introduce IPluginGraphAttributes to make configuring graph attributes more flexible

Author: smdn

src/Smdn.Net.MuninNode/Smdn.Net.MuninNode/NodeBase.cs

@@ -822,24 +822,11 @@ CancellationToken cancellationToken
       );
     }
 
-    var graphAttrs = plugin.GraphAttributes;
-
-    var responseLines = new List<string>() {
-      $"graph_title {graphAttrs.Title}",
-      $"graph_category {graphAttrs.Category}",
-      $"graph_args {graphAttrs.Arguments}",
-      $"graph_scale {(graphAttrs.Scale ? "yes" : "no")}",
-      $"graph_vlabel {graphAttrs.VerticalLabel}",
-    };
+    var responseLines = new List<string>(capacity: 20);
 
-    if (graphAttrs.UpdateRate.HasValue)
-      responseLines.Add($"update_rate {(int)graphAttrs.UpdateRate.Value.TotalSeconds}");
-    if (graphAttrs.Width.HasValue)
-      responseLines.Add($"graph_width {graphAttrs.Width.Value}");
-    if (graphAttrs.Height.HasValue)
-      responseLines.Add($"graph_height {graphAttrs.Height.Value}");
-    if (!string.IsNullOrEmpty(graphAttrs.Order))
-      responseLines.Add($"graph_order {graphAttrs.Order}");
+    responseLines.AddRange(
+      plugin.GraphAttributes.EnumerateAttributes()
+    );
 
     // The fields referenced by {fieldname}.negative must be defined ahread of others,
     // and thus lists the negative field settings first.

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

@@ -12,9 +12,10 @@ public interface IPlugin {
   /// <remarks>This value is used as the plugin name returned by the 'list' argument, or the plugin name specified by the 'fetch' argument.</remarks>
   string Name { get; }
 
-  /// <summary>Gets a <see cref="PluginGraphAttributes"/> that represents the graph attributes when the field values (<see cref="IPluginField"/>) are drawn as a graph.</summary>
+  /// <summary>Gets a <see cref="IPluginGraphAttributes"/> that represents the graph attributes when the field values (<see cref="IPluginField"/>) are drawn as a graph.</summary>
+  /// <seealso cref="IPluginGraphAttributes"/>
   /// <seealso cref="PluginGraphAttributes"/>
-  PluginGraphAttributes GraphAttributes { get; }
+  IPluginGraphAttributes GraphAttributes { get; }
 
   /// <summary>Gets a <see cref="IPluginDataSource"/> that serves as the data source for the plugin.</summary>
   /// <seealso cref="IPluginDataSource"/>

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

@@ -0,0 +1,17 @@
+// SPDX-FileCopyrightText: 2024 smdn <smdn@smdn.jp>
+// SPDX-License-Identifier: MIT
+using System.Collections.Generic;
+
+namespace Smdn.Net.MuninPlugin;
+
+/// <summary>
+/// Provides an interface that abstracts the plugin graph attributes, related to the drawing of a single graph.
+/// </summary>
+/// <seealso href="https://guide.munin-monitoring.org/en/latest/reference/plugin.html#global-attributes">Plugin reference - Global attributes</seealso>
+public interface IPluginGraphAttributes {
+  /// <summary>
+  /// Enumerates plugin graph attributes defined by types that implement this interface.
+  /// </summary>
+  /// <returns><see cref="IEnumerable{String}"/> that enumerates graph attributes.</returns>
+  IEnumerable<string> EnumerateAttributes();
+}

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

@@ -15,6 +15,8 @@ public class Plugin : IPlugin, IPluginDataSource, INodeSessionCallback {
   public IReadOnlyCollection<IPluginField> Fields { get; }
 
 #pragma warning disable CA1033
+  IPluginGraphAttributes IPlugin.GraphAttributes => GraphAttributes;
+
   IPluginDataSource IPlugin.DataSource => this;
 
   IReadOnlyCollection<IPluginField> IPluginDataSource.Fields => Fields;

