diff --git a/.github/workflows/nuget.yml b/.github/workflows/nuget.yml
new file mode 100644
index 0000000..3af3970
--- /dev/null
+++ b/.github/workflows/nuget.yml
@@ -0,0 +1,31 @@
+name: Publish on NuGet
+
+on:
+ push:
+ branches: [ main ]
+
+jobs:
+ publish:
+ name: Build and publish packages
+ runs-on: ubuntu-latest
+ environment:
+ name: nuget
+ url: https://github.com
+ steps:
+ - uses: actions/checkout@v3
+ with:
+ token: ${{ secrets.PAT }}
+
+ - name: Build and publish Incendium.Result if version changed
+ uses: alirezanet/publish-nuget@v3.0.3
+ with:
+ PROJECT_FILE_PATH: Incendium.Result/Incendium.Result.csproj
+ PACKAGE_NAME: Incendium.Result
+ NUGET_KEY: ${{ secrets.NUGET_KEY }}
+
+ - name: Build and publish Incendium.RetryPolicy if version changed
+ uses: alirezanet/publish-nuget@v3.0.3
+ with:
+ PROJECT_FILE_PATH: Incendium.RetryPolicy/Incendium.RetryPolicy.csproj
+ PACKAGE_NAME: Incendium.RetryPolicy
+ NUGET_KEY: ${{ secrets.NUGET_KEY }}
\ No newline at end of file
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..ad9cc7a
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,352 @@
+## Ignore Visual Studio temporary files, build results, and
+## files generated by popular Visual Studio add-ons.
+##
+## Get latest from https://github.com/github/gitignore/blob/master/VisualStudio.gitignore
+
+# User environment
+.env
+secrets.json
+logs/
+
+# Certificates
+*.p12
+
+# User-specific files
+*.rsuser
+*.suo
+*.user
+*.userosscache
+*.sln.docstates
+*.bat
+
+# User-specific files (MonoDevelop/Xamarin Studio)
+*.userprefs
+
+# Build results
+[Dd]ebug/
+[Dd]ebugPublic/
+[Rr]elease/
+[Rr]eleases/
+x64/
+x86/
+[Aa][Rr][Mm]/
+[Aa][Rr][Mm]64/
+bld/
+[Bb]in/
+[Oo]bj/
+[Ll]og/
+
+# Visual Studio 2015/2017 cache/options directory
+.vs/
+# Uncomment if you have tasks that create the project's static files in wwwroot
+#wwwroot/
+
+# Visual Studio 2017 auto generated files
+Generated\ Files/
+
+# MSTest test Results
+[Tt]est[Rr]esult*/
+[Bb]uild[Ll]og.*
+
+# NUNIT
+*.VisualState.xml
+TestResult.xml
+
+# Build Results of an ATL Project
+[Dd]ebugPS/
+[Rr]eleasePS/
+dlldata.c
+
+# Benchmark Results
+BenchmarkDotNet.Artifacts/
+
+# .NET Core
+project.lock.json
+project.fragment.lock.json
+artifacts/
+
+# StyleCop
+StyleCopReport.xml
+
+# Files built by Visual Studio
+*_i.c
+*_p.c
+*_h.h
+*.ilk
+*.meta
+*.obj
+*.iobj
+*.pch
+*.pdb
+*.ipdb
+*.pgc
+*.pgd
+*.rsp
+*.sbr
+*.tlb
+*.tli
+*.tlh
+*.tmp
+*.tmp_proj
+*_wpftmp.csproj
+*.log
+*.vspscc
+*.vssscc
+.builds
+*.pidb
+*.svclog
+*.scc
+
+# Chutzpah Test files
+_Chutzpah*
+
+# Visual C++ cache files
+ipch/
+*.aps
+*.ncb
+*.opendb
+*.opensdf
+*.sdf
+*.cachefile
+*.VC.db
+*.VC.VC.opendb
+
+# Visual Studio profiler
+*.psess
+*.vsp
+*.vspx
+*.sap
+
+# Visual Studio Trace Files
+*.e2e
+
+# TFS 2012 Local Workspace
+$tf/
+
+# Guidance Automation Toolkit
+*.gpState
+
+# ReSharper is a .NET coding add-in
+_ReSharper*/
+*.[Rr]e[Ss]harper
+*.DotSettings.user
+
+# JustCode is a .NET coding add-in
+.JustCode
+
+# TeamCity is a build add-in
+_TeamCity*
+
+# DotCover is a Code Coverage Tool
+*.dotCover
+
+# AxoCover is a Code Coverage Tool
+.axoCover/*
+!.axoCover/settings.json
+
+# Visual Studio code coverage results
+*.coverage
+*.coveragexml
+
+# NCrunch
+_NCrunch_*
+.*crunch*.local.xml
+nCrunchTemp_*
+
+# MightyMoose
+*.mm.*
+AutoTest.Net/
+
+# Web workbench (sass)
+.sass-cache/
+
+# Installshield output folder
+[Ee]xpress/
+
+# DocProject is a documentation generator add-in
+DocProject/buildhelp/
+DocProject/Help/*.HxT
+DocProject/Help/*.HxC
+DocProject/Help/*.hhc
+DocProject/Help/*.hhk
+DocProject/Help/*.hhp
+DocProject/Help/Html2
+DocProject/Help/html
+
+# Click-Once directory
+publish/
+
+# Publish Web Output
+*.[Pp]ublish.xml
+*.azurePubxml
+# Note: Comment the next line if you want to checkin your web deploy settings,
+# but database connection strings (with potential passwords) will be unencrypted
+*.pubxml
+*.publishproj
+
+# Microsoft Azure Web App publish settings. Comment the next line if you want to
+# checkin your Azure Web App publish settings, but sensitive information contained
+# in these scripts will be unencrypted
+PublishScripts/
+
+# NuGet Packages
+*.nupkg
+# The packages folder can be ignored because of Package Restore
+**/[Pp]ackages/*
+# except build/, which is used as an MSBuild target.
