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Merged
andrewlock merged 5 commits into from
Oct 15, 2025
Merged

Minor refactor and added tests for DynamicConfigurationManager #7652

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c5f0695
Refactor DynamicConfigurationManager to make it more testable
andrewlock Oct 14, 2025
cf0902f
Add unit tests for CombineApmTracingConfiguration to document expecta…
andrewlock Oct 14, 2025
d4d72c3
Reduce duration of lock
andrewlock Oct 14, 2025
a73cff2
Minor refactor to remove allocation
andrewlock Oct 14, 2025
ebdd094
nit: remove lock as we're not really threadsafe anyway and it ads a v…
andrewlock Oct 15, 2025
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94 changes: 50 additions & 44 deletions tracer/src/Datadog.Trace/Configuration/DynamicConfigurationManager.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -32,7 +32,6 @@ internal class DynamicConfigurationManager : IDynamicConfigurationManager
private readonly IRcmSubscriptionManager _subscriptionManager;
private readonly ConfigurationTelemetry _configurationTelemetry;
private readonly Dictionary<string, RemoteConfiguration> _activeConfigurations = new();
private readonly object _configLock = new();
private ISubscription? _subscription;

public DynamicConfigurationManager(IRcmSubscriptionManager subscriptionManager)
Expand Down Expand Up @@ -158,76 +157,83 @@ private static void OnConfigurationChanged(ConfigurationBuilder settings)
.ContinueWith(t => Log.Error(t?.Exception, "Error updating dynamic configuration for debugger"), TaskContinuationOptions.OnlyOnFaulted);
}

// Internal for testing
internal static List<RemoteConfiguration> CombineApmTracingConfiguration(
Dictionary<string, RemoteConfiguration> activeConfigurations,
Dictionary<string, List<RemoteConfiguration>> configByProduct,
Dictionary<string, List<RemoteConfigurationPath>>? removedConfigByProduct,
List<ApplyDetails> applyDetailsResult)
{
// Phase 1: Handle explicit removals from removedConfigByProduct
if (removedConfigByProduct?.TryGetValue(ProductName, out var removedConfigs) == true)
{
foreach (var removedConfig in removedConfigs)
{
if (activeConfigurations.Remove(removedConfig.Id))
{
Log.Debug("Explicitly removed APM_TRACING configuration {ConfigId}", removedConfig.Id);
applyDetailsResult.Add(ApplyDetails.FromOk(removedConfig.Path));
}
}
}

// Phase 2: Handle new/updated configurations and implicit removals
if (configByProduct.TryGetValue(ProductName, out var apmLibrary))
{
// if we have some config, then we will "overwrite" everything that's currently active
if (Log.IsEnabled(LogEventLevel.Debug) && activeConfigurations.Count > 0)
{
Log.Debug<int, int>("Implicitly removing {RemovedCount} APM_TRACING configurations and replacing with {AddedCount}", activeConfigurations.Count, apmLibrary.Count);
}

activeConfigurations.Clear();

// Add/update configurations
foreach (var config in apmLibrary)
{
activeConfigurations[config.Path.Id] = config;
applyDetailsResult.Add(ApplyDetails.FromOk(config.Path.Path));
}
}

return [..activeConfigurations.Values];
}

private ApplyDetails[] ConfigurationUpdated(
Dictionary<string, List<RemoteConfiguration>> configByProduct,
Dictionary<string, List<RemoteConfigurationPath>>? removedConfigByProduct)
{
lock (_configLock)
{
var applyDetailsResult = new List<ApplyDetails>();

try
{
// Phase 1: Handle explicit removals from removedConfigByProduct
if (removedConfigByProduct?.TryGetValue(ProductName, out var removedConfigs) == true)
{
foreach (var removedConfig in removedConfigs)
{
if (_activeConfigurations.Remove(removedConfig.Id))
{
Log.Debug("Explicitly removed APM_TRACING configuration {ConfigId}", removedConfig.Id);
applyDetailsResult.Add(ApplyDetails.FromOk(removedConfig.Path));
}
}
}

// Phase 2: Handle new/updated configurations and implicit removals
if (configByProduct.TryGetValue(ProductName, out var apmLibrary))
{
var receivedConfigIds = new HashSet<string>();

