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Modular Fish-Shell Configuration

Fish shell configuration is split into functions, completions and initalization code. But it's easy to split it further on a per feature basis.

The default fish configuration structure looks something like this:

~/.config/fish/
  - functions/
  - completions/

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Patch binary files with Java

Recently, I wanted to create an "intelligent" binary patcher, which not only replaces some chunk of binary data at a file's predefined offset, but instead performs search and replace. BinaryPatcher.java is the result.

The usage is pretty straight forward. Let's have a look at an basic example:

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Homebrew Bundle in a Nutshell

Bundle is a tap (aka extension) to run several Homebrew commands in one go. The list of commands is read from a plain-text Brewfile.

It has support for

• taps
• packages
• casks
• Mac App Store

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Calculation of Dew-point and Absolute Humidity

Dew-Point and absolute humidity can be calculated from temperature in celsius and relative humidity.

The Barometer class expects both values as inputs and calculates absolute humidity af and dew-point td.

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Migrating an RDS DB instance to an Aurora DB cluster with CloudFormation

There are several guides describing how to migrate a plain RDS instance to an Aurora cluster using read replica. But none of them describes how the new Aurora cluster can afterwards be maintained further with CloudFormation.

This guide describes a migration path I've used on production services. A few manual steps and a short downtime - or at least read-only mode - are required, but the final cluster will then be part of an already existing CloudFormation stack.

High-Level Process

With or without CloudFormation, the high-level steps are the following

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Use IntelliJ IDEA as Mergetool in Git

IntellJ IDEA contains a very good merge UI, ideal to resolve conflict during merge or rebase. The functionality is accessible also from command line, without having a project with the conflicting sources. Integration into the git commandline flow is quite easy, as git already has the concept of diff- and mergetools.

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Tips for Writing AsciiDoc in Gists

Syntax highlighting

Supported source languages: https://github.com/github/linguist/blob/master/lib/linguist/languages.yml

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Resilient RabbitMQ-Listener with Spring

In case of high error rates during message processing, it might be beneficial to stop message-consumption for some time. This does not only reduce the number of errors in the system, but also allows other consumers to process the message successfully.

Circuit-breakers are made for detecting high error rates and stop/restart the processing.

There is no prepared integration between RabbitMQ-Listeners and Circuit-Breakers, but the gap can be easiliy filled with a Resilience4j event-handler starting and stopping RabbitMQ-listener.

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Jooq-Codegen with Flyway and Testcontainers in Gradle

At the time of writing, the Gradle-Jooq-Plugin doesn’t offer a good way to use Testcontainers for generation. The fundamental issue is, that the JDBC-URL - or more specifically the port - can’t be read from TestContainers unless it’s started. Thus it can’t be used in the Plugin-configuration and setting it later is hardly possible.

So this example uses the plain Jooq-Generator classes.