+!**/[Pp]ackages/build/
+# Uncomment if necessary however generally it will be regenerated when needed
+#!**/[Pp]ackages/repositories.config
+# NuGet v3's project.json files produces more ignorable files
+*.nuget.props
+*.nuget.targets
+
+# Microsoft Azure Build Output
+csx/
+*.build.csdef
+
+# Microsoft Azure Emulator
+ecf/
+rcf/
+
+# Windows Store app package directories and files
+AppPackages/
+BundleArtifacts/
+Package.StoreAssociation.xml
+_pkginfo.txt
+*.appx
+
+# Visual Studio cache files
+# files ending in .cache can be ignored
+*.[Cc]ache
+# but keep track of directories ending in .cache
+!*.[Cc]ache/
+
+# Others
+ClientBin/
+~$*
+*~
+*.dbmdl
+*.dbproj.schemaview
+*.jfm
+*.pfx
+*.publishsettings
+orleans.codegen.cs
+
+# Including strong name files can present a security risk
+# (https://github.com/github/gitignore/pull/2483#issue-259490424)
+#*.snk
+
+# Since there are multiple workflows, uncomment next line to ignore bower_components
+# (https://github.com/github/gitignore/pull/1529#issuecomment-104372622)
+#bower_components/
+# ASP.NET Core default setup: bower directory is configured as wwwroot/lib/ and bower restore is true
+**/wwwroot/lib/
+
+# RIA/Silverlight projects
+Generated_Code/
+
+# Backup & report files from converting an old project file
+# to a newer Visual Studio version. Backup files are not needed,
+# because we have git ;-)
+_UpgradeReport_Files/
+Backup*/
+UpgradeLog*.XML
+UpgradeLog*.htm
+ServiceFabricBackup/
+*.rptproj.bak
+
+# SQL Server files
+*.mdf
+*.ldf
+*.ndf
+
+# Business Intelligence projects
+*.rdl.data
+*.bim.layout
+*.bim_*.settings
+*.rptproj.rsuser
+
+# Microsoft Fakes
+FakesAssemblies/
+
+# GhostDoc plugin setting file
+*.GhostDoc.xml
+
+# Node.js Tools for Visual Studio
+.ntvs_analysis.dat
+node_modules/
+
+# Visual Studio 6 build log
+*.plg
+
+# Visual Studio 6 workspace options file
+*.opt
+
+# Visual Studio 6 auto-generated workspace file (contains which files were open etc.)
+*.vbw
+
+# Visual Studio LightSwitch build output
+**/*.HTMLClient/GeneratedArtifacts
+**/*.DesktopClient/GeneratedArtifacts
+**/*.DesktopClient/ModelManifest.xml
+**/*.Server/GeneratedArtifacts
+**/*.Server/ModelManifest.xml
+_Pvt_Extensions
+
+# Paket dependency manager
+.paket/paket.exe
+paket-files/
+
+# FAKE - F# Make
+.fake/
+
+# JetBrains Rider
+.idea/
+*.sln.iml
+
+# CodeRush personal settings
+.cr/personal
+
+# Python Tools for Visual Studio (PTVS)
+__pycache__/
+*.pyc
+
+# Cake - Uncomment if you are using it
+# tools/**
+# !tools/packages.config
+
+# Tabs Studio
+*.tss
+
+# Telerik's JustMock configuration file
+*.jmconfig
+
+# BizTalk build output
+*.btp.cs
+*.btm.cs
+*.odx.cs
+*.xsd.cs
+
+# OpenCover UI analysis results
+OpenCover/
+
+# Azure Stream Analytics local run output
+ASALocalRun/
+
+# MSBuild Binary and Structured Log
+*.binlog
+
+# NVidia Nsight GPU debugger configuration file
+*.nvuser
+
+# MFractors (Xamarin productivity tool) working folder
+.mfractor/
+
+# Local History for Visual Studio
+.localhistory/
+
+.vscode
+.ionide
+
+.DS_Store
\ No newline at end of file
diff --git a/Images/icon.png b/Images/icon.png
new file mode 100644
index 0000000..5cf504a
Binary files /dev/null and b/Images/icon.png differ
diff --git a/Images/icon_big.png b/Images/icon_big.png
new file mode 100644
index 0000000..923824f
Binary files /dev/null and b/Images/icon_big.png differ
diff --git a/Incendium.Result/Error.cs b/Incendium.Result/Error.cs
new file mode 100644
index 0000000..1e6fd90
--- /dev/null
+++ b/Incendium.Result/Error.cs
@@ -0,0 +1,36 @@
+using System;
+
+namespace Incendium
+{
+ ///
+ /// Represents error struct that contains code, message and optionally exception
+ ///
+ /// Error code
+ /// Error message
+ /// Inner exception
+ public readonly struct Error(int code, string message, Exception? exception)
+ {
+ ///
+ /// Gets error code
+ ///
+ public int Code { get; init; } = code;
+ ///
+ /// Gets error message
+ ///
+ public string Message { get; init; } = message;
+ ///
+ /// Gets optional inner exception
+ ///
+ public Exception? Exception { get; init; } = exception;
+
+ ///
+ /// Initialize a new instance of the Error struct with a specified error code and message
