jeffjohnson9046

# These commands demonstrate how to determine how much memory is availble on a k8s worker node and how much memory is 
# available to the k8s _container_ hosted on that node.
# Source:
#   https://shuheikagawa.com/blog/2017/05/27/memory-usage/
#
# Other interesting articles:
#   https://docs.docker.com/engine/docker-overview/#the-underlying-technology
#   https://docs.docker.com/config/containers/resource_constraints/
#
# These values are approximations, because according to the first article, calculating/determining available memory 

jeffjohnson9046

# NOTE: These steps assume that zsh is already installed

# Download and install iTerm2, which can be found here:  https://iterm2.com/downloads/

# Install oh-my-zsh (details and alternate installation instructions can be found here: https://github.com/ohmyzsh/ohmyzsh):
sh -c "$(curl -fsSL https://raw.githubusercontent.com/ohmyzsh/ohmyzsh/master/tools/install.sh)"

# Install the Powerlevel9k theme for zsh (details for using the oh-my-zsh installation can be found here: https://github.com/Powerlevel9k/powerlevel9k/wiki/Install-Instructions#option-2-install-for-oh-my-zsh):
git clone https://github.com/bhilburn/powerlevel9k.git ~/.oh-my-zsh/custom/themes/powerlevel9k

jeffjohnson9046

# I have several AWS profiles in my ~/.aws/config thus there are several access keys and secret keys in my 
# ~/.aws/credentials file.  Sometimes (e.g. when using kops or kubectl) I need to have the AWS_ACCESS_KEY_ID 
# and AWS_SECRET_ACCESS_KEY environment variables set.  There doesn't seem to be a way to use the aws cli to set these
# environment variables for me, so... well... here we are.
#
# This script will:
# * Look at the ~/.aws/credentials file for the specified profile
# * Get the next two lines beneath the profile name, which are the access_key_id and secret_key respectively
# * Export those two values as environment variables 
#

jeffjohnson9046

# This is the function I created that's a wee bit less shitty than the file above.  I created a file called (oddly enough)
# ec2-instance-query.zsh and put it in my ~/.oh-my-zsh/custom directory.  After sourcing my ~/zshrc, I have a fancy-pants
# function for querying EC2 instances and ElasticIP addresses for a given IP:
function ec2-instance-query() {
    echo "Finding EC2 information for IP $1:"
    for r in `aws ec2 describe-regions --output text | cut -f4 | grep "us-"`
    do
        aws ec2 describe-instances \
            --region $r \
            --filter "Name=network-interface.addresses.association.public-ip, Values=$1" \

jeffjohnson9046

# From the second answer here - this SO answer gets all the credit:  
# https://stackoverflow.com/questions/32960857/how-to-convert-arbitrary-simple-json-to-csv-using-jq

# This is the filter to convert JSON to CSV output:
# NOTE:  This filter only works on "flat" JSON; nested properties don't work with this filter as-is.
jq -r '(.[0] | keys_unsorted) as $keys | ([$keys] + map([.[ $keys[] ]])) [] | @csv'

# For example:
aws ec2 describe-instances \
  --region us-west-2 \

jeffjohnson9046

# Assume the following scenario:
# * You have a bastion/jump server that is publicly available
# * You have an RDS instance that is _not_ publicly accessible, but the bastion can get to it
#
# We have this setup with some of our k8s clusters:  the cluster was created via kops, which _also_ sets up a VPC, a
# bastion server, all that good stuff.  We use a "private" network topology to minimize public access to any of the 
# resources in the cluster.
#
# We _also_ create our RDS instances in the same VPC.  The bastion and nodes get access to the RDS instance, but it isn't
# available to us common folk out here on the internet.  That's good; we want to minimize access to the database, too.

jeffjohnson9046

-- from here:  https://dataedo.com/kb/query/postgresql/list-foreign-keys
select kcu.table_schema || '.' ||kcu.table_name as foreign_table,
       '>-' as rel,
       rel_tco.table_schema || '.' || rel_tco.table_name as primary_table,
       string_agg(kcu.column_name, ', ') as fk_columns,
       kcu.constraint_name
from information_schema.table_constraints tco
join information_schema.key_column_usage kcu
          on tco.constraint_schema = kcu.constraint_schema
          and tco.constraint_name = kcu.constraint_name

jeffjohnson9046

<project name="condition-test" default="all">
    <target name="condition">
        <condition property="isTomcat">
            <matches pattern="^(tomcat)" string="${webContainer}" />
        </condition>
        <condition property="isWebLogic">
            <matches pattern="^(web)" string="${webContainer}" />
        </condition>
    </target>

jeffjohnson9046

// Source:
// https://dev.to/ycmjason/how-to-create-range-in-javascript-539i
function* range(start, end) {
  yield start;
  if (start === end) {
    return;
  }

  yield* range(start + 1, end);
}

jeffjohnson9046

{
    "workbench.iconTheme": "material-icon-theme",
    "workbench.startupEditor": "newUntitledFile",
    "workbench.colorCustomizations": {
        "editorRuler.foreground": "#1a1a1a",
        
        // Came from snazzy.json, here:  https://github.com/Tyriar/vscode-snazzy/blob/master/snazzy.json
        "terminalCursor.background": "#282a36",
        "terminalCursor.foreground": "#97979b",
        "terminal.selectionBackground": "#97979b33",