commit ea58e60aa9e77ab3f4abce4adcda819502805818
Author: Stefan Reimer <it@startux.de>
Date:   Thu Nov 22 18:31:59 2018 +0000

    Initial checkin

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..0459458
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,60 @@
+# Vim
+*.swp
+
+# Byte-compiled / optimized / DLL files
+__pycache__/
+*.py[cod]
+*$py.class
+
+# C extensions
+*.so
+
+# Distribution / packaging
+.Python
+env/
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib64/
+parts/
+sdist/
+var/
+*.egg-info/
+.installed.cfg
+*.egg
+
+# PyInstaller
+#  Usually these files are written by a python script from a template
+#  before PyInstaller builds the exe, so as to inject date/other infos into it.
+*.manifest
+*.spec
+
+# Installer logs
+pip-log.txt
+pip-delete-this-directory.txt
+
+# Unit test / coverage reports
+htmlcov/
+.tox/
+.coverage
+.coverage.*
+.cache
+.pytest*
+nosetests.xml
+coverage.xml
+*,cover
+.hypothesis/
+
+# Translations
+*.mo
+*.pot
+
+# dotenv
+.env
+
+# virtualenv
+venv/
+ENV/
diff --git a/cloudbender/__init__.py b/cloudbender/__init__.py
new file mode 100644
index 0000000..93a40c9
--- /dev/null
+++ b/cloudbender/__init__.py
@@ -0,0 +1,15 @@
+import logging
+
+__author__ = 'Stefan Reimer'
+__email__ = 'stefan@zero-downtimet.net'
+__version__ = '1.1.0'
+
+
+# Set up logging to ``/dev/null`` like a library is supposed to.
+# http://docs.python.org/3.3/howto/logging.html#configuring-logging-for-a-library
+class NullHandler(logging.Handler):  # pragma: no cover
+    def emit(self, record):
+        pass
+
+
+logging.getLogger('cloudbender').addHandler(NullHandler())
diff --git a/cloudbender/cli.py b/cloudbender/cli.py
new file mode 100644
index 0000000..e742c59
--- /dev/null
+++ b/cloudbender/cli.py
@@ -0,0 +1,171 @@
+import os
+import click
+import functools
+
+from concurrent.futures import ThreadPoolExecutor, wait
+
+from . import __version__
+from .core import CloudBender
+from .utils import setup_logging
+
+import logging
+logger = logging.getLogger(__name__)
+
+@click.group()
+@click.version_option(version=__version__, prog_name="CloudBender")
+@click.option("--debug", is_flag=True, help="Turn on debug logging.")
+@click.option("--dir", "directory", help="Specify cloudbender project directory.")
+@click.pass_context
+def cli(ctx, debug, directory):
+    logger = setup_logging(debug)
+
+    # Read global config
+    cb = CloudBender(directory if directory else os.getcwd())
+    cb.read_config()
+    cb.dump_config()
+
+    ctx.obj['cb'] = cb
+
+
+@click.command()
+@click.argument("stack_name")
+@click.option("--multi", is_flag=True, help="Allow more than one stack to match")
+@click.pass_context
+def render(ctx, stack_name, multi):
+    """ Renders template and its parameters """
+
+    stacks = _find_stacks(ctx, stack_name, multi)
+
+    for s in stacks:
+        s.render()
+        s.write_template_file()
+
+
+@click.command()
+@click.argument("stack_name")
+@click.option("--multi", is_flag=True, help="Allow more than one stack to match")
+@click.pass_context
+def validate(ctx, stack_name, multi):
+    stacks = _find_stacks(ctx, stack_name, multi)
+
+    for s in stacks:
+        s.validate()
+
+
+@click.command()
+@click.argument("stack_name")
+@click.option("--multi", is_flag=True, help="Allow more than one stack to match")
+@click.pass_context
+def provision(ctx, stack_name, multi):
+    """ Creates or updates stacks or stack groups """
+    stacks = _find_stacks(ctx, stack_name, multi)
+
+    for step in sort_stacks(ctx, stacks):
+        if step:
+            with ThreadPoolExecutor(max_workers=len(step)) as group:
+                futures = []
+                for stack in step:
+                    status = stack.get_status()
+                    if not status:
+                        futures.append(group.submit(stack.create))
+                    else:
+                        futures.append(group.submit(stack.update))
+                wait(futures)
+
+
+@click.command()
+@click.argument("stack_name")
+@click.option("--multi", is_flag=True, help="Allow more than one stack to match")
+@click.pass_context
+def delete(ctx, stack_name, multi):
+    """ Deletes stacks or stack groups """
+    stacks = _find_stacks(ctx, stack_name, multi)
+
+    # Reverse steps
+    steps = [s for s in sort_stacks(ctx, stacks)]
+    delete_steps = steps[::-1]
+    for step in delete_steps:
+        if step:
+            with ThreadPoolExecutor(max_workers=len(step)) as group:
+                futures = []
+                for stack in step:
+                    if stack.multi_delete:
+                        futures.append(group.submit(stack.delete))
+
+                wait(futures)
+
+
+@click.command()
+@click.pass_context
+def clean(ctx):
+    """ Deletes all previously rendered files locally """
+    cb = ctx.obj['cb']
+    cb.clean()
+
+
+def sort_stacks(ctx, stacks):
+    """ Sort stacks by dependencies """
+    cb = ctx.obj['cb']
+
+    data = {}
+    for s in stacks:
+        # Resolve dependencies
+        deps = []
+        for d in s.dependencies:
+            # For now we assume deps are artifacts so we prepend them with our local profile and region to match stack.id
+            for dep_stack in cb.filter_stacks({'region': s.region, 'profile': s.profile, 'provides': d}):
+                deps.append(dep_stack.id)
+        
+        data[s.id] = set(deps)
+
+    for k, v in data.items():
+        v.discard(k) # Ignore self dependencies
+
+    extra_items_in_deps = functools.reduce(set.union, data.values()) - set(data.keys())