+ ///
+ /// Error code
+ /// Error message
+ public Error(int code, string message)
+ : this(code, message, exception: null)
+ {
+ }
+ }
+}
diff --git a/Incendium.Result/Extensions/ErrorExtensions.cs b/Incendium.Result/Extensions/ErrorExtensions.cs
new file mode 100644
index 0000000..da576ae
--- /dev/null
+++ b/Incendium.Result/Extensions/ErrorExtensions.cs
@@ -0,0 +1,26 @@
+using System;
+
+namespace Incendium.Extensions
+{
+ public static class ErrorExtensions
+ {
+ ///
+ /// Gets error code
+ ///
+ /// Nullable error
+ /// Error code
+ public static int Code(this Error? error) => error!.Value.Code;
+ ///
+ /// Gets error message
+ ///
+ /// Nullable error
+ /// Error message
+ public static string Message(this Error? error) => error!.Value.Message;
+ ///
+ /// Gets inner exception
+ ///
+ /// Nullable error
+ /// Inner exception
+ public static Exception? Exception(this Error? error) => error!.Value.Exception;
+ }
+}
diff --git a/Incendium.Result/Incendium.Result.csproj b/Incendium.Result/Incendium.Result.csproj
new file mode 100644
index 0000000..22dc1b7
--- /dev/null
+++ b/Incendium.Result/Incendium.Result.csproj
@@ -0,0 +1,45 @@
+
+
+
+ netstandard2.1
+ preview
+ enable
+ $(SolutionName)
+
+
+
+ icon.png
+ result;noexcept
+ README.md
+ LICENSE.txt
+
+ git
+ https://github.com/matsakiv/Incendium
+
+ Incendium.Result
+ mativ
+ Provides a Result<T> type that allows a method to return both a value and an error in Rust style without exceptions
+ 1.0.0
+ Copyright © Igor Matsak
+
+
+
+
+ True
+ \
+
+
+ True
+ \
+
+
+ True
+ \
+
+
+
+
+
+
+
+
diff --git a/Incendium.Result/IsExternalInit.cs b/Incendium.Result/IsExternalInit.cs
new file mode 100644
index 0000000..11f062f
--- /dev/null
+++ b/Incendium.Result/IsExternalInit.cs
@@ -0,0 +1,4 @@
+namespace System.Runtime.CompilerServices
+{
+ internal static class IsExternalInit { }
+}
diff --git a/Incendium.Result/Result.cs b/Incendium.Result/Result.cs
new file mode 100644
index 0000000..debf13e
--- /dev/null
+++ b/Incendium.Result/Result.cs
@@ -0,0 +1,78 @@
+namespace Incendium
+{
+ ///
+ /// Represents result type that can contain a not null success value or error
+ ///
+ /// Type of value
+ public readonly struct Result
+ {
+ ///
+ /// Not null success value
+ ///
+ public T Value { get; init; }
+ ///
+ /// Error value
+ ///
+ public Error? Error { get; init; }
+
+ ///
+ /// Initialize result instance from success value
+ ///
+ /// Value if success
+ public static implicit operator Result(T value) => new() { Value = value };
+ ///
+ /// Initialize result instance from error value
+ ///
+ /// Error value
+ public static implicit operator Result(Error error) => new() { Error = error };
+ ///
+ /// Initialize result instance from nullable error value
+ ///
+ /// Nullable error value
+ public static implicit operator Result(Error? error) => new() { Error = error };
+
+ public void Deconstruct(out T value, out Error? error)
+ {
+ value = Value;
+ error = Error;
+ }
+ }
+
+ ///
+ /// Represents result type that can contain a nullable success value or error
+ ///
+ ///
+ public readonly struct NullableResult
+ {
+ ///
+ /// Not null success value
+ ///
+ public T? Value { get; init; }
+ ///
+ /// Error value
+ ///
+ public Error? Error { get; init; }
+
+ ///
+ /// Initialize result instance from success value
+ ///
+ /// Value if success
+ public static implicit operator NullableResult(T value) => new() { Value = value };
+ ///
+ /// Initialize result instance from error value
+ ///
+ /// Error value
+ public static implicit operator NullableResult(Error error) => new() { Error = error };
+ ///
+ /// Initialize result instance from nullable error value
+ ///
+ /// Nullable error value
+ public static implicit operator NullableResult(Error? error) => new() { Error = error };
+
+ public void Deconstruct(out T? value, out Error? error)
+ {
+ value = Value;
+ error = Error;
+ }
+ }
+}
diff --git a/Incendium.RetryPolicy/Abstract/IRateGate.cs b/Incendium.RetryPolicy/Abstract/IRateGate.cs
new file mode 100644
index 0000000..866e34d
--- /dev/null
+++ b/Incendium.RetryPolicy/Abstract/IRateGate.cs
