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Kafka Topics

List existing topics

bin/kafka-topics.sh --zookeeper localhost:2181 --list

Describe a topic

bin/kafka-topics.sh --zookeeper localhost:2181 --describe --topic mytopic

Purge a topic

bin/kafka-topics.sh --zookeeper localhost:2181 --alter --topic mytopic --config retention.ms=1000

... wait a minute ...

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Kafka Cheat Sheet

Display Topic Information

$ kafka-topics.sh --describe --zookeeper localhost:2181 --topic beacon
Topic:beacon	PartitionCount:6	ReplicationFactor:1	Configs:
	Topic: beacon	Partition: 0	Leader: 1	Replicas: 1	Isr: 1
	Topic: beacon	Partition: 1	Leader: 1	Replicas: 1	Isr: 1

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Utilities you'll care about

All these are already installed on epyc.

• kafkacat (conda install -c conda-forge kafkacat)

• kt (grab it from https://github.com/fgeller/kt/releases)

• kafka-* (come with kafka, if you yum install if from Confluent's repo, or via Docker if you're so inclined). Warning -- JVM based and dreadfully slow.

• jq (conda install -c conda-forge jq or use your favorite package manager)

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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.

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Virtual Hosts on nginx (CSC309)

When hosting our web applications, we often have one public IP address (i.e., an IP address visible to the outside world) using which we want to host multiple web apps. For example, one may wants to host three different web apps respectively for example1.com, example2.com, and example1.com/images on the same machine using a single IP address.

How can we do that? Well, the good news is Internet browsers

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# UPDATED 17 February 2019
# Redirect all HTTP traffic to HTTPS
server {
   listen 80;
   listen [::]:80; 	
   server_name www.domain.com domain.com;
   return 301 https://$host$request_uri;
}

# SSL configuration

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aws s3api put-bucket-versioning \
	--bucket bucket \
	--versioning-configuration '{"MFADelete":"Enabled","Status":"Enabled"}' \
	--mfa 'arn:aws:iam::aws_account_id:mfa/root-account-mfa-device passcode'

aws s3api get-bucket-versioning --bucket bucket

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#place in /etc/letsencrypt/renewal-hooks/post

export AWS_ACCESS_KEY_ID=XXX
export AWS_SECRET_ACCESS_KEY=XXX
#certs must be in us-east-1 to use with cloudfront
export AWS_DEFAULT_REGION=us-east-1

#run without --certificate-arn first time then specify arn for updates
aws acm import-certificate --certificate file:///etc/letsencrypt/live/site.com/cert.pem --private-key file:///etc/letsencrypt/live/site.com/privkey.pem --certificate-chain file:///etc/letsencrypt/live/site.com/chain.pem  --certificate-arn specifyarnforupdate

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#!/usr/bin/env python

# Prereq: PyCrypto
# Validation: https://www.samltool.com/decrypt.php

# Usage: ./decrypt_saml_response.py --key PRIVATE_KEY --pretty-print RESPONSE_XML

import sys
import optparse
import base64

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javascript:!function(){var n,e,r,i;n=window,e=document.body,r=JSON.parse,i=JSON.stringify,n.isf||(e.innerHTML="<pre>"+i(r(e.innerText),null,4).replace(/\"(.*)[^\:]\:/g,'<span style="color:#9C3636">$1&colon;</span>')+"</pre>",n.isf=!0)}();

//usage:
//save as bookmark and click it whenever you open a json response in a browser tab/window