Making block_devices non mandatory in EC2 block definition.

This fixes #3

README.rst

@@ -76,7 +76,7 @@ This tool needs AWS credentials to create stacks and the credentials should be p
 
 Project specific YAML file
 +++++++++++++++++++++++++++
-The YAML file below highlights what is possible with all the bootstrap-cfn features available to date. The minimum requirement is that it must contain an *ec2* block, you **do not** have to use RDS, S3 or ELB's.
+The YAML file below highlights what is possible with all the bootstrap-cfn features available to date. The minimum requirement is that it must contain an *ec2* block, you **do not** have to use RDS, S3 or ELB's. Block devices in EC2 block is non mandatory as well.
 
 ::
 
@@ -173,9 +173,9 @@ Salt specific configuration
 
 In order to rsync your salt states to the salt master you need to add a `salt` section to the top level of your project's YAML file. The following parameters specify the rsync sources and targets:
 
-- **local_salt_dir**: Directory containing all the files you want to have in your salt root (for example top.sls or project specific states). 
+- **local_salt_dir**: Directory containing all the files you want to have in your salt root (for example top.sls or project specific states).
     **Default value**: ./salt
-- **local_pillar_dir**: Directory containing all the files you want to have in your pillar root. 
+- **local_pillar_dir**: Directory containing all the files you want to have in your pillar root.
     **Default value**: ./pillar
 - **local_vendor_dir**: Directory containing formulas cloned by salt-shaker.
     **Default value**: ./vendor

bootstrap_cfn/config.py

@@ -262,9 +262,12 @@ def ec2(self):
 
         # BLOCK DEVICE MAPPING
         devices = []
-        for i in self.data['ec2']['block_devices']:
-            devices.append(
-                {'DeviceName': i['DeviceName'], 'Ebs': {'VolumeSize': i['VolumeSize']}})
+        try:
+            for i in self.data['ec2']['block_devices']:
+                devices.append(
+                    {'DeviceName': i['DeviceName'], 'Ebs': {'VolumeSize': i['VolumeSize']}})
+        except KeyError:
+            pass
         template['BaseHostLaunchConfig']['Properties'][
             'BlockDeviceMappings'] = devices
 

tests/tests.py

@@ -5,6 +5,8 @@
 import bootstrap_cfn.errors as errors
 from testfixtures import compare
 
+import pprint
+
 
 class TestConfig(unittest.TestCase):
 
@@ -542,6 +544,13 @@ def test_ec2(self):
                 'dev').config, 'my-stack-name')
         compare(known, config.ec2())
 
+    def test_ec2_with_no_block_device_specified(self):
+        from testfixtures import compare
+        project_config = ProjectConfig('tests/sample-project.yaml', 'dev')
+        project_config.config.pop('rds')
+        project_config.config['ec2'].pop('block_devices')
+        config = ConfigParser(project_config.config, 'my-stack-name')
+        config.process()
 
 if __name__ == '__main__':
     unittest.main()