import os import re import hashlib import yaml import time import pathlib import pprint from datetime import datetime, timedelta from dateutil.tz import tzutc from botocore.exceptions import ClientError from .utils import dict_merge, search_refs, ensure_dir, get_s3_url from .connection import BotoConnection from .jinja import JinjaEnv, read_config_file from . import __version__ from .exceptions import ParameterNotFound, ParameterIllegalValue from .hooks import exec_hooks import cfnlint.core import cfnlint.template import cfnlint.graph try: import importlib.resources as pkg_resources except ImportError: import importlib_resources as pkg_resources from . import templates import logging logger = logging.getLogger(__name__) # Ignore any ! during re-loading of CFN templates class SafeLoaderIgnoreUnknown(yaml.SafeLoader): def ignore_unknown(self, node): return node.tag SafeLoaderIgnoreUnknown.add_constructor(None, SafeLoaderIgnoreUnknown.ignore_unknown) class Stack(object): def __init__(self, name, template, path, rel_path, ctx): self.stackname = name self.template = template self.path = pathlib.Path(path) self.rel_path = rel_path self.ctx = ctx self.tags = {} self.parameters = {} self.outputs = {} self.options = {'Legacy': False} self.region = 'global' self.profile = '' self.onfailure = 'DELETE' self.notfication_sns = [] self.id = (self.profile, self.region, self.stackname) self.aws_stackid = None self.md5 = None self.mode = 'CloudBender' self.provides = template self.cfn_template = None self.cfn_parameters = [] self.cfn_data = None self.connection_manager = BotoConnection(self.profile, self.region) self.status = None self.store_outputs = False self.dependencies = set() self.hooks = {'post_create': [], 'post_update': [], 'pre_create': [], 'pre_update': []} self.default_lock = None self.multi_delete = True self.template_bucket_url = None def dump_config(self): logger.debug("".format(self.id, pprint.pformat(vars(self)))) def read_config(self, sg_config={}): """ reads stack config """ # First set various attributes based on parent stackgroup config self.tags.update(sg_config.get('tags', {})) self.parameters.update(sg_config.get('parameters', {})) self.options.update(sg_config.get('options', {})) # by default inherit parent group settings for p in ['region', 'profile', 'notfication_sns', 'template_bucket_url']: if p in sg_config: setattr(self, p, sg_config[p]) # now override stack specific settings _config = read_config_file(self.path, sg_config.get('variables', {})) for p in ["region", "stackname", "template", "default_lock", "multi_delete", "provides", "onfailure", "notification_sns", "template_bucket_url"]: 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 if not explicitly set if 'Artifact' not in self.tags: self.tags['Artifact'] = self.provides if 'options' in _config: self.options = dict_merge(self.options, _config['options']) if 'Mode' in self.options: self.mode = self.options['Mode'] if 'StoreOutputs' in self.options and self.options['StoreOutputs']: self.store_outputs = True if 'dependencies' in _config: for dep in _config['dependencies']: self.dependencies.add(dep) # Some sanity checks if self.onfailure not in ["DO_NOTHING", "ROLLBACK", "DELETE"]: raise ParameterIllegalValue("onfailure must be one of DO_NOTHING | ROLLBACK | DELETE") logger.debug("Stack {} added.".format(self.id)) def render(self): """Renders the cfn jinja template for this stack""" template_metadata = { 'Template.Name': self.template, 'Template.Hash': "__HASH__", 'CloudBender.Version': __version__ } _config = {'mode': self.mode, 'options': self.options, 'metadata': template_metadata} jenv = JinjaEnv(self.ctx['artifact_paths']) jenv.globals['_config'] = _config template = jenv.get_template('{0}{1}'.format(self.template, '.yaml.jinja')) logger.info('Rendering %s', template.filename) try: self.cfn_template = template.render(_config) self.cfn_data = yaml.load(self.cfn_template, Loader=SafeLoaderIgnoreUnknown) except Exception as e: # In case we rendered invalid yaml this helps to debug if self.cfn_template: _output = "" for i, line in enumerate(self.cfn_template.splitlines(), start=1): _output = _output + '{}: {}\n'.format(i, line) logger.error(_output) raise e if not re.search('CloudBender::', self.cfn_template) and not re.search('Iterate:', self.cfn_template): logger.info("CloudBender not required -> removing Transform and Conglomerate parameter") self.cfn_template = self.cfn_template.replace('Transform: [CloudBender]', '') _res = """ Conglomerate: Type: String Description: Project / Namespace this stack is part of """ self.cfn_template = re.sub(_res, '', self.cfn_template) # Add Legacy FortyTwo resource to prevent AWS from replacing existing resources for NO reason ;-( include = [] search_refs(self.cfn_data, include, self.mode) if self.mode != "Piped" and len(include) and self.options['Legacy']: _res = """ FortyTwo: Type: Custom::FortyTwo Properties: ServiceToken: Fn::Sub: "arn:aws:lambda:${{AWS::Region}}:${{AWS::AccountId}}:function:FortyTwo" UpdateToken: __HASH__ Include: {}""".format(sorted(set(include))) self.cfn_template = re.sub(r'Resources:', r'Resources:' + _res + '\n', self.cfn_template) logger.info("Legacy Mode -> added Custom::FortyTwo") elif self.mode == "Piped" and len(include): _res = "" for attr in include: _res = _res + """ {0}: Type: String Description: Parameter to provide remote stack attribute {0}""".format(attr) self.cfn_template = re.sub(r'Parameters:', r'Parameters:' + _res + '\n', self.cfn_template) logger.info("Piped mode: Added parameters for remote stack references") # Re-read updated template self.cfn_data = yaml.load(self.cfn_template, Loader=SafeLoaderIgnoreUnknown) # Check for empty top level Parameters, Outputs and Conditions and remove for key in ['Parameters', 'Outputs', 'Conditions']: if key in self.cfn_data and not self.cfn_data[key]: del self.cfn_data[key] self.cfn_template = self.cfn_template.replace('\n' + key + ":", '') # Remove and condense multiple empty lines self.cfn_template = re.sub(r'\n\s*\n', '\n\n', self.cfn_template) self.cfn_template = re.sub(r'^\s*', '', self.cfn_template) self.cfn_template = re.sub(r'\s*$', '', self.cfn_template) # set md5 last self.md5 = hashlib.md5(self.cfn_template.encode('utf-8')).hexdigest() self.cfn_template = self.cfn_template.replace('__HASH__', self.md5) # Update internal data structures self._parse_metadata() def _parse_metadata(self): # Extract dependencies try: for dep in self.cfn_data['Metadata']['CloudBender']['Dependencies']: self.dependencies.add(dep) except KeyError: pass # Add CloudBender or FortyTwo dependencies include = [] search_refs(self.cfn_data, include, self.mode) for ref in include: if self.mode != "Piped": self.dependencies.add(ref.split('.')[0]) else: self.dependencies.add(ref.split('DoT')[0]) # Extract hooks try: for hook, func in self.cfn_data['Metadata']['Hooks'].items(): if hook in ['post_update', 'post_create', 'pre_create', 'pre_update']: if isinstance(func, list): self.hooks[hook].extend(func) else: self.hooks[hook].append(func) except KeyError: pass def write_template_file(self): if self.cfn_template: yaml_file = os.path.join(self.ctx['template_path'], self.rel_path, self.stackname + ".yaml") ensure_dir(os.path.join(self.ctx['template_path'], self.rel_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) # upload template to s3 if set if self.template_bucket_url: try: (bucket, path) = get_s3_url(self.template_bucket_url, self.rel_path, self.stackname + ".yaml") self.connection_manager.call( 's3', 'put_object', {'Bucket': bucket, 'Key': path, 'Body': self.cfn_template, 'ServerSideEncryption': 'AES256'}, profile=self.profile, region=self.region) logger.info("Uploaded template to s3://{}/{}".format(bucket, path)) except ClientError as e: logger.error("Error trying to upload template so S3: {}, {}".format(self.template_bucket_url, e)) else: if len(self.cfn_template) > 51200: logger.warning("template_bucket_url not set and rendered template exceeds maximum allowed size of 51200, actual size: {} !".format(len(self.cfn_template))) 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 if self.template_bucket_url: try: (bucket, path) = get_s3_url(self.template_bucket_url, self.rel_path, self.stackname + ".yaml") self.connection_manager.call( 's3', 