Why Elixir works magic?
(and Ruby does in limited amounts ;))
Hubert Łępicki
2015-10-17
- Hubert Łępicki
- @hubertlepicki
- @amberbit
I work with web apps
Web apps suck
Why?
JavaScript
Server-side
Why making it work is hard?
- shared mutable data
- no built-in crash recovery mechanisms
- GC is hard
- threading is hard
- preempting is hard
- monitoring is hard
if only was there better VM
taking care of all those issues...
Let's discuss memory allocation
Stack
- LIFO structure
- each function called adds stuff on top
- each function finished removes stuff from top
- VMs handle 1 stack per thread
Heap
- shared memory between all threads
- classes and types metadata
- dynamically allocated memory
Heap of problems
- global state needs synchronization
- slow access by different CPUs/cores
- single point of failure
- GC is a rocket science
Entirely different VM
There is no shared heap
There is no problem synchronizing access to one
Elixir
Writing supervised code
Hardware failure
OTP app cluster
- connect N nodes via (fast) web
- concurrency / message passing just works
- minimal changes to your code
- yay, you wrote distributed app by accident
- production-ready (remember dRB?)
- failover
- load balancing
- sleep well
Zero-downtime deployments
- elixir/erlang allows code hot-swapping
- your app is modular
- replace individual parts of system (applications)
- do not miss a single message
- do not loose a single HTTP request
Less infrastructure is more
Ruby on Rails
- [web] unicorn/puma + nginx/apache
- [worker] resque
- [scheduled tasks] cron + rake
- [websockets] faye/pusher
Elixir
[web] elixir
[worker] elixir
[scheduled tasks] elixir
[websockets] elixir