+    data.update({item:set() for item in extra_items_in_deps})
+    while True:
+        ordered = set(item for item,dep in data.items() if not dep)
+        if not ordered:
+            break
+
+        # return list of stack objects rather than just names
+        result = []
+        for o in ordered:
+            for s in stacks:
+                if s.id == o: result.append(s)
+        yield result
+
+        data = {item: (dep - ordered) for item,dep in data.items()
+                if item not in ordered}
+    assert not data, "A cyclic dependency exists amongst %r" % data
+
+
+def _find_stacks(ctx, stack_name,multi):
+    cb = ctx.obj['cb']
+
+    # ALL acts ass config and multi=True
+    if stack_name == "ALL":
+        multi = True
+        stack_name = "config"
+
+    stacks = cb.resolve_stacks(stack_name)
+
+    if not stacks:
+        logger.error('Cannot find stack matching: {}'.format(stack_name))
+        raise click.Abort()
+
+    if not multi and len(stacks) > 1:
+        logger.error('Found more than one ({}) stacks matching name {}: {}. Abort.'.format(len(stacks), stack_name, [s.stackname for s in stacks]))
+        raise click.Abort()
+
+    return stacks
+
+
+cli.add_command(render)
+cli.add_command(validate)
+cli.add_command(provision)
+cli.add_command(delete)
+cli.add_command(clean)
+
+if __name__ == '__main__':
+    cli(obj={})
diff --git a/cloudbender/connection.py b/cloudbender/connection.py
new file mode 100644
index 0000000..6dbcbfd
--- /dev/null
+++ b/cloudbender/connection.py
@@ -0,0 +1,55 @@
+import os
+
+import boto3
+import botocore.session
+from botocore import credentials
+
+import logging
+
+logger = logging.getLogger(__name__)
+
+class BotoConnection():
+    _sessions= {}
+    _clients = {}
+
+    def __init__(self, profile=None, region=None):
+        self.region = region
+        self.profile = profile
+
+
+    def _get_session(self, profile=None, region=None):
+        if self._sessions.get((profile,region)):
+            return self._sessions[(profile,region)]
+
+        # Construct botocore session with cache
+        # Setup boto to cache STS tokens for MFA
+        # Change the cache path from the default of ~/.aws/boto/cache to the one used by awscli
+        session_vars = {}
+        if profile:
+            session_vars['profile'] = (None,None,profile,None)
+        if region and region != 'global':
+            session_vars['region'] = (None,None,region,None)
+
+        session = botocore.session.Session(session_vars=session_vars)
+        cli_cache = os.path.join(os.path.expanduser('~'),'.aws/cli/cache')
+        session.get_component('credential_provider').get_provider('assume-role').cache = credentials.JSONFileCache(cli_cache)
+
+        self._sessions[(profile,region)] = session
+
+        return session
+
+
+    def _get_client(self, service, profile=None, region=None):
+        if self._clients.get((profile,region,service)):
+            return self._clients[(profile,region,service)]
+
+        session = self._get_session(profile,region)
+        client = boto3.Session(botocore_session=session).client(service)
+
+        self._clients[(profile,region,service)] = client
+        return client
+
+
+    def call(self, service, command, kwargs={}, profile=None, region=None):
+        client = self._get_client(service, profile, region)
+        return getattr(client, command)(**kwargs)
diff --git a/cloudbender/core.py b/cloudbender/core.py
new file mode 100644
index 0000000..45f46cb
--- /dev/null
+++ b/cloudbender/core.py
@@ -0,0 +1,120 @@
+import os
+import glob
+import logging
+
+from .utils import read_yaml_file, ensure_dir
+from .stack import Stack
+from .stackgroup import StackGroup
+from .connection import BotoConnection
+
+logger = logging.getLogger(__name__)
+
+class CloudBender(object):
+    """ Config Class to handle recursive conf/* config tree """
+    def __init__(self, root_path):
+        self.root = root_path
+        self.sg = None
+        self.all_stacks = []
+        self.ctx = {
+            "config_path": os.path.join(self.root, "config"),
+            "template_path": os.path.join(self.root, "cloudformation"),
+            "parameter_path": os.path.join(self.root, "parameters"),
+            "artifact_paths": [os.path.join(self.root, "artifacts")]
+                    }
+
+        if not os.path.isdir(self.root):
+            raise "Check '{0}' exists and is a valid project folder.".format(root_path)
+
+
+    def read_config(self):
+        """Load the <path>/config.yaml, <path>/*.yaml as stacks, sub-folders are child groups """
+
+        # Read top level config.yaml and extract CloudBender CTX
+        _config = read_yaml_file(os.path.join(self.ctx['config_path'], 'config.yaml'))
+        if _config:
+            self.ctx.update(_config.get('CloudBender'))
+
+        # Make sure all paths are abs
+        for k, v in self.ctx.items():
+            if k in ['config_path','template_path','parameter_path','artifact_paths']:
+                if isinstance(v, list):
+                    new_list = []
+                    for path in v:
+                        if not os.path.isabs(path):
+                            new_list.append(os.path.normpath(os.path.join(self.root, path)))
+                        else:
+                            new_list.append(path)
+                    self.ctx[k] = new_list
+
+                elif isinstance(v, str):
+                    if not os.path.isabs(v):
