> ## Documentation Index
> Fetch the complete documentation index at: https://docs.usefused.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Configure multiple telemetry sinks

> Fan out Harnest traces and logs to multiple OTLP destinations.

Create one `@lifecycle.telemetry_exporter` factory for each destination:

```python extensions/telemetry.py theme={null}
import os

from harnest import TelemetryExporter, lifecycle
from opentelemetry.exporter.otlp.proto.http._log_exporter import OTLPLogExporter
from opentelemetry.exporter.otlp.proto.http.trace_exporter import OTLPSpanExporter


@lifecycle.telemetry_exporter(order=10)
def primary_observability():
    """Send traces and logs to the primary backend."""

    headers = {"Authorization": f"Bearer {os.environ['PRIMARY_OTLP_TOKEN']}"}
    return TelemetryExporter(
        name="primary-observability",
        traces=OTLPSpanExporter(
            endpoint=os.environ["PRIMARY_OTLP_TRACES_ENDPOINT"],
            headers=headers,
        ),
        logs=OTLPLogExporter(
            endpoint=os.environ["PRIMARY_OTLP_LOGS_ENDPOINT"],
            headers=headers,
        ),
    )


@lifecycle.telemetry_exporter(order=20)
def compliance_logs():
    """Send logs to the compliance backend."""

    return TelemetryExporter(
        name="compliance-logs",
        logs=OTLPLogExporter(
            endpoint=os.environ["COMPLIANCE_OTLP_LOGS_ENDPOINT"],
            headers={
                "Authorization": f"Bearer {os.environ['COMPLIANCE_OTLP_TOKEN']}"
            },
        ),
    )
```

Configure complete OTLP/HTTP signal URLs:

```bash theme={null}
export PRIMARY_OTLP_TRACES_ENDPOINT=https://primary.example.com/v1/traces
export PRIMARY_OTLP_LOGS_ENDPOINT=https://primary.example.com/v1/logs
export PRIMARY_OTLP_TOKEN=primary-secret
export COMPLIANCE_OTLP_LOGS_ENDPOINT=https://compliance.example.com/v1/logs
export COMPLIANCE_OTLP_TOKEN=compliance-secret
harnest serve support-agent
```

## Factory contract

| Requirement                        | Behavior                                        |
| ---------------------------------- | ----------------------------------------------- |
| Unique `TelemetryExporter.name`    | Duplicate names stop runtime startup            |
| Synchronous, zero-argument factory | Runs once during runtime bootstrap              |
| `traces`, `logs`, or both          | Metrics exporters are not supported             |
| `order=`                           | Resolves factories in ascending lifecycle order |
| Startup failure                    | Already-created exporters are shut down         |

Harnest batches each configured signal, flushes one-shot runs, and shuts exporters down with the server.

OTLP/HTTP exporters are included. Add the exporter package to `pyproject.toml` when using another backend-specific exporter type.

## Combine environment and authored sinks

The standard environment sink is additive. If `OTEL_EXPORTER_OTLP_ENDPOINT` is set alongside these factories, it receives signals too.

`HARNEST_OTEL_ENABLED=false` disables only the environment sink. Authored factories remain active.

Use an OpenTelemetry Collector instead when routing and fan-out should be managed outside the agent process.