[#11] adding Stats Collector

lib/poa_agent/entity/ethereum/statistics.ex

@@ -7,9 +7,7 @@ defmodule POAAgent.Entity.Ethereum.Statistics do
     mining?: boolean,
     hashrate: non_neg_integer,
     peers: non_neg_integer,
-    pending: non_neg_integer,
     gas_price: Literal.Decimal.t(),
-    block: POAAgent.Entity.Ethereum.Block.t(),
     syncing?: boolean,
     uptime: non_neg_integer
   }
@@ -19,9 +17,7 @@ defmodule POAAgent.Entity.Ethereum.Statistics do
     mining?: nil,
     hashrate: nil,
     peers: nil,
-    pending: nil,
     gas_price: nil,
-    block: %POAAgent.Entity.Ethereum.Block{},
     syncing?: nil,
     uptime: nil
   ]
@@ -34,8 +30,7 @@ defmodule POAAgent.Entity.Ethereum.Statistics do
         gas_price: :gasPrice,
         syncing?: :syncing
       ]
-      x = Enum.reduce(mapping, x, &POAAgent.Entity.Name.change/2)
-      Map.update!(x, :block, &POAAgent.Entity.NameConvention.from_elixir_to_node/1)
+      Enum.reduce(mapping, x, &POAAgent.Entity.Name.change/2)
     end
   end
 end

lib/poa_agent/plugins/collector.ex

@@ -81,11 +81,14 @@ defmodule POAAgent.Plugins.Collector do
   @doc """
     A callback executed when the Collector Plugin starts.
     The argument is retrieved from the configuration file when the Collector is defined
-    It must return `{:ok, state}`, that `state` will be keept as in `GenServer` and can be
+    It can return `{:ok, state}`, that `state` will be keept as in `GenServer` and can be
     retrieved in the `collect/1` function.
+    There are some cases where we want to send data to the transfer after initialize the
+    Collector, if that is the case you must return `{:transfer, data, state}` where the data is the
+    metrics we want to send to the transfer
   """
-  @callback init_collector(args :: term()) ::
-      {:ok, any()}
+  @callback init_collector(args :: term()) :: {:ok, state :: any()}
+                                            | {:transfer, data :: any(), state :: any()}
 
   @doc """
     In this callback is where the metrics collection logic must be placed.
@@ -113,7 +116,14 @@ defmodule POAAgent.Plugins.Collector do
 
       @doc false
       def init(state) do
-        {:ok, internal_state} = init_collector(state[:args])
+        internal_state =
+          case init_collector(state[:args]) do
+            {:ok, internal_state} ->
+              internal_state
+            {:transfer, _, _} = transfer ->
+              transfer |> transfer(state.label, state.transfers)
+          end
+
         set_collector_timer(state.frequency)
         {:ok, Map.put(state, :internal_state, internal_state)}
       end

