Merge pull request #110 from cfstacks/feature/diff

Feature/diff

.gitignore

@@ -9,6 +9,7 @@ __pycache__/
 # Distribution / packaging
 .Python
 env/
+venv/
 build/
 develop-eggs/
 dist/

requirements.txt

@@ -0,0 +1,10 @@
+awscli>=1.11.130
+configargparse>=0.9.3
+PyYAML<=3.13,>=3.10
+Jinja2>=2.7.3
+boto>=2.40.0
+tabulate>=0.7.5
+setuptools
+pytz
+tzlocal
+moto

stacks/__about__.py

@@ -1,4 +1,4 @@
-__version__ = '0.4.2'
+__version__ = '0.4.3'
 __licence__ = 'MIT'
 __url__ = 'https://stacks.tools'
 __maintainer__ = 'Vaidas Jablonskis'

stacks/aws.py

@@ -5,6 +5,7 @@
 
 def throttling_retry(func):
     """Retry when AWS is throttling API calls"""
+
     def retry_call(*args, **kwargs):
         retries = 0
         while True:
@@ -13,12 +14,13 @@ def retry_call(*args, **kwargs):
                 return retval
             except BotoServerError as err:
                 if (err.code == 'Throttling' or err.code == 'RequestLimitExceeded') and retries <= 3:
-                    sleep = 3 * (2**retries)
+                    sleep = 3 * (2 ** retries)
                     print('Being throttled. Retrying after {} seconds..'.format(sleep))
                     time.sleep(sleep)
                     retries += 1
                 else:
                     raise err
+
     return retry_call
 
 
@@ -87,3 +89,13 @@ def get_stack_resource(conn, stack_name, logical_id):
         if r.logical_resource_id == logical_id:
             return r.physical_resource_id
     return None
+
+
+@throttling_retry
+def get_stack_template(conn, stack_name):
+    """Return a template body of live stack"""
+    try:
+        template = conn.get_template(stack_name)
+        return template['GetTemplateResponse']['GetTemplateResult']['TemplateBody'], []
+    except BotoServerError as e:
+        return None, [e.message]

stacks/cf.py

@@ -1,19 +1,17 @@
 """
 Cloudformation related functions
 """
-# An attempt to support python 2.7.x
-from __future__ import print_function
-
 import builtins
+import difflib
 import hashlib
 import json
 import sys
 import time
+from collections import Mapping, Set, Sequence
 from datetime import datetime
 from fnmatch import fnmatch
 from operator import attrgetter
 from os import path
-from collections import Mapping, Set, Sequence
 
 import boto
 import jinja2
@@ -25,8 +23,7 @@
 from jinja2 import meta
 from tabulate import tabulate
 
-from stacks.aws import get_stack_tag
-from stacks.aws import throttling_retry
+from stacks.aws import get_stack_tag, get_stack_template, throttling_retry
 from stacks.states import FAILED_STACK_STATES, COMPLETE_STACK_STATES, ROLLBACK_STACK_STATES, IN_PROGRESS_STACK_STATES
 
 YES = ['y', 'Y', 'yes', 'YES', 'Yes']
@@ -180,15 +177,14 @@ def create_stack(conn, stack_name, tpl_file, config, update=False, dry=False, cr
     if metadata:
         tags = _extract_tags(metadata)
         tags.update(default_tags)
-        name_from_metadata = metadata.get('name')
-        disable_rollback = metadata.get('disable_rollback')
+        name_from_metadata = metadata.get('name', None)
+        disable_rollback = metadata.get('disable_rollback', None)
     else:
         name_from_metadata = None
         tags = default_tags
         disable_rollback = None
 
-    if not stack_name:
-        stack_name = name_from_metadata
+    stack_name = stack_name or name_from_metadata
     if not stack_name:
         print('Stack name must be specified via command line argument or stack metadata.')
         sys.exit(1)
@@ -397,3 +393,31 @@ def validate_template(tpl):
                 "/{} 'null' values are not allowed in templates".format('/'.join(map(str, k)))
             )
     return errors
+
+
+def print_stack_diff(conn, stack_name, tpl_file, config):
+    local_template, metadata, errors = gen_template(tpl_file, config)
+
+    if metadata:
+        name_from_metadata = metadata.get('name', None)
+    else:
+        name_from_metadata = None
+
+    stack_name = stack_name or name_from_metadata
+    if not stack_name:
+        print('Stack name must be specified via command line argument or stack metadata.')
+        sys.exit(1)
+    if errors:
+        for err in errors:
+            print('ERROR: ' + err)
+
+    live_template, errors = get_stack_template(conn, stack_name)
+    if errors:
+        for err in errors:
+            print('ERROR: ' + err)
+            sys.exit(1)
+
+    if local_template == live_template:
+        return
+    for line in difflib.ndiff(live_template.split('\n'), local_template.split('\n')):
+        print(line)

stacks/cli.py

@@ -102,6 +102,22 @@ def parse_options():
                                help='Poll for new events until stopped (overrides -n)')
     parser_events.add_argument('-n', '--lines', default=100, type=int)
 
+    # diff subparser
+    parser_create = subparsers.add_parser('diff', help='Print diff of current vs compiled template')
+    parser_create.add_argument('-t', '--template', required=True, type=configargparse.FileType())
+    # noinspection PyArgumentList
+    parser_create.add_argument('-c', '--config', default='config.yaml',
+                               env_var='STACKS_CONFIG', required=False,
+                               type=_is_file)
+    # noinspection PyArgumentList
+    parser_create.add_argument('--config-dir', default='config.d',
+                               env_var='STACKS_CONFIG_DIR', required=False,
+                               type=_is_dir)
+    parser_create.add_argument('name', nargs='?', default=None)
+    # noinspection PyArgumentList
+    parser_create.add_argument('-e', '--env', env_var='STACKS_ENV', required=False, default=None)
+    parser_create.add_argument('-P', '--property', required=False, action='append')
+
     return parser, parser.parse_args()
 
 

stacks/main.py

@@ -1,27 +1,24 @@
-# An attempt to support python 2.7.x
-from __future__ import print_function
-
-import sys
 import os
 import signal
-import pytz
+import sys
 from datetime import datetime
 
+import boto.cloudformation
 import boto.ec2
-import boto.vpc
 import boto.route53
-import boto.cloudformation
 import boto.s3
+import boto.vpc
+import pytz
 
-from stacks import cli
 from stacks import aws
 from stacks import cf
+from stacks import cli
 from stacks.config import config_load
-from stacks.config import get_region_name
 from stacks.config import get_default_region_name
+from stacks.config import get_region_name
+from stacks.config import print_config
 from stacks.config import profile_exists
 from stacks.config import validate_properties
-from stacks.config import print_config
 from stacks.states import FAILED_STACK_STATES, ROLLBACK_STACK_STATES
 
 
@@ -151,6 +148,12 @@ def main():
     if args.subcommand == 'events':
         cf.print_events(cf_conn, args.name, args.events_follow, args.lines)
 
+    if args.subcommand == 'diff':
+        if args.property:
+            properties = validate_properties(args.property)
+            config.update(properties)
+        cf.print_stack_diff(cf_conn, args.name, args.template, config)
+
 
 def handler(signum, _):
     print('Signal {} received. Stopping.'.format(signum))