Download pptx - Finite State Machines - Why the fear?

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Erlang and gen_fsm

@dieswaytoofast (V.P. Ubiquiti Networks)

The Business

The Metrics

Phone Calls per Second

The Metrics

Phone Calls per Second

The Metrics

Simultaneous Phone Calls

The Metrics

Simultaneous Phone Calls

The Metrics

HTTP API requests

The Metrics

HTTP API requests

The Metrics

Self-hosted (kinda)

Voice Response

Call Handling

Call Routing

Call Handling

Self-hosted (kinda)

Bet the farm moment

Concurrency

The Big SixFrom http://www.erlang.org/download/armstrong_thesis_2003.pdf

Concurrency

Error encapsulation


Concurrency

Error encapsulation

Fault detection


Concurrency

Error encapsulation

Fault detection

Fault identification


Concurrency

Error encapsulation

Fault detection


Code upgrade


Concurrency

Error encapsulation

Fault detection


Code upgrade

Stable Storage


Erlang

Erlang

gen_server

Behaviours

gen_server

gen_tcp

Behaviours

gen_server

gen_tcp

gen_event

Behaviours

gen_server

gen_tcp

gen_event

gen_fsm

Behaviours

gen_server

gen_tcp

gen_event

gen_fsm

…

Behaviours

gen_server

gen_tcp

gen_event

gen_fsm

…

Behaviours

A System has States

Finite State Machines

A System has States

States transition


A System has States

States transition

Transitions are Atomic


A System has States

States transition

Transitions are Atomic

Events at Entry and Exit


Everything is an FSM






Voice Response


Voice Response


Voice Response


Encapsulation

Call Routing


Templates are your friend

So are BIG sheets of paper

Think “Real World”

The Bottom Line