feat: Add RustFS artifact object store and migration tool

- Implemented RustFsArtifactObjectStore for managing artifacts in RustFS.
- Added unit tests for RustFsArtifactObjectStore functionality.
- Created a RustFS migrator tool to transfer objects from S3 to RustFS.
- Introduced policy preview and report models for API integration.
- Added fixtures and tests for policy preview and report functionality.
- Included necessary metadata and scripts for cache_pkg package.

bench/Scanner.Analyzers/StellaOps.Bench.ScannerAnalyzers/Reporting/BenchmarkJsonWriter.cs

@@ -0,0 +1,108 @@
+using System.Text.Json;
+using System.Text.Json.Serialization;
+using StellaOps.Bench.ScannerAnalyzers.Baseline;
+
+namespace StellaOps.Bench.ScannerAnalyzers.Reporting;
+
+internal static class BenchmarkJsonWriter
+{
+    private static readonly JsonSerializerOptions SerializerOptions = new(JsonSerializerDefaults.Web)
+    {
+        WriteIndented = true,
+        DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull
+    };
+
+    public static async Task WriteAsync(
+        string path,
+        BenchmarkJsonMetadata metadata,
+        IReadOnlyList<BenchmarkScenarioReport> reports,
+        CancellationToken cancellationToken)
+    {
+        ArgumentException.ThrowIfNullOrWhiteSpace(path);
+        ArgumentNullException.ThrowIfNull(metadata);
+        ArgumentNullException.ThrowIfNull(reports);
+
+        var resolved = Path.GetFullPath(path);
+        var directory = Path.GetDirectoryName(resolved);
+        if (!string.IsNullOrEmpty(directory))
+        {
+            Directory.CreateDirectory(directory);
+        }
+
+        var document = new BenchmarkJsonDocument(
+            metadata.SchemaVersion,
+            metadata.CapturedAtUtc,
+            metadata.Commit,
+            metadata.Environment,
+            reports.Select(CreateScenario).ToArray());
+
+        await using var stream = new FileStream(resolved, FileMode.Create, FileAccess.Write, FileShare.None);
+        await JsonSerializer.SerializeAsync(stream, document, SerializerOptions, cancellationToken).ConfigureAwait(false);
+        await stream.FlushAsync(cancellationToken).ConfigureAwait(false);
+    }
+
+    private static BenchmarkJsonScenario CreateScenario(BenchmarkScenarioReport report)
+    {
+        var baseline = report.Baseline;
+        return new BenchmarkJsonScenario(
+            report.Result.Id,
+            report.Result.Label,
+            report.Result.Iterations,
+            report.Result.SampleCount,
+            report.Result.MeanMs,
+            report.Result.P95Ms,
+            report.Result.MaxMs,
+            report.Result.ThresholdMs,
+            baseline is null
+                ? null
+                : new BenchmarkJsonScenarioBaseline(
+                    baseline.Iterations,
+                    baseline.SampleCount,
+                    baseline.MeanMs,
+                    baseline.P95Ms,
+                    baseline.MaxMs),
+            new BenchmarkJsonScenarioRegression(
+                report.MaxRegressionRatio,
+                report.MeanRegressionRatio,
+                report.RegressionLimit,
+                report.RegressionBreached));
+    }
+
+    private sealed record BenchmarkJsonDocument(
+        string SchemaVersion,
+        DateTimeOffset CapturedAt,
+        string? Commit,
+        string? Environment,
+        IReadOnlyList<BenchmarkJsonScenario> Scenarios);
+
+    private sealed record BenchmarkJsonScenario(
+        string Id,
+        string Label,
+        int Iterations,
+        int SampleCount,
+        double MeanMs,
+        double P95Ms,
+        double MaxMs,
+        double ThresholdMs,
+        BenchmarkJsonScenarioBaseline? Baseline,
+        BenchmarkJsonScenarioRegression Regression);
+
+    private sealed record BenchmarkJsonScenarioBaseline(
+        int Iterations,
+        int SampleCount,
+        double MeanMs,
+        double P95Ms,
+        double MaxMs);
+
+    private sealed record BenchmarkJsonScenarioRegression(
+        double? MaxRatio,
+        double? MeanRatio,
+        double Limit,
+        bool Breached);
+}
+
+internal sealed record BenchmarkJsonMetadata(
+    string SchemaVersion,
+    DateTimeOffset CapturedAtUtc,
+    string? Commit,
+    string? Environment);

bench/Scanner.Analyzers/StellaOps.Bench.ScannerAnalyzers/Reporting/BenchmarkScenarioReport.cs

