ansible-galaxy - increase page size and add retry decorator for throttling (#74240)

* Get available collection versions with page_size=100 for v2 and limit=100 for v3

* Update unit tests for larger page sizes

* Add a generic retry decorator in module_utils/api.py that accepts an Iterable of delays and a callable to determine if an exception inheriting from Exception should be retried

* Use the new decorator to handle Galaxy API rate limiting

* Add unit tests for new retry decorator

* Preserve the decorated function's metadata with functools.wraps

Co-authored-by: Matt Martz <matt@sivel.net>
Co-authored-by: Sviatoslav Sydorenko <wk.cvs.github@sydorenko.org.ua>

lib/ansible/galaxy/api.py

@@ -19,9 +19,11 @@ import threading
 from ansible import constants as C
 from ansible.errors import AnsibleError
 from ansible.galaxy.user_agent import user_agent
+from ansible.module_utils.api import retry_with_delays_and_condition
+from ansible.module_utils.api import generate_jittered_backoff
 from ansible.module_utils.six import string_types
 from ansible.module_utils.six.moves.urllib.error import HTTPError
-from ansible.module_utils.six.moves.urllib.parse import quote as urlquote, urlencode, urlparse
+from ansible.module_utils.six.moves.urllib.parse import quote as urlquote, urlencode, urlparse, parse_qs, urljoin
 from ansible.module_utils._text import to_bytes, to_native, to_text
 from ansible.module_utils.urls import open_url, prepare_multipart
 from ansible.utils.display import Display
@@ -36,6 +38,11 @@ except ImportError:
 
 display = Display()
 _CACHE_LOCK = threading.Lock()
+COLLECTION_PAGE_SIZE = 100
+RETRY_HTTP_ERROR_CODES = [  # TODO: Allow user-configuration
+    429,  # Too Many Requests
+    520,  # Galaxy rate limit error code (Cloudflare unknown error)
+]
 
 
 def cache_lock(func):
@@ -46,6 +53,13 @@ def cache_lock(func):
     return wrapped
 
 
+def is_rate_limit_exception(exception):
+    # Note: cloud.redhat.com masks rate limit errors with 403 (Forbidden) error codes.
+    # Since 403 could reflect the actual problem (such as an expired token), we should
+    # not retry by default.
+    return isinstance(exception, GalaxyError) and exception.http_code in RETRY_HTTP_ERROR_CODES
+
+
 def g_connect(versions):
     """
     Wrapper to lazily initialize connection info to Galaxy and verify the API versions required are available on the
@@ -309,10 +323,15 @@ class GalaxyAPI:
         # Calling g_connect will populate self._available_api_versions
         return self._available_api_versions
 
+    @retry_with_delays_and_condition(
+        backoff_iterator=generate_jittered_backoff(retries=6, delay_base=2, delay_threshold=40),
+        should_retry_error=is_rate_limit_exception
+    )
     def _call_galaxy(self, url, args=None, headers=None, method=None, auth_required=False, error_context_msg=None,
                      cache=False):
         url_info = urlparse(url)
         cache_id = get_cache_id(url)
+        query = parse_qs(url_info.query)
         if cache and self._cache:
             server_cache = self._cache.setdefault(cache_id, {})
             iso_datetime_format = '%Y-%m-%dT%H:%M:%SZ'
@@ -322,7 +341,8 @@ class GalaxyAPI:
                 expires = datetime.datetime.strptime(server_cache[url_info.path]['expires'], iso_datetime_format)
                 valid = datetime.datetime.utcnow() < expires
 
-            if valid and not url_info.query:
+            is_paginated_url = 'page' in query or 'offset' in query
+            if valid and not is_paginated_url:
                 # Got a hit on the cache and we aren't getting a paginated response
                 path_cache = server_cache[url_info.path]
                 if path_cache.get('paginated'):
@@ -342,7 +362,7 @@ class GalaxyAPI:
 
                 return res
 
-            elif not url_info.query:
+            elif not is_paginated_url:
                 # The cache entry had expired or does not exist, start a new blank entry to be filled later.
                 expires = datetime.datetime.utcnow()
                 expires += datetime.timedelta(days=1)
@@ -781,7 +801,8 @@ class GalaxyAPI:
             api_path = self.available_api_versions['v2']
             pagination_path = ['next']
 
-        versions_url = _urljoin(self.api_server, api_path, 'collections', namespace, name, 'versions', '/')
+        page_size_name = 'limit' if 'v3' in self.available_api_versions else 'page_size'
+        versions_url = _urljoin(self.api_server, api_path, 'collections', namespace, name, 'versions', '/?%s=%d' % (page_size_name, COLLECTION_PAGE_SIZE))
         versions_url_info = urlparse(versions_url)
 
         # We should only rely on the cache if the collection has not changed. This may slow things down but it ensures
@@ -838,6 +859,9 @@ class GalaxyAPI:
             elif relative_link:
                 # TODO: This assumes the pagination result is relative to the root server. Will need to be verified
                 # with someone who knows the AH API.
+
+                # Remove the query string from the versions_url to use the next_link's query
+                versions_url = urljoin(versions_url, urlparse(versions_url).path)
                 next_link = versions_url.replace(versions_url_info.path, next_link)
 
             data = self._call_galaxy(to_native(next_link, errors='surrogate_or_strict'),

lib/ansible/module_utils/api.py

@@ -26,6 +26,8 @@ The 'api' module provides the following common argument specs:
 from __future__ import (absolute_import, division, print_function)
 __metaclass__ = type
 
