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Merged
merged 2 commits into from
Apr 8, 2021
Merged

[pull] master from DataDog:master #21

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201247a
Simplify moving average calculator (#1350)
andrewlock Apr 8, 2021
e2a5e12
Update Uri cleaning algorithm to be more aggressive (#1327)
andrewlock Apr 8, 2021
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53 changes: 18 additions & 35 deletions src/Datadog.Trace/Agent/MovingAverageKeepRateCalculator.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,9 @@ internal class MovingAverageKeepRateCalculator : IKeepRateCalculator
private readonly TaskCompletionSource<bool> _processExit = new TaskCompletionSource<bool>();

private int _index = 0;
private long _totals = 0;
private ulong _sumDrops = 0;
private ulong _sumCreated = 0;
private double _keepRate = 0;

private long _latestDrops = 0;
private long _latestKeeps = 0;
Expand Down Expand Up @@ -84,14 +86,8 @@ public void IncrementDrops(int count)
/// </summary>
public double GetKeepRate()
{
var totals = Interlocked.Read(ref _totals);
UnpackBits(totals, out var totalDropped, out var totalCreated);
if (totalCreated == 0)
{
return 0;
}

return 1 - ((double)totalDropped / totalCreated);
// Essentially Interlock.Read(double)
return Volatile.Read(ref _keepRate);
}

/// <summary>
Expand All @@ -111,21 +107,23 @@ internal void UpdateBucket()
var previousDropped = _dropped[index];
var previousCreated = _created[index];

var latestDropped = Math.Min(Interlocked.Exchange(ref _latestDrops, 0), uint.MaxValue);
var latestCreated = Math.Min(Interlocked.Exchange(ref _latestKeeps, 0) + latestDropped, uint.MaxValue);
// Cap at uint.MaxValue events. Very unlikely to reach this value!
var latestDropped = (uint)Math.Min(Interlocked.Exchange(ref _latestDrops, 0), uint.MaxValue);
var latestCreated = (uint)Math.Min(Interlocked.Exchange(ref _latestKeeps, 0) + latestDropped, uint.MaxValue);

var totals = _totals;
UnpackBits(totals, out var previousTotalDropped, out var previousTotalCreated);
var newSumDropped = _sumDrops - previousDropped + latestDropped;
var newSumCreated = _sumCreated - previousCreated + latestCreated;

var newTotalDropped = (uint)Math.Min(((long)previousTotalDropped) - previousDropped + latestDropped, uint.MaxValue);
var newTotalCreated = (uint)Math.Min(((long)previousTotalCreated) - previousCreated + latestCreated, uint.MaxValue);
var keepRate = newSumCreated == 0
? 0
: 1 - ((double)newSumDropped / newSumCreated);

// Pack the totals into a single value we can read and write atomically
var packedTotal = PackBits(newTotalDropped, newTotalCreated);
Interlocked.Exchange(ref _totals, packedTotal);
Volatile.Write(ref _keepRate, keepRate);

_dropped[index] = (uint)latestDropped;
_created[index] = (uint)latestCreated;
_sumDrops = newSumDropped;
_sumCreated = newSumCreated;
_dropped[index] = latestDropped;
_created[index] = latestCreated;
_index = (index + 1) % _windowSize;
}

Expand Down Expand Up @@ -156,20 +154,5 @@ await Task.WhenAny(
#endif
}
}

[MethodImpl(MethodImplOptions.AggressiveInlining)]
private long PackBits(uint hits, uint total)
{
long result = hits;
result = result << 32;
return result | (long)total;
}

[MethodImpl(MethodImplOptions.AggressiveInlining)]
private void UnpackBits(long bits, out uint hits, out uint total)
{
hits = (uint)(bits >> 32);
total = (uint)(bits & 0xffffffffL);
}
}
}
123 changes: 58 additions & 65 deletions src/Datadog.Trace/Util/UriHelpers.cs
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Original file line number Diff line number Diff line change
@@ -1,10 +1,16 @@
using System;
using System.Runtime.CompilerServices;

namespace Datadog.Trace.Util
{
internal static class UriHelpers
{
/// <summary>
/// Remove the querystring, user information, and fragment from a URL.
/// Optionally reduce cardinality by replacing segments that look like IDs with <c>?</c>.
/// </summary>
/// <param name="uri">The URI to clean</param>
/// <param name="removeScheme">Should the scheme be removed?</param>
/// <param name="tryRemoveIds">Should IDs be replaced with <c>?</c></param>
public static string CleanUri(Uri uri, bool removeScheme, bool tryRemoveIds)
{
var path = tryRemoveIds ? GetCleanUriPath(uri.AbsolutePath) : uri.AbsolutePath;
Expand All @@ -22,17 +28,17 @@ public static string CleanUri(Uri uri, bool removeScheme, bool tryRemoveIds)
}

