feat: add Ollama embedder with batching and retries

src/companion/rag/embedder.py

@@ -0,0 +1,44 @@
+import time
+from typing import List
+
+import httpx
+
+
+class OllamaEmbedder:
+    def __init__(self, base_url: str, model: str, batch_size: int):
+        self.base_url = base_url.rstrip("/")
+        self.model = model
+        self.batch_size = batch_size
+
+    def embed(
+        self, texts: List[str], retries: int = 3, backoff: float = 1.0
+    ) -> List[List[float]]:
+        all_embeddings: List[List[float]] = []
+        url = f"{self.base_url}/api/embed"
+
+        for i in range(0, len(texts), self.batch_size):
+            batch = texts[i : i + self.batch_size]
+            last_exception: Exception | None = None
+
+            for attempt in range(retries):
+                try:
+                    with httpx.Client(timeout=300.0) as client:
+                        response = client.post(
+                            url,
+                            json={"model": self.model, "input": batch},
+                        )
+                        response.raise_for_status()
+                        data = response.json()
+                        embeddings = data["embeddings"]
+                        all_embeddings.extend(embeddings)
+                        break
+                except Exception as exc:
+                    last_exception = exc
+                    if attempt < retries - 1:
+                        time.sleep(backoff * (2**attempt))
+            else:
+                raise RuntimeError(
+                    f"Failed to embed batch after {retries} retries"
+                ) from last_exception
+
+        return all_embeddings

tests/test_embedder.py

@@ -0,0 +1,21 @@
+import pytest
+import respx
+from httpx import Response
+
+from companion.rag.embedder import OllamaEmbedder
+
+
+@respx.mock
+def test_embed_batch():
+    route = respx.post("http://localhost:11434/api/embed").mock(
+        return_value=Response(200, json={"embeddings": [[0.1] * 1024, [0.2] * 1024]})
+    )
+    embedder = OllamaEmbedder(
+        base_url="http://localhost:11434", model="mxbai-embed-large", batch_size=2
+    )
+    result = embedder.embed(["hello world", "goodbye world"])
+    assert len(result) == 2
+    assert len(result[0]) == 1024
+    assert result[0][0] == 0.1
+    assert result[1][0] == 0.2
+    assert route.called