joshbuchea

Semantic Commit Messages

See how a minor change to your commit message style can make you a better programmer.

Format: <type>(<scope>): <subject>

<scope> is optional

Example

olih

Processing JSON using jq

jq is useful to slice, filter, map and transform structured json data.

Installing jq

On Mac OS

brew install jq

subfuzion

Common Options

-#, --progress-bar Make curl display a simple progress bar instead of the more informational standard meter.

-b, --cookie <name=data> Supply cookie with request. If no =, then specifies the cookie file to use (see -c).

-c, --cookie-jar <file name> File to save response cookies to.

KartikTalwar

The fastest remote directory rsync over ssh archival I can muster (40MB/s over 1gb NICs)

This creates an archive that does the following:

rsync (Everyone seems to like -z, but it is much slower for me)

• a: archive mode - rescursive, preserves owner, preserves permissions, preserves modification times, preserves group, copies symlinks as symlinks, preserves device files.
• H: preserves hard-links
• A: preserves ACLs

jakebrinkmann

import pandas as pd
import pandas.io.sql as sqlio
import psycopg2

conn = psycopg2.connect("host='{}' port={} dbname='{}' user={} password={}".format(host, port, dbname, username, pwd))
sql = "select count(*) from table;"
dat = sqlio.read_sql_query(sql, conn)
conn = None

abdennour

apiVersion: v1
kind: Pod
spec:
  # dnsConfig:
  #   options:
  #     - name: ndots
  #       value: "1"
  containers:
  - name: dind
    image: abdennour/docker:19-dind-bash

Bill-tran

How To Install OpenSSL 1.1.1 on CentOS 7

This tutorial goes through how to install openssl 1.1.1 on CentOS 7, since the yum repo only installs up to openssl 1.0.

Requirements

Upgrade the system

yum -y update

nchaigne

Building GCC 9.2.0 on CentOS 7

Introduction

CentOS 7 distribution (as well as RHEL 7) ships with a somewhat outdated version of the GCC compiler (4.8.5 on CentOS 7.5), which may not be suitable to your compilation requirements. For example, C11 - which supersedes C99 - is fully supported only starting from GCC 4.9).

Additionally, recent versions of GCC (GCC6, GCC7, GCC8, GCC9) come with improvements which help detect issues at build time and offer suggestions on how to fix them. Sometimes, these are even actually helpful!

This note describes how to build the latest GCC (9.2.0 as of October 2019) from sources on CentOS 7. This should be applicable as is on RHEL 7. For other Linux distributions, adapt as needed.

max-rocket-internet

CPU: percentage of limit

A lot of people land when trying to find out how to calculate CPU usage metric correctly in prometheus, myself included! So I'll post what I eventually ended up using as I think it's still a little difficult trying to tie together all the snippets of info here and elsewhere.

This is specific to k8s and containers that have CPU limits set.

To show CPU usage as a percentage of the limit given to the container, this is the Prometheus query we used to create nice graphs in Grafana:

sum(rate(container_cpu_usage_seconds_total{name!~".*prometheus.*", image!="", container_name!="POD"}[5m])) by (pod_name, container_name) /

popravich

The standard names for indexes in PostgreSQL are:

{tablename}_{columnname(s)}_{suffix}

where the suffix is one of the following:

• pkey for a Primary Key constraint;
• key for a Unique constraint;
• excl for an Exclusion constraint;
• idx for any other kind of index;