lib/poa_agent/plugins/collectors/eth/stats.ex

@@ -0,0 +1,103 @@
+defmodule POAAgent.Plugins.Collectors.Eth.Stats do
+  use POAAgent.Plugins.Collector
+
+  @moduledoc """
+  This is a Collector's Plugin which makes requests to a Ethereum node in order to know if
+  the stats has been changed.
+
+  This Collector needs the url of the node to iteract. That url must be placed in the args field 
+  in the config file. For example:
+
+      {:eth_stats, POAAgent.Plugins.Collectors.Eth.Stats, 5000, :eth_stats, [url: "http://localhost:8545"]}
+
+  In this example, the Collector will check with the Ethereum node every 5 seconds if the stats of the
+  node has changed. If that is the case it will send it to the Transfers
+  encapsulated in a `POAAgent.Entity.Ethereum.Statistics` struct
+
+  """
+
+  @typep internal_state :: %{last_stats: POAAgent.Entity.Ethereum.Statistics.t | nil,
+                             tries: non_neg_integer,
+                             down: non_neg_integer}
+
+  @doc false
+  @spec init_collector(term()) :: {:ok, internal_state()}
+  def init_collector(args) do
+    :ok = config(args)
+
+    case get_stats(0, 0) do
+      {:ok, stats, tries, down} ->
+        {:transfer, stats, %{last_stats: stats, tries: tries, down: down}}
+      {:error, tries, down} ->
+        {:ok, %{last_stats: nil, tries: tries, down: down}}
+    end
+  end
+
+  @doc false
+  @spec collect(internal_state()) :: term()
+  def collect(%{last_stats: last_stats, tries: tries, down: down} = state) do
+    case get_stats(tries, down) do
+      {:ok, ^last_stats, tries, down} ->
+        {:notransfer, %{state | tries: tries, down: down}}
+      {:ok, stats, tries, down} ->
+        {:transfer, stats, %{state | last_stats: stats, tries: tries, down: down}}
+      {:error, tries, down} ->
+        {:notransfer, %{state | tries: tries, down: down}}
+    end
+  end
+
+  @doc false
+  @spec terminate(internal_state()) :: :ok
+  def terminate(_state) do
+    :ok
+  end
+
+  @doc false
+  defp config([url: url]) do
+    Application.put_env(:ethereumex, :url, url)
+    :ok
+  end
+
+  @doc false
+  defp get_stats(tries, down) do
+    tries = tries + 1
+
+    with {:ok, peers} <- Ethereumex.HttpClient.net_peer_count(),
+         {:ok, mining} <- Ethereumex.HttpClient.eth_mining(),
+         {:ok, hashrate} <- Ethereumex.HttpClient.eth_hashrate(),
+         {:ok, syncing} <- Ethereumex.HttpClient.eth_syncing(),
+         {:ok, gas_price} <- Ethereumex.HttpClient.eth_gas_price()
+    do
+      peers = String.to_integer(POAAgent.Format.Literal.Hex.decimalize(peers))
+      hashrate = String.to_integer(POAAgent.Format.Literal.Hex.decimalize(hashrate))
+      gas_price = String.to_integer(POAAgent.Format.Literal.Hex.decimalize(gas_price))
+
+      down =
+        if peers == 0 do
+          down + 1
+        else
+          down
+        end
+ 
+      stats =
+        %POAAgent.Entity.Ethereum.Statistics{
+          active?: peers > 0,
+          mining?: mining,
+          hashrate: hashrate,
+          peers: peers,
+          gas_price: gas_price,
+          syncing?: syncing,
+          uptime: uptime(tries, down)
+        }
+
+      {:ok, stats, tries, down}
+    else
+      _error -> {:error, tries, down}
+    end
+  end
+
+  defp uptime(tries, down) do
+    ((tries - down) / tries) * 100
+  end
+
+end

mix.exs

@@ -47,7 +47,8 @@ defmodule POAAgent.MixProject do
           POAAgent.Plugins.Transfer,
         ],
         "Ethereum Plugins": [
-          POAAgent.Plugins.Collectors.Eth.LatestBlock
+          POAAgent.Plugins.Collectors.Eth.LatestBlock,
+          POAAgent.Plugins.Collectors.Eth.Stats
         ]
       ]
     ]

test/poa_agent/plugins/collectors/eth/stats_test.exs

@@ -0,0 +1,39 @@
+defmodule POAAgent.Plugins.Collectors.Eth.StatsTest do
+  use ExUnit.Case
+  import Mock
+
+  test "stats sent to the transfer" do
+    with_mock Ethereumex.HttpClient, [
+        net_peer_count: fn() -> {:ok, "0x3"} end,
+        eth_mining: fn() -> {:ok, false} end,
+        eth_hashrate: fn() -> {:ok, "0x0"} end,
+        eth_syncing: fn() -> {:ok, syncing()} end,
+        eth_gas_price: fn() -> {:ok, "0x0"} end
+      ] do
+
+      {:transfer, stats, _} = POAAgent.Plugins.Collectors.Eth.Stats.collect(%{last_stats: nil, tries: 0, down: 0})
+      assert stats == expected_stats()
+    end
+  end
+
+  def syncing() do
+    %{
+      "currentBlock" => "0x44ee0",
+      "highestBlock" => "0x44ee2",
+      "startingBlock" => "0x40ad3",
+      "warpChunksAmount" => nil,
+      "warpChunksProcessed" => nil
+    }
+  end
+
+  def expected_stats() do
+    %POAAgent.Entity.Ethereum.Statistics{
+      active?: true,
+      gas_price: 0,
+      hashrate: 0,
+      mining?: false,
+      peers: 3,
+      syncing?: syncing(),
+      uptime: 100.0}
+  end
+end