[exporter/prometheus_remote_write] Add exporter ID to WAL telemetry attributes

[charanck9]

Description

When running multiple prometheusremotewrite exporter instances (e.g.,
prometheusremotewrite/ext and prometheusremotewrite/internal), the WAL telemetry
metrics (like wal_lag) have no exporter label, making it impossible to tell which
instance they belong to. The exporter-level metrics correctly include this label,
but the WAL metrics initialize otelAttrs as an empty slice.

For example, otelcol_exporter_prometheusremotewrite_wal_lag currently has no
component identifier:
otelcol_exporter_prometheusremotewrite_wal_lag{instance="ip:port", job="https",
namespace="test", pod_name="collector-6b97f867d4-dhds4", service_name="collector"}

This change sets the "exporter" attribute (the component ID) on the WAL telemetry
so the metrics can be distinguished per exporter instance.

Link to tracking issue

#49130
Fixes

Testing

Documentation

Authorship

• [✓ ] I, a human, wrote this pull request description myself.

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Pull request dashboard status

Merged · refreshed 2026-08-05 23:12 UTC

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[dashpole]

We would ideally use otelcol.component.id, but the rest of the prw exporter self-obs metrics already use exporter. We can make that switch at a future point for the whole exporter.

[charanck9]

comments are addressed

[ArthurSens]

LGTM, thanks!

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