fix(nc_texttotext): retries and graceful error handling for schedule (#179)

fix: richer error message for embedding server start fail

---------

Signed-off-by: Anupam Kumar <kyteinsky@gmail.com>

Author: kyteinsky

context_chat_backend/dyn_loader.py

@@ -71,6 +71,7 @@ def load(self):
 			)
 			pid.value = proc.pid
 
+		last_resp, last_exc = None, None
 		# poll for heartbeat
 		try_ = 0
 		while try_ < 20:
@@ -84,12 +85,17 @@ def load(self):
 					)
 					if response.status_code == 200:
 						return
-				except Exception:
+					last_resp = response
+				except Exception as e:
+					last_exc = e
 					logger.debug(f'Try {try_} failed in exception')
 				try_ += 1
 				sleep(3)
 
-		raise EmbeddingException('Error: the embedding server is not responding')
+		raise EmbeddingException(
+			'Error: the embedding server is not responding or could not be started. '
+			+ (f'\nLast error: {last_resp.status_code} {last_resp.text}' if last_resp else '')
+		) from last_exc
 
 	def offload(self):
 		global pid

context_chat_backend/models/nc_texttotext.py

@@ -69,11 +69,34 @@ def _call(
 		else:
 			logger.warning('No user ID provided for Nextcloud TextToText provider')
 
-		response = nc.ocs(
-			'POST',
-			'/ocs/v1.php/taskprocessing/schedule',
-			json={'type': 'core:text2text', 'appId': 'context_chat_backend', 'input': {'input': prompt}},
-		)
+		sched_tries = 3
+		while True:
+			try:
+				sched_tries -= 1
+				if sched_tries <= 0:
+					raise LlmException('Failed to schedule Nextcloud TaskProcessing task, tried 3 times')
+
+				response = nc.ocs(
+					'POST',
+					'/ocs/v1.php/taskprocessing/schedule',
+					json={'type': 'core:text2text', 'appId': 'context_chat_backend', 'input': {'input': prompt}},
+				)
+				break
+			except NextcloudException as e:
+				if e.status_code == httpx.codes.PRECONDITION_FAILED:
+					raise LlmException(
+						'Failed to schedule Nextcloud TaskProcessing task: '
+						'This app is setup to use a text generation provider in Nextcloud. '
+						'No such provider is installed on Nextcloud instance. '
+						'Please install integration_openai, llm2 or any other text2text provider.'
+					) from e
+
+				if e.status_code == httpx.codes.TOO_MANY_REQUESTS:
+					logger.warning('Rate limited during task scheduling, waiting 10s before retrying')
+					time.sleep(10)
+					continue
+
+				raise LlmException('Failed to schedule Nextcloud TaskProcessing task') from e
 
 		try:
 			task = Response.model_validate(response).task
@@ -103,8 +126,8 @@ def _call(
 					i += 1
 					continue
 				except NextcloudException as e:
-					if e.status_code == 429:
-						logger.warning('Rate limited during task polling, waiting 10s more')
+					if e.status_code == httpx.codes.TOO_MANY_REQUESTS:
+						logger.warning('Rate limited during task polling, waiting 10s before retrying')
 						time.sleep(10)
 						i += 2
 						continue