// Add/update configurations
foreach (var config in apmLibrary)
{
receivedConfigIds.Add(config.Path.Id);
_activeConfigurations[config.Path.Id] = config;
applyDetailsResult.Add(ApplyDetails.FromOk(config.Path.Path));
}

// Remove configurations not in this update
var configsToRemove = _activeConfigurations.Keys
.Where(configId => !receivedConfigIds.Contains(configId))
.ToList();

foreach (var configId in configsToRemove)
{
_activeConfigurations.Remove(configId);
Log.Debug("Implicitly removed APM_TRACING configuration {ConfigId} (not in update)", configId);
}
}
// This is all non-thread safe, but we're called in a single threaded way by
// the RcmSubscriptionManager so that's fine
var valuesToApply = CombineApmTracingConfiguration(_activeConfigurations, configByProduct, removedConfigByProduct, applyDetailsResult);

// Phase 3: Apply merged configuration
ApplyMergedConfiguration();
ApplyMergedConfiguration(valuesToApply);

return applyDetailsResult.ToArray();
return [..applyDetailsResult];
}
catch (Exception ex)
{
Log.Error(ex, "Error while applying dynamic configuration");
return applyDetailsResult.Select(r => ApplyDetails.FromError(r.Filename, ex.ToString())).ToArray();
return [..applyDetailsResult.Select(r => ApplyDetails.FromError(r.Filename, ex.ToString()))];
}
}
}

private void ApplyMergedConfiguration()
private void ApplyMergedConfiguration(List<RemoteConfiguration> remoteConfigurations)
{
// Get current service/environment for filtering
var currentSettings = Tracer.Instance.Settings;
var serviceName = currentSettings.ServiceName;
var environment = currentSettings.Environment ?? Tracer.Instance.DefaultServiceName;

var mergedConfigJToken = ApmTracingConfigMerger.MergeConfigurations(
_activeConfigurations.Values.ToList(),
remoteConfigurations,
serviceName,
environment);

Expand Down
244 changes: 244 additions & 0 deletions tracer/test/Datadog.Trace.Tests/Configuration/DynamicConfigurationManagerTests.cs
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Original file line number Diff line number Diff line change
@@ -0,0 +1,244 @@
// <copyright file="DynamicConfigurationManagerTests.cs" company="Datadog">
// Unless explicitly stated otherwise all files in this repository are licensed under the Apache 2 License.
// This product includes software developed at Datadog (https://www.datadoghq.com/). Copyright 2017 Datadog, Inc.
// </copyright>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using Datadog.Trace.Configuration;
using Datadog.Trace.RemoteConfigurationManagement;
using FluentAssertions;
using Xunit;

namespace Datadog.Trace.Tests.Configuration;

public class DynamicConfigurationManagerTests
{
private const string ProductName = DynamicConfigurationManager.ProductName;
private static int _version;

[Fact]
public void CombineApmTracingConfiguration_WhenNoConfiguration_ReturnsEmptyCollection()
{
Dictionary<string, RemoteConfiguration> activeConfigs = new();
Dictionary<string, List<RemoteConfiguration>> configByProduct = new();
Dictionary<string, List<RemoteConfigurationPath>> removedConfigByProduct = new();
List<ApplyDetails> applyDetails = [];
var results = DynamicConfigurationManager.CombineApmTracingConfiguration(
new(activeConfigs), // create a copy to avoid mutating the original
configByProduct,
removedConfigByProduct,
applyDetails);

results.Should().BeEmpty();
applyDetails.Should().BeEmpty();
}

[Fact]
public void CombineApmTracingConfiguration_WhenUnknownProducts_ReturnsEmptyCollection()
{
Dictionary<string, RemoteConfiguration> activeConfigs = new();
Dictionary<string, List<RemoteConfiguration>> configByProduct = new()
{
{ "Something else", [CreateConfig()] },
{ "Blah", [CreateConfig()] },
};
Dictionary<string, List<RemoteConfigurationPath>> removedConfigByProduct = new();
List<ApplyDetails> applyDetails = [];
var results = DynamicConfigurationManager.CombineApmTracingConfiguration(
new(activeConfigs), // create a copy to avoid mutating the original
configByProduct,
removedConfigByProduct,
applyDetails);

results.Should().BeEmpty();
AssertApplyDetails(applyDetails, activeConfigs, configByProduct, removedConfigByProduct);
}

