[repo/AWS.Sampler] Prepare to .NET9 (#2266)

src/OpenTelemetry.Sampler.AWS/AWSXRayRemoteSampler.cs

@@ -14,7 +14,7 @@ public sealed class AWSXRayRemoteSampler : Trace.Sampler, IDisposable
 {
     internal static readonly TimeSpan DefaultTargetInterval = TimeSpan.FromSeconds(10);
 
-    private static readonly Random Random = new Random();
+    private static readonly Random Random = new();
     private bool isFallBackEventToWriteSwitch = true;
 
     [SuppressMessage("Performance", "CA5394: Do not use insecure randomness", Justification = "Secure random is not required for jitters.")]
@@ -111,9 +111,9 @@ public void Dispose()
         Justification = "using insecure random is fine here since clientId doesn't need to be secure.")]
     private static string GenerateClientId()
     {
-        char[] hex = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
-        char[] clientIdChars = new char[24];
-        for (int i = 0; i < clientIdChars.Length; i++)
+        char[] hex = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'];
+        var clientIdChars = new char[24];
+        for (var i = 0; i < clientIdChars.Length; i++)
         {
             clientIdChars[i] = hex[Random.Next(hex.Length)];
         }
@@ -133,7 +133,7 @@ private void Dispose(bool disposing)
 
     private async void GetAndUpdateRules(object? state)
     {
-        List<SamplingRule> rules = await this.Client.GetSamplingRules().ConfigureAwait(false);
+        var rules = await this.Client.GetSamplingRules().ConfigureAwait(false);
 
         this.RulesCache.UpdateRules(rules);
 
@@ -143,14 +143,14 @@ private async void GetAndUpdateRules(object? state)
 
     private async void GetAndUpdateTargets(object? state)
     {
-        List<SamplingStatisticsDocument> statistics = this.RulesCache.Snapshot(this.Clock.Now());
+        var statistics = this.RulesCache.Snapshot(this.Clock.Now());
 
-        GetSamplingTargetsRequest request = new GetSamplingTargetsRequest(statistics);
-        GetSamplingTargetsResponse? response = await this.Client.GetSamplingTargets(request).ConfigureAwait(false);
+        var request = new GetSamplingTargetsRequest(statistics);
+        var response = await this.Client.GetSamplingTargets(request).ConfigureAwait(false);
         if (response != null)
         {
-            Dictionary<string, SamplingTargetDocument> targets = new Dictionary<string, SamplingTargetDocument>();
-            foreach (SamplingTargetDocument target in response.SamplingTargetDocuments)
+            Dictionary<string, SamplingTargetDocument> targets = [];
+            foreach (var target in response.SamplingTargetDocuments)
             {
                 if (target.RuleName != null)
                 {
@@ -174,7 +174,7 @@ private async void GetAndUpdateTargets(object? state)
 
         // schedule next target poll
         var nextTargetFetchTime = this.RulesCache.NextTargetFetchTime();
-        TimeSpan nextTargetFetchInterval = nextTargetFetchTime.Subtract(this.Clock.Now());
+        var nextTargetFetchInterval = nextTargetFetchTime.Subtract(this.Clock.Now());
         if (nextTargetFetchInterval < TimeSpan.Zero)
         {
             nextTargetFetchInterval = DefaultTargetInterval;

src/OpenTelemetry.Sampler.AWS/AWSXRaySamplerClient.cs

@@ -26,7 +26,7 @@ public AWSXRaySamplerClient(string host)
 
     public async Task<List<SamplingRule>> GetSamplingRules()
     {
-        List<SamplingRule> samplingRules = new List<SamplingRule>();
+        List<SamplingRule> samplingRules = [];
 
         using (var request = new HttpRequestMessage(HttpMethod.Post, this.getSamplingRulesEndpoint)
         {
@@ -37,7 +37,7 @@ public async Task<List<SamplingRule>> GetSamplingRules()
 