@@ -0,0 +1,30 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Incendium.RetryPolicy.Abstract
+{
+ public interface IRateGate : IDisposable
+ {
+ ///
+ /// Asynchronously waits to proceed execution
+ ///
+ /// A cancellation token to cancel operation
+ /// The task object representing the asynchronous operation
+ Task WaitToProceedAsync(CancellationToken cancellationToken = default);
+ ///
+ /// Asynchronously waits to proceed execution during
+ ///
+ /// Timeout in milliseconds
+ /// A cancellation token to cancel operation
+ /// The task object representing the asynchronous operation
+ Task WaitToProceedAsync(int millisecondsTimeout, CancellationToken cancellationToken = default);
+ ///
+ /// Asynchronously waits to proceed execution during
+ ///
+ /// Timeout
+ /// A cancellation token to cancel operation
+ /// The task object representing the asynchronous operation
+ Task WaitToProceedAsync(TimeSpan timeout, CancellationToken cancellationToken = default);
+ }
+}
\ No newline at end of file
diff --git a/Incendium.RetryPolicy/Common/ConcurrentRandom.cs b/Incendium.RetryPolicy/Common/ConcurrentRandom.cs
new file mode 100644
index 0000000..d4c3a6c
--- /dev/null
+++ b/Incendium.RetryPolicy/Common/ConcurrentRandom.cs
@@ -0,0 +1,21 @@
+using System;
+
+namespace Incendium.RetryPolicy.Common
+{
+ internal sealed class ConcurrentRandom(int? seed = null)
+ {
+ private static readonly Random _static_random = new();
+
+ private readonly Random _random = !seed.HasValue
+ ? _static_random
+ : new Random(seed.Value);
+
+ public double NextDouble()
+ {
+ lock (_random)
+ {
+ return _random.NextDouble();
+ }
+ }
+ }
+}
diff --git a/Incendium.RetryPolicy/Delays.cs b/Incendium.RetryPolicy/Delays.cs
new file mode 100644
index 0000000..805e0a1
--- /dev/null
+++ b/Incendium.RetryPolicy/Delays.cs
@@ -0,0 +1,117 @@
+using System;
+using System.Collections.Generic;
+using Incendium.RetryPolicy.Common;
+
+namespace Incendium.RetryPolicy
+{
+ public static class Delays
+ {
+ ///
+ /// Gets a set of constant delays which are equal to
+ ///
+ /// For example, calling with count equal to 3 will create an enumeration like [delay, delay, delay]
+ /// Delay
+ /// Number of delays
+ /// Enumeration containing delays
+ ///
+ public static IEnumerable Constant(TimeSpan delay, int count)
+ {
+ if (delay < TimeSpan.Zero)
+ throw new ArgumentOutOfRangeException(nameof(delay), delay, "Should be >= 0ms");
+
+ if (count < 0)
+ throw new ArgumentOutOfRangeException(nameof(count), count, "Should be >= 0");
+
+ if (count == 0)
+ yield break;
+
+ for (var i = 0; i < count; i++)
+ yield return delay;
+ }
+
+ ///
+ /// Gets a set of exponential delays starting with and multiplying them by a
+ ///
+ /// For example, calling with count equal to 3 and factor 2 will create an enumeration like [firstDelay, firstDelay*2, firstDelay*4]
+ /// First delay
+ /// Number of delays
+ /// Factor, default is 2
+ /// Enumeration containing delays
+ ///
+ public static IEnumerable Exponential(TimeSpan firstDelay, int count, double factor = 2)
+ {
+ if (firstDelay < TimeSpan.Zero)
+ throw new ArgumentOutOfRangeException(nameof(firstDelay), firstDelay, "Should be >= 0ms");
+
+ if (count < 0)
+ throw new ArgumentOutOfRangeException(nameof(count), count, "Should be >= 0");
+
+ if (factor <= 0)
+ throw new ArgumentOutOfRangeException(nameof(factor), factor, "Should be > 0");
+
+ if (count == 0)
+ yield break;
+
+ for (var i = 0; i < count; i++)
+ {
+ yield return firstDelay;
+
+ firstDelay *= factor;
+ }
+ }
+
+ ///
+ /// Gets a set of exponential delays with randomized deviation (jitter) to prevent peak loads
+ ///
+ /// Median first delay
+ /// Number of delays
+ /// Seed for additional jitter randomization
+ /// Flag indicating whether the first delay should be set to zero (fast)
+ /// Enumeration containing delays
+ ///
+ public static IEnumerable DecorrelatedJitterBackoffV2(
+ TimeSpan medianFirstDelay,
+ int count,
+ int? seed = null,
+ bool fastFirst = false)
+ {
+ if (medianFirstDelay < TimeSpan.Zero)
+ throw new ArgumentOutOfRangeException(nameof(medianFirstDelay), medianFirstDelay, "Should be >= 0ms");
+
+ if (count < 0)
