Chandra Sekar's Blog

Making pylsp Work in Vim

Sat, 03 May 2025 19:04:31 +0530

Language servers enable IDE-like features in text editors that support the Language Server Protocol. pylsp is a language server for Python. I use vim-lsp to integrate language servers into Vim. Configuring a language server in vim-lsp is straightforward for most languages, but not for Python.

Any non-trivial Python codebase uses a virtual environment (venv) to store its dependencies. pylsp needs to know the location of the venv, for the currently open file, to function correctly. When using Vim in the terminal, pylsp can be made aware of the location by activating the venv, before starting Vim. It is not possible to do this when starting a Vim GUI, like GVim, outside the terminal. If you use a modern Python dependency manager like uv or Poetry, this post offers a solution that works both inside and outside the terminal.

FIRE and Personal Finance Inspirations

Sat, 28 Sep 2024 16:52:25 +0530

There are two key problems to solve on the journey to attaining Financial Independence and Retiring Early (FIRE): 1) ensuring you have enough money for the rest of your life and 2) figuring out what to do after retiring. While the latter is critical for a fulfilling retirement, it is also highly personal. However, the path to achieving the former is quite common to most people.

One’s attitude towards money, not their skills, is the largest determinant of their financial success. This post shares some of the resources I found inspiring and useful to calibrate mine. Many of the behaviours encouraged by these apply even if you do not intend to FIRE, but want to maintain a stable financial position throughout your life.

Productivity as an Employed Software Engineer

Wed, 15 Nov 2023 18:35:14 +0530

There has been a lot of talk about employee productivity in recent days, with some Indian tech entrepreneurs asking people to work 70 hours a week. Productivity is not the sole purpose of life. Health and relationships that we value are more important and productivity must never come at the cost of these. With that out of the way, here is my view of productivity and ways to improve it as a software engineer working as a full-time employee.

The Tale of a Corrupt Backup

Sat, 25 Feb 2023 23:28:13 +0530

As I mentioned in the post about my backup system, I run restic check regularly, to test the integrity of my backup. It has never reported any error in my repository. It performs a quick, shallow check, and does not verify that all the data is intact. I also restore a random file, whenever I run restic check, to test recoverability.

Shortly after I wrote the previous post, I decided to run restic check --read-data for the first time ever. This reads every file in the repository and simulates a full restore. To my utter horror, it reported many errors like these!

Pack ID does not match, want 5e66c2ac, got e80051de
pack d64be86d contains 1 errors: [Blob ID does not match, want 8ebf2c10, got 350f6ba1]

My Personal Backup System

Sat, 24 Dec 2022 21:24:22 +0530

Computing devices and online services can fail catastrophically and take our data with them. It is crucial that we have a robust system to backup and restore our data, to protect against such events. This post details what I wanted from the backup system for my personal data and the tools I use to achieve them. This system has served me well over the last 5 years, across fat-fingerings and disk failures.

Connection Leak in PgBouncer Behind AWS NLB

Sun, 10 May 2020 18:04:50 +0530

At a previous job, we had several instances of Ruby on Rails applications connecting to PostgreSQL through PgBouncer. The services and databases were deployed on bare-metal servers and chugged along fine. We then decided to migrate to AWS. Upon migration, we noticed that PgBouncer started leaking connections to PostgreSQL like a sieve, leading to exhaustion of the maximum number of connections configured in RDS.

Using Command-Line Tools on Vim Buffers

Thu, 23 Apr 2020 22:34:43 +0530

Vim offers many ways to use the command-line tools available on your system when editing. You can:

insert the output of a command into the current buffer - e.g., insert the current date.
process lines of the current buffer through a command - e.g., sum up a list of numbers in the file.
manipulate lines of the current buffer using a command - e.g., sort a list of names in the file.

GnuCash for Personal Finance: Online Quotes

Sat, 28 Jul 2018 13:32:12 +0530

This is third in the series of posts describing how I use GnuCash to manage my finances. In previous posts, I had discussed how I organize my accounts, record transactions and handle taxation in GnuCash. In this post I’ll show how GnuCash can be configured to fetch the current NAV of mutual funds from the Internet.

GnuCash for Personal Finance: Transactions and Taxes

Thu, 26 Jul 2018 19:13:27 +0530

This is second in the series of posts describing how I use GnuCash to manage my finances. In the previous post I had discussed how I organize my accounts in GnuCash. In this post I’ll describe how I record transactions and use GnuCash to help with computation of taxes and filing of tax returns.