             try
             {
-                GetSamplingRulesResponse? getSamplingRulesResponse = JsonSerializer
+                var getSamplingRulesResponse = JsonSerializer
 #if NET
                     .Deserialize(responseJson, SourceGenerationContext.Default.GetSamplingRulesResponse);
 #else
@@ -89,7 +89,7 @@ public async Task<List<SamplingRule>> GetSamplingRules()
 
         try
         {
-            GetSamplingTargetsResponse? getSamplingTargetsResponse = JsonSerializer
+            var getSamplingTargetsResponse = JsonSerializer
 #if NET
                 .Deserialize(responseJson, SourceGenerationContext.Default.GetSamplingTargetsResponse);
 #else

src/OpenTelemetry.Sampler.AWS/FallbackSampler.cs

@@ -9,23 +9,16 @@ internal class FallbackSampler : Trace.Sampler
 {
     private readonly Trace.Sampler reservoirSampler;
     private readonly Trace.Sampler fixedRateSampler;
-    private readonly Clock clock;
 
     public FallbackSampler(Clock clock)
     {
-        this.clock = clock;
         this.reservoirSampler = new ParentBasedSampler(new RateLimitingSampler(1, clock));
         this.fixedRateSampler = new ParentBasedSampler(new TraceIdRatioBasedSampler(0.05));
     }
 
     public override SamplingResult ShouldSample(in SamplingParameters samplingParameters)
     {
-        SamplingResult result = this.reservoirSampler.ShouldSample(in samplingParameters);
-        if (result.Decision != SamplingDecision.Drop)
-        {
-            return result;
-        }
-
-        return this.fixedRateSampler.ShouldSample(in samplingParameters);
+        var result = this.reservoirSampler.ShouldSample(in samplingParameters);
+        return result.Decision != SamplingDecision.Drop ? result : this.fixedRateSampler.ShouldSample(in samplingParameters);
     }
 }

src/OpenTelemetry.Sampler.AWS/Matcher.cs

@@ -36,9 +36,9 @@ public static bool WildcardMatch(string? text, string? globPattern)
 
         // it is faster to check if we need a regex comparison than
         // doing always regex comparison, even where we may not need it.
-        foreach (char c in globPattern)
+        foreach (var c in globPattern)
         {
-            if (c == '*' || c == '?')
+            if (c is '*' or '?')
             {
                 return Regex.IsMatch(text, ToRegexPattern(globPattern));
             }
@@ -59,7 +59,7 @@ public static bool AttributeMatch(IEnumerable<KeyValuePair<string, object?>>? ta
             return false;
         }
 
-        int matchedCount = 0;
+        var matchedCount = 0;
 
         foreach (var tag in tags)
         {
@@ -77,23 +77,18 @@ public static bool AttributeMatch(IEnumerable<KeyValuePair<string, object?>>? ta
             }
         }
 
-        if (matchedCount == ruleAttributes.Count)
-        {
-            return true;
-        }
-
-        return false;
+        return matchedCount == ruleAttributes.Count;
     }
 
     private static string ToRegexPattern(string globPattern)
     {
-        int tokenStart = -1;
-        StringBuilder patternBuilder = new StringBuilder();
+        var tokenStart = -1;
+        var patternBuilder = new StringBuilder();
 
-        for (int i = 0; i < globPattern.Length; i++)
+        for (var i = 0; i < globPattern.Length; i++)
         {
-            char c = globPattern[i];
-            if (c == '*' || c == '?')
+            var c = globPattern[i];
+            if (c is '*' or '?')
             {
                 if (tokenStart != -1)
                 {

src/OpenTelemetry.Sampler.AWS/RateLimiter.cs

@@ -20,7 +20,7 @@ internal RateLimiter(double creditsPerSecond, double maxBalance, Clock clock)
 
