Heroku

Installation

• Windows 10 Laptop

Concepts

• all Heroku applications run in a collection of lightweight Linux containers called Dynos. To find out the dynos:

heroku ps

• Procfiles can contain additional process types. For example, you can declare a background worker that processes items off a queue.
• The set of dynos declared in your Procfile and managed by the dyno manager via heroku ps:scale are known as the dyno formation. These dynos do the app’s regular business (such as handling web requests and processing background jobs) as it runs. When you wish to do one-off administrative or maintenance tasks for the app, or execute some task periodically using Heroku Scheduler, you can spin up a one-off dyno.

Interface

• Dashboard

Config and Environment Variables

• config variables are static and available via heroku config or via the Heroku Dashboard
• environment variables are dynamic and are available via heroku run env

Add Ons

Databases

• documentation
• connection information see config var DATABASE_URL [database type]://[username]:[password]@[host]:[port]/[database name]

Postgres

• DB info dashboard -> <APPLICATION> -> Resources

Operation

Delete Application

heroku apps:destroy uweheuer-capstone

List all Applications

heroku apps

List all Domains (for Applications)

heroku domains

Logging

heroku logs --tail

Example

Official Tutorial

• from official python tutorial

PS C:\Temp\python-getting-started> heroku login

• clone example
• create app and push code
• start the app

PS C:\Temp\python-getting-started> heroku ps:scale web=1
Scaling dynos... done, now running web at 1:Free
PS C:\Temp\python-getting-started> heroku open
// opens https://arcane-peak-78109.herokuapp.com/

• open the dashboard
• stop it or scale it down to 0

heroku ps:scale web=0

• prepare for running locally

PS C:\Temp\python-getting-started> python -m venv venv
PS C:\Temp\python-getting-started> .\venv\Scripts\activate
(venv) PS C:\Temp\python-getting-started> pip install -r .\requirements.txt

• run it locally

(venv) PS C:\Temp\python-getting-started> python manage.py collectstatic
(venv) PS C:\Temp\python-getting-started> heroku local -f .\Procfile.windows

• open it http://localhost:5000/

Spring Boot

• from offical Spring Boot tutorial

cd C:\Uwes\eclipse\workspace_2020-12\SpringBoot
spring init --dependencies=web demo1 // create a spring app with Spring CLI
cd demo1

• edit C:\Uwes\eclipse\workspace_2020-12\SpringBoot\demo1\src\main\java\com\example\demo1

git init
git add .
git commit -m "first commit"
heroku login
heroku create // creates an app and a Git remote (named heroku) associated with your local Git repository

• When deploying an app, Heroku reads pom.xml file and installs the dependencies by running mvn clean install.
• in order to run it locally change java version in pom.xml from 11 to 8
• create C:\Uwes\eclipse\workspace_2020-12\SpringBoot\demo1\src\main\java\com\example\demo1\system.properties and add java version 1.8

git add .
git push heroku master
heroku open // opens the application https://intense-caverns-96515.herokuapp.com/ in a browser 
heroku addons:create heroku-postgresql // add a PostgrsSQL database
heroku config // shows DB connection URL postgres://cepxizounlueue:e78e393778c5d3e6b5dd26d6ebff081f50d3e5c34a817ec4e8653b1dcf99e91e@ec2-3-230-122-20.compute-1.amazonaws.com:5432/defpfuas3qslld
  postgres:
  //
  cepxizounlueue // username
  :
  e78e393778c5d3e6b5dd26d6ebff081f50d3e5c34a817ec4e8653b1dcf99e91e // password
  @
  ec2-3-230-122-20.compute-1.amazonaws.com
  :
  5432
  /
  defpfuas3qslld // DB

• check DB connection by

C:\Uwes\Programme\PostgreSQL\12\bin> .\psql -h ec2-3-230-122-20.compute-1.amazonaws.com -U cepxizounlueue defpfuas3qslld

• more infos

heroku info // shows basic application information
heroku run env // shows all dynamic environment varialbles

Run Locally

• create Procfile Procfile.windows for running locally with command to start the Spring application java -jar target/demo1-0.0.1-SNAPSHOT.jar

mvn install
heroku local -f Procfile.windows

Resources

• Tutorial
• Heroku dashboard