Building a transactional pipeline with TDD and Elixir

Slide 1

Slide 1 text

Transactional Pipeline function() Building a with TDD and Elixir #scpna17 #teamtinyp

Slide 2

Slide 2 text

jacegu jacegu javieracero.com

Slide 3

Slide 3 text

https://dnsimple.com

Slide 4

Slide 4 text

d s n http://howdns.works

Slide 5

Slide 5 text

pamplonaswcraft.com 192.30.252.153 192.30.252.154

Slide 6

Slide 6 text

pamplonaswcraft.com

Slide 7

Slide 7 text

https://help.github.com/articles/using-a-custom-domain-with-github-pages

Slide 8

Slide 8 text

https://help.github.com/articles/using-a-custom-domain-with-github-pages

Slide 9

Slide 9 text

No content

Slide 10

Slide 10 text

No content

Slide 11

Slide 11 text

domains services Connect to

Slide 12

Slide 12 text

api

Slide 13

Slide 13 text

api

Slide 14

Slide 14 text

connectors http://platform.dnsimple.com

Slide 15

Slide 15 text

No content

Slide 16

Slide 16 text

transactional

Slide 17

Slide 17 text

No content

Slide 18

Slide 18 text

if elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif elsif else end

Slide 19

Slide 19 text

connection |> add_alias_record(…) |> add_cname_record(…) |> configure_cname_file(…) |> save_connection(…)

Slide 20

Slide 20 text

WHERE ARE MY OBJECTS WHERE ARE MY OBJECTS

Slide 21

Slide 21 text

No content

Slide 22

Slide 22 text

Runs anonymous functions without params 1

Slide 23

Slide 23 text

Runs anonymous functions without params defmodule TpTest do use ExUnit.Case test "runs anonymous functions without params" do assert Tp.run(fn -> 2 + 2 end) == 4 end end 1 test/tp_test.ex Test [1/1]

Slide 24

Slide 24 text

test "runs anonymous functions without params" do assert Tp.run(fn -> 2 + 2 end) == 4 end Runs anonymous functions without params 1 test/tp_test.ex Test [1/1]

Slide 25

Slide 25 text

test "runs anonymous functions without params" do assert Tp.run(fn -> 2 + 2 end) == 4 end Runs anonymous functions without params 1 test/tp_test.ex Test [1/1]

Slide 26

Slide 26 text

Runs anonymous functions without params defmodule Tp do def run(_) do nil end end 1 lib/tp.ex

Slide 27

Slide 27 text

Runs anonymous functions without params def run(_) do nil end 1 lib/tp.ex

Slide 28

Slide 28 text

Runs anonymous functions without params def run(_) do 4 end 1 lib/tp.ex

Slide 29

Slide 29 text

Runs anonymous functions without params test "runs an anonymous function without params" do assert Tp.run(fn -> 2 + 2 end) == 4 end 1 test/tp_test.ex Test [1/1]

Slide 30

Slide 30 text

Runs anonymous functions without params test "runs an anonymous function without params" do assert Tp.run(fn -> 2 + 2 end) == 4 assert Tp.run(fn -> String.upcase("x") end) == "X" end 1 test/tp_test.ex Test [1/1]

Slide 31

Slide 31 text

Runs anonymous functions without params def run(_) do 4 end 1 lib/tp.ex

Slide 32

Slide 32 text

Runs anonymous functions without params def run(fun) do fun.() end 1 lib/tp.ex

Slide 33

Slide 33 text

Runs anonymous functions with 1 parameter 2

Slide 34

Slide 34 text

test "runs anonymous functions with 1 param" do assert Tp.run(fn(x) -> 2 + x end, 2) == 4 end Runs anonymous functions with 1 parameter 2 test/tp_test.ex Test [2/2]

Slide 35

Slide 35 text

Runs anonymous functions with 1 parameter def run(fun) do fun.() end 2 lib/tp.ex

Slide 36

Slide 36 text

Runs anonymous functions with 1 parameter def run(fun) do fun.() end def run(fun, param), do: fun.(param) 2 lib/tp.ex

Slide 37

Slide 37 text

Runs anonymous functions with 1 parameter def run(fun), do: fun.() def run(fun, param), do: fun.(param) 2 lib/tp.ex

Slide 38

Slide 38 text

Runs anonymous functions with 2 parameters 3

Slide 39

Slide 39 text

Runs anonymous functions with 2 parameters test "runs an anonymous function with 2 params" do assert Tp.run(fn(x, y) -> x+y end, [1, 2]) == 3 end 3 test/tp_test.ex Test [3/3]

