langgenius/dify · critical · InternalServerError

Internal Server Error

Error message

Internal Server Error

What it means

Returned (HTTP 500, generic) by POST .../draft/iteration/nodes/<node_id>/run when any exception other than ConversationNotExistsError, ConversationCompletedError, or ValueError escapes `PipelineGenerateService.generate_single_iteration`. The controller logs the traceback (`logging.exception`) and re-raises as werkzeug InternalServerError — the original cause is not surfaced to the client.

Source

Thrown at api/controllers/console/datasets/rag_pipeline/rag_pipeline_workflow.py:299

        Run draft workflow iteration node
        """
        args = req_data.model_dump(exclude_none=True)

        try:
            response = PipelineGenerateService.generate_single_iteration(
                pipeline=pipeline, user=current_user, node_id=node_id, args=args, session=db.session(), streaming=True
            )

            return helper.compact_generate_response(response)
        except services.errors.conversation.ConversationNotExistsError:
            raise NotFound("Conversation Not Exists.")
        except services.errors.conversation.ConversationCompletedError:
            raise ConversationCompletedError()
        except ValueError as e:
            raise e
        except Exception:
            logging.exception("internal server error.")
            raise InternalServerError()


@console_ns.route("/rag/pipelines/<uuid:pipeline_id>/workflows/draft/loop/nodes/<string:node_id>/run")
class RagPipelineDraftRunLoopNodeApi(Resource):
    @console_ns.expect(console_ns.models[NodeRunPayload.__name__])
    @console_ns.response(200, "Success", console_ns.models[RagPipelineOpaqueResponse.__name__])
    @setup_required
    @login_required
    @account_initialization_required
    @edit_permission_required
    @rbac_permission_required(RBACResourceScope.DATASET, RBACPermission.DATASET_EDIT)
    @with_current_user
    @get_rag_pipeline
    @model_validate(NodeRunPayload)
    def post(self, req_data: NodeRunPayload, current_user: Account, pipeline: Pipeline, node_id: str):
        """
        Run draft workflow loop node
        """

View on GitHub (pinned to ef8544b173)

Solutions

1. Inspect the Dify backend logs for the `internal server error.` traceback to find the root cause.
2. Reproduce with the same node_id and inputs after addressing the logged exception.
3. If the cause is a provider error, validate credentials and rate limits on the LLM model provider.
4. File a bug with the traceback, node_id, and inputs (redacted) if no actionable cause appears.

Example fix

// not a client-side fix; server logs are required
// 1) grep backend logs: `logging.exception("internal server error.")`
// 2) read the traceback, fix the underlying node/service
// 3) retry the iteration run

// cannot fully prevent — server-side bug. Add precondition checks to reduce incidence:
if (!nodeId) throw new Error('nodeId required')
if (!pipelineId) throw new Error('pipelineId required')
// then call; if 500, surface the server-side traceback to ops

try {
  await post(`${base}/draft/iteration/nodes/${nodeId}/run`, payload)
} catch (e) {
  if (e.status === 500) {
    // surface 'internal error, please contact support'; do NOT blind-retry
    // correlate with backend log line `internal server error.`
  } else throw e
}

When it happens

Trigger: Database connectivity loss mid-run, serialization failures, unhandled KeyError in a node implementation, plugin/model-runtime crashes, infrastructure errors (redis, storage), or bugs in the iteration node's execution path.

Common situations: Misconfigured LLM provider credentials. Node plugin throws an unexpected exception. Transient infra outages. Schema drift between graph and node runtime.

Understand the failure class

• HTTP status errors: handling 4xx and 5xx responses — how to handle 4xx and 5xx responses properly.

Related errors

• Conversation Not Exists.
• conversation_completed
• expected dict for file, got {type(raw_value)}
• expected list for files, got {type(raw_value)}
• expected dict for files[0], got {type(raw_value)}

AI-assisted analysis of langgenius/dify@ef8544b173 (2026-08-12). Data as JSON: /api/errors/dfd4216116f9470e. Report an issue: GitHub.