sqitch VS OPA (Open Policy Agent)

We use https://sqitch.org/ and we’re fairly happy with it. Sqitch manages the files to deploy which are applied fits to a local database.

We use GitHub actions for deployment and database migrations are just one step of the pipeline. The step invokes sqitch deploy which runs all the pending migration files.

Then, all the approval process is standard for the environment. We require approvals in pull requests before merging to the main branch.

I'm experimenting with it right now using Squitch [1] to make maintenance easier. It still feels like a hack and I also still have my doubts about the viability of this for real-world use. It's fun though and I'm learning about all kinds of advanced Postgres features.

[1] https://sqitch.org/

For developing I find the official Perl docker images, running on a lightweight version of Debian, to be perfectly fine. Later on you might hand roll the skinniest possible image but the beauty of this setup is you can do that later and you don't need to change anything else. There's really not a lot going on here. First I declare the base image, which is as I said the official Perl image. I'm not using the latest Perl here because the application uses Sqitch for managing database migrations and that needs an update (there's a PR pending) to run on the most recent Perl so we'll just use a very nearly recent one instead. WORKDIR just defines where your application is installed. You can put it anywhere you want within reason. I like simple things so I use the most simple of all the conventions I've seen around.

Also, https://sqitch.org/

Some possible upsides of codd: - No need to manually write verification SQL. Codd will update schema representation files when you codd add some-migration.sql and will compare those to the actual schema when deploying (I'd say in ways which would be very hard to replicate manually, see an example of what codd checks, giving you the option to rollback if they don't match or proceed but log non-matching db objects. - It seems to be much simpler to set codd up. You need 3 env vars to start, a folder to store your migrations and a self-contained statically linked executable. Just codd add migration.sql your way in after that - This might be very wrong as I couldn't find it explicitly documented, but this GH issue suggests it's not so simple to apply all pending migrations in a single transaction with Sqitch? Maybe it requires some bundling or something along those lines and then it's fine, though. In any case, codd will do this automatically when you run codd up (provided postgresql allows it).

How can we handle this? Are there any mechanisms to prevent or at least to some extent safeguard this kind of issues without falling back to a manual workflow? There is. One huge advantage of sticking to (de-facto) standards like Terraform is that first we are probably not the first ones to come up with this question and second there is a huge ecosystem around Terraform that might help us with such challenges. And for this specific scenario the solution is the Open Policy Agent. Let us take a closer look how the solution could look like.

A popular Policy-as-Code tool for Terraform is OPA, everyone's favorite versatile open-source policy engine that enforces security and compliance policies across your cloud-native stack, making it easier to manage and maintain consistent policy enforcement in complex, multi-service environments.

Harness Policy As Code uses Open Policy Agent (OPA) as the central service to store and enforce policies for the different entities and processes across the Harness platform. In this section, you will define a policy that will deny a pipeline execution if there is no approval step defined in a deployment stage.

OPA: While OPA is an open-source, general-purpose policy engine capable of enforcing unified and context-aware policies throughout the stack, it can also accept and output data in formats such as JSON, effectively functioning as a tool for generating or modifying configurations. Although it does not provide out-of-the-box schema definition support, it allows the integration of JsonSchema definitions.

In essence, container image signing involves adding a digital stamp to an image, affirming its authenticity. This digital assurance guarantees that the image is unchanged from creation to deployment. In this blog, I'll explain how to sign container images for Kubernetes using Cosign and the Open Policy Agent. I will also share a tutorial that demonstrates these concepts.

In this post we will explores two powerful solutions for addressing this issue: the Open Policy Language (OPA) and Google’s Zanzibar.

Rego is a declarative query language from the makers of the Open Policy Agent (OPA) framework. The Cloud Native Computing Foundation (CNCF) accepted OPA as an incubation-level hosted project in April 2019, and OPA graduated from incubating status in 2021.

Now there are more subdivided practice: * Policy as Code: Sentinel, OPA * Database as Code: bytebase * AppConfiguration as Code: KusionStack, Acorn * ...... (Welcome to add more)