Add a retry mechanism on swagger.json

EsiApp will now try up to 3 times to get the swagger.json spec.

.gitignore

@@ -89,3 +89,5 @@ ENV/
 .ropeproject
 
 env3/
+
+\.vscode/

esipy/__init__.py

@@ -8,7 +8,7 @@
     from .app import EsiApp  # noqa
     from pyswagger import App  # noqa
 except ImportError:  # pragma: no cover
-            # Not installed or in install (not yet installed) so ignore
+    # Not installed or in install (not yet installed) so ignore
     pass
 
-__version__ = '1.0.0'
+__version__ = '1.1.0'

esipy/app.py

@@ -2,12 +2,17 @@
 """ App entry point. Uses Esi Meta Endpoint to work """
 import time
 
+import logging
 import requests
+from six.moves.urllib.error import HTTPError
 
 from pyswagger import App
 
 from .utils import check_cache
 from .utils import get_cache_time_left
+from .exceptions import APIException
+
+LOGGER = logging.getLogger(__name__)
 
 
 class EsiApp(object):
@@ -103,8 +108,30 @@ def __get_or_create_app(self, url, cache_key):
             return cached_app
 
         # ok, cache is not accurate, make the full stuff
-        app = App.create(app_url)
-        if self.caching:
+        # also retry up to 3 times if we get any errors
+        app = None
+        for _retry in range(1, 4):
+            try:
+                app = App.create(app_url)
+            except HTTPError as error:
+                LOGGER.warning(
+                    "[failure #%d] %s %d: %r",
+                    _retry,
+                    app_url,
+                    error.code,
+                    error.msg
+                )
+                continue
+            break
+
+        if app is None:
+            raise APIException(
+                app_url,
+                500,
+                response="Cannot fetch '%s'." % app_url
+            )
+
+        if self.caching and app:
             self.cache.set(cache_key, (app, res.headers, timeout))
 
         return app

test/test_app.py

@@ -4,11 +4,13 @@
 
 from esipy import EsiApp
 from esipy.cache import DictCache
+from esipy.exceptions import APIException
 from pyswagger import App
 
 import httmock
 import mock
 import unittest
+from six.moves.urllib.error import HTTPError
 
 from .mock import _swagger_spec_mock_
 from .mock import make_expire_time_str
@@ -182,3 +184,40 @@ def fail_if_request(url, request):
             urlopen_mock.return_value = open(TestEsiApp.ESI_META_SWAGGER)
             EsiApp(cache_time=None, cache=cache, cache_prefix='esipy_test')
             urlopen_mock.return_value.close()
+
+    @mock.patch('six.moves.urllib.request.urlopen')
+    def test_app_http_error_retry_fail(self, urlopen_mock):
+        urlopen_mock.side_effect = HTTPError(
+            "http://mock.test",
+            500,
+            "HTTP 500 whatever",
+            None,
+            None
+        )
+        with httmock.HTTMock(*_swagger_spec_mock_):
+            with self.assertRaises(APIException):
+                self.app = EsiApp(cache_prefix='esipy_test')
+            self.assertEqual(urlopen_mock.call_count, 3)
+
+    @mock.patch('six.moves.urllib.request.urlopen')
+    def test_app_http_error_retry_ok(self, urlopen_mock):
+        http_error = HTTPError(
+            "http://mock.test",
+            500,
+            "HTTP 500 whatever",
+            None,
+            None
+        )
+
+        # this will make the function raise exception / return the value
+        # in this given order
+        side_effect_results = [
+            http_error,
+            http_error,
+            open(TestEsiApp.ESI_META_SWAGGER)
+        ]
+
+        urlopen_mock.side_effect = side_effect_results
+        with httmock.HTTMock(*_swagger_spec_mock_):
+            EsiApp(cache_prefix='esipy_test')
+            self.assertEqual(urlopen_mock.call_count, 3)