+                        self.ctx[k]=os.path.normpath(os.path.join(self.root, v))
+
+            if k in ['template_path','parameter_path']:
+                ensure_dir(self.ctx[k])
+
+        self.sg = StackGroup(self.ctx['config_path'], self.ctx)
+        self.sg.read_config()
+
+        self.all_stacks = self.sg.get_stacks()
+
+        # If cfn vars config is completely empty set some default for tests to work
+        # if "vars" not in _config:
+        #     _config = { "vars": { 'Azs': {'TestAZ': 'Next'}, 'Segments': {'Testnet': 'internet'}, "Mode": "Piped" } }
+        #     self.vars.update(_config.get('vars'))
+
+
+    def dump_config(self):
+        logger.debug("<CloudBender: {}>".format(vars(self)))
+        self.sg.dump_config()
+
+
+    def clean(self):
+        for s in self.all_stacks:
+            s.delete_template_file()
+            s.delete_parameter_file()
+
+
+    def resolve_stacks(self, token):
+        stacks = None
+
+        # remove optional leading "config/" to allow bash path expansions 
+        if token.startswith("config/"):
+            token = token[7:]
+
+        # If path ends with yaml we look for stacks
+        if token.endswith('.yaml'):
+            stacks = self.sg.get_stacks(token, match_by='path')
+
+        # otherwise assume we look for a group, if we find a group return all stacks below
+        else:
+            # Strip potential trailing slash
+            token = token.rstrip('/')
+
+            sg = self.sg.get_stackgroup(token, match_by='path')
+            if sg:
+                stacks = sg.get_stacks()
+
+        return stacks
+
+
+    def filter_stacks(self, filter_by, stacks=None):
+        # filter_by is a dict { property, value }
+
+        # if no group of stacks provided, look in all available
+        if not stacks:
+            stacks = self.all_stacks
+
+        matching_stacks = []
+        for s in stacks:
+            match = True
+
+            for p,v in filter_by.items():
+                if not (hasattr(s, p) and getattr(s, p) == v):
+                    match = False
+                    break
+
+            if match:
+                matching_stacks.append(s)
+            
+        return matching_stacks
diff --git a/cloudbender/jinja.py b/cloudbender/jinja.py
new file mode 100644
index 0000000..8803415
--- /dev/null
+++ b/cloudbender/jinja.py
@@ -0,0 +1,179 @@
+import os
+import io
+import gzip
+import jinja2
+import oyaml as yaml
+import re
+import base64
+
+import pyminifier.token_utils
+import pyminifier.minification
+import pyminifier.compression
+import pyminifier.obfuscate
+import types
+
+
+import logging
+logger = logging.getLogger(__name__)
+
+@jinja2.contextfunction
+def get_custom_att(context, att=None, ResourceName="FortyTwo", attributes={}, flush=False, dump=False, dependencies=False):
+    """ Returns the rendered required fragement and also collects all foreign
+        attributes for the specified CustomResource to include them later in
+        the actual CustomResource include property """
+
+    # If flush is set all we do is empty our state dict
+    if flush:
+        attributes.clear()
+        return
+
+    # return all registered attributes
+    if dump:
+        return attributes
+
+    # If dependencies, return all Artifacts this stack depends on, which are the attr of FortyTwo
+    if dependencies:
+        deps = set()
+        if ResourceName in attributes:
+            for att in attributes[ResourceName]:
+                deps.add(att.split('.')[0])
+
+        return list(deps)
+    
+    # If call with an attribute, return fragement and register
+    if att:
+        if ResourceName not in attributes:
+            attributes[ResourceName] = set()
+
+        attributes[ResourceName].add(att)
+        config = context.get_all()['_config']
+        if config['cfn']['Mode'] == "FortyTwo":
+            return('{{ "Fn::GetAtt": ["{0}", "{1}"] }}'.format(ResourceName, att))
+        elif config['cfn']['Mode'] == "AWSImport" and ResourceName == "FortyTwo":
+            # AWS only allows - and :, so replace '.' with ":"
+            return('{{ "Fn::ImportValue": {{ "Fn::Sub": "${{Conglomerate}}:{0}" }} }}'.format(att.replace('.',':')))
+        else:
+            # We need to replace . with some PureAlphaNumeric thx AWS ...
+            return('{{ Ref: {0} }}'.format(att.replace('.','DoT')))
+
+
+@jinja2.contextfunction
+def include_raw_gz(context, files=None, gz=True):
+    jenv = context.environment
+    output = ''
+    for name in files:
+        output = output + jinja2.Markup(jenv.loader.get_source(jenv, name)[0])
+
+    # logger.debug(output)
+
+    if not gz:
+        return(output)
+
+    buf = io.BytesIO()
+    f = gzip.GzipFile(mode='w', fileobj=buf, mtime=0)
+    f.write(output.encode())
+    f.close()
+
+    return base64.b64encode(buf.getvalue()).decode('utf-8')
+
+
+@jinja2.contextfunction
+def render_once(context, name=None, resources=set(), reset=False):
+    """ Utility function to True only once """
+
+    if reset:
+        resources.clear()
+        return
+
+    if name and name not in resources:
+        resources.add(name)
+        return True
+
+    return False
+
+
+@jinja2.contextfunction
+def raise_helper(context, msg):
+    raise Exception(msg)
+
+
+# Custom tests
+def regex(value='', pattern='', ignorecase=False, match_type='search'):
+    ''' Expose `re` as a boolean filter using the `search` method by default.
+        This is likely only useful for `search` and `match` which already
+        have their own filters.