+ throw new ArgumentOutOfRangeException(nameof(count), count, "Should be >= 0");
+
+ if (count == 0)
+ return [];
+
+ return Enumerate(medianFirstDelay, count, fastFirst, new ConcurrentRandom(seed));
+
+ static IEnumerable Enumerate(TimeSpan scaleFirstTry, int maxRetries, bool fast, ConcurrentRandom random)
+ {
+ var maxValue = TimeSpan.MaxValue;
+ var maxTimeSpanDouble = maxValue.Ticks - 1000.0;
+ int i = 0;
+
+ if (fast)
+ {
+ i++;
+ yield return TimeSpan.Zero;
+ }
+
+ var targetTicksFirstDelay = scaleFirstTry.Ticks;
+ var num = 0.0;
+
+ for (; i < maxRetries; i++)
+ {
+ var num2 = i + random.NextDouble();
+ var next = Math.Pow(2.0, num2) * Math.Tanh(Math.Sqrt(4.0 * num2));
+ var num3 = next - num;
+
+ yield return TimeSpan.FromTicks((long)Math.Min(num3 * 0.7142857142857143 * targetTicksFirstDelay, maxTimeSpanDouble));
+
+ num = next;
+ }
+ }
+ }
+ }
+}
diff --git a/Incendium.RetryPolicy/Incendium.RetryPolicy.csproj b/Incendium.RetryPolicy/Incendium.RetryPolicy.csproj
new file mode 100644
index 0000000..4321985
--- /dev/null
+++ b/Incendium.RetryPolicy/Incendium.RetryPolicy.csproj
@@ -0,0 +1,40 @@
+
+
+
+ netstandard2.1
+ preview
+ enable
+
+
+
+ icon.png
+ LICENSE.txt
+ README.md
+ retry;retrypolicy;rate;ratelimit
+
+ git
+ https://github.com/matsakiv/Incendium
+
+ Incendium.RetryPolicy
+ mativ
+ Provides classes for easily managing requests rate limits and retrying after errors
+ 1.0.0
+ Copyright © Igor Matsak
+
+
+
+
+ True
+ \
+
+
+ True
+ \
+
+
+ True
+ \
+
+
+
+
diff --git a/Incendium.RetryPolicy/IsExternalInit.cs b/Incendium.RetryPolicy/IsExternalInit.cs
new file mode 100644
index 0000000..11f062f
--- /dev/null
+++ b/Incendium.RetryPolicy/IsExternalInit.cs
@@ -0,0 +1,4 @@
+namespace System.Runtime.CompilerServices
+{
+ internal static class IsExternalInit { }
+}
diff --git a/Incendium.RetryPolicy/RateGate.cs b/Incendium.RetryPolicy/RateGate.cs
new file mode 100644
index 0000000..6e64db7
--- /dev/null
+++ b/Incendium.RetryPolicy/RateGate.cs
@@ -0,0 +1,150 @@
+using System;
+using System.Collections.Concurrent;
+using System.Threading;
+using System.Threading.Tasks;
+using Incendium.RetryPolicy.Abstract;
+
+namespace Incendium.RetryPolicy
+{
+ ///
+ /// Represents a class that controls the number of requests in a given time unit
+ ///
+ public class RateGate : IDisposable, IRateGate
+ {
+ private readonly SemaphoreSlim _semaphore;
+ private readonly ConcurrentQueue _exitTimes;
+ private readonly Timer _exitTimer;
+ private bool _isDisposed;
+
+ ///
+ /// Number of requests per time unit
+ ///
+ public int Occurrences { get; private set; }
+ ///
+ /// Time unit in milliseconds
+ ///
+ public int TimeUnitMilliseconds { get; private set; }
+
+ ///
+ /// Initialize a new instance of the RateGate with the number of requests and time unit
+ ///
+ /// Number of requests per time unit
+ /// Time unit
+ ///
+ public RateGate(int occurrences, TimeSpan timeUnit)
+ {
+ if (occurrences <= 0)
+ throw new ArgumentOutOfRangeException(nameof(occurrences), "Number of occurrences must be a positive integer");
+ if (timeUnit != timeUnit.Duration())
+ throw new ArgumentOutOfRangeException(nameof(timeUnit), "Time unit must be a positive span of time");
+ if (timeUnit >= TimeSpan.FromMilliseconds(uint.MaxValue))
+ throw new ArgumentOutOfRangeException(nameof(timeUnit), "Time unit must be less than 2^32 milliseconds");
+
+ Occurrences = occurrences;
+ TimeUnitMilliseconds = (int)timeUnit.TotalMilliseconds;
+
+ _semaphore = new SemaphoreSlim(Occurrences, Occurrences);
+ _exitTimes = new ConcurrentQueue();
+ _exitTimer = new Timer(ExitTimerCallback, null, TimeUnitMilliseconds, -1);
+ }
+
+ private void ExitTimerCallback(object? state)
+ {
+ try
+ {
+ var exitTimeValid = _exitTimes.TryPeek(out int exitTime);
+
+ while (exitTimeValid)
+ {
+ if (unchecked(exitTime - Environment.TickCount) > 0)
+ break;
+
+ _semaphore.Release();
+ _exitTimes.TryDequeue(out exitTime);
+
+ exitTimeValid = _exitTimes.TryPeek(out exitTime);
+ }
+
+ var timeUntilNextCheck = exitTimeValid
+ ? Math.Min(TimeUnitMilliseconds, Math.Max(0, exitTime - Environment.TickCount))
+ : TimeUnitMilliseconds;
+
+ _exitTimer.Change(timeUntilNextCheck, -1);
