feat: integrate config file loading and SIGHUP hot reload

Wire up the config parsing infrastructure into the server: - NatsServer: add ReloadConfig() with digest-based change detection, diff/validate, CLI override preservation, and side-effect triggers - Program.cs: two-pass CLI parsing — load config file first, then apply CLI args on top with InCmdLine tracking for reload precedence - SIGHUP handler upgraded from stub warning to actual reload - Remove config file "not yet supported" warning from StartAsync - Add integration tests for config loading, CLI overrides, and reload validation
2026-02-23 04:57:34 -05:00
parent d21243bc8a
commit 684ee222ad
3 changed files with 298 additions and 7 deletions
--- a/tests/NATS.Server.Tests/ConfigIntegrationTests.cs
+++ b/tests/NATS.Server.Tests/ConfigIntegrationTests.cs
@@ -0,0 +1,76 @@
+using NATS.Server.Configuration;
+
+namespace NATS.Server.Tests;
+
+public class ConfigIntegrationTests
+{
+    [Fact]
+    public void Server_WithConfigFile_LoadsOptionsFromFile()
+    {
+        var dir = Path.Combine(Path.GetTempPath(), $"nats_test_{Guid.NewGuid():N}");
+        Directory.CreateDirectory(dir);
+        try
+        {
+            var confPath = Path.Combine(dir, "test.conf");
+            File.WriteAllText(confPath, "port: 14222\nmax_payload: 2mb\ndebug: true");
+
+            var opts = ConfigProcessor.ProcessConfigFile(confPath);
+            opts.Port.ShouldBe(14222);
+            opts.MaxPayload.ShouldBe(2 * 1024 * 1024);
+            opts.Debug.ShouldBeTrue();
+        }
+        finally
+        {
+            Directory.Delete(dir, true);
+        }
+    }
+
+    [Fact]
+    public void Server_CliOverridesConfig()
+    {
+        var dir = Path.Combine(Path.GetTempPath(), $"nats_test_{Guid.NewGuid():N}");
+        Directory.CreateDirectory(dir);
+        try
+        {
+            var confPath = Path.Combine(dir, "test.conf");
+            File.WriteAllText(confPath, "port: 14222\ndebug: true");
+
+            var opts = ConfigProcessor.ProcessConfigFile(confPath);
+            opts.Port.ShouldBe(14222);
+
+            // Simulate CLI override: user passed -p 5222 on command line
+            var cliSnapshot = new NatsOptions { Port = 5222 };
+            var cliFlags = new HashSet<string> { "Port" };
+            ConfigReloader.MergeCliOverrides(opts, cliSnapshot, cliFlags);
+
+            opts.Port.ShouldBe(5222);
+            opts.Debug.ShouldBeTrue(); // Config file value preserved
+        }
+        finally
+        {
+            Directory.Delete(dir, true);
+        }
+    }
+
+    [Fact]
+    public void Reload_ChangingPort_ReturnsError()
+    {
+        var oldOpts = new NatsOptions { Port = 4222 };
+        var newOpts = new NatsOptions { Port = 5222 };
+        var changes = ConfigReloader.Diff(oldOpts, newOpts);
+        var errors = ConfigReloader.Validate(changes);
+        errors.Count.ShouldBeGreaterThan(0);
+        errors[0].ShouldContain("Port");
+    }
+
+    [Fact]
+    public void Reload_ChangingDebug_IsValid()
+    {
+        var oldOpts = new NatsOptions { Debug = false };
+        var newOpts = new NatsOptions { Debug = true };
+        var changes = ConfigReloader.Diff(oldOpts, newOpts);
+        var errors = ConfigReloader.Validate(changes);
+        errors.ShouldBeEmpty();
+        changes.ShouldContain(c => c.IsLoggingChange);
+    }
+}