Add GetMetricData implementation

lib/ex_aws/cloudwatch.ex

@@ -325,6 +325,37 @@ defmodule ExAws.Cloudwatch do
     |> build_request(:get_metric_statistics)
   end
 
+
+
+  @type get_metric_data_query :: [
+    id: binary,
+    metric_stat: get_metric_data_query_stat
+  ]
+  @type get_metric_data_query_stat :: [
+    metric: get_metric_data_query_stat_metric,
+    period: integer,
+    stat: binary,
+    unit: binary
+  ]
+  @type get_metric_data_query_stat_metric :: [
+    namespace: binary,
+    metric_name: binary,
+    dimensions: [dimension]
+  ]
+  @spec get_metric_data(
+    start_time :: %DateTime{},
+    end_time :: %DateTime{},
+    queries :: [get_metric_data_query]
+  ) :: ExAws.Operation.Query.t()
+  def get_metric_data(start_time, end_time, queries) do
+    [
+      {:start_time, start_time},
+      {:end_time, end_time},
+      {:metric_data_queries, queries}
+    ]
+    |> build_request(:get_metric_data)
+  end
+
   @doc """
   Returns a list of the dashboards for your account.
 
@@ -660,10 +691,28 @@ defmodule ExAws.Cloudwatch do
     |> format(prefix: "MetricData.member")
   end
 
+  defp format_param({:metric_data_queries, metric_data_queries}) do
+    metric_data_queries
+    |> Enum.map(fn(metric_data_query) -> format_param({:metric_data_query, metric_data_query}) end)
+    |> format(prefix: "MetricDataQueries.member")
+  end
+
+  defp format_param({:metric_data_query, metric_data_query}) do
+    metric_data_query |> Enum.flat_map(&format_param/1)
+  end
+
   defp format_param({:metric_datum, metric_datum}) do
     metric_datum |> Enum.flat_map(&format_param/1)
   end
 
+  defp format_param({:metric_stat, metric_stat}) do
+    metric_stat |> Enum.flat_map(&format_param/1) |> format(prefix: "MetricStat")
+  end
+
+  defp format_param({:metric, metric}) do
+    metric |> Enum.flat_map(&format_param/1) |> format(prefix: "Metric")
+  end
+
   defp format_param({:ok_actions, ok_actions}) do
     ok_actions |> format(prefix: "OKActions.member")
   end

lib/ex_aws/cloudwatch/parsers.ex

@@ -55,6 +55,18 @@ if Code.ensure_loaded?(SweetXml) do
       {:ok, Map.put(resp, :body, parsed_body)}
     end
 
+    def parse({:ok, %{body: xml} = resp}, :get_metric_data) do
+      parsed_body =
+        xml
+        |> SweetXml.xpath(
+          ~x"//GetMetricDataResponse",
+          metric_data: metric_data_description(),
+          request_id: ~x"./ResponseMetadata/RequestId/text()"s
+        )
+
+      {:ok, Map.put(resp, :body, parsed_body)}
+    end
+
     def parse({:ok, %{body: xml} = resp}, :list_dashboards) do
       parsed_body =
         xml
@@ -174,6 +186,16 @@ if Code.ensure_loaded?(SweetXml) do
       ]
     end
 
+    defp metric_data_description do
+      [
+        ~x"./GetMetricDataResult/MetricDataResults/member"l,
+        timestamps: ~x"./Timestamps/member/text()"ls |> SweetXml.transform_by(&to_timestamp/1),
+        values: ~x"./Values/member/text()"lf,
+        label: ~x"./Label/text()"s,
+        id: ~x"./Id/text()"s,
+      ]
+    end
+
     defp dashboards_description() do
       [
         ~x"./ListDashboardsResult/DashboardEntries/member"l,
@@ -208,6 +230,13 @@ if Code.ensure_loaded?(SweetXml) do
     defp to_boolean(xpath) do
       xpath |> SweetXml.transform_by(&(&1 == "true"))
     end
+
+    defp to_timestamp(list) when is_list(list), do: Enum.map(list, &to_timestamp/1)
+    defp to_timestamp(xpath) do
+      xpath
+      |> DateTime.from_iso8601()
+      |> elem(1)
+    end
   end
 else
   defmodule ExAws.Cloudwatch.Parsers do