Postgresql on Marcello Barnaba

ChronoModel 1.0: Seven Years to Ship

Sat, 06 Apr 2019 00:00:00 +0000

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2026 retrospective
My last release was v1.2.2 in May 2019. After that, Geremia Taglialatela took over and pushed it to v5.0.0 with Rails 8.1 and Ruby 4.0 support. 34 releases spanning 14 years, 201 stars, and still actively maintained. The API documentation and the repo are both alive.

Seven years ago I released ChronoModel v0.1.0 — a Ruby gem that gives ActiveRecord models temporal capabilities on PostgreSQL. Five days of hacking, thirty-six commits, no tests, and a confession about monkey-patching the PostgreSQL adapter constant.

Today I’m tagging v1.0.0. The commit message is :gem: this is v1.0.0. Not much of a speech, but the code speaks for itself: 506 commits, 31 releases, 52 files changed, 5,392 lines added. The core idea — updatable views on public, current data on temporal, history on history with table inheritance — never changed. Everything else did.

Eaco: The Holder of the Keys of Hades

Sat, 28 Feb 2015 00:00:00 +0000

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2026 retrospective
Eaco reached v1.0.0 on May 5, 2016 — commit message: “This is v1.0.0. Two years in production.” It grew to 54 stars, 8 forks, 240 commits, and ran authorization at IFAD for five more years after that. Geremia Taglialatela picked it up in 2020 and kept it running on Rails 6.0 and 6.1, then modernized the CI in late 2025. The ABAC-with-hash-ACLs pattern turned out to be exactly right for an organization where access is determined by position, department, and working group — not just “admin or not.” The repo is still online, and the YARD documentation is still some of the most thorough I’ve ever written for a gem.

Scriptoria is an internal workflow application at IFAD — a UN specialized agency in Rome — and its authorization layer has been annoying me for months. The code works, but it’s tangled into the app. Every time we need to add a new role or change who can access what, we’re editing application code that shouldn’t care about authorization semantics.

So eight days ago I started extracting it. Today I’m releasing the result: Eaco — an Attribute-Based Access Control framework for Ruby, named after Eacus, the holder of the keys of Hades in Greek mythology.

172 commits. Five releases. 100% test coverage. And a Saturday afternoon I’ll never get back.

ChronoModel: Time Travel for PostgreSQL

Mon, 07 May 2012 00:00:00 +0000

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2026 retrospective
ChronoModel is still alive — 14 years, 41 releases, 201 stars. The rules got replaced by INSTEAD OF triggers in v0.6 (2014), the box()/point() hack by proper tsrange columns, and the monkey-patching by a proper adapter registration. Geremia Taglialatela took over maintenance in 2020 and pushed it to v5.0.0 with Rails 8.1 and Ruby 4.0 support. The core idea — updatable views on public, current data on temporal, history on history with table inheritance — never changed. The repo is healthy and actively maintained.

We’re building a CRM at IFAD — a UN specialized agency in Rome — and one of the hard requirements is temporal data. We need to know what a record looked like at any point in the past. What was this project’s budget on March 15th? When did this beneficiary’s address change? Who approved what, and what did the record look like at the time?

I’d been prototyping a PostgreSQL schema approach for this — views, rules, table inheritance — and it worked. Then Amedeo, my boss, looked at it and said: “This shouldn’t live inside the CRM. Make it a reusable framework.”

He was right. The temporal pattern has nothing to do with CRM logic. It belongs in a gem.

So I had five days of uninterrupted focus, and today I’m releasing ChronoModel — an ActiveRecord extension that gives your models full temporal capabilities on PostgreSQL. What Oracle sells as Flashback Queries and charges enterprise money for, we can do with standard SQL on Postgres 9.0+.