Fix/dbt deps retry none answer (#4225)

* Fix issue #4178
Allow retries when the answer is None

* Include fix for #4178
Allow retries when the answer from dbt deps is None

* Add link to the PR

* Update exception and shorten line size

* Add test when dbt deps returns None

CHANGELOG.md

@@ -11,6 +11,7 @@
 
 ### Fixes
 - Changes unit tests using `assertRaisesRegexp` to `assertRaisesRegex` ([#4136](https://github.com/dbt-labs/dbt-core/issues/4132), [#4136](https://github.com/dbt-labs/dbt-core/pull/4136))
+- Allow retries when the answer from a `dbt deps` is `None` ([#4178](https://github.com/dbt-labs/dbt-core/issues/4178))
 
 ### Under the hood
 - Bump artifact schema versions for 1.0.0: manifest v4, run results v4, sources v3. Notable changes: schema test + data test nodes are renamed to generic test + singular test nodes; freshness threshold default values ([#4191](https://github.com/dbt-labs/dbt-core/pull/4191))
@@ -23,6 +24,7 @@ Contributors:
 - [@Kayrnt](https://github.com/Kayrnt) ([#4136](https://github.com/dbt-labs/dbt-core/pull/4170))
 - [@VersusFacit](https://github.com/VersusFacit) ([#4104](https://github.com/dbt-labs/dbt-core/pull/4104))
 - [@joellabes](https://github.com/joellabes) ([#4104](https://github.com/dbt-labs/dbt-core/pull/4104))
+- [@b-per](https://github.com/b-per) ([#4225](https://github.com/dbt-labs/dbt-core/pull/4225))
 
 
 ## dbt-core 1.0.0b2 (October 25, 2021)

core/dbt/clients/registry.py

@@ -30,6 +30,10 @@ def _get(path, registry_base_url=None):
     logger.debug('Response from registry: GET {} {}'.format(url,
                                                             resp.status_code))
     resp.raise_for_status()
+    if resp is None:
+        raise requests.exceptions.ContentDecodingError(
+            'Request error: The response is None', response=resp
+        )
     return resp.json()
 
 

core/dbt/utils.py

@@ -615,7 +615,11 @@ def _connection_exception_retry(fn, max_attempts: int, attempt: int = 0):
     """
     try:
         return fn()
-    except (requests.exceptions.ConnectionError, requests.exceptions.Timeout) as exc:
+    except (
+        requests.exceptions.ConnectionError,
+        requests.exceptions.Timeout,
+        requests.exceptions.ContentDecodingError,
+    ) as exc:
         if attempt <= max_attempts - 1:
             logger.debug('Retrying external call. Attempt: ' +
                          f'{attempt} Max attempts: {max_attempts}')

test/unit/test_core_dbt_utils.py

@@ -22,6 +22,11 @@ def test_connection_exception_retry_success(self):
         connection_exception_retry(lambda: Counter._add_with_limited_exception(), 5)
         self.assertEqual(2, counter) # 2 = original attempt plus 1 retry
 
+    def test_connection_exception_retry_success_none_response(self):
+        Counter._reset()
+        connection_exception_retry(lambda: Counter._add_with_none_exception(), 5)
+        self.assertEqual(2, counter) # 2 = original attempt returned None, plus 1 retry
+
 
 counter:int = 0 
 class Counter():
@@ -37,6 +42,11 @@ def _add_with_limited_exception():
         counter+=1
         if counter < 2:
             raise requests.exceptions.ConnectionError
+    def _add_with_none_exception():
+        global counter
+        counter+=1
+        if counter < 2:
+            raise requests.exceptions.ContentDecodingError
     def _reset():
         global counter
         counter = 0