CHANGELOG.md

Change log

All notable changes to the LaunchDarkly .NET Server-Side SDK will be documented in this file. This project adheres to Semantic Versioning.

[5.8.0] - 2019-10-01

Added:

• Added support for upcoming LaunchDarkly experimentation features. See ILdClient.Track(string, User, LdValue, double).

Fixed:

• Fixed a bug due to incorrect use of a lock that could cause a read from InMemoryFeatureStore to fail if done at the same time as an update. (Thanks, JeffAshton!)

[5.7.1] - 2019-09-13

(The changes below were originally released in 5.7.0, but that release was broken; 5.7.1 is its replacement.)

This release includes new types and deprecations that correspond to upcoming changes in version 6.0.0. Developers are encouraged to start adopting these changes in their code now so that migrating to 6.0.0 in the future will be easier. Most of these changes are related to the use of mutable types, which are undesirable in a concurrent environment. User and Configuration are currently mutable types; they will be made immutable in the future, so there are now builders for them. Arbitrary JSON values are currently represented with the Newtonsoft.Json type JToken, which is mutable (if it contains an array or a JSON object); the new type LdValue is safer, and will eventually completely replace JToken in the public API.

Also, generated HTML documentation for all of the SDK's public types, properties, and methods is now available online at https://launchdarkly.github.io/dotnet-server-sdk/. Currently this will only show the latest released version.

Added:

• Configuration.Builder provides a fluent builder pattern for constructing Configuration objects. This is now the preferred method for building a user, rather than using ConfigurationExtension methods like WithStartWaitTime() that modify the existing configuration object.
• Configuration.EventCapacity and Configuration.EventFlushInterval (new names for EventQueueCapacity and EventQueueFrequency, for consistency with other LaunchDarkly SDKs).
• User.Builder provides a fluent builder pattern for constructing User objects. This is now the preferred method for building a user, rather than setting User properties directly or using UserExtension methods like AndName() that modify the existing user object.
• User.IPAddress is equivalent to User.IpAddress, but has the standard .NET capitalization for two-letter acronyms.
• The new LdValue type is a better alternative to using JToken, JValue, JArray, etc. for arbitrary JSON values (such as the return value of JsonVariation, or a custom attribute for a user).
• There is now more debug-level logging for stream connection state changes.
• XML documentation comments are now included in the package for all target frameworks. Previously they were only included for .NET Standard 1.4.

Changed:

• Calls to flag evaluation methods such as BoolVariation are now somewhat more efficient because they no longer convert the default value to a JToken internally; also, user attributes no longer need to be converted to JToken internally when evaluating flag rules. If flag evaluations are very frequent, this reduces the number of ephemeral objects created on the heap.

Fixed:

• Due to the default parsing behavior of Newtonsoft.Json, strings in the date/time format "1970-01-01T00:00:01Z" or "1970-01-01T00:00:01.001Z" would not be considered equal to an identical string in a flag rule.

Deprecated:

• All ConfigurationExtension methods are now deprecated.
• Configuration.SamplingInterval. The intended use case for the SamplingInterval feature was to reduce analytics event network usage in high-traffic applications. This feature is being deprecated in favor of summary counters, which are meant to track all events.
• Configuration.EventQueueCapacity and Configuration.EventQueueFrequency (see new names above).
• User constructors (use User.WithKey or User.Builder).
• User.IpAddress (use IPAddress).
• All UserExtension methods are now deprecated. The setters for all User properties should also be considered deprecated, although C# does not allow these to be marked with [Obsolete].
• IBaseConfiguration and ICommonLdClient interfaces.
• The InMemoryFeatureStore constructor. Use Components.InMemoryFeatureStore.

[5.6.5] - 2019-05-30

Fixed:

• If streaming is disabled, polling requests could stop working if the client ever received an HTTP error from LaunchDarkly. This bug was introduced in the 5.6.3 release.