     public bool TrySpend(double itemCost)
     {
-        long cost = (long)(itemCost / this.creditsPerMillisecond);
+        var cost = (long)(itemCost / this.creditsPerMillisecond);
         long currentMillis;
         long currentBalanceMillis;
         long availableBalanceAfterWithdrawal;
@@ -29,7 +29,7 @@ public bool TrySpend(double itemCost)
         {
             currentBalanceMillis = Interlocked.Read(ref this.currentBalance);
             currentMillis = this.clock.NowInMilliSeconds();
-            long currentAvailableBalance = currentMillis - currentBalanceMillis;
+            var currentAvailableBalance = currentMillis - currentBalanceMillis;
             if (currentAvailableBalance > this.maxBalance)
             {
                 currentAvailableBalance = this.maxBalance;

src/OpenTelemetry.Sampler.AWS/RulesCache.cs

@@ -20,7 +20,7 @@ public RulesCache(Clock clock, string clientId, Resource resource, Trace.Sampler
         this.ClientId = clientId;
         this.Resource = resource;
         this.FallbackSampler = fallbackSampler;
-        this.RuleAppliers = new List<SamplingRuleApplier>();
+        this.RuleAppliers = [];
         this.UpdatedAt = this.Clock.Now();
     }
 
@@ -54,7 +54,7 @@ public void UpdateRules(List<SamplingRule> newRules)
         // sort the new rules
         newRules.Sort((x, y) => x.CompareTo(y));
 
-        List<SamplingRuleApplier> newRuleAppliers = new List<SamplingRuleApplier>();
+        List<SamplingRuleApplier> newRuleAppliers = [];
         foreach (var rule in newRules)
         {
             // If the ruleApplier already exists in the current list of appliers, then we reuse it.
@@ -104,7 +104,7 @@ public SamplingResult ShouldSample(in SamplingParameters samplingParameters)
 
     public List<SamplingStatisticsDocument> Snapshot(DateTimeOffset now)
     {
-        List<SamplingStatisticsDocument> snapshots = new List<SamplingStatisticsDocument>();
+        List<SamplingStatisticsDocument> snapshots = [];
         foreach (var ruleApplier in this.RuleAppliers)
         {
             snapshots.Add(ruleApplier.Snapshot(now));
@@ -115,10 +115,10 @@ public List<SamplingStatisticsDocument> Snapshot(DateTimeOffset now)
 
     public void UpdateTargets(Dictionary<string, SamplingTargetDocument> targets)
     {
-        List<SamplingRuleApplier> newRuleAppliers = new List<SamplingRuleApplier>();
+        List<SamplingRuleApplier> newRuleAppliers = [];
         foreach (var ruleApplier in this.RuleAppliers)
         {
-            targets.TryGetValue(ruleApplier.RuleName, out SamplingTargetDocument? target);
+            targets.TryGetValue(ruleApplier.RuleName, out var target);
             if (target != null)
             {
                 newRuleAppliers.Add(ruleApplier.WithTarget(target, this.Clock.Now()));
@@ -154,12 +154,7 @@ public DateTimeOffset NextTargetFetchTime()
             .Select(r => r.NextSnapshotTime)
             .Min();
 
-        if (minPollingTime < this.Clock.Now())
-        {
-            return defaultPollingTime;
-        }
-
-        return minPollingTime;
+        return minPollingTime < this.Clock.Now() ? defaultPollingTime : minPollingTime;
     }
 
     public void Dispose()

src/OpenTelemetry.Sampler.AWS/SamplingRule.cs

@@ -73,7 +73,7 @@ public SamplingRule(
 
     public int CompareTo(SamplingRule? other)
     {
-        int result = this.Priority.CompareTo(other?.Priority);
+        var result = this.Priority.CompareTo(other?.Priority);
         if (result == 0)
         {
             result = string.Compare(this.RuleName, other?.RuleName, StringComparison.Ordinal);

src/OpenTelemetry.Sampler.AWS/SamplingRuleApplier.cs

@@ -116,25 +116,18 @@ public bool Matches(SamplingParameters samplingParameters, Resource resource)
         // URL path may be in either http.target or http.url
         if (httpTarget == null && httpUrl != null)
         {
-            int schemeEndIndex = httpUrl.IndexOf("://", StringComparison.Ordinal);
+            var schemeEndIndex = httpUrl.IndexOf("://", StringComparison.Ordinal);
 