+ }
+ catch (Exception)
+ {
+ // can throw if called when disposing
+ }
+ }
+
+ ///
+ ///
+ ///
+ ///
+ public async Task WaitToProceedAsync(
+ int millisecondsTimeout,
+ CancellationToken cancellationToken = default)
+ {
+ if (millisecondsTimeout < -1)
+ throw new ArgumentOutOfRangeException(nameof(millisecondsTimeout));
+
+ CheckDisposed();
+
+ var entered = await _semaphore.WaitAsync(millisecondsTimeout, cancellationToken);
+
+ if (entered)
+ {
+ var timeToExit = unchecked(Environment.TickCount + TimeUnitMilliseconds);
+ _exitTimes.Enqueue(timeToExit);
+ }
+
+ return entered;
+ }
+
+ ///
+ ///
+ ///
+ ///
+ public Task WaitToProceedAsync(
+ TimeSpan timeout,
+ CancellationToken cancellationToken = default)
+ {
+ return WaitToProceedAsync((int)timeout.TotalMilliseconds, cancellationToken);
+ }
+
+ ///
+ ///
+ ///
+ ///
+ public async Task WaitToProceedAsync(CancellationToken cancellationToken = default)
+ {
+ await WaitToProceedAsync(Timeout.Infinite, cancellationToken);
+ }
+
+ private void CheckDisposed()
+ {
+ if (_isDisposed)
+ throw new ObjectDisposedException("RateGate is already disposed");
+ }
+
+ public void Dispose()
+ {
+ Dispose(true);
+ GC.SuppressFinalize(this);
+ }
+
+ protected virtual void Dispose(bool isDisposing)
+ {
+ if (!_isDisposed)
+ {
+ if (isDisposing)
+ {
+ _semaphore.Dispose();
+ _exitTimer.Dispose();
+
+ _isDisposed = true;
+ }
+ }
+ }
+ }
+}
diff --git a/Incendium.RetryPolicy/RetryHttpClientHandler.cs b/Incendium.RetryPolicy/RetryHttpClientHandler.cs
new file mode 100644
index 0000000..063d6a6
--- /dev/null
+++ b/Incendium.RetryPolicy/RetryHttpClientHandler.cs
@@ -0,0 +1,146 @@
+using Incendium.RetryPolicy.Abstract;
+using System;
+using System.Collections.Generic;
+using System.Net;
+using System.Net.Http;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Incendium.RetryPolicy
+{
+ ///
+ /// Represents HTTP client handler which allows you to resend requests in case of errors and control the number of requests sent per unit of time
+ ///
+ /// Inner HTTP message handler used to send requests
+ public class RetryHttpClientHandler(HttpMessageHandler httpMessageHandler)
+ : DelegatingHandler(httpMessageHandler)
+ {
+ private bool _isDisposed;
+ private IRateGate? _rateGate;
+
+ ///
+ /// Retry count
+ ///
+ public int RetryCount { get; init; }
+ ///
+ /// Flag indicating whether the request should be resent in case of an HttpRequestException error
+ ///
+ public bool RetryOnHttpRequestException { get; init; }
+ ///
+ /// Delay for first retry attempt
+ ///
+ public TimeSpan FirstRetryDelay { get; init; }
+ ///
+ /// An object that controls the number of requests per unit of time. If equal to null, no control is performed
+ ///
+ public IRateGate? RateGate { get => _rateGate; init => _rateGate = value; }
+ ///
+ /// A custom factory used to get a set of delays. By default Delays.DecorrelatedJitterBackoffV2 is used
+ ///
+ public Func>? RetryDelaysFactory { get; init; }
+
+ protected override async Task SendAsync(
+ HttpRequestMessage request,
+ CancellationToken cancellationToken)
+ {
+ IEnumerator? delays = null;
+ var retryCount = RetryCount;
+
+ while (true)
+ {
+ try
+ {
+ if (_rateGate != null)
+ await _rateGate.WaitToProceedAsync(cancellationToken);
+
+ var response = await base.SendAsync(request, cancellationToken);
+
+ if (!response.IsSuccessStatusCode &&
+ retryCount > 0 &&
+ (IsServerError(response.StatusCode) ||
+ IsRequestTimeoutError(response.StatusCode) ||
+ IsTooManyRequestsError(response.StatusCode)))
+ {
+ delays ??= GetRetryDelays().GetEnumerator();
+
+ if (delays.MoveNext())
+ {
+ var delay = delays.Current;
+
+ retryCount--;
+
+ await Task.Delay(delay, cancellationToken);
+
+ continue;
+ }
+ }
+
+ return response;
+ }
+ catch (HttpRequestException)
+ {
+ if (!RetryOnHttpRequestException)
+ throw;
+
+ delays ??= GetRetryDelays().GetEnumerator();
+
+ if (retryCount > 0 && delays.MoveNext())
+ {
+ var delay = delays.Current;
+
+ retryCount--;
+
+ await Task.Delay(delay, cancellationToken);
+
+ continue;
+ }
+
+ throw;
+ }
+ }
+ }
+
+ private IEnumerable GetRetryDelays() => RetryDelaysFactory?.Invoke() ??