+    '''
+    if ignorecase:
+        flags = re.I
+    else:
+        flags = 0
+    _re = re.compile(pattern, flags=flags)
+    if getattr(_re, match_type, 'search')(value) is not None:
+      return True
+    return False
+
+
+def match(value, pattern='', ignorecase=False):
+    ''' Perform a `re.match` returning a boolean '''
+    return regex(value, pattern, ignorecase, 'match')
+
+
+def search(value, pattern='', ignorecase=False):
+    ''' Perform a `re.search` returning a boolean '''
+    return regex(value, pattern, ignorecase, 'search')
+
+
+# Custom filters
+def regex_replace(value='', pattern='', replace='', ignorecase=False):
+    if ignorecase:
+        flags = re.I
+    else:
+        flags = 0
+    return re.sub(pattern,replace,value,flags=flags)
+
+
+def pyminify(source, obfuscate=False, minify=True):
+    # pyminifier options
+    options = types.SimpleNamespace(tabs=False,replacement_length=1,use_nonlatin=0,
+                obfuscate=0,obf_variables=1,obf_classes=0,obf_functions=0,obf_import_methods=0,obf_builtins=0)
+
+    tokens = pyminifier.token_utils.listified_tokenizer(source)
+
+    if minify:
+        source = pyminifier.minification.minify(tokens, options)
+        tokens = pyminifier.token_utils.listified_tokenizer(source)
+
+    if obfuscate:
+        name_generator = pyminifier.obfuscate.obfuscation_machine(use_unicode=False)
+        pyminifier.obfuscate.obfuscate("__main__", tokens, options, name_generator=name_generator)
+        #source = pyminifier.obfuscate.apply_obfuscation(source)
+
+    source = pyminifier.token_utils.untokenize(tokens)
+    # logger.debug(source)
+    minified_source = pyminifier.compression.gz_pack(source)
+    logger.info("Compressed python code to {}".format(len(minified_source)))
+    return minified_source
+
+
+
+def JinjaEnv(template_locations=[]):
+    jenv = jinja2.Environment(trim_blocks=True, lstrip_blocks=True, undefined=jinja2.Undefined)
+
+    jinja_loaders = []
+    for _dir in template_locations:
+        jinja_loaders.append(jinja2.FileSystemLoader(_dir))
+    jenv.loader = jinja2.ChoiceLoader(jinja_loaders)
+
+    jenv.globals['include_raw'] = include_raw_gz
+    jenv.globals['get_custom_att'] = get_custom_att
+    jenv.globals['render_once'] = render_once
+    jenv.globals['raise'] = raise_helper
+
+    jenv.filters['regex_replace'] = regex_replace
+    jenv.filters['pyminify'] = pyminify
+
+    jenv.tests['match'] = match
+    jenv.tests['regex'] = regex
+    jenv.tests['search'] = search
+
+    return jenv
diff --git a/cloudbender/stack.py b/cloudbender/stack.py
new file mode 100644
index 0000000..3434a8c
--- /dev/null
+++ b/cloudbender/stack.py
@@ -0,0 +1,486 @@
+import os
+import re
+import semver
+import hashlib
+import oyaml as yaml
+import json
+import time
+
+from datetime import datetime, timedelta
+from dateutil.tz import tzutc
+
+import botocore
+from botocore.exceptions import ClientError
+
+from .utils import read_yaml_file, dict_merge
+from .connection import BotoConnection
+from .jinja import JinjaEnv
+from . import __version__
+
+import cfnlint.core
+
+import logging
+logger = logging.getLogger(__name__)
+
+
+class StackStatus(object):
+    """
+    StackStatus stores simplified stack statuses.
+    """
+    COMPLETE = "complete"
+    FAILED = "failed"
+    IN_PROGRESS = "in progress"
+    PENDING = "pending"
+
+
+class Stack(object):
+    def __init__(self, name, path, rel_path, tags=None, parameters=None, template_vars=None, region='global', profile=None, template=None, ctx={}):
+        self.id = (profile, region, name)
+        self.stackname = name
+        self.path = path
+        self.rel_path = rel_path
+        self.tags = tags
+        self.parameters = parameters
+        self.template_vars = template_vars
+        self.region = region
+        self.profile = profile
+        self.template = template
+        self.provides = template
+        self.cfn_template = None
+        self.cfn_parameters = []
+        self.connection_manager = BotoConnection(self.profile, self.region)
+        self.ctx = ctx
+        self.status = None
+        self.dependencies = set()
+        self.default_lock = None
+        self.multi_delete = True
+
+
+    def dump_config(self):
+        logger.debug("<Stack {}: {}>".format(self.id, vars(self)))
+
+
+    def read_config(self):
+        _config = read_yaml_file(self.path)
+        for p in ["stackname", "template", "dependencies", "default_lock", "multi_delete", "provides"]:
+            if p in _config:
+                setattr(self, p, _config[p])
+
+        for p in ["parameters", "tags"]:
+            if p in _config:
+                setattr(self, p, dict_merge(getattr(self, p), _config[p]))
+
+        # Inject Artifact for now hard coded
+        self.tags['Artifact'] = self.provides
+
+        if 'vars' in _config:
+            self.template_vars = dict_merge(self.template_vars, _config['vars'])
+
+        logger.info("Stack {} added.".format(self.id))
+
+
+    def check_fortytwo(self, template):
+        # Fail early if 42 is enabled but not available
+        if self.cfn['Mode'] == "FortyTwo" and self.template != 'FortyTwo':
+            try:
+                response = self.connection_manager.call('lambda', 'get_function', {'FunctionName': 'FortyTwo'},
+                                                profile=self.profile, region=self.region)
+
+                # Also verify version in case specified in the template's metadata
+                try:
+                    req_ver = template['Metadata']['FortyTwo']['RequiredVersion']
+                    if 'Release' not in response['Tags']:
+                        abort("Lambda FortyTwo has no Release Tag! Required: {}".format(req_ver))
+                    elif semver.compare(req_ver, re.sub("-.*$",'', response['Tags']['Release'])) > 0:
+                        abort("Lambda FortyTwo version is not recent enough! Required: {} vs. Found: {}".format(req_ver, response['Tags']['Release']))
+                except KeyError:
+                    pass
+
+            except botocore.exceptions.ClientError:
+                abort("No Lambda FortyTwo found in your account")
+
+
+    def render(self):
+        """Renders the cfn jinja template for this stack"""
+
+        jenv = JinjaEnv(self.ctx['artifact_paths'])
+
+        template = jenv.get_template('{0}{1}'.format(self.template, '.yaml.jinja'))
+
+        template_metadata = {
+            'Template.Name': self.template,
+            'Template.Hash': 'unknown',
+            'Template.GitComment': 'unknown',
+            'CloudBender.Version': __version__
+        }
+
+        jenv.globals['_config'] = { 'cfn': self.template_vars, 'Metadata': template_metadata }
+
+        # First render pass to calculate a md5 checksum
+        template_metadata['Template.Hash'] = hashlib.md5(template.render({ 'cfn': self.template_vars, 'Metadata': template_metadata }).encode('utf-8')).hexdigest()
+
+        # Reset and set Metadata for final render pass
+        jenv.globals['get_custom_att'](context={'_config': self.template_vars}, flush=True)
+        jenv.globals['render_once'](context={'_config': self.template_vars}, reset=True)
+
+        # try to get local git info
+        try:
+            self.template_vars['Metadata']['{}.Version'.format(PROJECT_NAME)] = subprocess.check_output('git describe --tags'.split(' '), universal_newlines=True)[:-1]
+
+        except:
+            pass
+
+        # Add latest tag/commit
+        try:
+            os.chdir(ROOT_DIR)
+            _version = subprocess.check_output('git describe --tags'.split(' '), universal_newlines=True)[:-1]
+            if _version:
+                self.template_vars['Metadata']['CloudBender.Version'] = _version
+
+            os.chdir(os.path.dirname(template.filename))
+            _comment = subprocess.check_output('git log -1 --pretty=%B {0}{1}'
+                        .format(input_file, TEMPLATE_EXT).split(' ')).decode('utf-8').strip() \
+                        .replace('"', '').replace('#', '').replace('\n', '').replace(':', ' ')
+            if _comment:
+                self.template_vars['Metadata']['Template.GitComment'] = _comment
+
+            os.chdir(PROJECT_DIR)
+
+        except:
+            pass
+
+        logger.info('Rendering %s', template.filename)
+        rendered = template.render({ 'cfn': self.template_vars, 'Metadata': template_metadata })
+
+        try:
+            data = yaml.load(rendered)
+        except:
+            # In case we rendered invalid yaml this helps to debug
+            logger.error(rendered)
+            raise
+
+        # Some sanity checks and final cosmetics
+        # Check for empty top level Parameters, Outputs and Conditions and remove
+        for key in ['Parameters', 'Outputs', 'Conditions']:
+            if key in data and data[key] is None:
+                # Delete from data structure which also takes care of json
+                del data[key]
+                # but also remove from rendered for the yaml file
+                rendered = rendered.replace('\n'+key+":",'')
+
+        # Condense multiple empty lines to one
+        self.cfn_template = re.sub(r'\n\s*\n', '\n\n', rendered)
+
+
+    def write_template_file(self):
+        if self.cfn_template:
+            yaml_file = os.path.join(self.ctx['template_path'], self.rel_path, self.stackname+".yaml")
+            self._ensure_dirs('template_path')
+            with open(yaml_file, 'w') as yaml_contents:
+                yaml_contents.write(self.cfn_template)
+                logger.info('Wrote %s to %s', self.template, yaml_file)
+
+        else:
+            logger.error('No cfn template rendered yet for stack {}.'.format(self.stackname))
+
+
+    def delete_template_file(self):
+        yaml_file = os.path.join(self.ctx['template_path'], self.rel_path, self.stackname+".yaml")
+        try:
+            os.remove(yaml_file)
+            logger.debug('Deleted cfn template %s.', yaml_file)
+        except OSError:
+            pass
+
+
+    def read_template_file(self):
+        yaml_file = os.path.join(self.ctx['template_path'], self.rel_path, self.stackname+".yaml")
+        with open(yaml_file, 'r') as yaml_contents:
+            self.cfn_template = yaml_contents.read()
+            logger.debug('Read cfn template %s.', yaml_file)
+
+
+    def validate(self):
+        """Validates the rendered template via cfn-lint"""
+        if not self.cfn_template:
+            self.read_template_file()
+
+        data = yaml.load(self.cfn_template)
+        try:
+            ignore_checks = data['Metadata']['cfnlint_ignore']
+        except KeyError:
+            ignore_checks = []
+
+        # Ignore some more checks around injected parameters as we generate these
+        if self.template_vars['Mode'] == "Piped":
+            ignore_checks = ignore_checks+['W2505','W2509','W2507']
+
+        filename = os.path.join(self.ctx['template_path'], self.rel_path, self.stackname+".yaml")
+        logger.info('Validating {0}'.format(filename))
+
+        lint_args = ['--template', filename]
+        if ignore_checks:
+            lint_args.append('--ignore-checks')
+            lint_args = lint_args+ignore_checks
+            logger.info('Ignoring checks: {}'.format(','.join(ignore_checks)))
+
+        (args, filenames, formatter) = cfnlint.core.get_args_filenames(lint_args)
+        (template, rules, matches) = cfnlint.core.get_template_rules(filename, args)
+        if not matches:
+            matches.extend(cfnlint.core.run_cli(filename, template, rules, ['us-east-1'], None))
+        if len(matches):
+            for match in matches:
+                logger.error(formatter._format(match))
+        else:
+            logger.info("Passed.")