             // Per spec, http.url is always populated with scheme://host/target. If scheme doesn't
             // match, assume it's bad instrumentation and ignore.
             if (schemeEndIndex > 0)
             {
-                int pathIndex = httpUrl.IndexOf('/', schemeEndIndex + "://".Length);
-                if (pathIndex < 0)
-                {
-                    httpTarget = "/";
-                }
-                else
-                {
-                    httpTarget = httpUrl.Substring(pathIndex);
-                }
+                var pathIndex = httpUrl.IndexOf('/', schemeEndIndex + "://".Length);
+                httpTarget = pathIndex < 0 ? "/" : httpUrl.Substring(pathIndex);
             }
         }
 
-        string serviceName = (string)resource.Attributes.FirstOrDefault(kvp =>
+        var serviceName = (string)resource.Attributes.FirstOrDefault(kvp =>
                 kvp.Key.Equals("service.name", StringComparison.Ordinal)).Value;
 
         return Matcher.AttributeMatch(samplingParameters.Tags, this.Rule.Attributes) &&
@@ -149,8 +142,8 @@ public bool Matches(SamplingParameters samplingParameters, Resource resource)
     public SamplingResult ShouldSample(in SamplingParameters samplingParameters)
     {
         Interlocked.Increment(ref this.Statistics.RequestCount);
-        bool reservoirExpired = this.Clock.Now() >= this.ReservoirEndTime;
-        SamplingResult result = !reservoirExpired
+        var reservoirExpired = this.Clock.Now() >= this.ReservoirEndTime;
+        var result = !reservoirExpired
             ? this.ReservoirSampler.ShouldSample(in samplingParameters)
             : new SamplingResult(SamplingDecision.Drop);
 
@@ -178,13 +171,13 @@ public SamplingResult ShouldSample(in SamplingParameters samplingParameters)
     // take the snapshot and reset the statistics.
     public SamplingStatisticsDocument Snapshot(DateTimeOffset now)
     {
-        double timestamp = this.Clock.ToDouble(now);
+        var timestamp = this.Clock.ToDouble(now);
 
-        long matchedRequests = Interlocked.Exchange(ref this.Statistics.RequestCount, 0L);
-        long sampledRequests = Interlocked.Exchange(ref this.Statistics.SampleCount, 0L);
-        long borrowedRequests = Interlocked.Exchange(ref this.Statistics.BorrowCount, 0L);
+        var matchedRequests = Interlocked.Exchange(ref this.Statistics.RequestCount, 0L);
+        var sampledRequests = Interlocked.Exchange(ref this.Statistics.SampleCount, 0L);
+        var borrowedRequests = Interlocked.Exchange(ref this.Statistics.BorrowCount, 0L);
 
-        SamplingStatisticsDocument statiscticsDocument = new SamplingStatisticsDocument(
+        var statiscticsDocument = new SamplingStatisticsDocument(
             this.ClientId,
             this.RuleName,
             matchedRequests,
@@ -197,27 +190,22 @@ public SamplingStatisticsDocument Snapshot(DateTimeOffset now)
 
     public SamplingRuleApplier WithTarget(SamplingTargetDocument target, DateTimeOffset now)
     {
-        Trace.Sampler newFixedRateSampler = target.FixedRate != null
+        var newFixedRateSampler = target.FixedRate != null
             ? new ParentBasedSampler(new TraceIdRatioBasedSampler(target.FixedRate.Value))
             : this.FixedRateSampler;
 