Slide 40

Slide 40 text

Runs anonymous functions with 2 parameters def run(fun), do: fun.() def run(fun, param), do: fun.(param) 3 lib/tp.ex

Slide 41

Slide 41 text

Runs anonymous functions with 2 parameters def run(fun), do: fun.() def run(fun, params) when is_list(params), do: apply(fun, params) def run(fun, param), do: fun.(param) 3 lib/tp.ex

Slide 42

Slide 42 text

Runs anonymous functions with 2 parameters test "runs an anonymous function with 2 params" do assert Tp.run(fn(x, y) -> x+y end, [1, 2]) == 3 end 3 test/tp_test.ex Test [3/3]

Slide 43

Slide 43 text

test "runs an anonymous function with 2 params" do assert Tp.run(fn -> 2 + 2 end, []) == 4 assert Tp.run(&String.upcase/1, ["x"]) == "X" assert Tp.run(fn(x, y) -> x+y end, [1, 2]) == 3 end 3 test/tp_test.ex Test [3/3] Runs anonymous functions with 2 parameters

Slide 44

Slide 44 text

test "runs a function" do assert Tp.run(fn -> 2 + 2 end, []) == 4 assert Tp.run(&String.upcase/1, ["x"]) == "X" assert Tp.run(fn(x, y) -> x+y end, [1, 2]) == 3 end 3 test/tp_test.ex Test [3/3] Runs a function Test [1/1]

Slide 45

Slide 45 text

Runs a function def run(fun), do: fun.() def run(fun, params) when is_list(params), do: apply(fun, params) def run(fun, param), do: fun.(param) 3 lib/tp.ex

Slide 46

Slide 46 text

Runs a function def run(fun, params), do: apply(fun, params) 3 lib/tp.ex

Slide 47

Slide 47 text

Runs multiple functions 4

Slide 48

Slide 48 text

Runs multiple functions test "runs multiple functions" do f1 = fn(x, y, z) -> [x*x, y*y, z*z] end f2 = fn(x, y, z) -> [z, y, x] end assert Tp.run([f1, f2], [2, 3, 5]) == [25, 9, 4] end 4 test/tp_test.ex Test [2/2]

Slide 49

Slide 49 text

Runs multiple functions def run(fun, params), do: apply(fun, params) 4 lib/tp.ex

Slide 50

Slide 50 text

Runs multiple functions def run([fun1, fun2], params) do apply(fun2, apply(fun1, params)) end def run(fun, params), do: apply(fun, params) 4 lib/tp.ex

Slide 51

Slide 51 text

Slide 52

Slide 52 text

Runs multiple functions test "runs multiple functions" do f1 = fn(x, y, z) -> [x*x, y*y, z*z] end f2 = fn(x, y, z) -> [z, y, x] end assert Tp.run([], [1, 2, 3]) == [1, 2, 3] assert Tp.run([f2], [7, 8, 9]) == [9, 8, 7] assert Tp.run([f1, f2], [2, 3, 5]) == [25, 9, 4] end 4 test/tp_test.ex Test [2/2]

Slide 53

Slide 53 text

Runs multiple functions def run([fun1, fun2], params) do apply(fun2, apply(fun1, params)) end def run(fun, params), do: apply(fun, params) 4 lib/tp.ex

Slide 54

Slide 54 text

Runs multiple functions def run([first|rest], params) do apply(fun2, apply(fun1, params)) end def run(fun, params), do: apply(fun, params) 4 lib/tp.ex

Slide 55

Slide 55 text

Runs multiple functions def run([first|rest], params) do run(rest, apply(first, params)) end def run(fun, params), do: apply(fun, params) 4 lib/tp.ex

Slide 56

Slide 56 text

Runs multiple functions def run([], params), do: params def run([first|rest], params) do run(rest, apply(first, params)) end def run(fun, params), do: apply(fun, params) 4 lib/tp.ex

Slide 57

Slide 57 text

Runs multiple functions 4 lib/tp.ex def run([], params), do: params def run([h|t], params), do: run(t, apply(h, params)) def run(fun, params), do: apply(fun, params)