[5.6.4] - 2019-05-10

Changed:

• The NuGet package name and assembly name have changed: they are now LaunchDarkly.ServerSdk instead of LaunchDarkly.Client. There are no other changes in this release; the namespace used in .NET code is still LaunchDarkly.Client. Substituting LaunchDarkly.Client version 5.6.3 with LaunchDarkly.ServerSdk version 5.6.4 will not affect functionality.

[5.6.3] - 2019-05-10

Fixed:

• If Track or Identify is called without a user, the SDK now will not send an analytics event to LaunchDarkly (since it would not be processed without a user).

Note on future releases

The LaunchDarkly SDK repositories are being renamed for consistency. This repository is now dotnet-server-sdk rather than dotnet-client.

The NuGet package name and assembly name will also change. In the 5.6.3 release, it is still LaunchDarkly.Client; in all releases after 5.6.3, it will be LaunchDarkly.ServerSdk. No further updates to the LaunchDarkly.Client package will be published after this release.

[5.6.2] - 2019-03-26

Changed:

• The default value for the configuration property capacity (maximum number of events that can be stored at once) is now 10000, consistent with the other SDKs, rather than 500.

Fixed:

• Under some circumstances, a CancellationTokenSource might not be disposed of after making an HTTP request, which could cause a timer object to be leaked. (#100)
• In polling mode, if the client received an HTTP error it would retry the same request one second later. This was inconsistent with the other SDKs; the correct behavior is for it to wait until the next scheduled poll.
• The HttpClientTimeout configuration property was being ignored when making HTTP requests to send analytics events.

[5.6.1] - 2019-01-14

Fixed:

• The assemblies in this package now have Authenticode signatures.

[5.6.0] - 2019-01-09

Added:

• There are now helper classes that make it much simpler to write a custom IFeatureStore implementation. See the LaunchDarkly.Client.Utils namespace.
• The new FeatureStoreCaching class will be used by database feature store integrations in the future. It is not used by the SDK client itself.

Changed:

• Some support code has been moved into a separate assembly, LaunchDarkly.Cache.
• The published assemblies are now built in Release configuration and no longer contain debug information.
• If you are building a copy of the SDK yourself, the Debug configuration no longer does any signing, so does not require a key file.

[5.5.0] - 2018-10-30

Added:

• It is now possible to inject feature flags into the client from local JSON or YAML files, replacing the normal LaunchDarkly connection. This would typically be for testing purposes. See LaunchDarkly.Client.Files.FileComponents.

• The AllFlagsState method now accepts a new option, FlagsStateOption.DetailsOnlyForTrackedFlags, which reduces the size of the JSON representation of the flag state by omitting some metadata. Specifically, it omits any data that is normally used for generating detailed evaluation events if a flag does not have event tracking or debugging turned on.

• The non-strong-named version of this library (LaunchDarkly.Common) can now be used with a non-strong-named version of LaunchDarkly.Client, which does not normally exist but could be built as part of a fork of the SDK.

Changed:

• Previously, the delay before stream reconnect attempts would increase exponentially only if the previous connection could not be made at all or returned an HTTP error; if it received an HTTP 200 status, the delay would be reset to the minimum even if the connection then immediately failed. Now, if the stream connection fails after it has been up for less than a minute, the reconnect delay will continue to increase.

Fixed:

• Fixed an unobserved exception that could occur following a stream timeout, which could cause a crash in .NET 4.0.

• Fixed a NullReferenceException that could sometimes appear in the log if a stream connection failed.

• Fixed the documentation for Configuration.StartWaitTime to indicate that the default is 10 seconds, not 5 seconds. (Thanks, KimboTodd!)

• JSON data from AllFlagsState is now slightly smaller even if you do not use the new option described above, because it completely omits the flag property for event tracking unless that property is true.

[5.4.0] - 2018-08-30

Added:

• The new LDClient methods BoolVariationDetail, IntVariationDetail, DoubleVariationDetail, StringVariationDetail, and JsonVariationDetail allow you to evaluate a feature flag (using the same parameters as you would for BoolVariation, etc.) and receive more information about how the value was calculated. This information is returned in an EvaluationDetail object, which contains both the result value and an EvaluationReason which will tell you, for instance, if the user was individually targeted for the flag or was matched by one of the flag's rules, or if the flag returned the default value due to an error.

