Added sanitization for Metric Units (#3151)

Author: jamescrosswell

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## Unreleased
+
+### Fixes
+
+- Metric unit names are now sanitized correctly. This was preventing some built in metrics from showing in the Sentry dashboard ([#3151](https://github.com/getsentry/sentry-dotnet/pull/3151))
+
 ## 4.1.1
 
 ### Fixes

src/Sentry/MetricHelper.cs

@@ -8,6 +8,8 @@ internal static partial class MetricHelper
     private const int RollupInSeconds = 10;
     private const string InvalidKeyCharactersPattern = @"[^a-zA-Z0-9_/.-]+";
     private const string InvalidValueCharactersPattern = @"[^\w\d_:/@\.\{\}\[\]$-]+";
+    // See https://docs.sysdig.com/en/docs/sysdig-monitor/integrations/working-with-integrations/custom-integrations/integrate-statsd-metrics/#characters-allowed-for-statsd-metric-names
+    private const string InvalidMetricUnitCharactersPattern = @"[^a-zA-Z0-9_/.]+";
 
 #if NET6_0_OR_GREATER
     private static readonly DateTimeOffset UnixEpoch = DateTimeOffset.UnixEpoch;
@@ -48,10 +50,18 @@ internal static DateTimeOffset GetCutoff() => DateTimeOffset.UtcNow
     [GeneratedRegex(InvalidValueCharactersPattern, RegexOptions.Compiled)]
     private static partial Regex InvalidValueCharacters();
     internal static string SanitizeValue(string input) => InvalidValueCharacters().Replace(input, "_");
+
+    [GeneratedRegex(InvalidMetricUnitCharactersPattern, RegexOptions.Compiled)]
+    private static partial Regex InvalidMetricUnitCharacters();
+    internal static string SanitizeMetricUnit(string input) => InvalidMetricUnitCharacters().Replace(input, "_");
 #else
     private static readonly Regex InvalidKeyCharacters = new(InvalidKeyCharactersPattern, RegexOptions.Compiled);
     internal static string SanitizeKey(string input) => InvalidKeyCharacters.Replace(input, "_");
+
     private static readonly Regex InvalidValueCharacters = new(InvalidValueCharactersPattern, RegexOptions.Compiled);
     internal static string SanitizeValue(string input) => InvalidValueCharacters.Replace(input, "_");
+
+    private static readonly Regex InvalidMetricUnitCharacters = new(InvalidMetricUnitCharactersPattern, RegexOptions.Compiled);
+    internal static string SanitizeMetricUnit(string input) => InvalidMetricUnitCharacters.Replace(input, "_");
 #endif
 }

src/Sentry/Protocol/Metrics/Metric.cs

@@ -108,9 +108,10 @@ public async Task SerializeAsync(Stream stream, IDiagnosticLogger? logger, Cance
         var metricName = MetricHelper.SanitizeKey(Key);
         await Write($"{metricName}@").ConfigureAwait(false);
         var unit = Unit ?? MeasurementUnit.None;
+        var sanitizedUnit = MetricHelper.SanitizeMetricUnit(unit.ToString());
         // We don't need ConfigureAwait(false) here as ConfigureAwait on metricName above avoids capturing the ExecutionContext.
 #pragma warning disable CA2007
-        await Write(unit.ToString());
+        await Write(sanitizedUnit);
 
         foreach (var value in SerializedStatsdValues())
         {

test/Sentry.Tests/MetricHelperTests.cs

@@ -47,4 +47,17 @@ public void SanitizeValue_ShouldReplaceInvalidCharactersWithUnderscore(string in
         // Assert
         result.Should().Be(expected);
     }
+
+    [Theory]
+    [InlineData("Test123_.", "Test123_.")] // Valid characters
+    [InlineData("test{value}", "test_value_")]
+    [InlineData("test-value", "test_value")]
+    public void SanitizeMetricUnit_ShouldReplaceInvalidCharactersWithUnderscore(string input, string expected)
+    {
+        // Act
+        var result = MetricHelper.SanitizeMetricUnit(input);
+
+        // Assert
+        result.Should().Be(expected);
+    }
 }