'delete_object', {'Bucket': bucket, 'Key': path}, profile=self.profile, region=self.region) logger.info("Deleted template from s3://{}/{}".format(bucket, path)) except ClientError as e: logger.error("Error trying to delete template from S3: {}, {}".format(self.template_bucket_url, e)) def read_template_file(self): """ Reads rendered yaml template from disk or s3 and extracts metadata """ if not self.cfn_template: if self.template_bucket_url: try: (bucket, path) = get_s3_url(self.template_bucket_url, self.rel_path, self.stackname + ".yaml") template = self.connection_manager.call( 's3', 'get_object', {'Bucket': bucket, 'Key': path}, profile=self.profile, region=self.region) logger.debug("Got template from s3://{}/{}".format(bucket, path)) self.cfn_template = template['Body'].read().decode('utf-8') # Overwrite local copy yaml_file = os.path.join(self.ctx['template_path'], self.rel_path, self.stackname + ".yaml") ensure_dir(os.path.join(self.ctx['template_path'], self.rel_path)) with open(yaml_file, 'w') as yaml_contents: yaml_contents.write(self.cfn_template) except ClientError as e: logger.error("Could not find template file on S3: {}/{}, {}".format(bucket, path, e)) else: yaml_file = os.path.join(self.ctx['template_path'], self.rel_path, self.stackname + ".yaml") try: with open(yaml_file, 'r') as yaml_contents: self.cfn_template = yaml_contents.read() logger.debug('Read cfn template %s.', yaml_file) except FileNotFoundError as e: logger.warn("Could not find template file: {}".format(yaml_file)) raise e self.cfn_data = yaml.load(self.cfn_template, Loader=SafeLoaderIgnoreUnknown) self._parse_metadata() else: logger.debug('Using cached cfn template %s.', self.stackname) def validate(self): """Validates the rendered template via cfn-lint""" self.read_template_file() try: ignore_checks = self.cfn_data['Metadata']['cfnlint_ignore'] except KeyError: ignore_checks = [] # Ignore some more checks around injected parameters as we generate these if self.mode == "Piped": ignore_checks = ignore_checks + ['W2505', 'W2509', 'W2507'] # Ignore checks regarding overloaded properties if self.mode == "CloudBender": ignore_checks = ignore_checks + ['E3035', 'E3002', 'E3012', 'W2001', 'E3001', 'E0002', 'E1012'] 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_checks(filename, template, rules, [self.region])) if len(matches): for match in matches: logger.error(formatter._format(match)) else: logger.info("Passed.") def get_outputs(self, include='.*', values=False): """ gets outputs of the stack """ try: stacks = self.connection_manager.call( "cloudformation", "describe_stacks", {'StackName': self.stackname}, profile=self.profile, region=self.region)['Stacks'] try: for output in stacks[0]['Outputs']: self.outputs[output['OutputKey']] = output['OutputValue'] logger.debug("Stack outputs for {} in {}: {}".format(self.stackname, self.region, self.outputs)) except KeyError: pass except ClientError: logger.warn("Could not get outputs of {}".format(self.stackname)) pass if self.outputs: logger.info('{} {} Outputs:\n{}'.format(self.region, self.stackname, pprint.pformat(self.outputs, indent=2))) if self.store_outputs: self.write_outputs_file() def write_outputs_file(self, template='outputs.yaml', filename=False): if not filename: output_file = os.path.join(self.ctx['outputs_path'], self.rel_path, self.stackname + ".yaml") else: output_file = os.path.join(self.ctx['outputs_path'], self.rel_path, filename) ensure_dir(os.path.join(self.ctx['outputs_path'], self.rel_path)) my_template = pkg_resources.read_text(templates, template) jenv = JinjaEnv() template = jenv.from_string(my_template) data = {'stackname': "/".join([self.rel_path, self.stackname]), 'timestamp': datetime.strftime(datetime.now(tzutc()), "%d/%m/%y %H:%M"), 'outputs': self.outputs, 'parameters': self.parameters} with open(output_file, 'w') as output_contents: output_contents.write(template.render(**data)) logger.info('Wrote outputs for %s to %s', self.stackname, output_file) def create_docs(self, template=False, graph=False): """ Read rendered template, parse documentation fragments, eg. parameter description and create a mardown