Slide 58

Slide 58 text

Runs multiple functions 4 test/tp_test.ex Test [1/1] test "runs a function" do assert Tp.run(fn -> 2 + 2 end, []) == 4 assert Tp.run(&String.upcase/1, ["x"]) == "X" assert Tp.run(fn(x, y) -> x+y end, [1, 2]) == 3 end

Slide 59

Slide 59 text

Runs multiple functions test "runs a function" do assert Tp.run([fn -> 2 + 2 end], []) == 4 assert Tp.run([&String.upcase/1], ["x"]) == "X" assert Tp.run([fn(x, y) -> x+y end], [1, 2]) == 3 end 4 test/tp_test.ex Test [1/1]

Slide 60

Slide 60 text

Slide 61

Slide 61 text

Runs multiple functions 4 lib/tp.ex def run([], params), do: params def run([h|t], params), do: run(t, apply(h, params)) def run(fun, params), do: apply(fun, params)

Slide 62

Slide 62 text

Runs multiple functions 4 lib/tp.ex def run([], params), do: params def run([h|t], params), do: run(t, apply(h, params))

Slide 63

Slide 63 text

No content

Slide 64

Slide 64 text

No content

Slide 65

Slide 65 text

No content

Slide 66

Slide 66 text

Runs functions with side effects Runs “real world” functions 5

Slide 67

Slide 67 text

Runs “real world” functions defmodule State do def start(initial \\ nil), do: #... def stop, do: #... def get, do: #... def put(new), do: #... end 5 test/test_helper.ex

Slide 68

Slide 68 text

Runs “real world” functions 5 test/tp_test.ex test "runs functions with side effects" do State.start f1 = fn(x) -> State.put(x); [x] end f2 = fn(x) -> [x*x*x] end assert Tp.run([f1, f2], [3]) == [27] assert State.get == 3 State.stop end Test [2/2]

Slide 69

Slide 69 text

Returns whether it failed 6

Slide 70

Slide 70 text

ERR R HANDLING

Slide 71

Slide 71 text

http://elixir-lang.org/getting-started/try-catch-and-rescue.html

Slide 72

Slide 72 text

http://elixir-lang.org/getting-started/try-catch-and-rescue.html

Slide 73

Slide 73 text

try do result = this_can_fail!(params) continue(result) rescue error -> handle_error(error) end case this_can_fail(params) do {:ok, result} -> continue(result) {:error, error} -> handle_error(params) end vs

Slide 74

Slide 74 text

Returns whether it failed 6

Slide 75

Slide 75 text

Returns whether it failed 6 test "returns whether it failed" do State.start f1 = fn(x) -> State.put(x); [x] end f2 = fn(x) -> [x*x*x] end f3 = fn(_) -> {:error, “KO"} end assert Tp.run([f1, f2], [3]) == [27] assert Tp.run([f3, f2], [3]) == {:error, “KO"} State.stop end test/tp_test.ex Test [3/3]

Slide 76

Slide 76 text

Returns whether it failed 6 lib/tp.ex def run([], params), do: params def run([h|t], params), do: run(t, apply(h, params))

Slide 77

Slide 77 text

Returns whether it failed 6 lib/tp.ex def run([], params), do: params def run([h|t], params) do run(t, apply(h, params)) end

Slide 78

Slide 78 text

Returns whether it failed 6 lib/tp.ex def run([], params), do: params def run([h|t], params) do case apply(h, params) do run(t,) end end

Slide 79

Slide 79 text

Returns whether it failed 6 lib/tp.ex def run([], params), do: params def run([h|t], params) do case apply(h, params) do {:error, details} -> {:error, details} run(t,) end end

Slide 80

Slide 80 text

Returns whether it failed 6 lib/tp.ex def run([], params), do: params def run([h | t], params) do case apply(h, params) do {:error, details} -> {:error, details} new_params -> run(t, new_params) end end

Slide 81

Slide 81 text

Returns whether it succeeded or failed 7

Slide 82

Slide 82 text

Returns whether it succeeded or failed 7 test/tp_test.ex Test [3/3] test "returns whether it failed" do State.start f1 = fn(x) -> State.put(x); [x] end f2 = fn(x) -> [x*x*x] end f3 = fn(_) -> {:error, "KO"} end assert Tp.run([f1, f2], [3]) == [27] assert Tp.run([f3, f2], [3]) == {:error, "KO"} State.stop end

