Added test of a riak_core cluster

* Test with several slave nodes in a cluster (configured in config/test.exs).
  To prevent running RiakCore on the master node (harmless, but clutters the logs),
  invoke with `mix test --no-start`
* Fixed a few warnings
* Updated riak_core.schema

Notes:
* Running this project on Elixir 1.6.5 with Erlang 20.3.6.
  I had to comment out "warnings_as_errors"
  in `deps/riak_ensemble/rebar.config` and in `deps/riak_core/rebar.config`
* This project uses riak_core_ng v3.0.9.
  Later riak_core_ng commits introduced gen_fsm_compat, which fails
  with newer Elixir+rebar3 because of "missing erl_vsn" issue:
  rebar_erl_vsn is a pre-compile hook in rebar.config of gen_fsm_compat
  and few other projects.
  Error seems to be caused by Mix not handling rebar3 hooks properly.
  See elixir-lang/elixir#7733
  and Kyorai/riak_core#23

  This issue is not specific to erl_vsn:
  for example, the forked https://github.com/gpad/cuttlefish (see mix.exs)
  differs from the official version only by rebar.config commenting out:
     % {provider_hooks, [{post, [{compile, {default, escriptize}}]}]}.

README.md

@@ -3,6 +3,7 @@
 Example application for the talk at [NoSlidesConf][0]. This application is a sample application with some functionalities available on riak_core.
 
 ## Erlang, Elixir, Rebar3 version
+
 On this branch I start to use [asdf][4] and as you can find [here](./.tool-versions) I compile everything with:
 
 ```
@@ -22,6 +23,23 @@ mix deps.get
 mix compile
 ```
 
+Run the unit test that executes the riak_core ring onseveral slave nodes in a cluster. Nodes are configured in `config/test.exs`. To prevent running RiakCore on the master node (which is harmless, but clutters the logs), invoke with:
+```shell
+mix test --no-start
+```
+
+### Comments on Erlang/Elixir compatibility
+(pmenhart, 2018-06-05) Hack to make the project working with erlang 20.3.6 and elixir 1.6.5:
+* After `mix deps.get`, I had to comment out "warnings_as_errors" in `deps/riak_ensemble/rebar.config` and in `deps/riak_core/rebar.config`.
+* Note this project is using `{:riak_core, "~> 3.0.9", hex: :riak_core_ng}`. Later riak_core_ng commits introduced gen_fsm_compat, which fails
+with newer Elixir+rebar3 because of "missing erl_vsn" issue: rebar_erl_vsn is a pre-compile hook in rebar.config of gen_fsm_compat and few other projects.
+Error seems to be caused by Mix not handling rebar3 hooks properly. See e.g. https://github.com/elixir-lang/elixir/issues/7733 and https://github.com/Kyorai/riak_core/issues/23
+* This issue is not specific to erl_vsn. For example, the forked https://github.com/gpad/cuttlefish (as used in mix.exs here) differs from the official version only by rebar.config commenting out:
+```
+% {provider_hooks, [{post, [{compile, {default, escriptize}}]}]}.
+```
+
+
 ## How to start a single node
 If you want run a single node you can execute in this way:
 

config/test.exs

@@ -0,0 +1,8 @@
+use Mix.Config
+
+ config :no_slides,
+   nodes: [
+    {"[email protected]", 8198, 8199},
+    {"[email protected]", 8298, 8299},
+    {"[email protected]", 8398, 8399}
+   ]

lib/no_slides/get_fsm_supervisor.ex

@@ -9,7 +9,7 @@ defmodule NoSlides.GetFsmSupervisor do
     Supervisor.start_link(__MODULE__, [], [name: __MODULE__])
   end
 
-  def init(arg) do
+  def init(_arg) do
     children = [
       worker(NoSlides.GetFsm, [], restart: :temporary)
     ]

lib/no_slides/service.ex

@@ -69,11 +69,6 @@ defmodule NoSlides.Service do
     end
   end
 
-  def ring_status() do
-    {:ok, ring} = :riak_core_ring_manager.get_my_ring
-    :riak_core_ring.pretty_print(ring, [:legend])
-  end
-
   def keys do
     req_id = NoSlides.CoverageFsmSupervisor.start_fsm(:keys)
     wait_result(req_id)

lib/no_slides/write_fsm_supervisor.ex

@@ -9,7 +9,7 @@ defmodule NoSlides.WriteFsmSupervisor do
     Supervisor.start_link(__MODULE__, [], [name: __MODULE__])
   end
 
