cfn-get-metadata: log metadata to standard output

Add display() method to the Metadata class that prints the metadata to
standard output if the metdata has been successfully retrieved (either
from local cache or from the remote server).

Change-Id: Idf6c1aecf2a5204d7cf7fbf3c8d826f750a72785
Fixes: bug #1183298

3 files changed, 49 insertions, 17 deletions

diff --git a/bin/cfn-get-metadata b/bin/cfn-get-metadata
index 5d27b6b..6aa9251 100755
--- a/bin/cfn-get-metadata
+++ b/bin/cfn-get-metadata
@@ -86,3 +86,4 @@ metadata = Metadata(args.stack_name,
                     credentials_file=args.credential_file)
 metadata.retrieve()
 LOG.debug(str(metadata))
+metadata.display()
diff --git a/heat_cfntools/cfntools/cfn_helper.py b/heat_cfntools/cfntools/cfn_helper.py
index 3d1e38f..5fa7b5a 100644
--- a/heat_cfntools/cfntools/cfn_helper.py
+++ b/heat_cfntools/cfntools/cfn_helper.py
@@ -1041,7 +1041,12 @@ class Metadata(object):
             meta_str=None,
             default_path='/var/lib/heat-cfntools/cfn-init-data',
             last_path='/var/cache/heat-cfntools/last_metadata'):
-        """Read the metadata from the given filename."""
+        """Read the metadata from the given filename or from the remote server.
+
+           Returns:
+               True -- success
+              False -- error
+        """
         if meta_str:
             self._data = meta_str
         else:
@@ -1116,9 +1121,16 @@ class Metadata(object):
             cf.write(json.dumps(self._metadata))
             os.rename(cf.name, last_path)
 
+        return True
+
     def __str__(self):
         return json.dumps(self._metadata)
 
+    def display(self):
+        if self._metadata is not None:
+            print str(self)
+        return
+
     def _is_valid_metadata(self):
         """Should find the AWS::CloudFormation::Init json key."""
         is_valid = self._metadata and \
diff --git a/heat_cfntools/tests/test_cfn_helper.py b/heat_cfntools/tests/test_cfn_helper.py
index a02f594..843f9e4 100644
--- a/heat_cfntools/tests/test_cfn_helper.py
+++ b/heat_cfntools/tests/test_cfn_helper.py
@@ -528,17 +528,16 @@ class TestMetadataRetrieve(testtools.TestCase):
             default_file.flush()
             self.assertThat(default_file.name, ttm.FileContains(md_str))
 
-            md.retrieve(
-                default_path=default_file.name,
-                last_path=self.last_file)
+            self.assertTrue(
+                md.retrieve(default_path=default_file.name,
+                            last_path=self.last_file))
 
             self.assertThat(self.last_file, ttm.FileContains(md_str))
             self.assertThat(md_data, ttm.Equals(md._metadata))
 
         md = cfn_helper.Metadata('teststack', None)
-        md.retrieve(
-            default_path=default_file.name,
-            last_path=self.last_file)
+        self.assertTrue(md.retrieve(default_path=default_file.name,
+                                    last_path=self.last_file))
         self.assertThat(md_data, ttm.Equals(md._metadata))
 
     def test_metadata_retrieve_none(self):
@@ -546,11 +545,17 @@ class TestMetadataRetrieve(testtools.TestCase):
         md = cfn_helper.Metadata('teststack', None)
         default_file = os.path.join(self.tdir.path, 'default_file')
 
-        md.retrieve(
-            default_path=default_file,
-            last_path=self.last_file)
+        self.assertFalse(md.retrieve(default_path=default_file,
+                                     last_path=self.last_file))
         self.assertIsNone(md._metadata)
 
