formica-cli 0.3.0

Simple AWS CloudFormation stack management tooling.

Formica makes it easy to create and deploy CloudFormation stacks. It uses CloudFormation syntax with yaml and json support to define your templates. Any existing stack can be used directly, but formica also has built-in modularity so you can reuse and share CloudFormation stack components easily. This allows you to start from an existing stack but split it up into separate files easily.

For dynamic elements in your templates Formica supports jinja2 as a templating engine. Jinja2 is widely used, for example in ansible configuration files.

Installation

Formica can be installed through pip:

pip install formica-cli

Alternatively you can clone this repository and run

python setup.py install

After installing Formica take a look at the quick start guide or the in-depth documentation and examples

AWS Credentials

Formica supports all the standard AWS credential settings, so you can use profiles through the --profile option, provide no specific profile which will use the default profile or set environment variables like AWS_ACCESS_KEY_ID. Take a look at the AWS credentials docs for more details on how to configure these credentials.

Why

AWS CloudFormation provides a great service for automatically deploying and updating your infrastructure. But while the service itself is great the tooling to deploy and manage CloudFormation has been lacking. This means that many teams aren’t using CloudFormation or automating their infrastructure as much as they should. Formica tries to be a great CloudFormation client by making it easy to build modular templates, make parts of templates reusable and give you great tooling to deploy to and inspect your CloudFormation stacks.

Our goal is that you should never have to log into the AWS Console to look at your CloudFormation stacks, because Formica gives you all the info you need right in your shell.

Quick Start Guide

You can also jump to the in-depth docs for more information.

You define your CloudFormation template through *.template.(json/yaml/yml) files. Those files will be automatically loaded from the current working directory and executed to create your template.

In this example we’ll create an S3 Bucket. We use jinja templating to set a variable and use it for the bucket logical name. Put the following into a bucket.template.yml file:

{% set bucket = "DeploymentBucket" %}
Resources:
  {{ bucket }}:
    Type: "AWS::S3::Bucket"

In the same folder run formica template which should show you the following template:

{
    "Resources": {
        "DeploymentBucket": {
            "Type": "AWS::S3::Bucket"
        }
    }
}

Now we’ll create a new stack with this template:

formica new --stack formica-example-stack

This will create a new ChangeSet in CloudFormation that we can deploy in a next step. It will also describe all the changes that will be done. Instead of setting --stack for every command you can also set the FORMICA_STACK environment variable which will be picked up automatically.

root@62d81801cc09:/app/examples/s3-bucket# formica new --stack formica-example-stack
Creating change set for new stack, ...
Change set submitted, waiting for CloudFormation to calculate changes ...
Change set created successfully
Deployment metadata:
+---------------+--+
| Parameters    |  |
+---------------+--+
| Tags          |  |
+---------------+--+
| Capabilities  |  |
+---------------+--+

Resource Changes:
+--------+------------------+------------+-----------------+-------------+---------+
| Action |    LogicalId     | PhysicalId |      Type       | Replacement | Changed |
+========+==================+============+=================+=============+=========+
| Add    | DeploymentBucket |            | AWS::S3::Bucket |             |         |
+--------+------------------+------------+-----------------+-------------+---------+
Change set created, please deploy.

For more detail on the ChangeSet description check out the describe command documentation.

All changes, whether you want to create a new stack or update an existing one, are done through ChangeSets. This makes sure you can inspect the specific actions that CloudFormation will take before deploying them. In a CI context you can of course simply run both commands one after the other to get a fully automated deployment.

Now we can deploy the changes:

formica deploy --stack formica-example-stack

The command will follow the CloudFormation stack events and print them to the command line. If the deployment fails, so will the command.