         Trace.Sampler newReservoirSampler = new AlwaysOffSampler();
-        DateTimeOffset newReservoirEndTime = DateTimeOffset.MaxValue;
+        var newReservoirEndTime = DateTimeOffset.MaxValue;
         if (target.ReservoirQuota != null && target.ReservoirQuotaTTL != null)
         {
-            if (target.ReservoirQuota > 0)
-            {
-                newReservoirSampler = new ParentBasedSampler(new RateLimitingSampler(target.ReservoirQuota.Value, this.Clock));
-            }
-            else
-            {
-                newReservoirSampler = new AlwaysOffSampler();
-            }
+            newReservoirSampler = target.ReservoirQuota > 0
+                ? new ParentBasedSampler(new RateLimitingSampler(target.ReservoirQuota.Value, this.Clock))
+                : new AlwaysOffSampler();
 
             newReservoirEndTime = this.Clock.ToDateTime(target.ReservoirQuotaTTL.Value);
         }
 
-        DateTimeOffset newNextSnapshotTime = target.Interval != null
+        var newNextSnapshotTime = target.Interval != null
             ? now.AddSeconds(target.Interval.Value)
             : now.Add(AWSXRayRemoteSampler.DefaultTargetInterval);
 
@@ -235,21 +223,17 @@ public SamplingRuleApplier WithTarget(SamplingTargetDocument target, DateTimeOff
 
     private static string GetServiceType(Resource resource)
     {
-        string cloudPlatform = (string)resource.Attributes.FirstOrDefault(kvp =>
+        var cloudPlatform = (string)resource.Attributes.FirstOrDefault(kvp =>
             kvp.Key.Equals("cloud.platform", StringComparison.Ordinal)).Value;
 
-        if (cloudPlatform == null)
-        {
-            return string.Empty;
-        }
-
-        return Matcher.XRayCloudPlatform.TryGetValue(cloudPlatform, out string? value) ? value : string.Empty;
+        return cloudPlatform == null ? string.Empty :
+            Matcher.XRayCloudPlatform.TryGetValue(cloudPlatform, out var value) ? value : string.Empty;
     }
 
     private static string GetArn(in SamplingParameters samplingParameters, Resource resource)
     {
         // currently the aws resource detectors only capture ARNs for ECS and Lambda environments.
-        string? arn = (string?)resource.Attributes.FirstOrDefault(kvp =>
+        var arn = (string?)resource.Attributes.FirstOrDefault(kvp =>
             kvp.Key.Equals("aws.ecs.container.arn", StringComparison.Ordinal)).Value;
 
         if (arn != null)

src/OpenTelemetry.Sampler.AWS/SystemClock.cs

@@ -6,7 +6,7 @@ namespace OpenTelemetry.Sampler.AWS;
 // A clock based on System time.
 internal class SystemClock : Clock
 {
-    private static readonly SystemClock Instance = new SystemClock();
+    private static readonly SystemClock Instance = new();
 
     private static readonly DateTimeOffset EpochStart = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
 
@@ -37,7 +37,7 @@ public override DateTimeOffset ToDateTime(double seconds)
     public override double ToDouble(DateTimeOffset dateTime)
     {
         var current = new TimeSpan(dateTime.ToUniversalTime().Ticks - EpochStart.Ticks);
-        double timestamp = Math.Round(current.TotalMilliseconds, 0) / 1000.0;
+        var timestamp = Math.Round(current.TotalMilliseconds, 0) / 1000.0;
         return timestamp;
     }
 }

src/Shared/Guard.cs

@@ -174,12 +174,9 @@ public static void ThrowIfOutOfRange(double value, [CallerArgumentExpression(nam
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static T ThrowIfNotOfType<T>([NotNull] object? value, [CallerArgumentExpression(nameof(value))] string? paramName = null)
         {
-            if (value is not T result)
-            {
-                throw new InvalidCastException($"Cannot cast '{paramName}' from '{value?.GetType().ToString() ?? "null"}' to '{typeof(T)}'");
-            }
-
-            return result;
+            return value is not T result
+                ? throw new InvalidCastException($"Cannot cast '{paramName}' from '{value?.GetType().ToString() ?? "null"}' to '{typeof(T)}'")
+                : result;
         }
 
         [DebuggerHidden]