feat: Enable configuration of High Security Mode via environment variable (NEW_RELIC_HIGH_SECURITY).

Resolves #1948

Author: tippmar-nr

src/Agent/NewRelic/Agent/Core/Configuration/DefaultConfiguration.cs

@@ -1247,7 +1247,16 @@ private IEnumerable<MatchRule> ParseExpectedStatusCodesArray(IEnumerable<string>
 
         public virtual string EntityGuid { get { return _serverConfiguration.EntityGuid; } }
 
-        public virtual bool HighSecurityModeEnabled => _localConfiguration.highSecurity.enabled;
+        private bool? _highSecurityModeEnabled;
+        public virtual bool HighSecurityModeEnabled
+        {
+            get
+            {
+                _highSecurityModeEnabled ??= EnvironmentOverrides(_localConfiguration.highSecurity.enabled, "NEW_RELIC_HIGH_SECURITY");
+
+                return _highSecurityModeEnabled.Value;
+            }
+        }
 
 
         private BoolConfigurationItem _customInstrumentationEditorIsEnabled;

tests/Agent/UnitTests/Core.UnitTest/Configuration/DefaultConfigurationTests.cs

@@ -694,6 +694,36 @@ public bool HighSecuritySetFromLocalOverridesServer(bool local, bool? server)
             return _defaultConfig.HighSecurityModeEnabled;
         }
 
+        [TestCase(true, null, ExpectedResult = true)]
+        [TestCase(true, "true", ExpectedResult = true)]
+        [TestCase(true, "1", ExpectedResult = true)]
+        [TestCase(true, "false", ExpectedResult = false)]
+        [TestCase(true, "0", ExpectedResult = false)]
+        [TestCase(true, "invalid", ExpectedResult = true)]
+        [TestCase(false, null, ExpectedResult = false)]
+        [TestCase(false, "true", ExpectedResult = true)]
+        [TestCase(false, "1", ExpectedResult = true)]
+        [TestCase(false, "false", ExpectedResult = false)]
+        [TestCase(false, "0", ExpectedResult = false)]
+        [TestCase(false, "invalid", ExpectedResult = false)]
+        [TestCase(null, "true", ExpectedResult = true)]
+        [TestCase(null, "1", ExpectedResult = true)]
+        [TestCase(null, "false", ExpectedResult = false)]
+        [TestCase(null, "0", ExpectedResult = false)]
+        [TestCase(null, "invalid", ExpectedResult = false)]
+        [TestCase(null, null, ExpectedResult = false)]
+        public bool HighSecuritySetFromEnvironmentOverridesLocal(bool? localConfigValue, string envConfigValue)
+        {
+            Mock.Arrange(() => _environment.GetEnvironmentVariable("NEW_RELIC_HIGH_SECURITY")).Returns(envConfigValue);
+
+            if (localConfigValue.HasValue)
+            {
+                _localConfig.highSecurity.enabled = localConfigValue.Value;
+            }
+
+            return _defaultConfig.HighSecurityModeEnabled;
+        }
+
         [TestCase(true, true, ExpectedResult = false)]
         [TestCase(true, false, ExpectedResult = false)]
         [TestCase(false, false, ExpectedResult = false)]