doc file for the stack same idea as eg. helm-docs for values.yaml """ try: self.read_template_file() except FileNotFoundError: return if not template: doc_template = pkg_resources.read_text(templates, 'stack-doc.md') jenv = JinjaEnv() template = jenv.from_string(doc_template) data = {} else: doc_template = template data['name'] = self.stackname data['description'] = self.cfn_data['Description'] data['dependencies'] = self.dependencies if 'Parameters' in self.cfn_data: data['parameters'] = self.cfn_data['Parameters'] set_parameters = self.resolve_parameters() for p in set_parameters: data['parameters'][p]['value'] = set_parameters[p] if 'Outputs' in self.cfn_data: data['outputs'] = self.cfn_data['Outputs'] # Check for existing outputs yaml, if found add current value column and set header to timestamp from outputs file output_file = os.path.join(self.ctx['outputs_path'], self.rel_path, self.stackname + ".yaml") try: with open(output_file, 'r') as yaml_contents: outputs = yaml.safe_load(yaml_contents.read()) for p in outputs['Outputs']: data['outputs'][p]['last_value'] = outputs['Outputs'][p] data['timestamp'] = outputs['TimeStamp'] except (FileNotFoundError, KeyError, TypeError): pass doc_file = os.path.join(self.ctx['docs_path'], self.rel_path, self.stackname + ".md") ensure_dir(os.path.join(self.ctx['docs_path'], self.rel_path)) with open(doc_file, 'w') as doc_contents: doc_contents.write(template.render(**data)) logger.info('Wrote documentation for %s to %s', self.stackname, doc_file) # Write Graph in Dot format if graph: filename = os.path.join(self.ctx['template_path'], self.rel_path, self.stackname + ".yaml") lint_args = ['--template', filename] (args, filenames, formatter) = cfnlint.core.get_args_filenames(lint_args) (template, rules, matches) = cfnlint.core.get_template_rules(filename, args) template_obj = cfnlint.template.Template(filename, template, [self.region]) path = os.path.join(self.ctx['docs_path'], self.rel_path, self.stackname + ".dot") g = cfnlint.graph.Graph(template_obj) try: g.to_dot(path) logger.info('DOT representation of the graph written to %s', path) except ImportError: logger.error( 'Could not write the graph in DOT format. Please install either `pygraphviz` or `pydot` modules.') def resolve_parameters(self): """ Renders parameters for the stack based on the source template and the environment configuration """ self.read_template_file() # if we run in Piped Mode, inspect all outputs of the running Conglomerate members if self.mode == "Piped": stack_outputs = {} try: stack_outputs = self._inspect_stacks(self.tags['Conglomerate']) except KeyError: pass _found = {} if 'Parameters' in self.cfn_data: _errors = [] self.cfn_parameters = [] for p in self.cfn_data['Parameters']: # In Piped mode we try to resolve all Paramters first via stack_outputs if self.mode == "Piped": try: # first reverse the rename due to AWS alphanumeric restriction for parameter names _p = p.replace('DoT', '.') value = str(stack_outputs[_p]) self.cfn_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..parameters. if p in self.parameters: value = str(self.parameters[p]) self.cfn_parameters.append({'ParameterKey': p, 'ParameterValue': value}) # Hide NoEcho parameters in shell output if 'NoEcho' in self.cfn_data['Parameters'][p] and self.cfn_data['Parameters'][p]['NoEcho']: value = '****' _found[p] = value else: # If we have a Default defined in the CFN skip, as AWS will use it if 'Default' not in self.cfn_data['Parameters'][p]: _errors.append(p) if _errors: raise ParameterNotFound('Cannot find value for parameters: {0}'.format(_errors)) # Warning of excessive parameters, might be useful to spot typos early _warnings = [] for p in self.parameters.keys(): if p not in self.cfn_data['Parameters']: _warnings.append(p) logger.info('{} {} set parameters:\n{}'.format(self.region, self.stackname, pprint.pformat(_found, indent=2))) if _warnings: logger.warning('Ignored additional parameters: {}.'