-  def init(arg) do
+  def init(_arg) do
     children = [
       worker(NoSlides.WriteFsm, [], restart: :temporary)
     ]

mix.exs

@@ -5,6 +5,7 @@ defmodule NoSlides.Mixfile do
     [app: :no_slides,
      version: "0.1.0",
      elixir: "~> 1.3",
+     elixirc_paths: elixirc_paths(Mix.env),
      build_embedded: Mix.env == :prod,
      start_permanent: Mix.env == :prod,
      deps: deps()]
@@ -18,6 +19,10 @@ defmodule NoSlides.Mixfile do
      mod: {NoSlides, []}]
   end
 
+  # Specifies which paths to compile per environment.
+  defp elixirc_paths(:test), do: ["lib", "test/support"]
+  defp elixirc_paths(_),     do: ["lib"]
+
   # Dependencies can be Hex packages:
   #
   #   {:mydep, "~> 0.3.0"}

priv/riak_core.schema

@@ -1,4 +1,5 @@
 %%-*- mode: erlang -*-
+
 %% @doc enable active anti-entropy subsystem
 {mapping, "anti_entropy", "riak_core.anti_entropy", [
   {datatype, {enum, [on, off, debug]}},
@@ -295,6 +296,157 @@ end
   Size =< 1024
  end}.
 
+{mapping, "buckets.default.pr", "riak_core.default_bucket_props.pr", [
+  {default, "0"},
+  {level, advanced}
+]}.
+
+%% Cut and paste translation screams to be rewritten as a datatype, but that's a
+%% "nice to have"
+{translation,
+  "riak_core.default_bucket_props.pr",
+  fun(Conf) ->
+    Setting = cuttlefish:conf_get("buckets.default.pr", Conf),
+    case Setting of
+      "quorum" -> quorum;
+      "all" -> all;
+      X ->
+        try list_to_integer(Setting) of
+          Int -> Int
+        catch
+          E:R -> error
+        end
+    end
+  end
+}.
+
+{mapping, "buckets.default.r", "riak_core.default_bucket_props.r", [
+  {default, "quorum"},
+  {level, advanced}
+]}.
+{translation,
+  "riak_core.default_bucket_props.r",
+  fun(Conf) ->
+    Setting = cuttlefish:conf_get("buckets.default.r", Conf),
+    case Setting of
+      "quorum" -> quorum;
+      "all" -> all;
+      X ->
+        try list_to_integer(Setting) of
+          Int -> Int
+        catch
+          E:R -> error
+        end
+    end
+  end
+}.
+
+{mapping, "buckets.default.w", "riak_core.default_bucket_props.w", [
+  {default, "quorum"},
+  {level, advanced}
+]}.
+{translation,
+  "riak_core.default_bucket_props.w",
+  fun(Conf) ->
+    Setting = cuttlefish:conf_get("buckets.default.w", Conf),
+    case Setting of
+      "quorum" -> quorum;
+      "all" -> all;
+      X ->
+        try list_to_integer(Setting) of
+          Int -> Int
+        catch
+          E:R -> error
+        end
+    end
+  end
+}.
+
+{mapping, "buckets.default.pw", "riak_core.default_bucket_props.pw", [
+  {default, "0"},
+  {level, advanced}
+]}.
+{translation,
+  "riak_core.default_bucket_props.pw",
+  fun(Conf) ->
+    Setting = cuttlefish:conf_get("buckets.default.pw", Conf),
+    case Setting of
+      "quorum" -> quorum;
+      "all" -> all;
+      X ->
+        try list_to_integer(Setting) of
+          Int -> Int
+        catch
+          E:R -> error
+        end
+    end
+  end
+}.
+
+{mapping, "buckets.default.dw", "riak_core.default_bucket_props.dw", [
+  {default, "quorum"},
+  {level, advanced}
+]}.
+{translation,
+  "riak_core.default_bucket_props.dw",
+  fun(Conf) ->
+    Setting = cuttlefish:conf_get("buckets.default.dw", Conf),
+    case Setting of
+      "quorum" -> quorum;
+      "all" -> all;
+      X ->
+        try list_to_integer(Setting) of
+          Int -> Int
+        catch
+          E:R -> error
+        end
+    end
+  end
+}.
+
+{mapping, "buckets.default.rw", "riak_core.default_bucket_props.rw", [
+  {default, "quorum"},
+  {level, advanced}
+]}.
+{translation,
+  "riak_core.default_bucket_props.rw",
+  fun(Conf) ->
+    Setting = cuttlefish:conf_get("buckets.default.rw", Conf),
+    case Setting of
+      "quorum" -> quorum;
+      "all" -> all;
+      X ->
+        try list_to_integer(Setting) of
+          Int -> Int
+        catch
+          E:R -> error
+        end
+    end
+  end
+}.
+
+%% {mapping, "buckets.default.basic_quorum", "riak_core.default_bucket_props.basic_quorum", false},
+%% {mapping, "buckets.default.notfound_ok", "riak_core.default_bucket_props.notfound_ok", true}
+
+%% @doc whether or not siblings are allowed.
+%% Note: See Vector Clocks for a discussion of sibling resolution.
+{mapping, "buckets.default.siblings", "riak_core.default_bucket_props.allow_mult", [
+  {datatype, {enum, [on, off]}},
+  {default, on},
+  {level, advanced}
+]}.
+
+{translation,
+ "riak_core.default_bucket_props.allow_mult",
+ fun(Conf) ->
+  Setting = cuttlefish:conf_get("buckets.default.siblings", Conf),
+    case Setting of
+      on -> true;
+      off -> false;
+      _Default -> true
+    end
+ end}.
+
 {validator, "ring_size^2", "not a power of 2",
  fun(Size) ->
   (Size band (Size-1) =:= 0)
@@ -364,7 +516,7 @@ end
   "can't be a local ip",
   fun(AddrString) ->
     case inet_parse:address(AddrString) of
-      {ok, {127, _, _, _}} -> false;
+      {ok, {127, 0, _, _}} -> false;
       {ok, _} -> true;
       {error, _} -> false
     end
@@ -427,6 +579,19 @@ end
   {datatype, flag}
 ]}.
 
