Kylie (can't get you out of my graph data base)

Kylie is a blond and small Elixir/Erlang client for Cayley graph data base

Cayley is an open-source graph data base written in go

---

Elixir Example:

>iex -S mix run -e "Kylie.start"
Erlang/OTP 19 [erts-8.1] [source-77fb4f8] [64-bit] [smp:4:4] [async-threads:10] [kernel-poll:false]


=INFO REPORT==== 14-Dec-2016::11:50:14 ===
Creating wpool ETS tableInteractive Elixir (1.3.4) - press Ctrl+C to exit (type h() ENTER for help)

iex(1)> Squad.new("Kylie", "is", "singer")
%{object: "singer", predicate: "is", subject: "Kylie"}

iex(2)> Kylie.add(Squad.new("Kylie", "is", "model"))
:ok
iex(3)> Kylie.add(Squad.new("Kylie", "is", "songwriter"))
:ok
iex(4)> Kylie.add(Squad.new("Kylie", "is", "actress"))
:ok

You can do a generic query with Subject and Predicate.

iex(4)> Kylie.get_result("Kylie", "is")
["model","singer","songwriter"]

You can also do a proplisp(?) and generate a query in the Gremblin way.

The idea is build this query:

  g.V("Kylie").Out("recorded").Out("incluided").All()"

With this proplisp:

   [{:graph_vertex, "Kylie"}, {:out, "recorded"}, {:out, "incluided"}, :all]

iex(5)> Kylie.add(Squad.new("Kylie", "recorded", "Fever"))
:ok
iex(6)> Kylie.add(Squad.new("Fever", "incluided", "Can't Get You Out of My Head"))
:ok
iex(7)> Kylie.add(Squad.new("Fever", "incluided", "In Your Eyes"))
:ok

iex(8)> propLispQuery = [{:graph_vertex, "Kylie"}, {:out, "recorded"}, {:out, "incluided"}, :all]
[{:graph_vertex, "Kylie"}, {:out, "recorded"}, {:out, "incluided"}, :all]

iex(9)> gremblinQuery = Kylie.build_gremblin_human_readable(propLispQuery)
"g.V("Kylie").Out("recorded").Out("incluided").All()"

iex(10)> {ok, result} = Kylie.query(gremblinQuery)
["Can't Get You Out of My Head","In Your Eyes"]

---

Example:

>rebar3 shell

===> Verifying dependencies...
===> Compiling kylie
Erlang/OTP 19 [erts-8.1] [source-77fb4f8] [64-bit] [smp:4:4] [async-threads:0] [kernel-poll:false]

Eshell V8.1  (abort with ^G)
1> squad:new("Kylie", "is", "singer").
#{object => "singer",predicate => "is",subject => "Kylie"}

2> kylie:add(squad:new(<<"Kylie">>, <<"is">>,<< "singer">>)).
ok
3> kylie:add(squad:new(<<"Kylie">>, <<"is">>,<< "songwriter">>)).
ok
4> kylie:add(squad:new(<<"Kylie">>, <<"is">>,<< "model">>)).
ok

You can do a generic query with Subject and Predicate.

5> kylie:get_result(<<"Kylie">>, <<"is">>).
[<<"model">>,<<"singer">>,<<"songwriter">>]

You can also do a proplisp(?) and generate a query in the Gremblin way.

The idea is build this query:

  g.V('Kylie').Out('recorded').Out('incluided').All()"

With this proplisp:

   [{graph_vertex, <<"Kylie">>}, {out, <<"recorded">>}, {out, <<"incluided">>}, all]

6> kylie:add(squad:new(<<"Kylie">>, <<"recorded">>, <<"Fever">>)).
ok
7> kylie:add(squad:new(<<"Fever">>, <<"incluided">>, <<"Can't Get You Out of My Head">>)).
ok
8> kylie:add(squad:new(<<"Fever">>, <<"incluided">>, <<"In Your Eyes">>)),
ok

9>PropLispQuery = [{graph_vertex, <<"Kylie">>}, {out, <<"recorded">>}, {out, <<"incluided">>}, all].
[{graph_vertex,<<"Kylie">>},{out,<<"recorded">>},{out,<<"incluided">>},all]

10>GremblinQuery = kylie:build_gremblin_human_readable(PropLispQuery).
<<"g.V('Kylie').Out('recorded').Out('incluided').All()">>

11>{ok, Result} = kylie:query(GremblinQuery).
[<<"Can't Get You Out of My Head">>,<<"In Your Eyes">>]

---

Testing

The suite is split in two so the pure logic can be exercised without network, and the real HTTP path can be verified end-to-end against a real Cayley server.

Unit tests (no Cayley required)

Pure, in-process tests for squad, the Gizmo/Gremlin query builder and the injection-escape helper. Run them on every push — they are fast and have zero external dependencies:

rebar3 unit

Integration tests (Docker-backed Cayley)

Exercises the full HTTP round-trip (add, delete, get_result, error path on an unreachable server). They expect a Cayley instance listening on 127.0.0.1:64210. If Cayley is not reachable the suite is skipped, not failed.

Start Cayley once:

docker run -d --name kylie-cayley \
  -p 64210:64210 \
  cayleygraph/cayley:latest \
  http --init --host=0.0.0.0:64210

Then run:

rebar3 integration

To tear Cayley down afterwards:

docker rm -f kylie-cayley

Both at once

rebar3 test

Configuring the query endpoint

Cayley renamed /api/v1/query/gremlin to /api/v1/query/gizmo. Kylie defaults to gizmo (current Cayley). For older servers, override in config/sys.config:

[{kylie, [ {query_path, <<"/api/v1/query/gremlin">>} ]}].