ouyi

#!/usr/bin/env bash

if (( $# < 2 )); then
    echo "Usage: $0 inventory host_group [other ansible options]"
    exit 1
fi

inventory="$1"
host_group="$2"

ouyi

#!/usr/bin/env bash

USAGE="$0 args"

if (( $# == 0 )); then
    echo "$USAGE"
    exit 1
fi

function get_ip() {

ouyi

ansible --vault-password-file my-vault-password.txt -m debug -a 'var=my_secret_password' \ 
-i my_inventory my_host.mydomain.com

ouyi

sudo snap connect remmina:avahi-observe :avahi-observe
sudo snap connect remmina:cups-control :cups-control
sudo snap connect remmina:mount-observe :mount-observe
sudo snap connect remmina:password-manager-service :password-manager-service

ouyi

# Find the owning package of a file / which package installed this file 
rpm -qf my_file_or_dir
dpkg -S filename_search_pattern

# List all files of a package
rpm -ql package_name
dpkg -L package_name
pip show -f package_name

ouyi

# --- Maven ---

# Skip test execution
mvn package -DskipTests

# Skip test compilation
mvn package -Dmaven.test.skip=true

# Retrieve the project version

ouyi

from kafka import KafkaProducer

producer = KafkaProducer(bootstrap_servers=['localhost:19092'])
data = bytes('hello', encoding='utf-8')
producer.send('test', value=data)

from kafka import KafkaConsumer

consumer = KafkaConsumer('test', bootstrap_servers=['localhost:19092'], consumer_timeout_ms=2000, auto_offset_reset='earliest')
event = next(consumer)

ouyi

Lessons learned

I. Software engineering

1. Automate everything, have CI/CD and test automation from the beginning
2. Security shall not be an afterthought (have TLS and avoid plain text passwords from the start)
3. Component shall be stateless, state shall be extracted and kept in a external store (key-value store or databases)
4. Favor open source and off-the-shelf solutions instead of building proprietary solutions
5. Avoid hard-coding dependencies, try to inject them via command line parameters, configuration files, env variables, etc

ouyi

# --- Join strings ---
function join_by { local IFS="$1"; shift; echo "$*"; }
# join_by ',' foo bar baz
# https://serverfault.com/questions/311856/portable-unix-way-to-join-strings-with-separator

echo -e "a\nb\nc" | tr '\n' ',' | sed 's/,$//g' # a,b,c

# --- Misc ---

# Retrieve the directory where the current script is in

ouyi

Char    Unicode
---------------
Ä       \u00c4
ä       \u00e4
Ö       \u00d6
ö       \u00f6
Ü       \u00dc
ü       \u00fc
ß       \u00df