+import functools
+import random
 import sys
 import time
 
@@ -114,3 +116,51 @@ def retry(retries=None, retry_pause=1):
 
         return retried
     return wrapper
+
+
+def generate_jittered_backoff(retries=10, delay_base=3, delay_threshold=60):
+    """The "Full Jitter" backoff strategy.
+
+    Ref: https://www.awsarchitectureblog.com/2015/03/backoff.html
+
+    :param retries: The number of delays to generate.
+    :param delay_base: The base time in seconds used to calculate the exponential backoff.
+    :param delay_threshold: The maximum time in seconds for any delay.
+    """
+    for retry in range(0, retries):
+        yield random.randint(0, min(delay_threshold, delay_base * 2 ** retry))
+
+
+def retry_never(exception_or_result):
+    return False
+
+
+def retry_with_delays_and_condition(backoff_iterator, should_retry_error=None):
+    """Generic retry decorator.
+
+    :param backoff_iterator: An iterable of delays in seconds.
+    :param should_retry_error: A callable that takes an exception of the decorated function and decides whether to retry or not (returns a bool).
+    """
+    if should_retry_error is None:
+        should_retry_error = retry_never
+
+    def function_wrapper(function):
+        @functools.wraps(function)
+        def run_function(*args, **kwargs):
+            """This assumes the function has not already been called.
+            If backoff_iterator is empty, we should still run the function a single time with no delay.
+            """
+            call_retryable_function = functools.partial(function, *args, **kwargs)
+
+            for delay in backoff_iterator:
+                try:
+                    return call_retryable_function()
+                except Exception as e:
+                    if not should_retry_error(e):
+                        raise
+                time.sleep(delay)
+
+            # Only or final attempt
+            return call_retryable_function()
+        return run_function
+    return function_wrapper

test/units/galaxy/test_api.py

@@ -791,9 +791,10 @@ def test_get_collection_versions(api_version, token_type, token_ins, response, m
     actual = api.get_collection_versions('namespace', 'collection')
     assert actual == [u'1.0.0', u'1.0.1']
 
+    page_query = '?limit=100' if api_version == 'v3' else '?page_size=100'
     assert mock_open.call_count == 1
     assert mock_open.mock_calls[0][1][0] == 'https://galaxy.server.com/api/%s/collections/namespace/collection/' \
-                                            'versions/' % api_version
+                                            'versions/%s' % (api_version, page_query)
     if token_ins:
         assert mock_open.mock_calls[0][2]['headers']['Authorization'] == '%s my token' % token_type
 
@@ -802,9 +803,9 @@ def test_get_collection_versions(api_version, token_type, token_ins, response, m
     ('v2', None, None, [
         {
             'count': 6,
-            'next': 'https://galaxy.server.com/api/v2/collections/namespace/collection/versions/?page=2',
+            'next': 'https://galaxy.server.com/api/v2/collections/namespace/collection/versions/?page=2&page_size=100',
             'previous': None,
-            'results': [
+            'results': [  # Pay no mind, using more manageable results than page_size would indicate
                 {
                     'version': '1.0.0',
                     'href': 'https://galaxy.server.com/api/v2/collections/namespace/collection/versions/1.0.0',
@@ -817,7 +818,7 @@ def test_get_collection_versions(api_version, token_type, token_ins, response, m
         },
         {
             'count': 6,
-            'next': 'https://galaxy.server.com/api/v2/collections/namespace/collection/versions/?page=3',
+            'next': 'https://galaxy.server.com/api/v2/collections/namespace/collection/versions/?page=3&page_size=100',
             'previous': 'https://galaxy.server.com/api/v2/collections/namespace/collection/versions',
             'results': [
                 {
@@ -833,7 +834,7 @@ def test_get_collection_versions(api_version, token_type, token_ins, response, m
         {
             'count': 6,
             'next': None,
-            'previous': 'https://galaxy.server.com/api/v2/collections/namespace/collection/versions/?page=2',
+            'previous': 'https://galaxy.server.com/api/v2/collections/namespace/collection/versions/?page=2&page_size=100',
             'results': [
                 {
                     'version': '1.0.4',
@@ -850,7 +851,8 @@ def test_get_collection_versions(api_version, token_type, token_ins, response, m
         {
             'count': 6,
             'links': {
-                'next': '/api/v3/collections/namespace/collection/versions/?page=2',
+                # v3 links are relative and the limit is included during pagination
+                'next': '/api/v3/collections/namespace/collection/versions/?limit=100&offset=100',
                 'previous': None,
             },
             'data': [
@@ -867,7 +869,7 @@ def test_get_collection_versions(api_version, token_type, token_ins, response, m
         {
             'count': 6,
             'links': {
-                'next': '/api/v3/collections/namespace/collection/versions/?page=3',
+                'next': '/api/v3/collections/namespace/collection/versions/?limit=100&offset=200',
                 'previous': '/api/v3/collections/namespace/collection/versions',
             },
             'data': [
@@ -885,7 +887,7 @@ def test_get_collection_versions(api_version, token_type, token_ins, response, m
             'count': 6,
             'links': {
                 'next': None,
-                'previous': '/api/v3/collections/namespace/collection/versions/?page=2',
+                'previous': '/api/v3/collections/namespace/collection/versions/?limit=100&offset=100',
             },
             'data': [
                 {
@@ -916,12 +918,22 @@ def test_get_collection_versions_pagination(api_version, token_type, token_ins,
     assert actual == [u'1.0.0', u'1.0.1', u'1.0.2', u'1.0.3', u'1.0.4', u'1.0.5']
 
