Simplifying systems with Elixir - Belgrade

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Simplifying systems with Elixir @sasajuric aircloak.com

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Elixir functional concurrent

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process ... foo(...) bar(...) ...

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functional Elixir modules and functions immutable data ﬁrst-class functions

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... spawn(fn -> ... end) ...

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process A ... foo(...) bar(...) ... process B ... baz(...) qux(...) ...

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send( process_b, some_message ) receive do message -> handle(message) end process a process b

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BEAM (Erlang VM)

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BEAM (Erlang VM)

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scheduler scheduler scheduler scheduler BEAM (Erlang VM) CPU CPU CPU CPU

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concurrent functional

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activities incoming requests background jobs in-memory state load control …

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managing activities multiple OS processes 3rd party products service managers

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uniformity simpler development simpler testing simpler deployment simpler maintenance improved collaboration

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theerlangelist.com

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git clone https://github.com/sasa1977/erlangelist.git mix deps.get && pushd assets && npm install && popd iex -S mix phx.server

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serving requests

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http listener https listener

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http listener https listener handler 1 handler 2 handler n …

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usage stats

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stats collector handler handler handler

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stats collector disk writer

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def store(path, data) do File.write!( path, :erlang.term_to_binary(data) ) end

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def read(path, default) do path |> File.read!() |> :erlang.binary_to_term() rescue ArgumentError -> default end

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cleanup

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scheduler cleanup job periodically starts

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HTTPS

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our system CA server certiﬁcate request challenge info challenge

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certiﬁer http server usage stats

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dev CA server

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service management

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defmodule StatsCollector do def start_link() do # ... end # ... end

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Supervisor.start_link( [ StatsCollector, Cleanup ], # .. )

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supervisor stats collector cleanup

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supervisor worker

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erlangelist usage stats web

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usage stats stats collector cleanup

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web ACME server main site certiﬁer

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technical feature built-in options services GenServer, Task service manager Supervisor service registry Registry k-v ets, mnesia web server phoenix, plug, cowboy periodical jobs :timer, quantum, periodic load regulation jobs, safetyvalve, sbroker concurrent ﬂows Flow, GenStage

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Elixir in a nutshell start simple go far

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Elixir guides Phoenix guides Learning resources Elixir forum

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40% off using code ctwelixirbg18 at manning.com slides available at bit.ly/elixirbg102018