[Fact]
public void CombineApmTracingConfiguration_WhenNoConfigsByProduct_ReturnsEmptyCollection()
{
Dictionary<string, RemoteConfiguration> activeConfigs = new();
Dictionary<string, List<RemoteConfiguration>> configByProduct = new();
Dictionary<string, List<RemoteConfigurationPath>> removedConfigByProduct = new()
{
{ ProductName, [RemoteConfigurationPath.FromPath("datadog/1/a/b/c"), RemoteConfigurationPath.FromPath("employee/1/2/3")] },
{ "Blep", [RemoteConfigurationPath.FromPath("datadog/1/d/b/c"), RemoteConfigurationPath.FromPath("employee/4/3/2")] },
};

List<ApplyDetails> applyDetails = [];
var results = DynamicConfigurationManager.CombineApmTracingConfiguration(
new(activeConfigs), // create a copy to avoid mutating the original
configByProduct,
removedConfigByProduct,
applyDetails);

results.Should().BeEmpty();
AssertApplyDetails(applyDetails, activeConfigs, configByProduct, removedConfigByProduct);
}

[Fact]
public void CombineApmTracingConfiguration_WhenExistingConfigIsRemoved_RemovesConfigAndLeavesRemaining()
{
const string pathToRemove = "datadog/1/a/some-random-id/c";
const string expectedPath = "employee/1/other-ID/3";
var configToRemove = CreateConfig(pathToRemove);
var expected = CreateConfig(expectedPath);
Dictionary<string, RemoteConfiguration> activeConfigs = new()
{
{ configToRemove.Path.Id, CreateConfig(pathToRemove) },
{ expected.Path.Id, expected },
};
Dictionary<string, List<RemoteConfiguration>> configByProduct = new();
Dictionary<string, List<RemoteConfigurationPath>> removedConfigByProduct = new()
{
{ ProductName, [RemoteConfigurationPath.FromPath(pathToRemove), RemoteConfigurationPath.FromPath("datadog/2/dont/remove/me")] },
};

List<ApplyDetails> applyDetails = [];
var results = DynamicConfigurationManager.CombineApmTracingConfiguration(
new(activeConfigs), // create a copy to avoid mutating the original
configByProduct,
removedConfigByProduct,
applyDetails);

results.Should().BeEquivalentTo([expected]);
AssertApplyDetails(applyDetails, activeConfigs, configByProduct, removedConfigByProduct);
}

[Fact]
public void CombineApmTracingConfiguration_WhenNewConfigIsProvided_ReplacesExistingConfig()
{
const string pathToRemove = "datadog/1/a/some-random-id/c";
const string expectedPath = "employee/1/other-ID/3";
var configToRemove = CreateConfig(pathToRemove);
var previous = CreateConfig(expectedPath);
var updated = CreateConfig(expectedPath); // different config for same id
Dictionary<string, RemoteConfiguration> activeConfigs = new()
{
{ configToRemove.Path.Id, CreateConfig(pathToRemove) },
{ previous.Path.Id, previous },
};
Dictionary<string, List<RemoteConfiguration>> configByProduct = new()
{
{ ProductName, [updated] },
};
Dictionary<string, List<RemoteConfigurationPath>> removedConfigByProduct = new()
{
{ ProductName, [RemoteConfigurationPath.FromPath(pathToRemove), RemoteConfigurationPath.FromPath("datadog/2/dont/remove/me")] },
};

List<ApplyDetails> applyDetails = [];
var results = DynamicConfigurationManager.CombineApmTracingConfiguration(
new(activeConfigs), // create a copy to avoid mutating the original
configByProduct,
removedConfigByProduct,
applyDetails);

results.Should().BeEquivalentTo([updated]);
AssertApplyDetails(applyDetails, activeConfigs, configByProduct, removedConfigByProduct);
}

