jreyesr's blog

In which we reveal the dark secret of which potentiometer to change when a piano’s pedal stops working due to years of use

This post uses the water level at a hydroelectric plant’s reservoir over the past year to derive a set of lines that approximately describe the water level’s changes across time, with a view to predicting the point in time at which the reservoir would emp…

This article presents a way to extract the shape of a stepwise function when the only available operation is to sample the function at a particular point, and uses it to extract a bank’s interest rate table for fixed-term investments.

In this article, we explore additional methods to assign people to voting centers, such that the average distance that each person must travel is minimized.

In this article, we create a new N8N node that integrates the Docxtemplater open-source library to render Word documents from templates, as well as providing user-extensible Transforms for data, and Data Sources that provide additional template data.

In this article, we obtain data about the location of people and voting centers in Ecuador, and we start exploring possible methods for assigning people to voting centers so that the distance that people have to travel is minimized.

This article reviews graph databases, as a storage technology similar to relational databases like Postgres and document stores like MongoDB.

In this article, we learn about linked-data visualizations, what they are and why they may more expressive than static visualizations.

In this article, we explore Typst, a new typesetting system similar to LaTeX.

In this article, we make some changes to the seed counting application that was presented in the previous post, such as making detection more robust to illumination changes, allowing the application to run offline, and providing a way for users to submit…

In this article, we develop an application that can automatically count fruit seeds, using OpenCV, entirely client-side.

Hello!

In this article, we explore a dashboard that provides information about Ecuador’s electrical grid generation and production, in the context of current rolling blackouts.

In this article, we review ways in which the Clickhouse analytical database engine can be made to interoperate with Steampipe, for the purpose of retrieving additional data to be added to events that are stored on Clickhouse, without requiring to list the…

In this article we extend the concept of refactorings, as used on source code, to data stored, for example, on YAML or JSON files.

In this article we review Langium, which is a language engineering tool that can be used when developing custom structured text languages.

Hello!

In this article we explore Flowpipe, a new tool to author and run workflows (i.e. sequences of steps that each fetch some data or perform some action, such as calling a REST API).

In this article we explore Telegram bots, with particular attention to the developer side of things: what are bots?

In this article we explore Semgrep, a static code analyzer.

In this article we review more authorization systems.

This article is the first in a deep-dive exploration of authorization/access control systems, which can be used to constrain the actions that the users of web applications can perform.

In this article, we explore several alternatives to provide user-definable logic on larger applications, such as transformation functions and filtering criteria.

In this article, we explore Streamsync’s recently released Custom Components.

In this article, we explore a blockchain system that has been used in a couple of Ecuador’s recent elections.

In this article, we present a new Steampipe plugin that can provide access to a plain PostgreSQL database.

In this article, we capture time-indexed partial results of Ecuador’s recent presidential elections, we review ways of saving them, and we then explore the data.

in this post, we start testing the Steampipe plugin that bridges to Terraform data sources with several random Terraform providers.

In this article we explore the Terraform Registry API, which hosts information about Terraform providers, in particular the URLs in which the actual provider binaries are hosted.

In this article, we use Terraform data sources to automatically declare tables for a Steampipe plugin, and we forward queries that come in for each table to the corresponding Terraform datasource.

In this article, we query the Data Sources of Terraform plugins from a standalone Go program (i.e., not via the Terraform CLI).

In this article, we explore the way in which Terraform runs its plugins, AKA providers.

In this article, we start a new project: giving Steampipe access to any* Terraform datasource.

In this devlog, we cover the implementation of a listener that can react to Telegram’s webhooks, which are sent when a bot receives a message from the user (among other events)

In this devlog, we explore XState, a state-machine library for Javascript.

In this article we explore Kaitai, a parser for binary file formats.

In this article, we will review a series of ways of hosting and running assorted scripts, using Python as a case study.

In this article, we’ll review Streamsync, a (young) framework that lets you create interactive web applications backed by Python code.

This article explores continues the exploration of Terraform, this time for dynamically generating configurations (e.g. generating one EC2 server for each entry in a DB)

This article explores the usage of Terraform as applied to the problem of configuring generic APIs (i.e., those not related to cloud infrastructure).

In this article, we create a new N8N node that integrates the Carbone open-source library to render Word documents from templates

In this devlog, we explore the observability capabilities that are provided by NextJS, and we instrument the OpenChatflow application.

In this devlog, we integrate a real DB (PostgreSQL with the Prisma ORM) with the OpenChatflow application, so that we can create, read and save conversations.

In this devlog, we add more nodes, and present a first version of the application, deployed to Vercel

In this devlog, we add several new nodes, the UI necessary to add nodes to the canvas, and we implement new types of nodes: async actions that run in the background and multiple-output nodes that route the conversation through different paths.

In this devlog, we cover the setup of a NextJS project, creating custom nodes in Reactflow, adding a configuration dialog to one node, edge validation so that only certain node connections are allowed, and more!

In this article, we introduce an application to design, test, run and monitor Telegram chatbots.

In this article, we explore the traces&metrics functionality implemented in Steampipe.

In this short article, we’ll explore the caching facilities available to a Steampipe plugin.

This article explores some advanced integration usecases in which Steampipe can be used, such as placing another Postgres instance in fron of it for greater control and more data sources.