feat(usage): rename metrics → tokens_embedded/pages_embedded + export token cost to Prometheus

Billing product model finalized (Deck #281): bill pages externally, record
tokens internally. Rename the data-plane metric literals to match the now-
canonical contract (Deck #284) — the control plane's METRIC_EVENT_NAMES is
already renamed, so the old names would be unmapped and never sync to Stripe.

Rename (values unchanged):
- embeddings_queries → tokens_embedded (value = real token count, already
  emitted by this PR; the unit upstream providers bill on).
- pages_chunks → pages_embedded (value kept as len(chunk_texts) interim;
  TODO(#282): real normalized "pages indexed" count — real pages for paginated
  types, chars/tokens-per-page constant otherwise — is deferred to the
  instrumentation card, this only lands the name/contract).
- All literals, log strings, docstrings, comments, the migration comment, and
  tests renamed; grep confirms zero old strings remain.

Observability (new): export embedding token cost to Prometheus as
astrolabe_embedding_tokens_total{provider,operation} (operation = index|query)
so the billed cost unit is visible in Grafana, not just the per-tenant billing
DB. Dedicated counter (doesn't inflate the existing chunk/request metrics) and
always-on (independent of USAGE_METERING_ENABLED, so OSS/self-host gets it).
Wired on both the indexing batch embed and the search query embed (query inside
the per-request cache-miss branch, so reused embeddings aren't double-counted).

Note: the rename orphans any pre-existing embeddings_queries/pages_chunks rows
in tenant app DBs (CP no longer maps them) — acceptable; pipeline is inert with
throwaway dev/sandbox data.

Deck #284 (folded into PR #875).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

This commit is contained in:

Chris Coutinho

2026-06-08 13:17:53 +02:00

co-authored by

Claude Opus 4.8

parent ddefb03701

commit 973f80e7b9

15 changed files with 129 additions and 45 deletions

									
										nextcloud_mcp_server/usage/store.py
									
		+2
		-2
	
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				@@ -102,8 +102,8 @@ class UsageEventStore:

				        logged and swallowed — this must never break the caller's operation.

				        Args:

				            metric: Catalog metric, e.g. ``"embeddings_queries"`` or

				                ``"pages_chunks"``.

				            metric: Catalog metric, e.g. ``"tokens_embedded"`` or

				                ``"pages_embedded"``.

				            value: Count/quantity for this event.

				            occurred_at: Operation completion time; defaults to now (UTC).

				            metadata: Optional rawest-unit context (provider, model, tokens,