     assert mock_open.call_count == 3
+
+    if api_version == 'v3':
+        query_1 = 'limit=100'
+        query_2 = 'limit=100&offset=100'
+        query_3 = 'limit=100&offset=200'
+    else:
+        query_1 = 'page_size=100'
+        query_2 = 'page=2&page_size=100'
+        query_3 = 'page=3&page_size=100'
+
     assert mock_open.mock_calls[0][1][0] == 'https://galaxy.server.com/api/%s/collections/namespace/collection/' \
-                                            'versions/' % api_version
+                                            'versions/?%s' % (api_version, query_1)
     assert mock_open.mock_calls[1][1][0] == 'https://galaxy.server.com/api/%s/collections/namespace/collection/' \
-                                            'versions/?page=2' % api_version
+                                            'versions/?%s' % (api_version, query_2)
     assert mock_open.mock_calls[2][1][0] == 'https://galaxy.server.com/api/%s/collections/namespace/collection/' \
-                                            'versions/?page=3' % api_version
+                                            'versions/?%s' % (api_version, query_3)
 
     if token_type:
         assert mock_open.mock_calls[0][2]['headers']['Authorization'] == '%s my token' % token_type

test/units/module_utils/test_api.py

@@ -7,11 +7,19 @@ from __future__ import (absolute_import, division, print_function)
 __metaclass__ = type
 
 
-from ansible.module_utils.api import rate_limit, retry
+from ansible.module_utils.api import rate_limit, retry, retry_with_delays_and_condition
 
 import pytest
 
 
+class CustomException(Exception):
+    pass
+
+
+class CustomBaseException(BaseException):
+    pass
+
+
 class TestRateLimit:
 
     def test_ratelimit(self):
@@ -26,17 +34,16 @@ class TestRateLimit:
 class TestRetry:
 
     def test_no_retry_required(self):
-        self.counter = 0
-
         @retry(retries=4, retry_pause=2)
         def login_database():
-            self.counter += 1
+            login_database.counter += 1
             return 'success'
 
+        login_database.counter = 0
         r = login_database()
 
         assert r == 'success'
-        assert self.counter == 1
+        assert login_database.counter == 1
 
     def test_catch_exception(self):
 
@@ -44,5 +51,71 @@ class TestRetry:
         def login_database():
             return 'success'
 
-        with pytest.raises(Exception):
+        with pytest.raises(Exception, match="Retry"):
             login_database()
+
+    def test_no_retries(self):
+
+        @retry()
+        def login_database():
+            assert False, "Should not execute"
+
+        login_database()
+
+
+class TestRetryWithDelaysAndCondition:
+
+    def test_empty_retry_iterator(self):
+        @retry_with_delays_and_condition(backoff_iterator=[])
+        def login_database():
+            login_database.counter += 1
+
+        login_database.counter = 0
+        r = login_database()
+        assert login_database.counter == 1
+
+    def test_no_retry_exception(self):
+        @retry_with_delays_and_condition(
+            backoff_iterator=[1],
+            should_retry_error=lambda x: False,
+        )
+        def login_database():
+            login_database.counter += 1
+            if login_database.counter == 1:
+                raise CustomException("Error")
+
+        login_database.counter = 0
+        with pytest.raises(CustomException, match="Error"):
+            login_database()
+        assert login_database.counter == 1
+
+    def test_no_retry_baseexception(self):
+        @retry_with_delays_and_condition(
+            backoff_iterator=[1],
+            should_retry_error=lambda x: True,  # Retry all exceptions inheriting from Exception
+        )
+        def login_database():
+            login_database.counter += 1
+            if login_database.counter == 1:
+                # Raise an exception inheriting from BaseException
+                raise CustomBaseException("Error")
+
+        login_database.counter = 0
+        with pytest.raises(CustomBaseException, match="Error"):
+            login_database()
+        assert login_database.counter == 1
+
+    def test_retry_exception(self):
+        @retry_with_delays_and_condition(
+            backoff_iterator=[1],
+            should_retry_error=lambda x: isinstance(x, CustomException),
+        )
+        def login_database():
+            login_database.counter += 1
+            if login_database.counter == 1:
+                raise CustomException("Retry")
+            return 'success'
+
+        login_database.counter = 0
+        assert login_database() == 'success'
+        assert login_database.counter == 2