We start going in to more complicated core architectures
Logistics
- Questions to ask in Slack
- Were you successful with NT Storage?
- Did you use a new gem? Which one?
- What problem did you hit, and were you able to overcome it?
- What is your heroku url?
- Let’s take a look at this active_record example: sinatra_activerecord_sample
Service Oriented Architectures
- Divide a system into “services” that communicate with each other
- Services can be implemented by one or multiple “servers”
- If more than one, then requests get sent to them based on some algorithm
How does this communication work?
- Almost always using tcp/ip (which requires an IP address)
- Often http but not always (e.g. database servers typically don’t use http)
- Each service has a way that it expects to be called
- This is called its “API”
APIs
- Almost always there’s a software library that encapsulates the API
- This is often referred to as the “binding” for that API in a certain programming language
- I.e. “Is there a python binding for MongoDB?”
- The client uses the binding to call the server
- Key parameter is the ip address or dns name of the server
Services
- A computer (a host, a vm, a droplet, a dyno) responds to a request. Call that a “server”
- You may have more than one of the same kind of server together responding to requests of that type
- These are not public IP addresses. They are not accessible outside of the internal infrastructure
- Still there are IP addresses and often dns names
Clients
- How does the client know what dns name or ip address to use?
- If there’s only one instance ever, it could be put right into the code (MongoDb.open_database(“ourdata”, “12.32.33.44”)
- Even that is dangerous. If you need to upgrade or otherwise change your network organized, the ip might change
- Github or other public repos
- Be careful: never put any secret keys from AWS, Twitter, or anyone else in your code
- Hackers constantly scan these public repos and find the keys and turn your account into a Bitcoin Mining Operation
- Also don’t include IP addresses
- Many approaches to dealing with this
- Simplest is Environment Variables
Choosing Software Engineering and technologies
- Everything is constantly changing
- Improved sometimes, made worse sometimes
- New alternatives are invented
- Totally new approaches are invented
- Key responsibility is to know the options
- Understand the tradeoffs
- Decide what is worth learning and what is just cargo culting
- Learn how to critically analyze your needs and the tradeoffs.
Technology Grid
| Subject | Default | Alternatives | Comments |
|---|---|---|---|
| ORM | ActiveRecord | Sequel, Mongoid | Of the others, I think Sequel is the most interesting alternative. If you are using NoSQL then you would be required to use a different ORM. |
| Database | Postgres | Amazon DynamoDB, MongoDB, | Relational databases are the obvious choice. But could you get better performance, scalability or programmer happiness from other choices? |
| Cloud Deployment | Heroku | Digital Ocean, AWS BeanStalk | Heroku is the easiest to use. But Beanstalk is a little more large scale for the same price, and Digital Ocean is somewhere in the middle |
| Continuous Testing and Deployment | Heroku | CodeShip, Github Actions | There are lots of choices and many of them are pretty similar. The one new entrant that is pretty interesting is Github actions |
| Logging and Error Tracking | Rails Built In | DataDog, Rollbar, Lograge, Sentry, Airbrake | Complex systems rely heavily on log and error tracking, for troubleshooting, notification, and billing. |
| Background Processing | SideKiq | SuckerPunch, Delayed::Job | There are options and tradeoffs. Here's a good article: https://scoutapp.com/blog/which-ruby-background-job-framework-is-right-for-you also: https://blog.appsignal.com/2022/02/15/delayed-job-vs-sidekiq-which-is-better.html?utm_source=ruby-magic&utm_medium=email&utm_campaign=rss-email&utm_content=button |
| Caching | Redis | CachedD | These are the two main ones |
| UI | HTML | Bootstream, React, Elm | I recommend keeping it simple with just HTML plus some css library like Bootstrap or others |
| Web Framework | Sinatra | Padrino, Hanami, Rails, many more | Good article: https://naturaily.com/blog/8-frameworks-ruby-not-rails |
(random Image from picsum.photos)