+
+
+    def resolve_parameters(self):
+        """ Renders parameters for the stack based on the source template and the environment configuration """
+
+        if not self.cfn_template:
+            self.read_template_file()
+
+        data = yaml.load(self.cfn_template)
+
+        # Inspect all outputs of the running Conglomerate members
+        # if we run in Piped Mode
+        # if self.template_vars['Mode'] == "Piped":
+        #     try:
+        #         stack_outputs = inspect_stacks(config['tags']['Conglomerate'])
+        #         logger.info(pprint.pformat(stack_outputs))
+        #     except KeyError:
+         #        pass
+
+        if 'Parameters' in data:
+            self.cfn_parameters = []
+            for p in data['Parameters']:
+                # In Piped mode we try to resolve all Paramters first via stack_outputs
+                #if config['cfn']['Mode'] == "Piped":
+                #    try:
+                #        # first reverse the rename due to AWS alphanumeric restriction for parameter names
+                #        _p = p.replace('DoT','.')
+                #        value = str(stack_outputs[_p])
+                #        parameters.append({'ParameterKey': p, 'ParameterValue': value })
+                #        logger.info('Got {} = {} from running stack'.format(p,value))
+                #        continue
+                #    except KeyError:
+                #        pass
+
+                # Key name in config tree is: stacks.<self.stackname>.parameters.<parameter>
+                try:
+                    value = str(self.parameters[p])
+                    self.cfn_parameters.append({'ParameterKey': p, 'ParameterValue': value })
+                    logger.info('Got {} = {}'.format(p,value))
+                except KeyError as e:
+                    # If we have a Default defined in the CFN skip, as AWS will use it
+                    if 'Default' in data['Parameters'][p]:
+                        continue
+                    else:
+                        logger.error('Cannot find value for parameter {0}'.format(p))
+
+
+    def write_parameter_file(self):
+        parameter_file = os.path.join(self.ctx['parameter_path'], self.rel_path, self.stackname+".yaml")
+
+        # Render parameters as json for AWS CFN
+        self._ensure_dirs('parameter_path')
+        with open(parameter_file, 'w') as parameter_contents:
+            parameter_contents.write(json.dumps(self.cfn_parameters, indent=2, separators=(',', ': '), sort_keys=True))
+            logger.info('Wrote json parameters for %s to %s', self.stackname, parameter_file)
+
+        if not self.cfn_parameters:
+            # Make sure there are no parameters from previous runs
+            if os.path.isfile(parameter_file):
+                os.remove(parameter_file)
+
+
+    def delete_parameter_file(self):
+        parameter_file = os.path.join(self.ctx['parameter_path'], self.rel_path, self.stackname+".yaml")
+        try:
+            os.remove(parameter_file)
+            logger.debug('Deleted parameter %s.', parameter_file)
+        except OSError:
+            pass
+
+
+    def create(self):
+        """Creates a stack """
+
+        # Prepare parameters
+        self.resolve_parameters()
+        self.write_parameter_file()
+
+        if not self.cfn_template:
+            self.read_template_file()
+
+        logger.info('Creating {0}'.format(self.stackname))
+        response = self.connection_manager.call('cloudformation', 'create_stack',
+                       {'StackName':self.stackname,
+                        'TemplateBody':self.cfn_template,
+                       'Parameters':self.cfn_parameters,
+                       'Tags':[ {"Key": str(k), "Value": str(v)} for k, v in self.tags.items() ],
+                       'Capabilities':['CAPABILITY_IAM', 'CAPABILITY_NAMED_IAM']},
+                        profile=self.profile, region=self.region)
+
+        return self._wait_for_completion()
+
+
+    def update(self):
+        """Updates an existing stack """
+
+        # Prepare parameters
+        self.resolve_parameters()
+        self.write_parameter_file()
+
+        if not self.cfn_template:
+            self.read_template_file()
+
+        logger.info('Updating {0}'.format(self.stackname))
+        try:
+            response = self.connection_manager.call('cloudformation', 'update_stack',
+                           {'StackName':self.stackname,
+                           'TemplateBody':self.cfn_template,
+                           'Parameters':self.cfn_parameters,
+                           'Tags':[ {"Key": str(k), "Value": str(v)} for k, v in self.tags.items() ],
+                           'Capabilities':['CAPABILITY_IAM', 'CAPABILITY_NAMED_IAM']},
+                            profile=self.profile, region=self.region)
+
+        except ClientError as e:
+            if 'No updates are to be performed' in e.response['Error']['Message']:
+                logger.info('No updates for {0}'.format(self.stackname))
+                return StackStatus.COMPLETE
+            else:
+                raise e
+
+        return self._wait_for_completion()
+
+
+    def delete(self):
+        """Deletes a stack """
+
+        logger.info('Deleting {0}'.format(self.stackname))
+        response = self.connection_manager.call('cloudformation', 'delete_stack',
+                       {'StackName':self.stackname}, profile=self.profile, region=self.region)
+
+        return self._wait_for_completion()
+
+
+    def describe(self):
+        """
+        Returns the a description of the stack.
+        :returns: A stack description.
+        """
+        return self.connection_manager.call(
+            "cloudformation",
+            "describe_stacks",
+            {"StackName": self.stackname},
+            profile=self.profile, region=self.region)
+
+
+    def get_status(self):
+        """
+        Returns the stack's status.
