# How to use @elastic/ecs-winston-format with winston-elasticsearch

**URL:** <https://discuss.elastic.co/t/how-to-use-elastic-ecs-winston-format-with-winston-elasticsearch/281418>\
**Category:** Elasticsearch\
**Created:** [August 14, 2021, 2:03am UTC](https://discuss.elastic.co/t/how-to-use-elastic-ecs-winston-format-with-winston-elasticsearch/281418 "2021-08-14T02:03:52Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![kkireyev](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/kkireyev/32/92135_2.png) [@kkireyev](https://discuss.elastic.co/u/kkireyev)\
**Post date:** [August 14, 2021, 2:03am UTC](https://discuss.elastic.co/t/how-to-use-elastic-ecs-winston-format-with-winston-elasticsearch/281418/1 "2021-08-14T02:03:52Z")

</div>

Hi! I'm trying to long events from Javascript (especially from express application) to ELK. I can write to console just fine:

```auto
const ecsFormat = require('@elastic/ecs-winston-format');
const myLogger = winston.createLogger({
  level: 'info',
  format: ecsFormat({ convertReqRes: true }),
  transports: [
    new winston.transports.Console(),
  ],
});

```

and then I can easily include the request object to send the right request metadata in log messages:

```auto
logger.info ("message", { req, res })

```

But if I want to write to ELK:

```auto
const Elasticsearch = require('winston-elasticsearch');
logger.add(new Elasticsearch({ ... }))

...
logger.info('Message', { req, res })

```

I get errors like this:

```auto
error: TypeError: Converting circular structure to JSON
    at JSON.stringify (<anonymous>)
    at Json.serialize (/app/node_modules/elasticsearch/src/lib/serializers/json.js:23:21)
    at Json.bulkBody (/app/node_modules/elasticsearch/src/lib/serializers/json.js:51:20)
    at Transport.request (/app/node_modules/elasticsearch/src/lib/transport.js:191:24)
    at exec (/app/node_modules/elasticsearch/src/lib/client_action.js:361:20)
    at EsApiClient.action [as bulk] (/app/node_modules/elasticsearch/src/lib/client_action.js:61:16)
    at BulkWriter.write (/app/node_modules/winston-elasticsearch/bulk_writer.js:89:22)
    at BulkWriter.flush (/app/node_modules/winston-elasticsearch/bulk_writer.js:69:15)
    at BulkWriter.tick (/app/node_modules/winston-elasticsearch/bulk_writer.js:45:8)
    at Timeout.timer.setTimeout [as _onTimeout] (/app/node_modules/winston-elasticsearch/bulk_writer.js:37:10)

```

I've tried different ways to work around it but have not been successful.

I'm also a bit confused on the difference in data types of the `format:` parameter to `winston.createLogger(...)` vs the `transform:` parameter to `new Elasticsearch(...)`. Can I use the former (ECS formatter) with `Elasticsearch`?

How can I easily log express "request" metadata in ECS format with a combination of `winston-elasticsearch` and `ecs-winston-format`?

---

<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:** [September 11, 2021, 2:04am UTC](https://discuss.elastic.co/t/how-to-use-elastic-ecs-winston-format-with-winston-elasticsearch/281418/2 "2021-09-11T02:04:36Z")

</div>

This topic was automatically closed 28 days after the last reply. New replies are no longer allowed.