# Mustache transform script throwing "Failed to compile inline script" error

**URL:** <https://discuss.elastic.co/t/mustache-transform-script-throwing-failed-to-compile-inline-script-error/127364>\
**Category:** Elasticsearch\
**Tags:** elastic-stack-alerting\
**Created:** [April 9, 2018, 5:50pm UTC](https://discuss.elastic.co/t/mustache-transform-script-throwing-failed-to-compile-inline-script-error/127364 "2018-04-09T17:50:50Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![singrahu](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/singrahu/32/12985_2.png) [@singrahu](https://discuss.elastic.co/u/singrahu)\
**Post date:** [April 9, 2018, 5:50pm UTC](https://discuss.elastic.co/t/mustache-transform-script-throwing-failed-to-compile-inline-script-error/127364/1 "2018-04-09T17:50:50Z")

</div>

Elastic stack: 6.2.2

I am trying to convert the payload to JSON and then pass it to a Webhook action.  
My Watcher transform script looks like:

```
{
  "trigger": {
    "schedule": {
      "interval": "1m"
    }
  },
  "input": {
    "search": {
      "request": {
        "search_type": "query_then_fetch",
        "indices": [
          ".watcher-history*"
        ],
        "types": [],
        "body": {
          "size": 10,
          "_source": [
            "@timestamp",
            "metadata.name",
            "watch_id"
          ],
          "query": {
            "bool": {
              "filter": [
                {
                  "range": {
                    "@timestamp": {
                      "gte": "now-1m/m"
                    }
                  }
                },
                {
                  "match": {
                    "watch_id": "Watch_1"
                  }
                }
              ]
            }
          },
          "sort": [
            {
              "@timestamp": {
                "order": "asc"
              }
            }
          ]
        }
      }
    }
  },
  "condition": {
    "compare": {
      "ctx.payload.hits.total": {
        "gt": 0
      }
    }
  },
  "actions": {
    "watcherWebHook": {
      "transform" : {
        "chain" : [
          {
            "script": {
              "lang": "mustache",
              "source": "{{#toJson}}ctx.payload.hits.hits{{/toJson}}"
            }
          },
          {
            "script": {
              "lang": "painless",
              "source": "return ['payload': ctx.payload._value.toString()]"
            }
          }
        ]
      },
      "webhook": {
        "scheme": "http",
        "host": "webhookEndPointServer",
        "port": 80,
        "method": "post",
        "path": "/raise",
        "params": {},
        "body": {
          "source": {
            "payload": {
              "execution_time": "{{ctx.execution_time}}",
              "watch_id": "{{ctx.watch_id}}",
              "body": "{{ctx.payload._value}}"
            }
          },
          "lang": "mustache",
          "options": {
            "content_type": "application/json; charset=UTF-8"
          }
        }
      }
    }
  },
  "throttle_period_in_millis": 1000
}

```

Whenever I try to save/simulate the watch, ES throws following error:

```
[WARN][r.suppressed] path: /_xpack/watcher/watch/_execute, params: {}
org.elasticsearch.script.GeneralScriptException: Failed to compile inline script [{{#toJson}}ctx.payload.hits.hits{{/toJson}}] using lang [mustache]
        at org.elasticsearch.script.ScriptService.compile(ScriptService.java:340) ~[elasticsearch-6.2.2.jar:6.2.2]
        at org.elasticsearch.xpack.watcher.transform.script.ExecutableScriptTransform.<init>(ExecutableScriptTransform.java:47) ~[?:?]
        at org.elasticsearch.xpack.watcher.transform.script.ScriptTransformFactory.createExecutable(ScriptTransformFactory.java:49) ~[?:?]
        at org.elasticsearch.xpack.watcher.transform.script.ScriptTransformFactory.createExecutable(ScriptTransformFactory.java:28) ~[?:?]
        at org.elasticsearch.xpack.core.watcher.transform.chain.ChainTransformFactory.createExecutable(ChainTransformFactory.java:55) ~[?:?]
        at org.elasticsearch.xpack.core.watcher.transform.chain.ChainTransformFactory.createExecutable(ChainTransformFactory.java:31) ~[?:?]
        at org.elasticsearch.xpack.core.watcher.transform.TransformFactory.parseExecutable(TransformFactory.java:53) ~[?:?]
        at org.elasticsearch.xpack.core.watcher.transform.TransformRegistry.parse(TransformRegistry.java:64) ~[?:?]
        at org.elasticsearch.xpack.core.watcher.transform.TransformRegistry.parse(TransformRegistry.java:53) ~[?:?]
        at org.elasticsearch.xpack.core.watcher.actions.ActionWrapper.parse(ActionWrapper.java:224) ~[?:?]
        at org.elasticsearch.xpack.core.watcher.actions.ActionRegistry.parseActions(ActionRegistry.java:73) ~[?:?]
        at org.elasticsearch.xpack.watcher.watch.WatchParser.parse(WatchParser.java:171) ~[?:?]
        at org.elasticsearch.xpack.watcher.watch.WatchParser.parse(WatchParser.java:123) ~[?:?]
        at org.elasticsearch.xpack.watcher.watch.WatchParser.parse(WatchParser.java:88) ~[?:?]
        at org.elasticsearch.xpack.watcher.transport.actions.execute.TransportExecuteWatchAction.masterOperation(TransportExecuteWatchAction.java:117) ~[?:?]
        at org.elasticsearch.xpack.watcher.transport.actions.execute.TransportExecuteWatchAction.masterOperation(TransportExecuteWatchAction.java:72) ~[?:?]
        at org.elasticsearch.action.support.master.TransportMasterNodeAction.masterOperation(TransportMasterNodeAction.java:88) ~[elasticsearch-6.2.2.jar:6.2.2]
        at org.elasticsearch.action.support.master.TransportMasterNodeAction$AsyncSingleAction$2.doRun(TransportMasterNodeAction.java:167) ~[elasticsearch-6.2.2.jar:6.2.2]
        at org.elasticsearch.common.util.concurrent.ThreadContext$ContextPreservingAbstractRunnable.doRun(ThreadContext.java:672) [elasticsearch-6.2.2.jar:6.2.2]
        at org.elasticsearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:37) [elasticsearch-6.2.2.jar:6.2.2]
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_161]
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_161]
        at java.lang.Thread.run(Thread.java:748) [?:1.8.0_161]
Caused by: java.lang.IllegalArgumentException: mustache engine does not know how to handle context [xpack_executable]
        at org.elasticsearch.script.mustache.MustacheScriptEngine.compile(MustacheScriptEngine.java:65) ~[?:?]
        at org.elasticsearch.script.ScriptService.compile(ScriptService.java:335) ~[elasticsearch-6.2.2.jar:6.2.2]
        ... 22 more

