, config.timeout());
} catch (EsRejectedExecutionException e) {
```
`threadContext.stashContext()` - saves old and creates new ThreadContext where we have no access to previous thread context's headers in `updateTask` thread.
Could you please explain, how we can obtain these headers in`updateTask` thread now (after changes of this issue)?
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [March 12, 2019, 8:56am UTC](https://discuss.elastic.co/t/threadcontext-loses-headers-between-threads/166741/3 "2019-03-12T08:56:46Z")
This topic was automatically closed 28 days after the last reply. New replies are no longer allowed.