maple-telemetry-conventions

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Maple's OpenTelemetry conventions — custom span attribute keys (`maple.*` vendor namespace, `query.context`, `db.query.*`, `result.*`, `cache.*`, `tenant.*`), Title Case status codes (`Ok`/`Error`/`Unset`), resource attribute dual-emit (`deployment.environment` + `deployment.environment.name`), span kinds, Tinybird MV pre-extracted columns, loop-prevention filters, and sampling. Use whenever writing or reviewing instrumentation code in any language (TypeScript, Rust, Python) in this repo — adding `setAttribute`/`setAttributes`/`record`/`#[instrument(fields(...))]` calls, setting span status, configuring an OTLP exporter, defining a new resource attribute, or wiring a new query through `WarehouseQueryService.sqlQuery()`.

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Maple Telemetry Conventions

Reference for the language-agnostic OpenTelemetry conventions Maple uses across TypeScript (apps/api, Cloudflare workers in lib/effect-sdk/), Rust (apps/ingest), and future Python services. These conventions are load-bearing — Tinybird materialized views pre-extract certain attribute keys into columns, dashboards filter on Title Case status strings, and sampling-aware throughput math relies on the SampleRate column. Use the exact attribute spellings here in every language.

When to apply

Adding setAttribute / Effect.annotateCurrentSpan / Span::current().record(...) / #[instrument(fields(...))] to any code path
Setting span status (Ok / Error / Unset)
Wiring a new query through WarehouseQueryService.sqlQuery() (the context and profile options become span attributes)
Configuring an OTLP exporter, tracer provider, or resource builder
Introducing a new pre-extracted MV column or a new vendor attribute under maple.*
Reviewing a PR that touches apps/api/src/services/WarehouseQueryService.ts, apps/ingest/src/main.rs, apps/api/src/app.ts, lib/effect-sdk/src/cloudflare/, or packages/domain/src/tinybird/materializations.ts

Index

rules/span-attributes.md — Master reference of every custom attribute key Maple emits, grouped by namespace, with file:line citations.
rules/status-and-kind.md — Title Case status code rule (Ok/Error/Unset) and span kind conventions (Server / Client / Internal).
rules/resource-attributes.md — service.* identity, deployment.environment.name resolution order, the legacy deployment.environment dual-emit, and maple_org_id.
rules/language-bindings.md — Parallel TypeScript / Rust / Python snippets that emit the same attribute keys.
rules/mv-first-class-columns.md — Which span and resource attributes Tinybird MVs pre-extract into columns (and the rule for adding new ones).
rules/service-map-attribution.md — Required span and resource attributes for the service map to render edges, runtime icons, and platform badges. Includes the canonical peer.service registry.
rules/loop-prevention.md — The three guards that prevent Maple's self-traffic from creating a feedback loop: API TracerDisabledWhen, ingest loopback guard, sampling.

Quick reference

Topic	Rule
Status codes	Always Title Case: `"Ok"`, `"Error"`, `"Unset"`. Never `OK`, `ERROR`, `SUCCESS`, `FAILED`.
Vendor namespace	Custom attributes go under `maple.`. Sub-namespaces: `maple.ingest.`, `maple.cloudflare.*`.
Standard semconv	Use OTel semconv keys verbatim: `service.name`, `http.request.method`, `db.system.name`, `error.type`.
Org identity	`orgId` (camelCase) in TypeScript spans, `maple.org_id` (dotted) in Rust spans. Don't unify until MVs migrate.
Deployment env	Dual-emit `deployment.environment` + `deployment.environment.name`. Keep both until MV `coalesce()` migration lands.
Warehouse SQL spans	Every span from `WarehouseQueryService.executeSql` carries `db.system.name`, `peer.service`, `db.query.text`, `db.query.fingerprint`, `db.duration_ms`, `result.rowCount`, `orgId`, `query.context`, `query.profile`. Legacy spans (pre 2026-06) use `db.statement*`/`db.system`; warehouse readers coalesce both.
Service map	Outbound spans need `peer.service` (HTTP/RPC) or `db.system.name` (DB) on a `Client`/`Producer` span. Resource attrs need `process.runtime.name`, `cloud.platform`, `maple.sdk.type` for runtime icon + platform badge. See `rules/service-map-attribution.md`.
Loop prevention	Never remove `HttpMiddleware.TracerDisabledWhen` (apps/api/src/app.ts:169-175) or the ingest loopback guard (apps/ingest/src/main.rs:499-514).

Canonical references (do not modify from this skill)

apps/api/src/services/WarehouseQueryService.ts:441-510 — executeSql span emission (the canonical example for TS).
apps/ingest/src/otel.rs — Resource builder + platform detection + forward-span helper for Rust. The canonical example for Rust resource and outbound-span attribution.
apps/ingest/src/main.rs — handle_signal and handle_cloudflare_logpush (search for tracing::info_span! with otel.kind = "server") — Server-kind span macros for OTLP inbound.
apps/api/src/app.ts:169-175 — TracerDisabledWhen filter.
lib/effect-sdk/src/cloudflare/index.ts — MapleCloudflareSDK tracer setup.
packages/domain/src/tinybird/materializations.ts — MV SELECT lists that pre-extract attribute keys into columns.