rduque1

ssh tunnel to a remote DB when software does not support different cipher

1. create ssh tunnel

ssh -p <ssh-port> -c <cipher_aes256-cb> -L 8888:<db-host>:<db-port_3306> <user>@<remote-host>

2. Open the application to connect to a DB

rduque1

# extract a circle from the image: translate to the middle of the image and define the radius to cut
convert IMG-TRM-1916-1038.jpg -alpha on -background none \( +clone -channel a -evaluate multiply 0 +channel -fill white -draw "translate 1500,1000 circle 0,0 0,150" \) -compose DstIn -composite -trim out.png

# convert a svg to png with resize the SVG to desired size
convert -background none -density 1536 -resize 4092x4092 roodwit.svg roodwitx4092_1536.png

# rounded rectangle crop
convert <image>.webp +repage -alpha on -background none \( +clone -channel a -evaluate multiply 0 +channel -fill white -draw "translate 225,225 roundrectangle  0,0 571,555 115,115" \) -compose DstIn -composite -trim out.webp

rduque1

How Next.js responds to a page request with HTML

We create the next request handler function via app.getRequestHandler(). This returns a standard express handler, so we use it like expressApp.get('*', middlewareA(), middlewareB(), nextApp.getRequestHandler()).

When the handler is invoked:

• Server#handleRequest (next-server/server/lib/next-server.js)
  • Parses URL + query string if not already done
• Server#run
• Searches for matching route

rduque1

rest-api-response-format

REST API response format based on some of the best practices

Rest API Popular Endpoint Formats

https://api.example.com/v1/items

https://example.com/api/v1/items

Rest API Success Responses

rduque1

# Resize the file system in UI, under VM -> Hardware -> Click on the disk to resize, click "Resize disk" button

# Confirm increase in disk space (1TB in my case)
$ lsblk
NAME                      MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda                         8:0    0    1T  0 disk
├─sda1                      8:1    0    1M  0 part
├─sda2                      8:2    0    1G  0 part /boot
└─sda3                      8:3    0    1T  0 part

rduque1

# get number of running pods
kubectl get -A pods --field-selector=status.phase=Running --output json | jq -j '.items | length'

# get number of NOT running pods
kubectl get -A pods --field-selector=status.phase!=Running --output json | jq -j '.items | length'

# find out why a pod is in pending
describe pod -n <namespace> <pod-name>

# get a node max number of pods

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sed 's/,/\t/g' test.txt > output.txt

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#! /usr/bin/env bash
#
# Run parallel commands and fail if any of them fails.
#

set -eu

pids=()

for x in 1 2 3; do

rduque1

/*
In the node.js intro tutorial (http://nodejs.org/), they show a basic tcp 
server, but for some reason omit a client connecting to it.  I added an 
example at the bottom.

Save the following server in example.js:
*/

var net = require('net');

rduque1

# https://serverfault.com/questions/843296/how-to-expose-the-docker-api-over-tcp
ncat -lknvp 2375 -c "ncat -U /var/run/docker.sock"