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

@@ -11,8 +11,9 @@ namespace Smdn.Net.MuninPlugin;
 /// Defines graph attributes that should be returned when the plugin is called with the 'config' argument.
 /// This type represents the collection of 'field name attributes'.
 /// </summary>
+/// <seealso cref="IPluginGraphAttributes"/>
 /// <seealso href="https://guide.munin-monitoring.org/en/latest/reference/plugin.html#global-attributes">Plugin reference - Global attributes</seealso>
-public sealed class PluginGraphAttributes {
+public sealed class PluginGraphAttributes : IPluginGraphAttributes {
   /// <summary>Gets a value for the <c>graph_title</c>.</summary>
   /// <seealso href="https://guide.munin-monitoring.org/en/latest/reference/plugin.html#graph-title">Plugin reference - Global attributes - graph_title</seealso>
   public string Title { get; }
@@ -56,45 +57,17 @@ public PluginGraphAttributes(
     string category,
     string verticalLabel,
     bool scale,
-    string arguments,
-    TimeSpan? updateRate = null,
-    int? width = null,
-    int? height = null
-  )
-    : this(
-      title: title,
-      category: category,
-      verticalLabel: verticalLabel,
-      scale: scale,
-      arguments: arguments,
-      updateRate: updateRate,
-      width: width,
-      height: height,
-      order: null
-    )
-  {
-  }
-
-  [Obsolete("This member will be deprecated in future version.")]
-  public PluginGraphAttributes(
-    string title,
-    string category,
-    string verticalLabel,
-    bool scale,
-    string arguments,
-    TimeSpan updateRate,
-    int? width = null,
-    int? height = null
+    string arguments
   )
     : this(
       title: title,
       category: category,
       verticalLabel: verticalLabel,
       scale: scale,
       arguments: arguments,
-      updateRate: updateRate,
-      width: width,
-      height: height,
+      updateRate: null,
+      width: null,
+      height: null,
       order: null
     )
   {
@@ -147,4 +120,22 @@ public PluginGraphAttributes(
 
     UpdateRate = updateRate;
   }
+
+  public IEnumerable<string> EnumerateAttributes()
+  {
+    yield return $"graph_title {Title}";
+    yield return $"graph_category {Category}";
+    yield return $"graph_args {Arguments}";
+    yield return $"graph_scale {(Scale ? "yes" : "no")}";
+    yield return $"graph_vlabel {VerticalLabel}";
+
+    if (UpdateRate.HasValue)
+      yield return $"update_rate {(int)UpdateRate.Value.TotalSeconds}";
+    if (Width.HasValue)
+      yield return $"graph_width {Width.Value}";
+    if (Height.HasValue)
+      yield return $"graph_height {Height.Value}";
+    if (!string.IsNullOrEmpty(Order))
+      yield return $"graph_order {Order}";
+  }
 }

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

@@ -289,7 +289,7 @@ await reader.ReadLineAsync(cancellationToken),
 
   private class PseudoPluginWithSessionCallback : IPlugin, INodeSessionCallback {
     public string Name => throw new NotImplementedException();
-    public PluginGraphAttributes GraphAttributes => throw new NotImplementedException();
+    public IPluginGraphAttributes GraphAttributes => throw new NotImplementedException();
     public IPluginDataSource DataSource => throw new NotImplementedException();
 
     private readonly bool setSessionCallbackNull;
@@ -683,7 +683,7 @@ private static System.Collections.IEnumerable YieldTestCases_ProcessCommandAsync
       "config plugin1",
       new Action<IReadOnlyList<string>>(
         responseLines => {
-          AssertGraphConfigurations(responseLines, plugins[0]);
+          AssertGraphConfigurations(responseLines, (PluginGraphAttributes)plugins[0].GraphAttributes);
 
           // plugin1field1
           Assert.That(responseLines, Has.Member("plugin1field1.label plugin1field1"), "plugin1field1.label");
@@ -701,7 +701,7 @@ private static System.Collections.IEnumerable YieldTestCases_ProcessCommandAsync
       "config plugin2",
       new Action<IReadOnlyList<string>>(
         responseLines => {
-          AssertGraphConfigurations(responseLines, plugins[1]);
+          AssertGraphConfigurations(responseLines, (PluginGraphAttributes)plugins[1].GraphAttributes);
 
           // plugin2field1
           Assert.That(responseLines, Has.Member("plugin2field1.label plugin2field1"), "plugin2field1.label");
@@ -712,17 +712,16 @@ private static System.Collections.IEnumerable YieldTestCases_ProcessCommandAsync
 
     static void AssertGraphConfigurations(
       IReadOnlyList<string> responseLines,
-      IPlugin expectedPlugin
+      PluginGraphAttributes attributes
     )
     {
-      var graph = expectedPlugin.GraphAttributes;
-      var scaleString = graph.Scale ? "yes" : "no";
+      var scaleString = attributes.Scale ? "yes" : "no";
 
-      Assert.That(responseLines, Has.Member($"graph_title {graph.Title}"), "graph_title");
-      Assert.That(responseLines, Has.Member($"graph_category {graph.Category}"), "graph_category");
-      Assert.That(responseLines, Has.Member($"graph_args {graph.Arguments}"), "graph_args");
+      Assert.That(responseLines, Has.Member($"graph_title {attributes.Title}"), "graph_title");
+      Assert.That(responseLines, Has.Member($"graph_category {attributes.Category}"), "graph_category");
+      Assert.That(responseLines, Has.Member($"graph_args {attributes.Arguments}"), "graph_args");
       Assert.That(responseLines, Has.Member($"graph_scale {scaleString}"), "graph_scale");
-      Assert.That(responseLines, Has.Member($"graph_vlabel {graph.VerticalLabel}"), "graph_vlabel");
+      Assert.That(responseLines, Has.Member($"graph_vlabel {attributes.VerticalLabel}"), "graph_vlabel");
     }
   }