Slide 83

Slide 83 text

Returns whether it succeeded or failed 7 test/tp_test.ex Test [3/3] test "returns whether it succeeded or failed" do State.start f1 = fn(x) -> State.put(x); [x] end f2 = fn(x) -> [x*x*x] end f3 = fn(_) -> {:error, "KO"} end assert Tp.run([f1, f2], [3]) == {:ok, [27]} assert Tp.run([f3, f2], [3]) == {:error, "KO"} State.stop end

Slide 84

Slide 84 text

Returns whether it succeeded or failed 7 test/tp_test.ex Test [3/3] test "returns whether it succeeded or failed" do State.start f1 = fn(x) -> State.put(x); {:ok, [x]} end f2 = fn(x) -> {:ok, [x*x*x]} end f3 = fn(_) -> {:error, "KO"} end assert Tp.run([f1, f2], [3]) == {:ok, [27]} assert Tp.run([f3, f2], [3]) == {:error, "KO"} State.stop end

Slide 85

Slide 85 text

Returns whether it succeeded or failed 7 test/tp_test.ex Test [2/3] test "runs functions with side effects" do State.start f1 = fn(x) -> State.put(x); [x] end f2 = fn(x) -> [x*x*x] end assert Tp.run([f1, f2], [3]) == [27] assert State.get == 3 State.stop end

Slide 86

Slide 86 text

Returns whether it succeeded or failed 7 test/tp_test.ex Test [2/3] test "runs functions with side effects" do State.start f1 = fn(x) -> State.put(x); {:ok, [x]} end f2 = fn(x) -> {:ok, [x*x*x]} end assert Tp.run([f1, f2], [3]) == {:ok, [27]} assert State.get == 3 State.stop end

Slide 87

Slide 87 text

Returns whether it succeeded or failed 7 test/tp_test.ex Test [1/3] test "runs multiple functions" do f1 = fn(x, y, z) -> [x*x, y*y, z*z] end f2 = fn(x, y, z) -> [z, y, x] end assert Tp.run([], [1, 2, 3]) == [1, 2, 3] assert Tp.run([f2], [7, 8, 9]) == [9, 8, 7] assert Tp.run([f1, f2], [2, 3, 5]) == [25, 9, 4] end

Slide 88

Slide 88 text

Returns whether it succeeded or failed 7 test/tp_test.ex Test [1/3] test "runs multiple functions" do f1 = fn(x, y, z) -> {:ok, [x*x, y*y, z*z]} end f2 = fn(x, y, z) -> {:ok, [z, y, x]} end assert Tp.run([], [1, 2, 3]) == {:ok, [1, 2, 3]} assert Tp.run([f2], [7, 8, 9]) == {:ok, [9, 8, 7]} assert Tp.run([f1, f2], [2, 3, 5]) == {:ok, [25, 9, 4]} end

Slide 89

Slide 89 text

Returns whether it succeeded or failed 7 lib/tp.ex def run([], params), do: params def run([h | t], params) do case apply(h, params) do {:error, details} -> {:error, details} new_params -> run(t, new_params) end end

Slide 90

Slide 90 text

Returns whether it succeeded or failed 7 lib/tp.ex def run([], params), do: params def run([h | t], params) do case apply(h, params) do {:error, details} -> {:error, details} {:ok, new_params} -> run(t, new_params) end end

Slide 91

Slide 91 text

Returns whether it succeeded or failed 7 lib/tp.ex def run([], params), do: {:ok, params} def run([h | t], params) do case apply(h, params) do {:error, details} -> {:error, details} {:ok, new_params} -> run(t, new_params) end end

Slide 92

Slide 92 text

Returns whether it succeeded or failed 7 lib/tp.ex def run([], params), do: {:ok, params} def run([h | t], params) do case apply(h, params) do {:ok, new_params} -> run(t, new_params) {:error, details} -> {:error, details} end end

Slide 93

Slide 93 text

Rolls back when it fails 8

Slide 94

Slide 94 text

Rolls back when it fails 8 test "rolls back when it fails" do State.start("initial") f1 = fn(x) -> State.put(x); {:ok, [x]} end f2 = fn(_) -> {:error, "BOOM!"} end Tp.run([f1, f2], [0]) assert State.get == "initial" State.stop end test/tp_test.ex Test [4/4]

Slide 95

Slide 95 text

Rolls back when it fails 8 test "rolls back when it fails" do State.start("initial") f1 = fn(x) -> state = State.get State.put(x) {:ok, [x], fn() -> State.put(state) end} end f2 = fn(_) -> {:error, "BOOM!"} end Tp.run([f1, f2], [0]) assert State.get == "initial" State.stop end test/tp_test.ex Test [4/4]

