fix(api): cap workflow credit deductions

api/core/app/llm/quota.py

@@ -122,14 +122,14 @@ def _deduct_used_llm_quota(*, tenant_id: str, provider: str, provider_configurat
             case ProviderQuotaType.TRIAL:
                 from services.credit_pool_service import CreditPoolService
 
-                CreditPoolService.check_and_deduct_credits(
+                CreditPoolService.deduct_credits_capped(
                     tenant_id=tenant_id,
                     credits_required=used_quota,
                 )
             case ProviderQuotaType.PAID:
                 from services.credit_pool_service import CreditPoolService
 
-                CreditPoolService.check_and_deduct_credits(
+                CreditPoolService.deduct_credits_capped(
                     tenant_id=tenant_id,
                     credits_required=used_quota,
                     pool_type="paid",

api/tests/unit_tests/core/app/test_llm_quota.py

@@ -16,6 +16,8 @@ from core.entities.provider_entities import ProviderQuotaType, QuotaUnit
 from core.errors.error import QuotaExceededError
 from graphon.model_runtime.entities.llm_entities import LLMUsage
 from graphon.model_runtime.entities.model_entities import ModelType
+from models import TenantCreditPool
+from models.enums import ProviderQuotaType as ModelProviderQuotaType
 from models.provider import Provider, ProviderType
 
 
@@ -97,7 +99,7 @@ def test_deduct_llm_quota_for_model_uses_identity_based_trial_billing() -> None:
 
     with (
         patch("core.app.llm.quota.create_plugin_provider_manager", return_value=provider_manager),
-        patch("services.credit_pool_service.CreditPoolService.check_and_deduct_credits") as mock_deduct_credits,
+        patch("services.credit_pool_service.CreditPoolService.deduct_credits_capped") as mock_deduct_credits,
     ):
         deduct_llm_quota_for_model(
             tenant_id="tenant-id",
@@ -112,6 +114,55 @@ def test_deduct_llm_quota_for_model_uses_identity_based_trial_billing() -> None:
     )
 
 
+def test_deduct_llm_quota_for_model_caps_trial_pool_when_usage_exceeds_remaining() -> None:
+    usage = LLMUsage.empty_usage()
+    usage.total_tokens = 3
+    provider_configuration = SimpleNamespace(
+        using_provider_type=ProviderType.SYSTEM,
+        system_configuration=SimpleNamespace(
+            current_quota_type=ProviderQuotaType.TRIAL,
+            quota_configurations=[
+                SimpleNamespace(
+                    quota_type=ProviderQuotaType.TRIAL,
+                    quota_unit=QuotaUnit.TOKENS,
+                    quota_limit=100,
+                )
+            ],
+        ),
+    )
+    provider_manager = MagicMock()
+    provider_manager.get_configurations.return_value.get.return_value = provider_configuration
+    engine = create_engine("sqlite:///:memory:")
+    TenantCreditPool.__table__.create(engine)
+    with engine.begin() as connection:
+        connection.execute(
+            TenantCreditPool.__table__.insert(),
+            {
+                "id": "trial-pool",
+                "tenant_id": "tenant-id",
+                "pool_type": ModelProviderQuotaType.TRIAL,
+                "quota_limit": 10,
+                "quota_used": 9,
+            },
+        )
+
+    with (
+        patch("core.app.llm.quota.create_plugin_provider_manager", return_value=provider_manager),
+        patch("services.credit_pool_service.db", SimpleNamespace(engine=engine)),
+    ):
+        deduct_llm_quota_for_model(
+            tenant_id="tenant-id",
+            provider="openai",
+            model="gpt-4o",
+            usage=usage,
+        )
+
+    with engine.connect() as connection:
+        quota_used = connection.scalar(select(TenantCreditPool.quota_used).where(TenantCreditPool.id == "trial-pool"))
+
+    assert quota_used == 10
+
+
 def test_deduct_llm_quota_for_model_returns_for_unbounded_quota() -> None:
     usage = LLMUsage.empty_usage()
     usage.total_tokens = 42
@@ -133,7 +184,7 @@ def test_deduct_llm_quota_for_model_returns_for_unbounded_quota() -> None:
 
     with (
         patch("core.app.llm.quota.create_plugin_provider_manager", return_value=provider_manager),
-        patch("services.credit_pool_service.CreditPoolService.check_and_deduct_credits") as mock_deduct_credits,
+        patch("services.credit_pool_service.CreditPoolService.deduct_credits_capped") as mock_deduct_credits,
     ):
         deduct_llm_quota_for_model(
             tenant_id="tenant-id",
@@ -166,7 +217,7 @@ def test_deduct_llm_quota_for_model_uses_credit_configuration() -> None:
     with (
         patch("core.app.llm.quota.create_plugin_provider_manager", return_value=provider_manager),
         patch.object(type(dify_config), "get_model_credits", return_value=9) as mock_get_model_credits,
-        patch("services.credit_pool_service.CreditPoolService.check_and_deduct_credits") as mock_deduct_credits,
+        patch("services.credit_pool_service.CreditPoolService.deduct_credits_capped") as mock_deduct_credits,
     ):
         deduct_llm_quota_for_model(
             tenant_id="tenant-id",
@@ -202,7 +253,7 @@ def test_deduct_llm_quota_for_model_uses_single_charge_for_times_quota() -> None
 
     with (
         patch("core.app.llm.quota.create_plugin_provider_manager", return_value=provider_manager),
-        patch("services.credit_pool_service.CreditPoolService.check_and_deduct_credits") as mock_deduct_credits,
+        patch("services.credit_pool_service.CreditPoolService.deduct_credits_capped") as mock_deduct_credits,
     ):
         deduct_llm_quota_for_model(
             tenant_id="tenant-id",
@@ -238,7 +289,7 @@ def test_deduct_llm_quota_for_model_uses_paid_billing_pool() -> None:
 
     with (
         patch("core.app.llm.quota.create_plugin_provider_manager", return_value=provider_manager),
-        patch("services.credit_pool_service.CreditPoolService.check_and_deduct_credits") as mock_deduct_credits,
+        patch("services.credit_pool_service.CreditPoolService.deduct_credits_capped") as mock_deduct_credits,
     ):
         deduct_llm_quota_for_model(
             tenant_id="tenant-id",
@@ -439,7 +490,7 @@ def test_deduct_llm_quota_for_model_ignores_unknown_quota_type() -> None:
 
     with (
         patch("core.app.llm.quota.create_plugin_provider_manager", return_value=provider_manager),
-        patch("services.credit_pool_service.CreditPoolService.check_and_deduct_credits") as mock_deduct_credits,
+        patch("services.credit_pool_service.CreditPoolService.deduct_credits_capped") as mock_deduct_credits,
         patch("core.app.llm.quota.sessionmaker") as mock_sessionmaker,
     ):
         deduct_llm_quota_for_model(
@@ -468,7 +519,7 @@ def test_deduct_llm_quota_for_model_ignores_custom_provider_configuration() -> N
 
     with (
         patch("core.app.llm.quota.create_plugin_provider_manager", return_value=provider_manager),
-        patch("services.credit_pool_service.CreditPoolService.check_and_deduct_credits") as mock_deduct_credits,
+        patch("services.credit_pool_service.CreditPoolService.deduct_credits_capped") as mock_deduct_credits,
         patch("core.app.llm.quota.sessionmaker") as mock_sessionmaker,
     ):
         deduct_llm_quota_for_model(