feat(dify-builder): log build_nodes empty/failed generation and starved resource sources

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

api/services/dify_builder/agent/build.py

@@ -5,6 +5,7 @@ Each degrades to an honest result on model-None / provider-error / parse-fail
 rather than crashing the advance. build_nodes lives in the same module
 (added in Task A6)."""
 
+import logging
 from typing import Any
 
 from core.app.app_config.entities import ModelConfig
@@ -16,6 +17,8 @@ from services.dify_builder.agent import graph_translate, llm, resources
 from services.dify_builder.agent.model_resolver import resolve_model_instance
 from services.workflow_generator_service import WorkflowGeneratorService
 
+logger = logging.getLogger(__name__)
+
 
 def analyze_goal(model, goal_text: str) -> dict[str, Any]:
     if model is None:
@@ -152,12 +155,23 @@ def build_nodes(tenant_id: str, model_config: dict[str, Any], plan_items: list[s
         )
         graph = result.get("graph") or {}
         if result.get("error") or not graph.get("nodes"):
+            logger.warning(
+                "Dify Builder: build_nodes produced no graph for tenant %s (%d plan items): error=%s",
+                tenant_id,
+                len(plan_items),
+                result.get("error"),
+            )
             return []
         intents = graph_translate.to_intents(graph)
         _ground(intents, mc, tenant_id, plan_items)
         applicable, _rejected = graph_ops.filter_applicable({"nodes": [], "edges": []}, intents, _ALLOWED_NODE_TYPES)
         return applicable
     except Exception:  # any generation/translation failure -> honest empty build
+        logger.exception(
+            "Dify Builder: build_nodes generation failed for tenant %s (%d plan items); returning empty build",
+            tenant_id,
+            len(plan_items),
+        )
         return []
 
 

api/services/dify_builder/agent/resources.py

@@ -5,6 +5,7 @@ models, datasets, and tools normalized to id+label. Each source degrades to
 an empty list on failure so a missing provider never breaks the advance.
 """
 
+import logging
 from dataclasses import dataclass
 from typing import Any
 
@@ -16,6 +17,8 @@ from extensions.ext_database import db
 from models.dataset import Dataset
 from services.model_provider_service import ModelProviderService
 
+logger = logging.getLogger(__name__)
+
 
 @dataclass(frozen=True)
 class ResourceRef:
@@ -45,10 +48,15 @@ def _list_tools(tenant_id: str) -> list[dict]:
     return list(build_tool_catalogue(tenant_id))
 
 
-def _safe(build) -> list:
+def _safe(build, source: str) -> list:
     try:
         return build()
     except Exception:  # a missing/mis-configured source degrades to empty, never raises
+        logger.warning(
+            "Dify Builder: resource source %r failed for the current tenant; treating as empty",
+            source,
+            exc_info=True,
+        )
         return []
 
 
@@ -72,7 +80,7 @@ def list_tenant_resources(tenant_id: str) -> TenantResources:
             for t in _list_tools(tenant_id)
         ]
 
-    models = _safe(build_models)
-    datasets = _safe(build_datasets)
-    tools = _safe(build_tools)
+    models = _safe(build_models, "models")
+    datasets = _safe(build_datasets, "datasets")
+    tools = _safe(build_tools, "tools")
     return TenantResources(models=models, datasets=datasets, tools=tools)

api/tests/unit_tests/services/dify_builder/test_build_nodes.py

@@ -1,3 +1,4 @@
+import logging
 from unittest.mock import patch
 
 from services.dify_builder.agent import build, resources
@@ -166,3 +167,35 @@ def test_build_nodes_dataset_ids_are_independent_lists_per_node():
     assert kb_configs[0]["dataset_ids"] == ["kb-real"]
     assert kb_configs[1]["dataset_ids"] == ["kb-real"]
     assert kb_configs[0]["dataset_ids"] is not kb_configs[1]["dataset_ids"]
+
+
+def test_build_nodes_logs_when_generator_reports_error(caplog):
+    with patch.object(build, "_generator_model_config", return_value=_fake_mc("anthropic", "x")), \
+         patch(
+             "services.dify_builder.agent.build.WorkflowGeneratorService.generate_workflow_graph",
+             return_value={"graph": {}, "error": "generator boom", "errors": []},
+         ), \
+         caplog.at_level(logging.WARNING, logger="services.dify_builder.agent.build"):
+        out = build.build_nodes("t1", {}, ["do a thing"])
+
+    assert out == []
+    warnings = [r for r in caplog.records if r.levelno == logging.WARNING]
+    assert len(warnings) == 1
+    assert "no graph" in warnings[0].getMessage()
+    assert "generator boom" in warnings[0].getMessage()
+
+
+def test_build_nodes_logs_traceback_when_generation_raises(caplog):
+    with patch.object(build, "_generator_model_config", return_value=_fake_mc("anthropic", "x")), \
+         patch(
+             "services.dify_builder.agent.build.WorkflowGeneratorService.generate_workflow_graph",
+             side_effect=RuntimeError("kaboom"),
+         ), \
+         caplog.at_level(logging.ERROR, logger="services.dify_builder.agent.build"):
+        out = build.build_nodes("t1", {}, ["do a thing"])
+
+    assert out == []
+    errors = [r for r in caplog.records if r.levelno == logging.ERROR]
+    assert len(errors) == 1
+    assert "generation failed" in errors[0].getMessage()
+    assert errors[0].exc_info is not None

api/tests/unit_tests/services/dify_builder/test_resources.py

@@ -1,3 +1,4 @@
+import logging
 from unittest.mock import patch
 
 
@@ -71,3 +72,28 @@ def test_malformed_tool_record_degrades():
     assert out.tools == []
     assert out.models == []
     assert out.datasets == []
+
+
+def test_list_tenant_resources_logs_when_a_source_fails(caplog):
+    from services.dify_builder.agent import resources
+
+    class _Model:
+        def __init__(self, m):
+            self.model = m
+
+    class _ProvResp:
+        def __init__(self, p, ms):
+            self.provider, self.models = p, [_Model(m) for m in ms]
+
+    with patch.object(resources, "_list_models", return_value=[_ProvResp("anthropic", ["claude-opus-4-8"])]), \
+         patch.object(resources, "_list_datasets", side_effect=RuntimeError("db down")), \
+         patch.object(resources, "_list_tools", return_value=[]), \
+         caplog.at_level(logging.WARNING, logger="services.dify_builder.agent.resources"):
+        out = resources.list_tenant_resources("t1")
+
+    assert out.datasets == []
+    assert out.models[0].id == "anthropic/claude-opus-4-8"
+    warnings = [r for r in caplog.records if r.levelno == logging.WARNING]
+    assert len(warnings) == 1
+    assert "datasets" in warnings[0].getMessage()
+    assert warnings[0].exc_info is not None