root@62d81801cc09:/app/examples/s3-bucket# formica deploy --stack formica-example-stack
+------------------------------+--------------------------+--------------------------------+--------------------------------+----------------------------------------------------+
|          Timestamp           |          Status          |              Type              |           Logical ID           |                   Status reason                    |
+------------------------------+--------------------------+--------------------------------+--------------------------------+----------------------------------------------------+
2017-02-15 10:14:27 UTC+0000   CREATE_IN_PROGRESS         AWS::CloudFormation::Stack       formica-example-stack            User Initiated
2017-02-15 10:14:31 UTC+0000   CREATE_IN_PROGRESS         AWS::S3::Bucket                  DeploymentBucket
2017-02-15 10:14:32 UTC+0000   CREATE_IN_PROGRESS         AWS::S3::Bucket                  DeploymentBucket                 Resource creation Initiated
2017-02-15 10:14:53 UTC+0000   CREATE_COMPLETE            AWS::S3::Bucket                  DeploymentBucket
2017-02-15 10:14:55 UTC+0000   CREATE_COMPLETE            AWS::CloudFormation::Stack       formica-example-stack

After the deployment we will now see our new S3 Bucket. As we didn’t set a name the name of the bucket is generated by S3:

root@62d81801cc09:/app/examples/s3-bucket# aws s3 ls
2017-02-15 11:21:18 formica-example-stack-deploymentbucket-57ouvt2o46yh

We can also check out all the resources for a specific stack with the resources command:

root@67c57a89511a:/app/docs/examples/s3-bucket# formica resources --stack formica-example-stack
+------------------+------------------------------------------------------+-----------------+-----------------+
|    Logical ID    |                     Physical ID                      |      Type       |     Status      |
+==================+======================================================+=================+=================+
| DeploymentBucket | formica-example-stack-deploymentbucket-57ouvt2o46yh  | AWS::S3::Bucket | CREATE_COMPLETE |
+------------------+------------------------------------------------------+-----------------+-----------------+

If we want to add an additional bucket we can change add a second file bucket2.template.json file with the following content:

{"Resources": {
  "DeploymentBucket2": {
    "Type": "AWS::S3::Bucket"
    }
  }
}

Running formica template again will now result in both files being picked up and merged:

{
    "Resources": {
        "DeploymentBucket": {
            "Type": "AWS::S3::Bucket"
        },
        "DeploymentBucket2": {
            "Type": "AWS::S3::Bucket"
        }
    }
}

and then run the change and deploy commands:

formica change --stack formica-example-stack
formica deploy --stack formica-example-stack

And we can now see both buckets in S3:

root@62d81801cc09:/app/examples/s3-bucket# aws s3 ls
2017-02-15 11:21:18 formica-example-stack-deploymentbucket-57ouvt2o46yh
2017-02-15 11:21:18 formica-example-stack-deploymentbucket2-1jv31cwqdh5gk

And we can list all the stacks to see the status with formica stacks:

root@62d81801cc09:/app/examples/s3-bucket# formica stacks
Current Stacks:
+-------------------------------+----------------------------------+----------------------------------+-----------------+
|             Name              |            Created At            |            Updated At            |     Status      |
+===============================+==================================+==================================+=================+
| formica-example-stack         | 2017-02-15 10:02:56.809000+00:00 | 2017-02-15 10:57:54.641000+00:00 | UPDATE_COMPLETE |
+-------------------------------+----------------------------------+----------------------------------+-----------------+

Last but not least we’ll remove the stack with formica remove --stack formica-example-stack

root@62d81801cc09:/app/examples/s3-bucket# formica remove --stack formica-example-stack
Removing Stack and waiting for it to be removed, ...
+------------------------------+--------------------------+--------------------------------+--------------------------------+----------------------------------------------------+
|          Timestamp           |          Status          |              Type              |           Logical ID           |                   Status reason                    |
+------------------------------+--------------------------+--------------------------------+--------------------------------+----------------------------------------------------+
2017-02-15 11:09:07 UTC+0000   DELETE_IN_PROGRESS         AWS::CloudFormation::Stack       formica-example-stack            User Initiated
2017-02-15 11:09:10 UTC+0000   DELETE_IN_PROGRESS         AWS::S3::Bucket                  DeploymentBucket
2017-02-15 11:09:31 UTC+0000   DELETE_COMPLETE            AWS::S3::Bucket                  DeploymentBucket
2017-02-15 11:09:32 UTC+0000   DELETE_COMPLETE            AWS::CloudFormation::Stack       formica-example-stack

And now you’ve created, inspected, updated, deployed and removed a CloudFormation stack with Formica.

For more in-depth information check out our documentation