Fixed:

• When evaluating a prerequisite feature flag, the analytics event for the evaluation did not include the result value if the prerequisite flag was off.

[5.3.1] - 2018-08-30

Fixed:

• Fixed a bug in streaming mode that prevented the client from reconnecting to the stream if it received an HTTP error status from the server (as opposed to simply losing the connection). (#88)
• Numeric flag values can now be queried with either IntVariation or FloatVariation and the result will be coerced to the requested type, as long as it is numeric. Previously, if the type of value that came from LaunchDarkly in JSON (or, more specifically, the type that Newtonsoft.Json decided to decode the value as) was different, it was considered an error and the default value would be returned. This change makes the .NET SDK consistent with the Go and Java SDKs.

[5.3.0] - 2018-08-27

Added:

• The new ILdClient method AllFlagsState() should be used instead of AllFlags() if you are passing flag data to the front end for use with the JavaScript SDK. It preserves some flag metadata that the front end requires in order to send analytics events correctly. Versions 2.5.0 and above of the JavaScript SDK are able to use this metadata, but the output of AllFlagsState() will still work with older versions.
• The AllFlagsState() method also allows you to select only client-side-enabled flags to pass to the front end, by using the option FlagsStateOption.ClientSideOnly.

Deprecated:

• ILdClient.AllFlags()

[5.2.2] - 2018-08-02

• In streaming mode, if the stream connection fails, there should be an increasing backoff interval before each reconnect attempt. Previously, it would log a message about waiting some number of milliseconds, but then not actually wait.
• The required package LaunchDarkly.EventSource no longer has PackageReferences to System assemblies.

[5.2.1] - 2018-08-01

Fixed:

• The internal classes representing feature flag and segment data were not JSON-serializable. This did not affect the SDK itself, but prevented any IFeatureStore implementation based on Json.Net serialization from working.
• The event processor did not post to the correct URI if the base events URI was set to a custom value with a non-root path. This did not affect normal usage, but would be a problem if events were being redirected to some other service.

[5.2.0] - 2018-07-27

Added:

• New configuration property UseLdd allows the client to use the "LaunchDarkly Daemon", i.e. getting feature flag data from a store that is updated by an ld-relay instance. However, this will not be usable until the Redis feature store integration is released (soon).

Changed:

• If you attempt to evaluate a flag before the client has established a connection, but you are using a feature store that has already been populated, the client will now use the last known values from the store instead of returning default values.
• The LaunchDarkly.Common package, which is used by LaunchDarkly.Client, has been renamed to LaunchDarkly.Common.StrongName. Note that you should not have to explicitly install this package; it will be imported automatically.

Fixed:

• The SDK was referencing several system assemblies via <PackageReference>, which could cause dependency conflicts. These have been changed to framework <Reference>s. A redundant reference to System.Runtime was removed. (#83)
• The client was logging (at debug level) a lengthy exception stacktrace whenever a string comparison operator was applied to a user property that was null. It no longer does this.

[5.1.1] - 2018-07-02

Changed:

• When targeting the .NET 4.5 framework, the dependency on Newtonsoft's JSON.Net framework has been changed: the minimum version is now 6.0.1 rather than 9.0.1. This was changed in order to support customer code that uses older versions of JSON.Net. For most applications, this change should have no effect since it is only a minimum version, which can be overridden by any higher version specified in your own dependencies. Note that when targeting .NET Standard, the minimum JSON.Net version is still 9.0.1 because earlier versions were not compatible with .NET Standard.
• The Identify method has been moved back into ILdClient rather than being in ILdCommonClient.

[5.1.0] - 2018-06-26

Added:

• A new overload of LDClient.Track allows you to pass any kind of JSON value for the custom event data, not just a string.
• The User class now implements Equals and GetHashCode, and has a copy constructor.