@@ -0,0 +1,55 @@
+using StellaOps.Bench.ScannerAnalyzers.Baseline;
+
+namespace StellaOps.Bench.ScannerAnalyzers.Reporting;
+
+internal sealed class BenchmarkScenarioReport
+{
+    private const double RegressionLimitDefault = 1.2d;
+
+    public BenchmarkScenarioReport(ScenarioResult result, BaselineEntry? baseline, double? regressionLimit = null)
+    {
+        Result = result ?? throw new ArgumentNullException(nameof(result));
+        Baseline = baseline;
+        RegressionLimit = regressionLimit is { } limit && limit > 0 ? limit : RegressionLimitDefault;
+        MaxRegressionRatio = CalculateRatio(result.MaxMs, baseline?.MaxMs);
+        MeanRegressionRatio = CalculateRatio(result.MeanMs, baseline?.MeanMs);
+    }
+
+    public ScenarioResult Result { get; }
+
+    public BaselineEntry? Baseline { get; }
+
+    public double RegressionLimit { get; }
+
+    public double? MaxRegressionRatio { get; }
+
+    public double? MeanRegressionRatio { get; }
+
+    public bool RegressionBreached => MaxRegressionRatio.HasValue && MaxRegressionRatio.Value >= RegressionLimit;
+
+    public string? BuildRegressionFailureMessage()
+    {
+        if (!RegressionBreached || MaxRegressionRatio is null)
+        {
+            return null;
+        }
+
+        var percentage = (MaxRegressionRatio.Value - 1d) * 100d;
+        return $"{Result.Id} exceeded regression budget: max {Result.MaxMs:F2} ms vs baseline {Baseline!.MaxMs:F2} ms (+{percentage:F1}%)";
+    }
+
+    private static double? CalculateRatio(double current, double? baseline)
+    {
+        if (!baseline.HasValue)
+        {
+            return null;
+        }
+
+        if (baseline.Value <= 0d)
+        {
+            return null;
+        }
+
+        return current / baseline.Value;
+    }
+}

bench/Scanner.Analyzers/StellaOps.Bench.ScannerAnalyzers/Reporting/PrometheusWriter.cs

@@ -0,0 +1,59 @@
+using System.Globalization;
+using System.Text;
+
+namespace StellaOps.Bench.ScannerAnalyzers.Reporting;
+
+internal static class PrometheusWriter
+{
+    public static void Write(string path, IReadOnlyList<BenchmarkScenarioReport> reports)
+    {
+        ArgumentException.ThrowIfNullOrWhiteSpace(path);
+        ArgumentNullException.ThrowIfNull(reports);
+
+        var resolved = Path.GetFullPath(path);
+        var directory = Path.GetDirectoryName(resolved);
+        if (!string.IsNullOrEmpty(directory))
+        {
+            Directory.CreateDirectory(directory);
+        }
+
+        var builder = new StringBuilder();
+        builder.AppendLine("# HELP scanner_analyzer_bench_duration_ms Analyzer benchmark duration metrics in milliseconds.");
+        builder.AppendLine("# TYPE scanner_analyzer_bench_duration_ms gauge");
+
+        foreach (var report in reports)
+        {
+            var scenarioLabel = Escape(report.Result.Id);
+            AppendMetric(builder, "scanner_analyzer_bench_mean_ms", scenarioLabel, report.Result.MeanMs);
+            AppendMetric(builder, "scanner_analyzer_bench_p95_ms", scenarioLabel, report.Result.P95Ms);
+            AppendMetric(builder, "scanner_analyzer_bench_max_ms", scenarioLabel, report.Result.MaxMs);
+            AppendMetric(builder, "scanner_analyzer_bench_threshold_ms", scenarioLabel, report.Result.ThresholdMs);
+
+            if (report.Baseline is { } baseline)
+            {
+                AppendMetric(builder, "scanner_analyzer_bench_baseline_max_ms", scenarioLabel, baseline.MaxMs);
+                AppendMetric(builder, "scanner_analyzer_bench_baseline_mean_ms", scenarioLabel, baseline.MeanMs);
+            }
+
+            if (report.MaxRegressionRatio is { } ratio)
+            {
+                AppendMetric(builder, "scanner_analyzer_bench_regression_ratio", scenarioLabel, ratio);
+                AppendMetric(builder, "scanner_analyzer_bench_regression_limit", scenarioLabel, report.RegressionLimit);
+                AppendMetric(builder, "scanner_analyzer_bench_regression_breached", scenarioLabel, report.RegressionBreached ? 1 : 0);
+            }
+        }
+
+        File.WriteAllText(resolved, builder.ToString(), Encoding.UTF8);
+    }
+
+    private static void AppendMetric(StringBuilder builder, string metric, string scenarioLabel, double value)
+    {
+        builder.Append(metric);
+        builder.Append("{scenario=\"");
+        builder.Append(scenarioLabel);
+        builder.Append("\"} ");
+        builder.AppendLine(value.ToString("G17", CultureInfo.InvariantCulture));
+    }
+
+    private static string Escape(string value) => value.Replace("\\", "\\\\", StringComparison.Ordinal).Replace("\"", "\\\"", StringComparison.Ordinal);
+}