```

The same watch definition is compiling in **ES 5.6.3** , but then it simply generates a string with value if a **PagedBytesReference** object reference, rather than original JSON value as base64 string.

---

<div class="post-metadata">

**Author:** ![spinscale](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/spinscale/32/25011_2.png) [@spinscale](https://discuss.elastic.co/u/spinscale)\
**Post date:** [April 10, 2018, 7:23am UTC](https://discuss.elastic.co/t/mustache-transform-script-throwing-failed-to-compile-inline-script-error/127364/2 "2018-04-10T07:23:08Z")

</div>

the `body` field of the webhook must be a single string.

It should look like this

```auto
"body" : "{{#toJson}}ctx.payload.my_field{{/toJson}}"

```

Before that you need a script transform, that creates the same data structure, that you created in the `body` with the `body`, `watch_id`, `execution_time` fields.

Hope that makes sense.

---

<div class="post-metadata">

**Author:** ![singrahu](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/singrahu/32/12985_2.png) [@singrahu](https://discuss.elastic.co/u/singrahu)\
**Post date:** [April 10, 2018, 10:55am UTC](https://discuss.elastic.co/t/mustache-transform-script-throwing-failed-to-compile-inline-script-error/127364/3 "2018-04-10T10:55:37Z")

</div>

Thanks for the reply.  
The problem is that we want to send the data not as JSON but Base64 array string.

Doing mustache transform of payload hits to JSON works fine in ES 5.6.3, but consecutive painless script transform (or even final body) receives the value as **org.elasticsearch.common.bytes.PagedBytesReference** :

```
      "chain": {
        "results": [
          {
            "type": "script",
            "status": "success",
            "payload": {
              "_value": "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"
            }
          },
          {
            "type": "script",
            "status": "success",
            "payload": {
              "payload": "org.elasticsearch.common.bytes.PagedBytesReference@c4c0ae52"
            }
          }
        ]
      }

```

The same logic throws compilation error in ES 6.x as depicted in my first post.

---

<div class="post-metadata">

**Author:** ![spinscale](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/spinscale/32/25011_2.png) [@spinscale](https://discuss.elastic.co/u/spinscale)\
**Post date:** [April 10, 2018, 11:10am UTC](https://discuss.elastic.co/t/mustache-transform-script-throwing-failed-to-compile-inline-script-error/127364/4 "2018-04-10T11:10:38Z")

</div>

the first `toJson` in the script transform is not needed, unless I am missing somthing obvious here

---

<div class="post-metadata">

**Author:** ![singrahu](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/singrahu/32/12985_2.png) [@singrahu](https://discuss.elastic.co/u/singrahu)\
**Post date:** [April 10, 2018, 1:18pm UTC](https://discuss.elastic.co/t/mustache-transform-script-throwing-failed-to-compile-inline-script-error/127364/5 "2018-04-10T13:18:22Z")

</div>

Thanks a lot for your help.  
`ctx.payload.hits.hits` is JSON and I had to convert it to String before encoding.  
Got it working with below transform script:

```
  "transform": {
    "script": {
      "source": "return ['payload': ctx.payload.hits.hits.toString().encodeBase64()]",
      "lang": "painless"
    }
  },
  "webhook": {
    "scheme": "http",
    "host": "webhookEndPointServer",
    "port": 80,
    "method": "post",
    "path": "/raise",
    "params": {},
    "body": {
      "source": {
        "payload": {
          "execution_time": "{{ctx.execution_time}}",
          "watch_id": "{{ctx.watch_id}}",
          "body": "{{ctx.payload}}"
        }
      },
      "lang": "mustache",
      "options": {
        "content_type": "application/json; charset=UTF-8"
      }
    }
  }
```

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [May 8, 2018, 1:18pm UTC](https://discuss.elastic.co/t/mustache-transform-script-throwing-failed-to-compile-inline-script-error/127364/6 "2018-05-08T13:18:38Z")

</div>

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