add support for 'graph_total' attribute

Author: smdn

src/Smdn.Net.MuninNode/Smdn.Net.MuninPlugin/PluginGraphAttributes.cs

@@ -52,6 +52,10 @@ public sealed class PluginGraphAttributes : IPluginGraphAttributes {
   /// <seealso href="https://guide.munin-monitoring.org/en/latest/reference/plugin.html#graph-order">Plugin reference - Global attributes - graph_order</seealso>
   public string? Order { get; }
 
+  /// <summary>Gets a value for the <c>graph_total</c>.</summary>
+  /// <seealso href="https://guide.munin-monitoring.org/en/latest/reference/plugin.html#graph-total">Plugin reference - Global attributes - graph_total</seealso>
+  public string? TotalValueLabel { get; }
+
   public PluginGraphAttributes(
     string title,
     string category,
@@ -68,7 +72,8 @@ string arguments
       updateRate: null,
       width: null,
       height: null,
-      order: null
+      order: null,
+      totalValueLabel: null
     )
   {
   }
@@ -82,7 +87,8 @@ public PluginGraphAttributes(
     TimeSpan? updateRate,
     int? width,
     int? height,
-    IEnumerable<string>? order
+    IEnumerable<string>? order,
+    string? totalValueLabel
   )
   {
     if (title == null)
@@ -114,6 +120,7 @@ public PluginGraphAttributes(
     Width = width;
     Height = height;
     Order = order is null ? null : string.Join(" ", order);
+    TotalValueLabel = totalValueLabel;
 
     if (updateRate.HasValue && updateRate.Value < TimeSpan.FromSeconds(1.0))
       throw new ArgumentOutOfRangeException(nameof(updateRate), updateRate, "must be at least 1 seconds");
@@ -137,5 +144,7 @@ public IEnumerable<string> EnumerateAttributes()
       yield return $"graph_height {Height.Value}";
     if (!string.IsNullOrEmpty(Order))
       yield return $"graph_order {Order}";
+    if (!string.IsNullOrEmpty(TotalValueLabel))
+      yield return $"graph_total {TotalValueLabel}";
   }
 }

tests/Smdn.Net.MuninNode/Smdn.Net.MuninNode/NodeBase.cs

@@ -774,7 +774,8 @@ private static System.Collections.IEnumerable YieldTestCases_ProcessCommandAsync
         updateRate: null,
         width: width,
         height: height,
-        order: null
+        order: null,
+        totalValueLabel: null
       );
 
       var plugin = PluginFactory.CreatePlugin(
@@ -817,7 +818,8 @@ private static System.Collections.IEnumerable YieldTestCases_ProcessCommandAsync
         updateRate: updateRate,
         width: null,
         height: null,
-        order: null
+        order: null,
+        totalValueLabel: null
       );
 
       var plugin = PluginFactory.CreatePlugin(
@@ -890,7 +892,8 @@ private static System.Collections.IEnumerable YieldTestCases_ProcessCommandAsync
         updateRate: TimeSpan.FromMinutes(1),
         width: null,
         height: null,
-        order: order
+        order: order,
+        totalValueLabel: null
       );
 
       var plugin = PluginFactory.CreatePlugin(
@@ -947,6 +950,80 @@ await StartSession(
     );
   }
 
+  private static System.Collections.IEnumerable YieldTestCases_ProcessCommandAsync_ConfigCommand_GraphTotal()
+  {
+    foreach (var total in new[] {
+      null,
+      string.Empty,
+      "Total",
+    }) {
+      var graphAttrs = new PluginGraphAttributes(
+        title: "title",
+        category: "test",
+        verticalLabel: "test",
+        scale: false,
+        arguments: "--args",
+        updateRate: TimeSpan.FromMinutes(1),
+        width: null,
+        height: null,
+        order: null,
+        totalValueLabel: total
+      );
+
+      var plugin = PluginFactory.CreatePlugin(
+        "plugin1",
+        graphAttrs,
+        new[] {
+          PluginFactory.CreateField("plugin1field1", static () => 1.1),
+          PluginFactory.CreateField("plugin1field2", PluginFieldGraphStyle.LineWidth3, static () => 1.2)
+        }
+      );
+
+      yield return new object[] {
+        plugin,
+        new Action<IReadOnlyList<string>>(
+          responseLines => {
+            if (string.IsNullOrEmpty(total))
+              Assert.That(responseLines, Has.No.Member("graph_total "), "graph_total");
+            else
+              Assert.That(responseLines, Has.Member($"graph_total {total}"), "graph_total");
+          }
+        )
+      };
+    }
+  }
+
+  [TestCaseSource(nameof(YieldTestCases_ProcessCommandAsync_ConfigCommand_GraphTotal))]
+  public async Task ProcessCommandAsync_ConfigCommand_GraphTotal(
+    IPlugin plugin,
+    Action<IReadOnlyList<string>> assertResponseLines
+  )
+  {
+    await StartSession(
+      plugins: new[] { plugin },
+      action: async (node, client, writer, reader, cancellationToken) => {
+        await writer.WriteLineAsync($"config {plugin.Name}", cancellationToken);
+        await writer.FlushAsync(cancellationToken);
+
+        var lines = new List<string>();
+
+        for (; ; ) {
+          var line = await reader.ReadLineAsync(cancellationToken);
+
+          if (line is null)
+            break;
+
+          lines.Add(line);
+
+          if (line == ".")
+            break;
+        }
+
+        assertResponseLines(lines);
+      }
+    );
+  }
+
   [TestCase(PluginFieldGraphStyle.Default, null, null)]
   [TestCase(PluginFieldGraphStyle.Area, "AREA", null)]
   [TestCase(PluginFieldGraphStyle.Stack, "STACK", null)]