fix(edge): meter and size-cap knowledge embeddings in embed-chunks and search-knowledge

server/supabase/functions/_shared/openai-embeddings.ts

@@ -0,0 +1,61 @@
+// server/supabase/functions/_shared/openai-embeddings.ts
+// Embedding provider port + OpenAI adapter shared by embed-chunks and
+// search-knowledge. The functions depend on the `EmbeddingProvider` port only,
+// so the quota/size policy can be tested without the network.
+
+export const EMBEDDING_MODEL = 'text-embedding-3-small'
+export const EMBEDDING_DIMENSIONS = 1536
+export const EMBEDDING_PROVIDER_TIMEOUT_MS = 45_000
+const OPENAI_EMBEDDINGS_URL = 'https://api.openai.com/v1/embeddings'
+
+export interface EmbeddingItem {
+  embedding?: unknown
+  index?: unknown
+}
+
+export type EmbeddingOutcome =
+  | { ok: true; data: EmbeddingItem[] }
+  /** `upstream`: transport error or non-2xx status. `invalid`: 2xx with an unusable body. */
+  | { ok: false; reason: 'upstream' | 'invalid' }
+
+export interface EmbeddingProvider {
+  embed(input: string | readonly string[]): Promise<EmbeddingOutcome>
+}
+
+export function isEmbedding(value: unknown): value is number[] {
+  return Array.isArray(value)
+    && value.length === EMBEDDING_DIMENSIONS
+    && value.every((entry) => typeof entry === 'number' && Number.isFinite(entry))
+}
+
+export function createOpenAIEmbeddingProvider(
+  apiKey: string,
+  fetchImpl: typeof fetch = fetch,
+): EmbeddingProvider {
+  return {
+    async embed(input) {
+      let response: Response
+      try {
+        response = await fetchImpl(OPENAI_EMBEDDINGS_URL, {
+          method: 'POST',
+          headers: {
+            Authorization: `Bearer ${apiKey}`,
+            'Content-Type': 'application/json',
+          },
+          body: JSON.stringify({
+            model: EMBEDDING_MODEL,
+            input,
+            dimensions: EMBEDDING_DIMENSIONS,
+          }),
+          signal: AbortSignal.timeout(EMBEDDING_PROVIDER_TIMEOUT_MS),
+        })
+      } catch {
+        return { ok: false, reason: 'upstream' }
+      }
+      if (!response.ok) return { ok: false, reason: 'upstream' }
+      const payload = await response.json().catch(() => null) as { data?: unknown } | null
+      if (!payload || !Array.isArray(payload.data)) return { ok: false, reason: 'invalid' }
+      return { ok: true, data: payload.data as EmbeddingItem[] }
+    },
+  }
+}