Jiri Daněk jiridanek

Kustomize

$ oc kustomize --output rstudio-rhoai28.yaml

Review rstudio-rhoai28.yaml and apply it to the cluster

$ oc apply -f rstudio-rhoai28.yaml

Build LLVM / Clang on MacOS

Problem

Built-in Clang / LLVM shipped by Xcode does not support Leak Santizer (-fsantize=leak) feature. For example, this code has memory leak:

// File: main.c

#include <stdlib.h>

I've been deceiving you all. I had you believe that Svelte was a UI framework — unlike React and Vue etc, because it shifts work out of the client and into the compiler, but a framework nonetheless.

But that's not exactly accurate. In my defense, I didn't realise it myself until very recently. But with Svelte 3 around the corner, it's time to come clean about what Svelte really is.

Svelte is a language.

Specifically, Svelte is an attempt to answer a question that many people have asked, and a few have answered: what would it look like if we had a language for describing reactive user interfaces?

A few projects that have answered this question:

Diagrams

Markdown Preview Enhanced supports rendering flow charts, sequence diagrams, mermaid, PlantUML, WaveDrom, GraphViz, Vega & Vega-lite, Ditaa diagrams. You can also render TikZ, Python Matplotlib, Plotly and all sorts of other graphs and diagrams by using Code Chunk.

Please note that some diagrams don't work well with file exports such as PDF, pandoc, etc.

Flow Charts

This feature is powered by flowchart.js.

When are Python circular imports fatal?

In your Python package, you have:

an __init__.py that designates this as a Python package
a module_a.py, containing a function action_a() that references an attribute (like a function or variable) in module_b.py, and
a module_b.py, containing a function action_b() that references an attribute (like a function or variable) in module_a.py.

This situation can introduce a circular import error: module_a attempts to import module_b, but can't, because module_b needs to import module_a, which is in the process of being interpreted.

But, sometimes Python is magic, and code that looks like it should cause this circular import error works just fine!

Effective Modern CMake

Getting Started

For a brief user-level introduction to CMake, watch C++ Weekly, Episode 78, Intro to CMake by Jason Turner. LLVM’s CMake Primer provides a good high-level introduction to the CMake syntax. Go read it now.

After that, watch Mathieu Ropert’s CppCon 2017 talk Using Modern CMake Patterns to Enforce a Good Modular Design (slides). It provides a thorough explanation of what modern CMake is and why it is so much better than “old school” CMake. The modular design ideas in this talk are based on the book [Large-Scale C++ Software Design](https://www.amazon.de/Large-Scale-Soft

Using py.test is great and the support for test fixtures is pretty awesome. However, in order to share your fixtures across your entire module, py.test suggests you define all your fixtures within one single conftest.py file. This is impractical if you have a large quantity of fixtures -- for better organization and readibility, you would much rather define your fixtures across multiple, well-named files. But how do you do that? ...No one on the internet seemed to know.

Turns out, however, you can define fixtures in individual files like this:

tests/fixtures/add.py

import pytest

@pytest.fixture

	#!/usr/bin/env python3

	import json
	import os
	from jsonpath_ng import JSONPath
	from jsonpath_ng.ext import parse

	CO_CMD = "oc get co -o json"
	QUERY = "items[?(@.status.conditions[?(@.type=='Degraded' & @.status=='True')])]"

	#!/bin/bash
	# useful articles:
	# https://vstinner.github.io/journey-to-stable-benchmark-system.html
	# http://perf.readthedocs.io/en/latest/system.html
	# https://baiweiblog.wordpress.com/2017/11/02/how-to-set-processor-affinity-in-linux-using-taskset/
	# https://wiki.archlinux.org/index.php/CPU_frequency_scaling#CPU_frequency_driver

	if [[ $EUID > 0 ]]; then
	echo "Please run as root"
	exit 1

	# Linux
	# add the following to "~/.gitconfig" file

	[merge]
	tool = intellij
	[mergetool "intellij"]
	cmd = /usr/local/bin/idea merge $(cd $(dirname "$LOCAL") && pwd)/$(basename "$LOCAL") $(cd $(dirname "$REMOTE") && pwd)/$(basename "$REMOTE") $(cd $(dirname "$BASE") && pwd)/$(basename "$BASE") $(cd $(dirname "$MERGED") && pwd)/$(basename "$MERGED")
	trustExitCode = true

	[diff]