Slide 96

Slide 96 text

Rolls back when it fails 8 lib/tp.ex def run([], params), do: {:ok, params} def run([h | t], params) do case apply(h, params) do {:ok, new_params} -> run(t, new_params) {:error, details} -> {:error, details} end end

Slide 97

Slide 97 text

Slide 98

Slide 98 text

Slide 99

Slide 99 text

Rolls back when it fails 8 lib/tp.ex def run([], params), do: {:ok, params} def run([h | t], params) do case apply(h, params) do {:ok, new_params} -> run(t, new_params) {:ok, new_params, new_rollback} -> run(t, new_params) {:error, details} -> rollback.() {:error, details} end end

Slide 100

Slide 100 text

Rolls back when it fails 8 lib/tp.ex def run([], params, _), do: {:ok, params} def run([h | t], params, rollback) do case apply(h, params) do {:ok, new_params} -> run(t, new_params, rollback) {:ok, new_params, new_rollback} -> run(t, new_params, new_rollback) {:error, details} -> rollback.() {:error, details} end end

Slide 101

Slide 101 text

Rolls back when it fails 8 lib/tp.ex defp do_run([], params, _), do: {:ok, params} defp do_run([h | t], params, rollback) do case apply(h, params) do {:ok, new_params} -> run(t, new_params, rollback) {:ok, new_params, new_rollback} -> run(t, new_params, new_rollback) {:error, details} -> rollback.() {:error, details} end end

Slide 102

Slide 102 text

Rolls back when it fails 8 lib/tp.ex def run(functions, params) do default_rollback = fn -> nil end do_run(functions, params, default_rollback) end

Slide 103

Slide 103 text

Rolls back when it fails 9

Slide 104

Slide 104 text

Rolls back when it fails 9 test/tp_test.ex Test [4/4] test "rolls back when it fails" do State.start("initial") f1 = fn(x) -> state = State.get {State.put(x), [x], fn() -> State.put(state) end} end f2 = fn(_) -> {:error, "BOOM!"} end Tp.run([f1, f2], [0]) assert State.get == "initial" State.stop end

Slide 105

Slide 105 text

Rolls back when it fails 9 test/tp_test.ex Test [4/4] test "rolls back when it fails" do State.start("initial") f1 = fn(x) -> state = State.get {State.put(x), [x], fn() -> State.put(state) end} end f2 = fn(_) -> {:error, "BOOM!"} end Tp.run([f1, f1, f2], [0]) assert State.get == "initial" State.stop end

Slide 106

Slide 106 text

Rolls back when it fails 8 lib/tp.ex def run(functions, params) do default_rollback = fn -> nil end do_run(functions, params, default_rollback) end

Slide 107

Slide 107 text

Rolls back when it fails 9 lib/tp.ex def run(functions, params) do do_run(functions, params, _rollback = []) end

Slide 108

Slide 108 text

Rolls back when it fails 9 lib/tp.ex defp do_run([], params, _), do: {:ok, params} defp do_run([h | t], params, rollback) do case apply(h, params) do {:ok, new_params} -> run(t, new_params, rollback) {:ok, new_params, new_rollback} -> run(t, new_params, new_rollback) {:error, details} -> rollback.() {:error, details} end end

Slide 109

Slide 109 text

Rolls back when it fails 9 lib/tp.ex defp do_run([], params, _), do: {:ok, params} defp do_run([h | t], params, rollback) do case apply(h, params) do {:ok, new_params} -> run(t, new_params, rollback) {:ok, new_params, new_rollback} -> run(t, new_params, [new_rollback | rollback]) {:error, details} -> rollback.() {:error, details} end end

Slide 110

Slide 110 text

Rolls back when it fails 9 lib/tp.ex defp do_run([], params, _), do: {:ok, params} defp do_run([h | t], params, rollback) do case apply(h, params) do {:ok, new_params} -> run(t, new_params, rollback) {:ok, new_params, new_rollback} -> run(t, new_params, [new_rollback | rollback]) {:error, details} -> Enum.each(rollback, fn(f) -> f.() end) {:error, details} end end

Slide 111

Slide 111 text

it works!!

Slide 112

Slide 112 text

Tp.run([ &add_alias_record/2, &add_cname_record/2, &configure_cname_file/2, &save_connection/2, ], [connection, …])