GnuCash for Personal Finance: Chart of Accounts

Sun, 22 Jul 2018 09:07:43 +0530

GnuCash is an open-source double-entry bookkeeping software. In a series of posts this week, I will describe how I use GnuCash to manage my finances. The series will be biased towards a portfolio composed primarily of Indian mutual funds. This post describes the chart of accounts involved and the purpose of each account.

Safe and Convenient Password Management

Mon, 09 Oct 2017 20:09:00 +0530

For better or worse, passwords are central to the safety of almost all our online accounts. 2-factor authentication systems are meant to protect users from compromise of their passwords. However, not all services support it. Also, several online services (including banks), use OTP sent over SMS as the second factor. This has several vulnerabilities and has been deprecated by NIST. That leaves password as a critical piece of these accounts’ security.

Prepared Statements Without Additional Round-Trip

Sun, 09 Jul 2017 08:12:00 +0530

Prepared statements are the best way to avoid SQL injections in applications accepting user input. However they require an additional round-trip to prepare the query, which increases latency when your queries are dynamic and the statements are not re-used. PostgreSQL allows execution of such queries without the additional cost!

Java's CompletableFuture and Threads

Fri, 19 May 2017 00:20:00 +0530

Quiz time. How many threads (other than main) will this program create on a dual-core machine?

public class App {
    public static void main(String[] args) {
        for (int i = 0; i < 10; i++) {
            CompletableFuture.runAsync(() -> {
                System.out.println(currentThread().getName());
            }).join();
        }
    }
}

Timing Equity MFs with PE

Mon, 08 May 2017 21:17:00 +0530

The rule of thumb for equity investments is to not time the market, but there are also several analyses correlating investing at high index PE levels with lower returns. So can we use the PE levels of indices to generate better returns than SIP and reduce volatility of the portfolio?

Arena Allocation in Go

Mon, 07 Jul 2014 13:55:00 +0530

One of the weaknesses of Go’s runtime today is the relatively naive GC implementation. This is evident from go performing consistently worse than most other languages in the binary trees benchmark. However, the language can make designing programs that reduce GC cost fairly straightforward.

Go Does Delegates Beautifully!

Fri, 06 Apr 2012 13:12:00 +0530

When working with object-oriented languages, there are many instances when one would want to implement an interface re-using code from another implementation of the interface. While inheritance will work, it couples the new implementation to the specific other implementation. Composition with delegation will be a better way of doing this.

How Git Outshines Subversion at Merging

Fri, 22 Jan 2010 18:49:00 +0530

I’ve recently started getting my head around Git having been a Subversion (sadly even CVS) user all along. While I liked the fact that it was distributed and way faster than Subversion at most operations, I couldn’t understand why many claimed it was better at merging than Subversion (1.5 and above). Even the “Branch Handling” section in Git’s wiki talks only about better history tracking but not about how Git is better at merging the content themselves.

Simple Layouts with JSP in Spring MVC

Sun, 13 Dec 2009 00:55:00 +0530

Every web application has elements common to all its pages which are good candidates for re-use. While Spring MVC provides integration with Tiles, it can be an overkill for simple applications and needs using Spring’s client side JS library for AJAX (correct me if I’m wrong).

Mocking Math.random() Using PowerMock

Sun, 01 Nov 2009 23:34:00 +0530

Let’s consider the below Game class in a guessing game where a random target is chosen by the system and the user guesses the target. The system returns an appropriate message based on whether the guess was higher, lower or equal to the random target.

ScriptEngineBuilder for Java

Fri, 28 Aug 2009 23:43:00 +0530

Java 6 allows you to execute and communicate with scripts written in any scripting language, using the Scripting API. However, the code needed to create a ScriptEngine and evaluate a set of script files within it, is quite verbose and throws several checked exceptions.

Keyboard Shortcuts in JSF Using AJAX4JSF

Mon, 06 Oct 2008 00:38:00 +0530

AJAX4JSF is library of JSF components which can be used to easily add AJAX capabilities to JSF web applications. AJAX4JSF is available as part of the Richfaces component library.

Python's String Translations for Java

Sun, 14 Sep 2008 19:21:00 +0530

Just as I started poking my nose into Python, I came across two really interesting functions in its string module.

Creating a Local APT repository

Fri, 09 Feb 2007 12:12:00 +0530

I have long been wanting to make a local directory, which contains all my Debian packages, as a repository to be added in, /etc/apt/sources.list. Finally, I did it.

Easy Way to Create Slack Packages

Tue, 23 Aug 2005 16:48:00 +0530

I came across this interesting utility which allows creation of slack packages easily.