Changed:

• Some classes and interfaces have been moved into a separate assembly, LaunchDarkly.Common (source code here), because they will also be used by the LaunchDarkly Xamarin SDK. The names and namespaces have not changed, so you do not need to make any code changes. LaunchDarkly.Common will be installed automatically when you upgrade LaunchDarkly.Client; all other dependencies are unchanged.
• The client now treats most HTTP 4xx errors as unrecoverable: that is, after receiving such an error, it will not make any more HTTP requests for the lifetime of the client instance, in effect taking the client offline. This is because such errors indicate either a configuration problem (invalid SDK key) or a bug, which is not likely to resolve without a restart or an upgrade. This does not apply if the error is 400, 408, 429, or any 5xx error.
• During initialization, if the client receives any of the unrecoverable errors described above, the client constructor will return immediately; previously it would continue waiting until a timeout. The Initialized() method will return false in this case.

Fixed:

• Ensured that all HttpClient instances managed by the client are disposed of immediately if you call Dispose on the client.
• Passing null for user when calling Identify or Track no longer causes a NullReferenceException. Instead, the appropriate event will be sent with no user.

[5.0.0] - 2018-05-10

Changed:

• To reduce the network bandwidth used for analytics events, feature request events are now sent as counters rather than individual events, and user details are now sent only at intervals rather than in each event. These behaviors can be modified through the LaunchDarkly UI and with the new configuration option InlineUsersInEvents. For more details, see Analytics Data Stream Reference.
• The IStoreEvents interface has been renamed to IEventProcessor, has slightly different methods, and includes IDisposable. Also, the properties of the Event classes have changed. This will only affect developers who created their own implementation of IStoreEvents.

Added:

• New extension methods on Configuration (WithUpdateProcessorFactory, WithFeatureStoreFactory, WithEventProcessorFactory) allow you to specify different implementations of each of the main client subcomponents (receiving feature state, storing feature state, and sending analytics events) for testing or for any other purpose. The Components class provides factories for all built-in implementations of these.

Deprecated:

• The WithFeatureStore configuration method is deprecated, replaced by the new factory-based mechanism described above.
• The LdClient constructor overload that takes an IEventProcessor (formerly IStoreEvents) is deprecated, replaced by WithEventProcessorFactory.

[4.1.1] - 2018-03-23

Fixed

• Fixed a bug in the event sampling feature that was introduced in 4.1.0: sampling might not work correctly if events were generated from multiple threads.

[4.1.0] - 2018-03-05

Added

• Configuration now has an EventSamplingInterval property. If greater than zero, this causes a fraction of analytics events to be sent to LaunchDarkly: one per that number of events (pseudo-randomly). For instance, setting it to 5 would cause 20% of events to be sent on average.

Changed

• ConfigurationExtensions.WithPollingInterval will no longer throw an exception if the parameter is lower than the minimum. Instead, it will simply set the value to the minimum and log a warning.

[4.0.0] - 2018-02-21

Added

• Support for a new LaunchDarkly feature: reusable user segments.

Changed

• The client now uses Common.Logging.
• The FeatureStore interface has been changed to support user segment data as well as feature flags. Existing code that uses InMemoryFeatureStore or RedisFeatureStore should work as before, but custom feature store implementations will need to be updated.
• Some previously public classes that were not meant to be public are now internal.

Fixed

• All previously undocumented methods now have documentation comments.

Removed

• Obsolete/deprecated methods have been removed.
• Removed Configuration.WithLoggerFactory since the logging framework has changed. For more details on setting up logging, see here.

[3.6.1] - 2018-02-21

Fixed

• Improved performance of the semantic version operators by precompiling a regex.

[3.6.0] - 2018-02-19

Added

• New property LdClient.Version returns the client's current version number.
• Adds support for a future LaunchDarkly feature, coming soon: semantic version user attributes.
• Custom attributes can now have long integer values.

Changed

• It is now possible to compute rollouts based on an integer attribute of a user, not just a string attribute.