[Obsolete("This method is deprecated and will be removed. Use GetCleanUriPath() instead. " +
"Kept for backwards compatability where there is a version mismatch between manual and automatic instrumentation")]
"Kept for backwards compatibility where there is a version mismatch between manual and automatic instrumentation")]
public static string GetRelativeUrl(Uri uri, bool tryRemoveIds)
=> GetRelativeUrl(uri.AbsolutePath, tryRemoveIds);

[Obsolete("This method is deprecated and will be removed. Use GetCleanUriPath() instead. " +
"Kept for backwards compatability where there is a version mismatch between manual and automatic instrumentation")]
"Kept for backwards compatibility where there is a version mismatch between manual and automatic instrumentation")]
public static string GetRelativeUrl(string uri, bool tryRemoveIds)
=> tryRemoveIds ? GetCleanUriPath(uri) : uri;

[Obsolete("This method is deprecated and will be removed. Use GetCleanUriPath() instead. " +
"Kept for backwards compatability where there is a version mismatch between manual and automatic instrumentation")]
"Kept for backwards compatibility where there is a version mismatch between manual and automatic instrumentation")]
public static string CleanUriSegment(string absolutePath)
=> GetCleanUriPath(absolutePath);

Expand All @@ -48,99 +54,86 @@ public static string GetCleanUriPath(string absolutePath)
return absolutePath;
}

#if NETCOREAPP
ReadOnlySpan<char> absPath = absolutePath.AsSpan();

// Sanitized url will be at worse as long as the original
var sb = StringBuilderCache.Acquire(absPath.Length);
var sb = StringBuilderCache.Acquire(absolutePath.Length);

int previousIndex = 0;
int index;
int segmentLength;

do
{
ReadOnlySpan<char> nStart = absPath.Slice(previousIndex);
index = nStart.IndexOf('/');
ReadOnlySpan<char> segment = index == -1 ? nStart : nStart.Slice(0, index);

// replace path segments that look like numbers or guid
// GUID format N "d85b1407351d4694939203acc5870eb1" length: 32
// GUID format D "d85b1407-351d-4694-9392-03acc5870eb1" length: 36 with dashes in indices 8, 13, 18 and 23.
if (long.TryParse(segment, out _) ||
(segment.Length == 32 && IsAGuid(segment, "N")) ||
(segment.Length == 36 && IsAGuid(segment, "D")))
index = absolutePath.IndexOf('/', previousIndex);

if (index == -1)
{
// Last segment
segmentLength = absolutePath.Length - previousIndex;
}
else
{
segmentLength = index - previousIndex;
}

if (IsIdentifierSegment(absolutePath, previousIndex, segmentLength))
{
sb.Append('?');
}
else
{
sb.Append(segment);
sb.Append(absolutePath, previousIndex, segmentLength);
}

if (index != -1)
{
sb.Append('/');
}

previousIndex += index + 1;
previousIndex = index + 1;
}
while (index != -1);

return StringBuilderCache.GetStringAndRelease(sb);
#else
// Sanitized url will be at worse as long as the original
var sb = StringBuilderCache.Acquire(absolutePath.Length);

int previousIndex = 0;
int index = 0;
}

do
private static bool IsIdentifierSegment(string absolutePath, int startIndex, int segmentLength)
{
if (segmentLength == 0)
{
index = absolutePath.IndexOf('/', previousIndex);

string segment;

if (index == -1)
{
// Last segment
segment = absolutePath.Substring(previousIndex);
}
else
{
segment = absolutePath.Substring(previousIndex, index - previousIndex);
}
return false;
}

// replace path segments that look like numbers or guid
// GUID format N "d85b1407351d4694939203acc5870eb1" length: 32
// GUID format D "d85b1407-351d-4694-9392-03acc5870eb1" length: 36 with dashes in indices 8, 13, 18 and 23.
if (long.TryParse(segment, out _) ||
(segment.Length == 32 && IsAGuid(segment, "N")) ||
(segment.Length == 36 && IsAGuid(segment, "D")))
{
segment = "?";
}
int lastIndex = startIndex + segmentLength;
var containsNumber = false;

sb.Append(segment);
for (int index = startIndex; index < lastIndex && index < absolutePath.Length; index++)
{
char c = absolutePath[index];

if (index != -1)
switch (c)
{
sb.Append("/");
case >= '0' and <= '9':
containsNumber = true;
continue;
case >= 'a' and <= 'f':
case >= 'A' and <= 'F':
if (segmentLength < 16)
{
// don't be too aggressive replacing
// short hex segments like "/a" or "/cab",
// they are likely not ids
return false;
}

continue;
case '-':
continue;
default:
return false;
}

previousIndex = index + 1;
}
while (index != -1);

return StringBuilderCache.GetStringAndRelease(sb);
#endif
return containsNumber;
}