[Fact]
public void CombineApmTracingConfiguration_WhenNewConfigIsProvided_ReplacesExistingConfigRegardlessOfRemovedConfig()
{
const string pathToRemove = "datadog/1/a/some-random-id/c";
const string expectedPath = "employee/1/other-ID/3";
var configToRemove = CreateConfig(pathToRemove);
var previous = CreateConfig(expectedPath);
var updated = CreateConfig(expectedPath); // different config for same id
Dictionary<string, RemoteConfiguration> activeConfigs = new()
{
{ configToRemove.Path.Id, CreateConfig(pathToRemove) },
{ previous.Path.Id, previous },
};
Dictionary<string, List<RemoteConfiguration>> configByProduct = new()
{
{ ProductName, [updated] },
};
Dictionary<string, List<RemoteConfigurationPath>> removedConfigByProduct = new()
{
// Note that we're _not_ explicitly removing the pathToRemove config, but as it's not in the "config by product", it gets removed
{ ProductName, [RemoteConfigurationPath.FromPath("datadog/2/dont/remove/me")] },
};

List<ApplyDetails> applyDetails = [];
var results = DynamicConfigurationManager.CombineApmTracingConfiguration(
new(activeConfigs), // create a copy to avoid mutating the original
configByProduct,
removedConfigByProduct,
applyDetails);

results.Should().BeEquivalentTo([updated]);
AssertApplyDetails(applyDetails, activeConfigs, configByProduct, removedConfigByProduct);
}

[Fact]
public void CombineApmTracingConfiguration_WhenNewConfigIsProvided_OverwritesNewAndExistingConfig()
{
const string pathToRemove = "datadog/1/a/some-random-id/c";
const string expectedPath = "employee/1/other-ID/3";
var configToRemove = CreateConfig(pathToRemove);
var previous = CreateConfig(expectedPath);
var updated1 = CreateConfig(expectedPath); // different configs for same id
var updated2 = CreateConfig(expectedPath); // different configs for same id
Dictionary<string, RemoteConfiguration> activeConfigs = new()
{
{ configToRemove.Path.Id, CreateConfig(pathToRemove) },
{ previous.Path.Id, previous },
};
Dictionary<string, List<RemoteConfiguration>> configByProduct = new()
{
{ ProductName, [updated1, updated2] },
};
Dictionary<string, List<RemoteConfigurationPath>> removedConfigByProduct = new()
{
// Note that we're _not_ explicitly removing the pathToRemove config, but as it's not in the "config by product", it gets removed
{ ProductName, [RemoteConfigurationPath.FromPath("datadog/2/dont/remove/me")] },
};

List<ApplyDetails> applyDetails = [];
var results = DynamicConfigurationManager.CombineApmTracingConfiguration(
new(activeConfigs), // create a copy to avoid mutating the original
configByProduct,
removedConfigByProduct,
applyDetails);

results.Should().BeEquivalentTo([updated2]); // updated1 is replaced
AssertApplyDetails(applyDetails, activeConfigs, configByProduct, removedConfigByProduct);
}

private static void AssertApplyDetails(
List<ApplyDetails> applyDetails,
Dictionary<string, RemoteConfiguration> originalConfig,
Dictionary<string, List<RemoteConfiguration>> configByProduct,
Dictionary<string, List<RemoteConfigurationPath>> removedConfigByProduct)
{
var removed = removedConfigByProduct
.Where(x => x.Key == ProductName)
.SelectMany(x => x.Value)
.Where(x => originalConfig.ContainsKey(x.Id)) // Only acknowledge the configs that we actually have
.Select(x => ApplyDetails.FromOk(x.Path));
var added = configByProduct
.Where(x => x.Key == ProductName)
.SelectMany(x => x.Value)
.Select(x => ApplyDetails.FromOk(x.Path.Path));
List<ApplyDetails> expected = [..removed, ..added];

applyDetails.Should().BeEquivalentTo(expected);
}

private static RemoteConfiguration CreateConfig(string path = null)
{
var version = Interlocked.Increment(ref _version);
path ??= $"datadog/{version}/product-{version}/id-{version}/path";
return new RemoteConfiguration(
RemoteConfigurationPath.FromPath(path),
contents: [],
length: 0,
hashes: new(),
version: Interlocked.Increment(ref _version)); // use version to create unique config values
}
}
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