+        :returns: The stack's status.
+        """
+        try:
+            status = self.describe()["Stacks"][0]["StackStatus"]
+        except ClientError as e:
+            if e.response["Error"]["Message"].endswith("does not exist"):
+                return None
+            else:
+                raise e
+        return status
+
+
+    def describe_events(self):
+        """
+        Returns a dictionary contianing the stack events.
+        :returns: The CloudFormation events for a stack.
+        """
+        try:
+            status = self.connection_manager.call(
+                "cloudformation",
+                "describe_stack_events",
+                {"StackName": self.stackname},
+                profile=self.profile, region=self.region)
+        except ClientError as e:
+            if e.response["Error"]["Message"].endswith("does not exist"):
+                return None
+            else:
+                raise e
+
+        return status
+
+
+    def _wait_for_completion(self, timeout=0):
+        """
+        Waits for a stack operation to finish. Prints CloudFormation events while it waits.
+        :param timeout: Timeout before returning
+        :returns: The final stack status.
+        """
+
+        def timed_out(elapsed):
+            return elapsed >= timeout if timeout else False
+
+        status = StackStatus.IN_PROGRESS
+
+        self.most_recent_event_datetime = (
+            datetime.now(tzutc()) - timedelta(seconds=3)
+        )
+        elapsed = 0
+        while status == StackStatus.IN_PROGRESS and not timed_out(elapsed):
+            status = self._get_simplified_status(self.get_status())
+            if not status:
+                return None
+
+            self._log_new_events()
+            time.sleep(4)
+            elapsed += 4
+
+        return status
+
+
+    @staticmethod
+    def _get_simplified_status(status):
+        """ Returns the simplified Stack Status.  """
+        if status:
+            if status.endswith("ROLLBACK_COMPLETE"):
+                return StackStatus.FAILED
+            elif status.endswith("_COMPLETE"):
+                return StackStatus.COMPLETE
+            elif status.endswith("_IN_PROGRESS"):
+                return StackStatus.IN_PROGRESS
+            elif status.endswith("_FAILED"):
+                return StackStatus.FAILED
+            else:
+                return 'Unknown'
+
+
+    def _log_new_events(self):
+        """
+        Log the latest stack events while the stack is being built.
+        """
+        events = self.describe_events()
+        if events:
+            events = events["StackEvents"]
+            events.reverse()
+            new_events = [
+                event for event in events
+                if event["Timestamp"] > self.most_recent_event_datetime
+            ]
+            for event in new_events:
+                logger.info(" ".join([
+                    self.stackname,
+                    event["LogicalResourceId"],
+                    event["ResourceType"],
+                    event["ResourceStatus"],
+                    event.get("ResourceStatusReason", "")
+                ]))
+                self.most_recent_event_datetime = event["Timestamp"]
+
+
+    def _ensure_dirs(self, path):
+        # Ensure output dirs exist
+        if not os.path.exists(os.path.join(self.ctx[path], self.rel_path)):
+            os.makedirs(os.path.join(self.ctx[path], self.rel_path))
diff --git a/cloudbender/stackgroup.py b/cloudbender/stackgroup.py
new file mode 100644
index 0000000..e4f6bd2
--- /dev/null
+++ b/cloudbender/stackgroup.py
@@ -0,0 +1,169 @@
+import os
+import glob
+import logging
+
+from .utils import read_yaml_file, dict_merge
+from .stack import Stack
+
+logger = logging.getLogger(__name__)
+
+
+class StackGroup(object):
+    def __init__(self, path, ctx):
+        self.name = None
+        self.ctx = ctx
+        self.path = path
+        self.rel_path = os.path.relpath(path ,ctx['config_path'])
+        self.config = {}
+        self.sgs = []
+        self.stacks = []
+
+        if self.rel_path == '.':
+            self.rel_path = ''
+
+
+    def dump_config(self):
+        for sg in self.sgs:
+            sg.dump_config()
+
+        logger.debug("<StackGroup {}: {}>".format(self.name, vars(self)))
+
+        for s in self.stacks:
+            s.dump_config()
+
+
+    def read_config(self, parent_config={}):
+
+        if not os.path.isdir(self.path):
+            return None
+
+        # First read config.yaml if present
+        _config = read_yaml_file(os.path.join(self.path, 'config.yaml'))
+
+        # Stack Group name if not explicit via config is derived from subfolder, or in case of root object the parent folder
+        if "stackgroupname" in _config:
+            self.name = _config["stackgroupname"]
+        elif not self.name:
+            self.name = os.path.split(self.path)[1]
+
+        # Merge config with parent config
+        _config = dict_merge(parent_config, _config)
+
+        tags = _config.get('tags', {})
+        parameters = _config.get('parameters', {})
+        template_vars = _config.get('vars', {})
+        region = _config.get('region', 'global')
+        profile = _config.get('profile', '')
+        stackname_prefix = _config.get('stacknameprefix', '')
+
+        logger.info("StackGroup {} added.".format(self.name))
+
+        # Add stacks
+        stacks = [s for s in glob.glob(os.path.join(self.path, '*.yaml')) if not s.endswith("config.yaml")]
+        for stack_path in stacks:
+            stackname = os.path.basename(stack_path).split('.')[0]
+            template = stackname
+            if stackname_prefix:
+                stackname = stackname_prefix + stackname
+
+            new_stack = Stack(name=stackname, template=template,
+                            path=stack_path, rel_path=str(self.rel_path),
+                            tags=dict(tags), parameters=dict(parameters),
+                            template_vars=dict(template_vars),