[MethodImpl(MethodImplOptions.NoInlining)]
private static bool IsAGuid(string segment, string format) => Guid.TryParseExact(segment, format, out _);

#if NETCOREAPP
[MethodImpl(MethodImplOptions.NoInlining)]
private static bool IsAGuid(ReadOnlySpan<char> segment, string format) => Guid.TryParseExact(segment, format, out _);
#endif
}
}
17 changes: 13 additions & 4 deletions test/Datadog.Trace.Tests/Util/UriHelpersTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -9,10 +9,19 @@ public class UriHelpersTests
[InlineData("/", "/")]
[InlineData("/controller/action/b37855d4bae34bd3b3357fc554ad334e", "/controller/action/?")]
[InlineData("/controller/action/14bb2eed-34f0-4aa2-b2c3-09c0e2166d4d", "/controller/action/?")]
[InlineData("/controller/action/14bb2eed-34f0X4aa2-b2c3-09c0e2166d4d", "/controller/action/14bb2eed-34f0X4aa2-b2c3-09c0e2166d4d")]
[InlineData("/controller/action/14bb2eed-34f0-4aa2Xb2c3-09c0e2166d4d", "/controller/action/14bb2eed-34f0-4aa2Xb2c3-09c0e2166d4d")]
[InlineData("/controller/action/14bb2eed-34f0A4aa2Bb2c3C09c0e2166d4d", "/controller/action/14bb2eed-34f0A4aa2Bb2c3C09c0e2166d4d")]
[InlineData("/DataDog/dd-trace-dotnet/blob/e2d83dec7d6862d4181937776ddaf72819e291ce/src/Datadog.Trace/Util/UriHelpers.cs", "/DataDog/dd-trace-dotnet/blob/e2d83dec7d6862d4181937776ddaf72819e291ce/src/Datadog.Trace/Util/UriHelpers.cs")]
[InlineData("/controller/action/14bb2eed-34f0X4aa2-b2c3-09c0e2166d4d", "/controller/action/14bb2eed-34f0X4aa2-b2c3-09c0e2166d4d")] // contains non-hex letters
[InlineData("/controller/action/14bb2eed-34f0-4aa2Xb2c3-09c0e2166d4d", "/controller/action/14bb2eed-34f0-4aa2Xb2c3-09c0e2166d4d")] // contains non-hex letters
[InlineData("/controller/action/14bb2eed-34f0A4aa2Bb2c3C09c0e2166d4d", "/controller/action/?")]
[InlineData("/controller/action/12345678901234567890123456789012345678901234567890", "/controller/action/?")]
[InlineData("/controller/action/eeeee123", "/controller/action/eeeee123")] // Too short
[InlineData("/controller/action/0123456789ABCDE", "/controller/action/0123456789ABCDE")] // Too short
[InlineData("/controller/action/01234567890ABCDEFGH", "/controller/action/01234567890ABCDEFGH")] // Contains non-hex letters
[InlineData("/controller/action/0123456789ABCDEF", "/controller/action/?")]
[InlineData("/controller/action/0123456789ABCDEF0", "/controller/action/?")]
[InlineData("/controller/action/01234567_89ABCDEF", "/controller/action/01234567_89ABCDEF")] // only hyphen '-' allowed other than hex
[InlineData("/controller/action/123-456-789", "/controller/action/?")]
[InlineData("/controller/action/eeeeeeeeeeeeeeeee", "/controller/action/eeeeeeeeeeeeeeeee")] // No numbers
[InlineData("/DataDog/dd-trace-dotnet/blob/e2d83dec7d6862d4181937776ddaf72819e291ce/src/Datadog.Trace/Util/UriHelpers.cs", "/DataDog/dd-trace-dotnet/blob/?/src/Datadog.Trace/Util/UriHelpers.cs")]
[InlineData("/controller/action/2022", "/controller/action/?")]
[InlineData("/controller/action/", "/controller/action/")]
public void GetCleanUriPath_ShouldRemoveIdsFromPaths(string url, string expected)
Expand Down