drbild / stratiform

Concise creation of AWS CloudFormation templates

stratiform

[DEPRECATED] This library is deprecated. Use something Hashicorp Terraform instead (although the limited expressiveness of declarative HCL is a significant step backwards).

Stratiform is a Python library for concisely creating AWS CloudFormation JSON templates. Python's expressiveness leads to simpler and easier-to-read templates than a purley declarative approach like JSON (or HCL), significantly reducing the number of accidental misconfigurations.

Install

pip install stratiform

Usage

A Stratiform template is simply a python script that defines the AWS resources as Stratiform objects and then prints corresponding CloudFormation JSON to stdout.

from stratiform import *
import stratiform.ec2 as ec2

# Create a template
t = template("VPC stack - VPC, Subnets, and Routing Rules")
Tags = tags(Deployment=t.Deployment, Stack=StackName)

# Define constants
CIDR_VPC    = cidr("10.20.0.0/16")
CIDR_PUBLIC = cidr("10.20.10.0/24")
ZONE        = az('us-west-2a')

# Define parameters, resources, outputs, etc., in the template
t.Deployment = string_parameter(description="Environment containing this stack.",
                                allowed_values=['dev', 'stage', 'prod'])

t.Vpc              = ec2.vpc(CIDR_VPC, Tags)
t.InternetGateway  = ec2.internet_gateway(t.Vpc, Tags)
t.PublicSubnet     = ec2.subnet(t.Vpc, ZONE, CIDR_PUBLIC, Tags)
t.PublicRouteTable = ec2.route_table("PublicRouteTable", t.Vpc, t.PublicSubnet, TagsPublicNamed) \
                        .route("PublicRoute", cidr_all, t.InternetGateway)

t.PublicNetworkAcl = ec2.network_acl("PublicNetworkAcl", t.Vpc, TagsPublicNamed)            \
                        .allow_ingress("HTTP",      100, tcp, cidr_all,     http)           \
                        .allow_ingress("HTTPS",     110, tcp, cidr_all,     https)          \
                        .allow_ingress("SSH",       120, tcp, CIDR_EXT,     ssh)            \
                        .allow_ingress("Ephemeral", 140, tcp, cidr_all,     ephemeral_elb)  \
                        .allow_ingress("NTP",       150, udp, cidr_all,     ntp)            \
                        .allow_ingress("SMTP",      160, tcp, CIDR_PRIVATE, port(587))      \
                        .allow_egress("HTTP",       100, tcp, cidr_all,     http)           \
                        .allow_egress("HTTPS",      110, tcp, cidr_all,     https)          \
                        .allow_egress("SSH",        120, tcp, CIDR_PRIVATE, ssh)            \
                        .allow_egress("Postgres",   130, tcp, CIDR_PRIVATE, postgresql)     \
                        .allow_egress("Ephemeral",  140, tcp, cidr_all,     ephemeral)      \
                        .allow_egress("NTP",        150, udp, cidr_all,     ntp)            \
                        .allow_egress("SMTP",       160, tcp, cidr_all,     port(587))

t.PublicNetworkAclAssociation = ec2.subnet_network_acl_association(t.PublicSubnet,
                                                                   t.PublicNetworkAcl)

# Define outputs
t.VpcId                     = output(value = t.Vpc)
t.PublicSubnetId            = output(value = t.PublicSubnet)
t.PrivateSubnetId           = output(value = t.PrivateSubnet)
t.PublicRouteTableId        = output(value = t.PublicRouteTable)

# Print the JSON
if __name__ == "__main__":
    print t.to_json()

Example

For a larger example with multiple CloudFormation stacks and additional resource types (RDS, EC2, S3, etc.), see the example/ directory.

Authors

David R. Bild

• https://www.davidbild.org
• https://github.com/drbild

License

Copyright 2015 David R. Bild

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this work except in compliance with the License. You may obtain a copy of the License from the LICENSE.txt file or at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.