infomaven

Ruby on Rails Cheatsheet

Architecture

Create a new application

Install the Rails gem if you haven't done so before

infomaven

CSV FILE DIFF SCRIPT

• Uses standard Python3 modules
• Finds diff between 2 CSV files & prints results to HTML
• Finds and prints list of items found in both files
• Does NOT find duplicates in same file

USAGE:

1. Download script file and sample CSVs to a directory on your computer
2. Run script with this command>> python3 compare_csv_files.py

• Script will generate html report in same directory

infomaven

#!bin/bash
yum install httpd -y
yum update -y
aws s3 cp s3://mywebbucket-cloudguru /var/www/html/ --recursive
service httpd start
chkconfig httpd on

infomaven

/*
Basic blocks of code that will build a CSV file using repsonse data from API calls

This is a "one-off" process, meaning you will 
1. run Gatling script to generate CSV file using REST calls (usually POSTS, but GETS or datbase queries could work ) 
2. copy the file into your project
3. compile and run Gatling 
*/

class MySimulation extends Simulation {

infomaven

What is the difference between "express": "^4.13.3" and "express": "~4.13.3" ? 

What happens if I use `npm install <package> --save` instead of `npm install <package> --save-dev` ? 

infomaven

/*
Take note of length - it is used as a String[] property > strings.length AND as a method for a String 
array element > strings[i].length().
*/
public Map<String, String> pairs(String[] strings) {
  Map<String,String> map = new HashMap<String,String>();
  
  for (int i = 0; i < strings.length; i++ ) {
    if (strings[i].length() == 1 ) {
      Character first = strings[i].charAt(0);

infomaven

/* MAVEN TO GRADLE */
- Navigate to directory where the POM is located
- Run gradle init
> this will convert the Maven build to Gradle build (new settings.gradle & one or more build.gradle files)


/* GRADLE TO MAVEN */
- Add Maven plugin to build.gradle file
ex. 
apply plugin: 'java'

infomaven

// create an alternative method for getting a list of defined enums to avoid system creating a clone of the String array
// this is the .values() method

public enum Car {
  TESLA, VOLVO, TOYOTA;
  }
  
// normally what would happen
public static Car[] values() {
  return (Car[])$VALUES.clone();

infomaven

package src.main.java;

import java.util.Collections;
import java.util.List;

/**
 * Created by nwhit8 on 11/1/15.
 */
public class Day {

infomaven

While you can get the public and private IP address of your Amazon EC2 instance via the AWS Console, it may be extremely useful to query it from anywhere you can make an HTTP request, such a shell script. The operation is really simple, just make a GET request to the following URL from within your EC2 instance:

Local IP:

curl http://169.254.169.254/latest/meta-data/local-ipv4
Public IP:

curl http://169.254.169.254/latest/meta-data/public-ipv4
I often use this feature to pre-configure services and update configuration files, as in EC2 you get a new IP Address each time you reboot