.format(_warnings)) # Return dict of explicitly set parameters return _found @exec_hooks def create(self): """Creates a stack """ # Prepare parameters self.resolve_parameters() logger.info('Creating {0} {1}'.format(self.region, self.stackname)) kwargs = {'StackName': self.stackname, 'Parameters': self.cfn_parameters, 'OnFailure': self.onfailure, 'NotificationARNs': self.notfication_sns, 'Tags': [{"Key": str(k), "Value": str(v)} for k, v in self.tags.items()], 'Capabilities': ['CAPABILITY_IAM', 'CAPABILITY_NAMED_IAM', 'CAPABILITY_AUTO_EXPAND']} kwargs = self._add_template_arg(kwargs) self.aws_stackid = self.connection_manager.call( 'cloudformation', 'create_stack', kwargs, profile=self.profile, region=self.region) status = self._wait_for_completion() self.get_outputs() return status @exec_hooks def update(self): """Updates an existing stack """ # Prepare parameters self.resolve_parameters() logger.info('Updating {0} {1}'.format(self.region, self.stackname)) try: kwargs = {'StackName': self.stackname, 'Parameters': self.cfn_parameters, 'NotificationARNs': self.notfication_sns, 'Tags': [{"Key": str(k), "Value": str(v)} for k, v in self.tags.items()], 'Capabilities': ['CAPABILITY_IAM', 'CAPABILITY_NAMED_IAM', 'CAPABILITY_AUTO_EXPAND']} kwargs = self._add_template_arg(kwargs) self.aws_stackid = self.connection_manager.call( 'cloudformation', 'update_stack', kwargs, 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 "COMPLETE" else: raise e status = self._wait_for_completion() self.get_outputs() return status @exec_hooks def delete(self): """Deletes a stack """ logger.info('Deleting {0} {1}'.format(self.region, self.stackname)) self.aws_stackid = self.connection_manager.call( 'cloudformation', 'delete_stack', {'StackName': self.stackname}, profile=self.profile, region=self.region) status = self._wait_for_completion() return status def create_change_set(self, change_set_name): """ Creates a Change Set with the name ``change_set_name``. """ # Prepare parameters self.resolve_parameters() self.read_template_file() logger.info('Creating change set {0} for stack {1}'.format(change_set_name, self.stackname)) kwargs = {'StackName': self.stackname, 'ChangeSetName': change_set_name, 'Parameters': self.cfn_parameters, 'Tags': [{"Key": str(k), "Value": str(v)} for k, v in self.tags.items()], 'Capabilities': ['CAPABILITY_IAM', 'CAPABILITY_NAMED_IAM']} kwargs = self._add_template_arg(kwargs) self.connection_manager.call( 'cloudformation', 'create_change_set', kwargs, profile=self.profile, region=self.region) return self._wait_for_completion() def get_status(self): """ Returns the stack's status. :returns: The stack's status. """ try: status = self.connection_manager.call( "cloudformation", "describe_stacks", {"StackName": self.stackname}, profile=self.profile, region=self.region)["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 = "IN_PROGRESS" self.most_recent_event_datetime = ( datetime.now(tzutc()) - timedelta(seconds=3) ) elapsed = 0 while status == "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 "FAILED" elif status.endswith("_COMPLETE"): return "COMPLETE" elif status.endswith("_IN_PROGRESS"): return "IN_PROGRESS" elif status.endswith("_FAILED"): return "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.region, self.stackname, event["LogicalResourceId"], event["ResourceType"], event["ResourceStatus"], event.get("ResourceStatusReason", "") ])) self.most_recent_event_datetime = event["Timestamp"] # stackoutput inspection def _inspect_stacks(self, conglomerate): # Get all stacks of the conglomertate running_stacks = self.connection_manager.call( "cloudformation", "describe_stacks", profile=self.profile, region=self.region) 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 def _add_template_arg(self, kwargs): if self.template_bucket_url: # https://bucket-name.s3.Region.amazonaws.com/key name # so we need the region, AWS as usual (bucket, path) = get_s3_url(self.template_bucket_url, self.rel_path, self.stackname + ".yaml") bucket_region = self.connection_manager.call('s3', 'get_bucket_location', {'Bucket': bucket}, profile=self.profile, region=self.region)['LocationConstraint'] kwargs['TemplateURL'] = 'https://{}.s3.{}.amazonaws.com/{}'.format(bucket, bucket_region, path) else: kwargs['TemplateBody'] = self.cfn_template return kwargs