+                            region=str(region), profile=str(profile),
+                            ctx=self.ctx
+                            )
+            new_stack.read_config()
+            self.stacks.append(new_stack)
+
+        # Create StackGroups recursively
+        for sub_group in [f.path for f in os.scandir(self.path) if f.is_dir() ]:
+            sg = StackGroup(sub_group, self.ctx)
+            sg.read_config(_config)
+
+            self.sgs.append(sg)
+
+        # Return raw, merged config to parent
+        return _config
+
+
+    def get_stacks(self, name=None, recursive=True, match_by='name'):
+        """ Returns [stack] matching stack_name or [all] """
+        stacks = []
+        if name:
+            logger.debug("Looking for stack {} in group {}".format(name, self.name))
+
+        for s in self.stacks:
+            if not name or (s.stackname == name and match_by == 'name') or (s.path.endswith(name) and match_by == 'path'):
+                if self.rel_path:
+                    logger.debug("Found stack {} in group {}".format(s.stackname, self.rel_path))
+                else:
+                    logger.debug("Found stack {}".format(s.stackname))
+                stacks.append(s)
+
+        if recursive:
+            for sg in self.sgs:
+                s = sg.get_stacks(name, recursive, match_by)
+                if s:
+                    stacks = stacks+s
+
+        return stacks
+
+
+    def get_stackgroup(self, name=None, recursive=True, match_by='name'):
+        """ Returns stack group matching stackgroup_name or all if None """
+        if not name or (self.name == name and match_by == 'name') or (self.path.endswith(name) and match_by == 'path'):
+            logger.debug("Found stack_group {}".format(self.name))
+            return self
+
+        if name and name != 'config':
+            logger.debug("Looking for stack_group {} in group {}".format(name, self.name))
+
+        if recursive:
+            for sg in self.sgs:
+                s = sg.get_stackgroup(name, recursive, match_by)
+                if s:
+                    return s
+
+        return None
+
+
+    # TODO: Integrate properly into stackgroup class, borken for now
+    # stackoutput inspection
+    def BROKEN_inspect_stacks(conglomerate):
+        # Get all stacks of the conglomertate
+        client = Connection.get_connection('cloudformation')
+        running_stacks=client.describe_stacks()
+
+        stacks = []
+        for stack in running_stacks['Stacks']:
+            for tag in stack['Tags']:
+                if tag['Key'] == 'Conglomerate' and tag['Value'] == conglomerate:
+                    stacks.append(stack)
+                    break
+
+
+        # Gather stack outputs, use Tag['Artifact'] as name space: Artifact.OutputName, same as FortyTwo
+        stack_outputs = {}
+        for stack in stacks:
+            # If stack has an Artifact Tag put resources into the namespace Artifact.Resource
+            artifact = None
+            for tag in stack['Tags']:
+                if tag['Key'] == 'Artifact':
+                    artifact = tag['Value']
+
+            if artifact:
+                key_prefix = "{}.".format(artifact)
+            else:
+                key_prefix = ""
+
+            try:
+                for output in stack['Outputs']:
+                    # Gather all outputs of the stack into one dimensional key=value structure
+                    stack_outputs[key_prefix+output['OutputKey']]=output['OutputValue']
+            except KeyError:
+                pass
+
+        # Add outputs from stacks into the data for jinja under StackOutput
+        return stack_outputs
+
diff --git a/cloudbender/utils.py b/cloudbender/utils.py
new file mode 100644
index 0000000..2fb9d93
--- /dev/null
+++ b/cloudbender/utils.py
@@ -0,0 +1,70 @@
+import os
+import yaml
+import copy
+import logging
+import boto3
+
+logger = logging.getLogger(__name__)
+
+def read_yaml_file(path):
+    data = {}
+    if os.path.exists(path):
+        with open(path, 'r') as config_file_contents:
+            logger.debug("Reading config file: {}".format(path))
+            try:
+                _data = yaml.load(config_file_contents.read())
+                if _data:
+                    data.update(_data)
+            except Exception as e:
+                logger.warning("Error reading config file: {} ({})".format(path,e))
+
+    return data
+
+
+def dict_merge(a, b):
+    """ Deep merge to allow proper inheritance for config files"""
+    if not a:
+        return b
+
+    if not b:
+        return a
+
+    if  not isinstance(a, dict) or not isinstance(b, dict):
+        raise TypeError
+
+    result = copy.deepcopy(a)
+    for k, v in b.items():
+        if k in result and isinstance(result[k], dict):
+                result[k] = dict_merge(result[k], v)
+        else:
+            result[k] = copy.deepcopy(v)
+    return result
+
+
+def ensure_dir(path):
+    """Creates dir if it does not already exist."""
+    if not os.path.exists(path):
+        os.makedirs(path)
+        logger.info('Created directory: %s', path)
+
+
+def setup_logging(debug):
+    if debug:
+        our_level = logging.DEBUG
+        # logging.getLogger("botocore").setLevel(logging.INFO)
+        boto3.set_stream_logger('')
+    else:
+        our_level = logging.INFO
+        logging.getLogger("botocore").setLevel(logging.CRITICAL)
+
+    formatter = logging.Formatter(
+        fmt="[%(asctime)s] - %(name)s - %(message)s",
+        datefmt="%Y-%m-%d %H:%M:%S"
+    )
+
+    log_handler = logging.StreamHandler()
+    log_handler.setFormatter(formatter)
+    logger = logging.getLogger("cloudbender")
+    logger.addHandler(log_handler)
+    logger.setLevel(our_level)
+    return logger
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..17b923a
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1,8 @@
+boto3
+Jinja2
+oyaml
+click
+pytest
+semver
+pyminifier
+cfn-lint