How to add attributes using the otel logger

[thibaultleouay]

Hey,

How can I add attributes when using the Otel logger? If I send them in the body, the attributes are processed twice.

[dahlia]

Hi @thibaultleouay! Thanks for bringing this up.

To help diagnose this issue, could you please share:

1. How are you calling the logger? For example:

   logger.info("message", { method: "GET", outcome: "success" });
   // or
   logger.info("message", { attributes: { method: "GET", outcome: "success" } });

2. Your LogTape configuration, particularly how you're setting up the OpenTelemetry sink?

3. Are you using any middleware or wrapper around the logger that might be modifying the properties?

Looking at the code, I can see that @logtape/otel automatically prefixes all properties with attributes. when converting to OpenTelemetry format (see convertToAttributes() function).

My initial hypothesis is that you might be passing properties nested under an attributes key, which would explain the double nesting. But I'd like to confirm this before suggesting a solution.

Also, this raises a broader question about whether the attributes. prefix is necessary at all for OpenTelemetry compatibility. I'll investigate the OTel spec to see if we can improve this behavior.

[thibaultleouay]

@dahlia this is how I'm trying to send attributes :

https://github.com/openstatusHQ/openstatus/pull/1718/changes#diff-7e19881e3e9f2c1c8acbd5e96f18d2e373ddb9edd544fb4ee29c89800123b4b7R137

[thibaultleouay]

And when trying to send the request with otelLogger.info("Request completed", { ...event });

This is the raw json i have

{
  "attributes": {
    "attributes": {
      "duration_ms": "0",
      "method": "GET",
      "outcome": "success",
      "requestId": "ad17e202-d452-40e3-953a-9e322c58f61e",
      "status_code": "404",
      "timestamp": "2026-01-07T08:33:57.150Z",
      "url": "http://localhost:3000/favicon.ico",
      "userAgent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:146.0) Gecko/20100101 Firefox/146.0"
    },
    "category": [
      "api-server-otel"
    ]
  },
  "resource": {
    "deployment": {
      "environment": "production"
    }
  },
  "telemetry": {
    "sdk": {
      "language": "nodejs",
      "name": "opentelemetry",
      "version": "2.2.0"
    }
  },
  "scope": {
    "name": "@logtape/otel",
    "version": "1.3.5"
  },
  "service": {
    "name": "openstatus-server"
  },
  "body": "Request completed",
  "observed_time": "2026-01-07T08:33:57.15Z",
  "severity": "info",
  "severity_number": 9,
  "severity_text": "info"
}

[dahlia]

Thanks for reporting this! I've investigated the issue and found the root cause.

The @logtape/otel package is adding an attributes. prefix to all property keys when converting to OpenTelemetry format. So when you call:

otelLogger.info({ method: "GET", outcome: "success", ... });

It gets sent to OpenTelemetry as:

{
  "attributes": {
    "attributes.method": "GET",
    "attributes.outcome": "success"
  }
}

Then Axiom displays the field path, which results in attributes.attributes.method.

I've created issue #130 to track fixing this. The solution is to remove the unnecessary attributes. prefix, which will be a breaking change but aligns with standard OpenTelemetry conventions.

[dahlia]

Fixed in a3cb852. The attributes. prefix has been removed from the OpenTelemetry sink, so properties are now sent as flat attributes (e.g., method, outcome) instead of attributes.method, attributes.outcome.

This will be included in the next release (1.4.0). If you want to try it now, you can use the pre-release version 1.4.0-dev.465.

Note that this is a breaking change, so if you have any queries or dashboards that rely on the old attributes.* key names, you'll need to update them.

[thibaultleouay]

Thanks for the quick fix !