Milestone 4 (Part 1): Implementing OTLP HTTP Core in Heka Insights Agent (M4-1, M4-2)

Heka Insights Agent already had a canonical metrics pipeline from Milestone 3.

In this part of Milestone 4, I implemented the OTLP HTTP core in two focused steps:

M4-1 : Canonical metrics -> OTLP payload mapping layer

M4-2 : OTLP HTTP request sender and exporter wiring

This post covers only these two items. Auth headers, resource attributes, retry/compression controls are intentionally deferred to later M4 tasks.

Why This Split Matters

By separating mapping from transport, we get:

stable internal metric model

explicit OTLP payload construction

transport logic that can evolve independently

clean foundation for New Relic/Datadog-style OTLP integrations later

What Was Implemented

M4-1: OTLP Payload Mapping Layer

I added a dedicated mapper that converts canonical metric records into OTLP HTTP JSON payloads.

Core behavior:

validates required canonical fields before send

supports explicit type mapping:

gauge ->…