improve catalog client exception handling

.gitignore

@@ -120,6 +120,7 @@ celerybeat.pid
 *.sage.py
 
 # Environments
+*.env
 .env
 .venv
 env/

dbt-adapters/src/dbt/adapters/clients/catalogs.py

@@ -1,27 +1,31 @@
 from dbt.adapters.protocol import CatalogIntegrationProtocol
+from dbt.adapters.exceptions import DbtCatalogIntegrationAlreadyExistsError
 
+from typing import Optional
 
 class CatalogIntegrations:
     def __init__(self):
         self._integrations = {}
 
-    def get(self, name: str) -> CatalogIntegrationProtocol:
-        return self.integrations[name]
+    def get(self, name: str) -> Optional[CatalogIntegrationProtocol]:
+        if name in self._integrations:
+            return self._integrations[name]
+        return None
 
     @property
     def integrations(self) -> dict[str, CatalogIntegrationProtocol]:
         return self._integrations
 
     def add_integration(self, integration: CatalogIntegrationProtocol, catalog_name: str):
+        if catalog_name in self._integrations:
+            raise DbtCatalogIntegrationAlreadyExistsError(catalog_name)
         self._integrations[catalog_name] = integration
 
-
 _CATALOG_CLIENT = CatalogIntegrations()
 
 
-def get_catalog(integration_name: str) -> CatalogIntegrationProtocol:
+def get_catalog(integration_name: str) -> Optional[CatalogIntegrationProtocol]:
     return _CATALOG_CLIENT.get(integration_name)
 
-
 def add_catalog(integration: CatalogIntegrationProtocol, catalog_name: str):
     _CATALOG_CLIENT.add_integration(integration, catalog_name)

dbt-adapters/src/dbt/adapters/exceptions/__init__.py

@@ -38,3 +38,6 @@
     IndexConfigNotDictError,
     UnexpectedDbReferenceError,
 )
+from dbt.adapters.exceptions.catalog_integration import (
+    DbtCatalogIntegrationAlreadyExistsError,
+)

dbt-adapters/src/dbt/adapters/exceptions/catalog_integration.py

@@ -0,0 +1,9 @@
+
+from dbt_common.exceptions import DbtRuntimeError
+
+
+class DbtCatalogIntegrationAlreadyExistsError(DbtRuntimeError):
+    def __init__(self, catalog_name: str):
+        self.catalog_name = catalog_name
+        msg = f"Catalog integration {self.catalog_name} already exists"
+        super().__init__(msg)

dbt-adapters/tests/unit/clients/test_catalogs.py

@@ -1,7 +1,19 @@
+import pytest
 from dbt.adapters.clients.catalogs import add_catalog, get_catalog
+from dbt.adapters.exceptions.catalog_integration import DbtCatalogIntegrationAlreadyExistsError
 
 
 def test_adding_and_getting_catalog_integration(fake_catalog_integration):
     catalog = fake_catalog_integration
     add_catalog(catalog, catalog_name="fake_catalog")
     assert get_catalog("fake_catalog").catalog_name == catalog.catalog_name
+
+def test_adding_catalog_integration_that_already_exists(fake_catalog_integration):
+    catalog = fake_catalog_integration
+    catalog_name = "fake_catalog_2"
+    add_catalog(catalog, catalog_name=catalog_name)
+    with pytest.raises(DbtCatalogIntegrationAlreadyExistsError):
+        add_catalog(catalog, catalog_name=catalog_name)
+
+def test_getting_catalog_integration_that_does_not_exist():
+    assert get_catalog("non_existent_catalog") is None