[3.5.0] - 2018-01-29

Added

• Support for specifying private user attributes in order to prevent user attributes from being sent in analytics events back to LaunchDarkly. See the AllAttributesPrivate and PrivateAttributeNames methods on Configuration as well as the AndPrivateX methods on User.

Changed

• The stream connection will now restart when a large feature flag update fails repeatedly to ensure that the client is using most recent flag values.
• Client no longer reconnects after detecting an invalidated SDK key.

[3.4.1] - 2018-01-19

Added

• Framework target for netstandard1.4 and netstandard2.0. Thanks @nolanblew and @ISkomorokh!
• Added the Apache 2.0 license to LaunchDarkly.Client.csproj

Changed

• Fixed a bug causing ASP.NET applications to be blocked during client initialization.
• Removed unused and transitive dependencies.
• Improved logging. Thanks @MorganVergara and @JeffAshton!

[3.4.0] - 2017-11-29

Added

• 🚀 Support for Streaming via Server-Sent Events as an alternative to Polling. HTTP-based streaming is favored over polling to reduce network traffic and propagate feature flag updates faster. 🚀
• New builder parameters to complement streaming functionality
  • WithIsStreamingEnabled: Set whether streaming mode should be enabled, true by default.
  • WithStreamUri: Set the base URL of the LaunchDarkly streaming server. May be used in conjunction with the LaunchDarkly Relay Proxy.
  • WithReadTimeout: The timeout when reading data from the streaming API. Defaults to 5 minutes
  • WithReconnectTime: The time to wait before attempting to reconnect to the streaming API. Defaults to 1 second
• Apache 2.0 License

Changed

• Streaming is now used to retrieve feature flag configurations by default.
• Minimum (and default) polling interval changed from 1 second to 30 seconds.
• PollingProcessor no longer retries failed feature flag polling attempts.

[3.3.2] - 2017-08-30

Changed

• Updated dependency versions. Thanks @ISkomorokh!
• Exceptions in FeatureRequestor are rethrown without replacing stack information

[3.3.1] - 2017-07-14

Fixed

• UserExtensions.AndName updates user.Name instead of user.LastName

[3.3.0] - 2017-06-16

Added

• Config option to use custom implementation of IFeatureStore
• Artifact is now signed

Changed

• Removed NETStandard.Library from dependencies so it isn't brought in by non-.NET core projects.
• Project files migrated to current *.csproj standard
• Fixed release that inadvertently removed the ability to set a custom HttpClientHandler

[3.2.0] - 2017-05-25

Added

• Config option to use custom implementation of IFeatureStore
• Artifact is now signed

Changed

• Removed NETStandard.Library from dependencies so it isn't brought in by non-.NET core projects.
• Project files migrated to current *.csproj standard

[3.1.1] - 2017-01-16

Changed

• Improved error handling when sending events

[3.1.0] - 2016-12-07

Added

• Configurable http request timeout

Changed

• Made http requests more resilient and logging more informative.

[3.0.0] - 2016-10-27

Changed

• Addresses Unnecesary Lock contention when polling: launchdarkly#18
• Logging framework: Now using Microsoft.Extensions.Logging
• No longer depending on ASP.NET: launchdarkly#8

Added

• Support for .NET core: launchdarkly#9
• Http client now has a request timeout: launchdarkly#27

Deprecated

• File-based configuration override option has been removed

[2.0.3] - 2016-10-10

Changed

• Code cleanup

[2.0.2] - 2016-10-06

Added

• Address launchdarkly#27
• Improve error logging- we're now logging messages from inner exceptions.

[2.0.1] - 2016-10-05

Changed

• Async http client code improvements.

[2.0.0] - 2016-08-10

Added

• Support for multivariate feature flags. New methods StringVariation, JsonVariation and IntVariation and FloatVariation for multivariates.
• New AllFlags method returns all flag values for a specified user.
• New SecureModeHash function computes a hash suitable for the new LaunchDarkly JavaScript client's secure mode feature.

Changed

• LdClient now implements a new interface: ILdClient

Deprecated

• The Toggle call has been deprecated in favor of BoolVariation.