+        displayed = self.useFixture(fixtures.StringStream('stdout'))
+        fake_stdout = displayed.stream
+        self.useFixture(fixtures.MonkeyPatch('sys.stdout', fake_stdout))
+        md.display()
+        fake_stdout.flush()
+        self.assertEqual(displayed.getDetails()['stdout'].as_text(), "")
+
     def test_metadata_retrieve_passed(self):
 
         md_data = {"AWS::CloudFormation::Init": {"config": {"files": {
@@ -558,14 +563,26 @@ class TestMetadataRetrieve(testtools.TestCase):
         md_str = json.dumps(md_data)
 
         md = cfn_helper.Metadata('teststack', None)
-        md.retrieve(meta_str=md_str, last_path=self.last_file)
+        self.assertTrue(md.retrieve(meta_str=md_str,
+                                    last_path=self.last_file))
         self.assertThat(md_data, ttm.Equals(md._metadata))
 
         md = cfn_helper.Metadata('teststack', None)
-        md.retrieve(meta_str=md_data, last_path=self.last_file)
+        self.assertTrue(md.retrieve(meta_str=md_data,
+                                    last_path=self.last_file))
         self.assertThat(md_data, ttm.Equals(md._metadata))
         self.assertEqual(md_str, str(md))
 
+        displayed = self.useFixture(fixtures.StringStream('stdout'))
+        fake_stdout = displayed.stream
+        self.useFixture(fixtures.MonkeyPatch('sys.stdout', fake_stdout))
+        md.display()
+        fake_stdout.flush()
+        self.assertEqual(displayed.getDetails()['stdout'].as_text(),
+                         "{\"AWS::CloudFormation::Init\": {\"config\": {"
+                         "\"files\": {\"/tmp/foo\": {\"content\": \"bar\"}"
+                         "}}}}\n")
+
     def test_metadata_creates_cache(self):
         temp_home = tempfile.mkdtemp()
 
@@ -584,7 +601,7 @@ class TestMetadataRetrieve(testtools.TestCase):
 
         self.assertFalse(os.path.exists(last_path),
                          "last_metadata file already exists")
-        md.retrieve(meta_str=md_str, last_path=last_path)
+        self.assertTrue(md.retrieve(meta_str=md_str, last_path=last_path))
         self.assertTrue(os.path.exists(last_path),
                         "last_metadata file should exist")
         # Ensure created dirs and file have right perms
@@ -597,7 +614,8 @@ class TestMetadataRetrieve(testtools.TestCase):
             "/tmp/foo": {"content": "bar"}}}}}
 
         md = cfn_helper.Metadata('teststack', None)
-        md.retrieve(meta_str=md_data, last_path=self.last_file)
+        self.assertTrue(
+            md.retrieve(meta_str=md_data, last_path=self.last_file))
 
         self.assertThat(md_data, ttm.Equals(md._metadata))
         self.assertTrue(md._is_valid_metadata())
@@ -627,7 +645,7 @@ class TestMetadataRetrieve(testtools.TestCase):
                 None,
                 access_key='foo',
                 secret_key='bar')
-            md.retrieve(last_path=self.last_file)
+            self.assertTrue(md.retrieve(last_path=self.last_file))
             self.assertThat(md_data, ttm.Equals(md._metadata))
 
             with tempfile.NamedTemporaryFile(mode='w') as fcreds:
@@ -635,7 +653,7 @@ class TestMetadataRetrieve(testtools.TestCase):
                 fcreds.flush()
                 md = cfn_helper.Metadata(
                     'teststack', None, credentials_file=fcreds.name)
-                md.retrieve(last_path=self.last_file)
+                self.assertTrue(md.retrieve(last_path=self.last_file))
             self.assertThat(md_data, ttm.Equals(md._metadata))
 
             m.VerifyAll()
@@ -649,7 +667,8 @@ class TestMetadataRetrieve(testtools.TestCase):
                 foo_file.name: {"content": "bar"}}}}}
 
             md = cfn_helper.Metadata('teststack', None)
-            md.retrieve(meta_str=md_data, last_path=self.last_file)
+            self.assertTrue(
+                md.retrieve(meta_str=md_data, last_path=self.last_file))
             md.cfn_init()
             self.assertThat(foo_file.name, ttm.FileContains('bar'))