+ Delays.DecorrelatedJitterBackoffV2(FirstRetryDelay, RetryCount);
+
+ ///
+ /// Check if HTTP status code represents server error (5xx)
+ ///
+ /// HTTP status code
+ /// true if code represents server error, otherwise false
+ public static bool IsServerError(HttpStatusCode code) =>
+ code >= HttpStatusCode.InternalServerError && (int)code < 600;
+
+ ///
+ /// Check if HTTP status code represents request timeout error (408)
+ ///
+ /// HTTP status code
+ /// true if code represents request timeout error, otherwise false
+ public static bool IsRequestTimeoutError(HttpStatusCode code) =>
+ code == HttpStatusCode.RequestTimeout;
+
+ ///
+ /// Check if HTTP status code represents too many requests (429)
+ ///
+ /// HTTP status code
+ /// true if code represents too many request error, otherwise false
+ public static bool IsTooManyRequestsError(HttpStatusCode code) =>
+ code == HttpStatusCode.TooManyRequests;
+
+ protected override void Dispose(bool disposing)
+ {
+ if (!_isDisposed)
+ {
+ if (disposing)
+ {
+ _rateGate?.Dispose();
+ _rateGate = null;
+ }
+
+ _isDisposed = true;
+ }
+
+ base.Dispose(disposing);
+ }
+ }
+}
diff --git a/Incendium.Tests/Incendium.Tests.csproj b/Incendium.Tests/Incendium.Tests.csproj
new file mode 100644
index 0000000..9a99cc5
--- /dev/null
+++ b/Incendium.Tests/Incendium.Tests.csproj
@@ -0,0 +1,29 @@
+
+
+
+ net8.0
+ enable
+ enable
+
+ false
+ true
+ $(SolutionName)
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
diff --git a/Incendium.Tests/Result/ResultsTests.cs b/Incendium.Tests/Result/ResultsTests.cs
new file mode 100644
index 0000000..b7773a8
--- /dev/null
+++ b/Incendium.Tests/Result/ResultsTests.cs
@@ -0,0 +1,81 @@
+using Incendium.Extensions;
+
+namespace Incendium.Result
+{
+ public class ResultsTests
+ {
+ private record TestObject(int IntField, string? StringField);
+
+ [Fact]
+ public void Test_Result_DeconstructWhenSuccess()
+ {
+ // act
+ var (result, error) = GetResult(withError: false);
+
+ // asserts
+ Assert.Equal(12, result.IntField);
+ Assert.Equal("Test", result.StringField);
+ Assert.NotNull(result);
+ Assert.Null(error);
+ }
+
+ [Fact]
+ public void Test_Result_DeconstructWhenError()
+ {
+ // act
+ var (result, error) = GetResult(withError: true);
+
+ // asserts
+ Assert.Null(result);
+ Assert.NotNull(error);
+ Assert.Equal(100, error.Value.Code);
+ Assert.Equal("Error", error.Value.Message);
+ Assert.Equal(100, error.Code());
+ Assert.Equal("Error", error.Message());
+ }
+
+ [Fact]
+ public void Test_NullableResult_DeconstructWhenSuccess()
+ {
+ // act
+ var (result, error) = GetNullableResult(withError: false);
+
+ // asserts
+ Assert.Equal(12, result!.IntField);
+ Assert.Equal("Test", result.StringField);
+ Assert.NotNull(result);
+ Assert.Null(error);
+ }
+
+ [Fact]
+ public void Test_NullableResult_DeconstructWhenError()
+ {
+ // act
+ var (result, error) = GetNullableResult(withError: true);
+
+ // asserts
+ Assert.Null(result);
+ Assert.NotNull(error);
+ Assert.Equal(100, error.Value.Code);
+ Assert.Equal("Error", error.Value.Message);
+ Assert.Equal(100, error.Code());
+ Assert.Equal("Error", error.Message());
+ }
+
+ private static Result GetResult(bool withError)
+ {
+ if (withError)
+ return new Error(code: 100, message: "Error");
+
+ return new TestObject(12, "Test");
+ }
+
+ private static NullableResult GetNullableResult(bool withError)
+ {
+ if (withError)
+ return new Error(code: 100, message: "Error");
+
+ return new TestObject(12, "Test");
+ }
+ }
+}
diff --git a/Incendium.Tests/RetryPolicy/RateGateTests.cs b/Incendium.Tests/RetryPolicy/RateGateTests.cs
new file mode 100644
index 0000000..8d18251
--- /dev/null
+++ b/Incendium.Tests/RetryPolicy/RateGateTests.cs
@@ -0,0 +1,31 @@
