Alerting message template strange behavior

Hi, all.

I am a newbie on using opendistro for elasticsearch, and I’m stuck on making alert.

I want to send alert in webhook method, and the request goes successfully, but the request payload is different with the one in preview.

The query result is below:

    "_shards": {
        "total": 1,
        "failed": 0,
        "successful": 1,
        "skipped": 0
    "hits": {
        "hits": [],
        "total": {
            "value": 20,
            "relation": "eq"
        "max_score": null
    "took": 3,
    "timed_out": false,
    "aggregations": {
        "hashed": {
            "doc_count_error_upper_bound": 0,
            "sum_other_doc_count": 0,
            "buckets": [
                    "doc_count": 26,
                    "key": "eJyl08tuAiEUBuB9n4KlXQjOQKslvaQ2k2"
# the `key` inside `buckets` is much much longer, but I reduced it for readability.

Like the sample, there is aggregation result on my query result, and I want to send it with application/json style, so I made like below:

  {{ #ctx.results }}{{ #aggregations.hashed.buckets }}
    "{{&key}}": {{doc_count}},
  {{ /aggregations.hashed.buckets }}{{ /ctx.results }}
  "end": 0  <- being used like EOF, End of Payload ..

and the preview on kibana:

"eJyl08tuAiEUBuB9n4KlXQjOQKslvaQ2k2": 20,
  "end": 0

But the actual request is:

  "": ,
  "end": 0

This behavior can be observed in both real alerting, and sending test message.
Please guide me if I’m doing something wrong. :sob: Thank you in advance!

ps. This is how I have defined Destination.

Hi @shlee,

Don’t be sad. :thinking: There are some inconsistency between the preview in Kibana and the actual message is sent. There was an similar issue in Github Alerting trigger variables are empty · Issue #176 · opendistro-for-elasticsearch/alerting · GitHub.
Thank you for providing the information. This might be a bug to be fixed, and we will work on this.
Could you try to remove the space between {{ and }} to see if this can be a workaround.