Terraform Modules & Private repositories

A common way of sharing terraform code is by using modules. However, modules often end up extracted into a separate repo. This starts to create issues when integrating with a CICD tool as the tool needs to have access to all modules in order to download them.

For example, let’s assume we have the following module imported into our terraform configuration:

module "abc" {
  source = "git@github.com:username/repository"
}

This implies that our CICD need to have access to the username/repository.

AWS & MFA

Amazon Web Service is a key threat for hackers. If hackers have access to your AWS account, they can endure you a tremendous cost. The trend has been to use AWS credentials found online (through an unwanted commit, or other means) to spin up EC2 instances that mine on some kind of blockchain.

One way to mitigate the risk, which Amazon recommends, is to use MFA (Multi Factor Authentication). However, AWS’ recommendation only applies to the Web Console, not programmatic access. If your users have programmatic access (with a key secret pair), it can be harder to enforce requiring MFA.

Environments

When developing a piece of software, it is important to think of what kind of environments you may need.

Here are a list of questions targeted at helping you identify the needs:

1. Where do you develop?

• Locally
• On the we

1. Where do you run you tests?

• Specific machine
• Load tests
• Test-suite
• Regressions

1. Where do you test a feature that has not been merged?
2. Where do other people test your code?

• Other developers
• Non-developers - Quality assurance / engineers
• Internal services integrations
• External customers

1. How do you cherry-pick / hotfix to an environment?
2. How / where do you debug a issue that happened?
3. Do you need external services to integrate in a sandboxed environment?
4. How does each environment interact with 3rd parties?

• E-mail
• External request
• Services
• Databases (Read - Read & Write - Append)

1. Where do you test recovery

• Revert of code to a previous state
• Revert of data to a previous state
• Revert of schema to a previous state
  • Recovering multiple of the above (imagine an earthquake taking your system down…)

Hereafter is a flow I came up with that addresses many of these questions. While specific questions might be addressed with specific environments.

Pull Request as a skill

As Github gets more and more traction (yes! I’m writing this blogpost on Github) some things I’ve learned as an engineer is that not everything is a given.

For example, reviewing a pull request (or code in general). I’ve been lucky to have a manager who taught me the importance of a reviewer. It is not somebody who just looks at the code, gives a thumbs up and moves on. In his words:

FactoryGirl (1-1 Associations)

This blog post goes about a common problem I’ve haven’t found much documentation on.

It follows issues mentioned of multiple places like here and variations of it.

I’ve written some code to illustrate the problem on my Github FactoryGirl-Problem to accompany this.

Problem

How to create factories such that the association is a 1-1, and all models can be created independently.

Models

# app/models/user.rb
class User < ActiveRecord::Base
  has_one :profile
end

# app/models/profile.rb
class Profile < ActiveRecord::Base
  belongs_to :user

  validates :user,
    presence: true,
    uniqueness: true
end

How to create the factories to get the following tests to pass