Configure multiple telemetry sinks - Fused

Create one @lifecycle.telemetry_exporter factory for each destination:

extensions/telemetry.py

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:

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.