Category: Coding

• March 26, 2022

  How long should it take to solve the FizzBuzz coding question?

  So, it was past midnight, and I was pretty much done for the day when one of those random thoughts ran past me like a fleeting glimpse (thanks, Roger) and I just couldn’t let go: if I were asking a candidate to solve the FizzBuzz problem, how long would be fair to expect them to…
• December 27, 2021

  Publishing a Java Library to Maven Central

  Created by M. Massenzio, 2021-12-26 Motivation Publishing one’s own source code under an Open Source license (Apache 2 being my favorite one) and making the code publicly available on GitHub is only half the story, these days, in ensuring that your open source project will reach a wide audience. A critical part is also packaging…
• November 4, 2021

  Using Multiple Identities with GitHub

  When using multiple accounts with GitHub, it may be necessary to commit changes to private repositories which may not accessible by all accounts. This is how to generate the key and add it to the SSH agent; then add it to the GitHub account too. The original solution was here.
• March 31, 2021

  Docker ENTRYPOINT (and a note about $@)

  This is something I keep forgetting, so I figure I’ll write it down so it’s here for future reference. General rule: use the exec form of ENTRYPOINT, in other words do this: As expected, this will run apache in the foreground, with PID 1 (unless you’re being a complete idiot and using hostPID – see…
• March 29, 2021

  How to create an iOS App Icon set

  The process is relatively straightforward, but I want to keep it here so I’ll remember it next time. The first step is to start from a relatively high-resolution PNG logo: Once you have the PNG, you need to generate the entire set of icons that are required for various devices/resolution; this can be done at…
• February 7, 2021

  JSON Web Tokens (JWT) utilities

  A simple utility to generate and decode JSON Web Tokens (JWTs) that can be used to authenticate against web applications. The code is released under the Apache 2 Open Source License. See JWT-OPA for an example of how JWTs can be used to authenticate/authorize access to protected online resources/applications. Usage Use –help (or -h) for…
• February 5, 2021

  Integrating Open Policy Agent with Spring Security Reactive and JSON Web Tokens

  We present a Java library that simplifies adopting the Open Policy Agent server to manage user authorization for a Spring Boot microservice, while also managing API Token (JWT) authentication. Motivation Spring Security assumes a fairly simplistic Role-Based access control (RBAC) where the service authenticates the user (via some credentials, typically username/password) and returns a UserDetails…
• January 4, 2021

  Implement the Envelope Wrapper Pattern in C++ using Google Protocol Buffers

  The Envelope Wrapper pattern This pattern, described in “Enterprise Integration Patterns” (Ch. 8, “The Envelope Wrapper”), is used typically in messaging systems, when a number of metadata fields (for routing, security, etc.) are kept in a header, while the data used by service endpoints is serialized in a payload. For the system to be generically…
• December 29, 2020

  Support multiple JDKs in Debian Linux

  With the relatively recent change in the frequency of Java releases (every six months) it has become pretty much required to be able to have multiple JDKs on one’s development machine, and being able to run/test them at different times, for different projects, or even for the same project. Motivation While some wizardry with symlinks…
• August 4, 2020

  Parse Args in Bash Scripts

  There is something to be said for the immediacy of using Bash scripts, especially when dealing with relatively simple system operations; however, parsing command line arguments has always been rather cumbersome and usually done along the lines of painful if [[ ${1} == ‘–build’ ]]; then …. On the other hand, Python is pretty convenient…