Gracefully handle httpx.ConnectError from Client and AsyncClient

fixes ollama#304

ollama/_client.py

@@ -115,11 +115,13 @@ def __init__(self, host: Optional[str] = None, **kwargs) -> None:
     super().__init__(httpx.Client, host, **kwargs)
 
   def _request_raw(self, *args, **kwargs):
-    r = self._client.request(*args, **kwargs)
     try:
+      r = self._client.request(*args, **kwargs)
       r.raise_for_status()
     except httpx.HTTPStatusError as e:
       raise ResponseError(e.response.text, e.response.status_code) from None
+    except httpx.ConnectError:
+      raise ResponseError("error connecting to ollama server: have you checked that it's running?", 500)
     return r
 
   @overload
@@ -617,11 +619,13 @@ def __init__(self, host: Optional[str] = None, **kwargs) -> None:
     super().__init__(httpx.AsyncClient, host, **kwargs)
 
   async def _request_raw(self, *args, **kwargs):
-    r = await self._client.request(*args, **kwargs)
     try:
+      r = await self._client.request(*args, **kwargs)
       r.raise_for_status()
     except httpx.HTTPStatusError as e:
       raise ResponseError(e.response.text, e.response.status_code) from None
+    except httpx.ConnectError:
+      raise ResponseError("error connecting to ollama server: have you checked that it's running?", 500)
     return r
 
   @overload

tests/test_client.py

@@ -1,6 +1,8 @@
 import os
 import io
 import json
+
+import httpx
 from pydantic import ValidationError, BaseModel
 import pytest
 import tempfile
@@ -10,6 +12,7 @@
 from PIL import Image
 
 from ollama._client import Client, AsyncClient, _copy_tools
+from ollama._types import ResponseError
 
 
 class PrefixPattern(URIPattern):
@@ -182,6 +185,29 @@ class ResponseFormat(BaseModel):
   assert response['message']['content'] == '{"answer": "Because of Rayleigh scattering", "confidence": 0.95}'
 
 
+def test_client_gracefully_handles_ollama_server_not_running(httpserver: HTTPServer):
+  httpserver.expect_ordered_request(
+    '/api/chat',
+    method='POST',
+    json={
+      'model': 'dummy',
+      'messages': [{'role': 'user', 'content': 'Why is the sky blue?'}],
+      'tools': [],
+      'format': 'json',
+      'stream': False,
+    },
+  ).respond_with_handler(lambda _: Response())
+
+  def _monkey_patched_request_func(*args, **kwargs):
+    raise httpx.ConnectError("[Errno 111] Connection refused")
+
+  client = Client(httpserver.url_for('/'))
+  client._client.request = _monkey_patched_request_func
+
+  with pytest.raises(ResponseError):
+    client.chat('dummy', messages=[{'role': 'user', 'content': 'Why is the sky blue?'}], format='json')
+
+
 @pytest.mark.asyncio
 async def test_async_client_chat_format_json(httpserver: HTTPServer):
   httpserver.expect_ordered_request(
@@ -244,6 +270,30 @@ class ResponseFormat(BaseModel):
   assert response['message']['content'] == '{"answer": "Because of Rayleigh scattering", "confidence": 0.95}'
 
 
+@pytest.mark.asyncio
+async def test_async_client_chat_format_json(httpserver: HTTPServer):
+  httpserver.expect_ordered_request(
+    '/api/chat',
+    method='POST',
+    json={
+      'model': 'dummy',
+      'messages': [{'role': 'user', 'content': 'Why is the sky blue?'}],
+      'tools': [],
+      'format': 'json',
+      'stream': False,
+    },
+  ).respond_with_handler(lambda _: Response())
+
+  async def _monkey_patched_request_func(*args, **kwargs):
+    raise httpx.ConnectError("[Errno 111] Connection refused")
+
+  client = AsyncClient(httpserver.url_for('/'))
+  client._client.request = _monkey_patched_request_func
+
+  with pytest.raises(ResponseError):
+    await client.chat('dummy', messages=[{'role': 'user', 'content': 'Why is the sky blue?'}], format='json')
+
+
 def test_client_generate(httpserver: HTTPServer):
   httpserver.expect_ordered_request(
     '/api/generate',