+%% consistent on/off (in lieu of enabled/disabled, true/false)
+{ translation,
+  "riak_core.dtrace_support",
+  fun(Conf) ->
+    Setting = cuttlefish:conf_get("dtrace", Conf),
+    case Setting of
+      on -> true;
+      off -> false;
+      _Default -> false
+    end
+  end
+}.
+
 %% @doc Platform-specific installation paths (substituted by rebar)
 {mapping, "platform_bin_dir", "riak_core.platform_bin_dir", [
   {datatype, directory},
@@ -545,3 +710,20 @@ end
     lists:sort(lists:foldl(Fold, [],
         cuttlefish_variable:filter_by_prefix(["cluster", "job"], Conf)))
  end}.
+
+
+%% @doc Some requests to the vnodes are handled by an asyncronous worker pool.
+%% This parameter allows for tuning this pools behaviour when it comes dealing
+%% with requests that are queued.
+%% The default (fifo) will serve requests in the order they arrive at the worker
+%% pool. The alternative is to serve the requests in the reverse order, dealing
+%% with the most recent request first.
+%% There are pro's and con's for both aproaches, it is best to test out what
+%% works best for the desired characteristics.
+%%
+%% As a very rought rule of thumb:
+%%  - fifo will lead to lower extremes
+%%  - filo will lead to lower medians/mediums
+{mapping, "worker.queue_strategy", "riak_core.queue_worker_strategy",
+ [{default, fifo},
+  {datatype, {enum, [fifo, filo]}}]}.

test/no_slides_test.exs

@@ -1,8 +1,55 @@
 defmodule NoSlidesTest do
   use ExUnit.Case
+  alias NoSlides.RiakCluster
+
   doctest NoSlides
 
-  test "the truth" do
-    assert 1 + 1 == 2
+  # "setup_all" is called once per module before any test runs
+  setup_all do
+    # start the RiakCore cluster
+    assert !Node.alive?()
+    nodeNames = RiakCluster.start_test_nodes()
+    assert Node.alive?()
+    IO.inspect Node.list
+
+    #IO.inspect NoSlides.Service.ring_status() # local, meaningless. Fails without RiakCore running, e.g. 'mix test --no-start'
+    IO.inspect RiakCluster.ring_status(hd(nodeNames)) # remote call
+    [nodes: nodeNames]
+  end
+
+
+  test "ping different nodes in a RiakCore cluster", context do
+    nodeNames = context.nodes
+    :pong = rc_command(hd(nodeNames), :ping)
+
+    for _n <- 1..100 do
+      i = :rand.uniform(length(nodeNames)) - 1 # index of node to use
+      :pong = rc_command(Enum.at(nodeNames, i), :ping, [:rand.uniform(100_000_000)])
+    end
+  end
+
+  test "try key-value pairs in a RiakCore cluster", context do
+    nodeNames = context.nodes
+    first_node = hd(nodeNames)
+
+
+    :ok = rc_command(first_node, :put, [:k1, :v1])
+    :ok = rc_command(first_node, :put, [:k2, :v2])
+    :ok = rc_command(first_node, :put, [:k3, :v3])
+
+    # get from any of the nodes
+    for node <- nodeNames do
+      :v1 = rc_command(node, :get, [:k1])
+      :v2 = rc_command(node, :get, [:k2])
+      :v3 = rc_command(node, :get, [:k3])
+      nil = rc_command(node, :get, [:k10])
+    end
   end
+
+  defp rc_command(node, command) do rc_command(node, command, []) end
+
+  defp rc_command(node, command, args) do
+    :rpc.call(String.to_atom(node), NoSlides.Service, command, args)
+  end
+
 end