Add explicit os_collect_config exceptions.

os_collect_config/collect.py

@@ -16,6 +16,8 @@
 import httplib2
 import json
 
+from os_collect_config import exc
+
 
 EC2_METADATA_URL = 'http://169.254.169.254/latest/meta-data'
 
@@ -24,7 +26,10 @@ h = httplib2.Http()
 
 def _fetch_metadata(sub_url):
     global h
-    (resp, content) = h.request('%s%s' % (EC2_METADATA_URL, sub_url))
+    try:
+        (resp, content) = h.request('%s%s' % (EC2_METADATA_URL, sub_url))
+    except httplib2.socks.HTTPError:
+        raise exc.Ec2MetadataNotAvailable
     if resp.status != 200:
         raise Exception('Error fetching %s' % sub_url)
     if sub_url[-1] == '/':

os_collect_config/exc.py

@@ -0,0 +1,10 @@
+class SourceNotAvailable(RuntimeError):
+    """The requested data source is unavailable."""
+
+
+class Ec2MetadataNotAvailable(SourceNotAvailable):
+    """The EC2 metadata service is not available."""
+
+
+class CfnMetadataNotAvailable(SourceNotAvailable):
+    """The cfn metadata service is not available."""

os_collect_config/tests/test_collect.py

@@ -14,12 +14,14 @@
 # limitations under the License.
 
 import fixtures
+import httplib2
 import testtools
 from testtools import matchers
 import urlparse
 import uuid
 
 from os_collect_config import collect
+from os_collect_config import exc
 
 
 META_DATA = {'local-ipv4':     '192.0.2.1',
@@ -67,6 +69,11 @@ class FakeHttp(object):
         return (FakeResponse(), META_DATA[path])
 
 
+class FakeFailHttp(object):
+    def request(self, url):
+        raise httplib2.socks.HTTPError(403, 'Forbidden')
+
+
 class TestCollect(testtools.TestCase):
     def test_collect_ec2(self):
         self.useFixture(
@@ -84,3 +91,10 @@ class TestCollect(testtools.TestCase):
         self.assertEquals(
             {'0': {'openssh-key': 'ssh-rsa AAAAAAAAABBBBBBBBCCCCCCCC'}},
             ec2['public-keys'])
+
+    def test_collect_ec2_fail(self):
+        self.useFixture(
+            fixtures.MonkeyPatch(
+                'os_collect_config.collect.h', FakeFailHttp()))
+        self.assertRaises(exc.Ec2MetadataNotAvailable,
+                          collect.collect_ec2)