+using System.Diagnostics;
+
+namespace Incendium.RetryPolicy
+{
+ public class RateGateTests
+ {
+ [Fact]
+ public async Task Test_RateGate_LimitRequestsByOneThread()
+ {
+ // arrange
+ const int callsPerTimeUnit = 5;
+ const int callsCount = 15;
+
+ var timeUnit = TimeSpan.FromSeconds(1);
+ var expectedDuration = timeUnit * (callsCount - callsPerTimeUnit) / callsPerTimeUnit;
+
+ var rateGate = new RateGate(occurrences: callsPerTimeUnit, timeUnit);
+
+ var stopWatch = Stopwatch.StartNew();
+
+ // act
+ for (var i = 0; i < callsCount; ++i)
+ await rateGate.WaitToProceedAsync();
+
+ stopWatch.Stop();
+
+ // asserts
+ Assert.True(stopWatch.Elapsed >= expectedDuration);
+ }
+ }
+}
diff --git a/Incendium.Tests/RetryPolicy/RetryHttpClientHandlerTests.cs b/Incendium.Tests/RetryPolicy/RetryHttpClientHandlerTests.cs
new file mode 100644
index 0000000..a846e05
--- /dev/null
+++ b/Incendium.Tests/RetryPolicy/RetryHttpClientHandlerTests.cs
@@ -0,0 +1,236 @@
+using System.Diagnostics;
+using System.Net;
+
+namespace Incendium.RetryPolicy
+{
+ public class RetryHttpClientHandlerTests
+ {
+ private class MockHttpClientHandler : HttpMessageHandler
+ {
+ public const string MESSAGE = "Test HttpRequestException";
+ public int SendCallCount { get; private set; }
+
+ private readonly HttpStatusCode _responseCode;
+ private readonly bool _throwHttpRequestException;
+
+ public MockHttpClientHandler(bool throwHttpRequestException)
+ {
+ _throwHttpRequestException = throwHttpRequestException;
+ }
+
+ public MockHttpClientHandler(HttpStatusCode responseCode)
+ {
+ _responseCode = responseCode;
+ }
+
+ protected override Task SendAsync(
+ HttpRequestMessage request,
+ CancellationToken cancellationToken)
+ {
+ SendCallCount++;
+
+ if (_throwHttpRequestException)
+ throw new HttpRequestException(MESSAGE);
+
+ return Task.FromResult(new HttpResponseMessage(_responseCode));
+ }
+ }
+
+ [Fact]
+ public async Task Test_RetryHttpClientHandler_RetryOnHttpException()
+ {
+ // arrange
+ var retryCount = 3;
+ var mockHttpClientHandler = new MockHttpClientHandler(throwHttpRequestException: true);
+ var retryHttpClientHandler = new RetryHttpClientHandler(mockHttpClientHandler)
+ {
+ RetryCount = retryCount,
+ RetryOnHttpRequestException = true,
+ FirstRetryDelay = TimeSpan.FromMilliseconds(100)
+ };
+ var httpClient = new HttpClient(retryHttpClientHandler);
+ var httpRequestMessage = new HttpRequestMessage(HttpMethod.Get, "http://localhost");
+ HttpRequestException? exception = null;
+
+ // act
+ try
+ {
+ await httpClient.SendAsync(httpRequestMessage);
+ }
+ catch (HttpRequestException e)
+ {
+ exception = e;
+ }
+
+ // asserts
+ Assert.Equal(retryCount, mockHttpClientHandler.SendCallCount - 1);
+ Assert.NotNull(exception);
+ Assert.Equal(MockHttpClientHandler.MESSAGE, exception.Message);
+ }
+
+ [Fact]
+ public async Task Test_RetryHttpClientHandler_RetryOnServerError()
+ {
+ // arrange
+ var retryCount = 3;
+ var mockHttpClientHandler = new MockHttpClientHandler(HttpStatusCode.InternalServerError);
+ var retryHttpClientHandler = new RetryHttpClientHandler(mockHttpClientHandler)
+ {
+ RetryCount = retryCount,
+ RetryOnHttpRequestException = true,
+ FirstRetryDelay = TimeSpan.FromMilliseconds(100)
+ };
+ var httpClient = new HttpClient(retryHttpClientHandler);
+ var httpRequestMessage = new HttpRequestMessage(HttpMethod.Get, "http://localhost");
+
+ // act
+ var response = await httpClient.SendAsync(httpRequestMessage);
+
+ // asserts
+ Assert.Equal(retryCount, mockHttpClientHandler.SendCallCount - 1);
+ Assert.NotNull(response);
+ Assert.Equal(HttpStatusCode.InternalServerError, response.StatusCode);
+ }
+
+ [Fact]
+ public async Task Test_RetryHttpClientHandler_RetryOnRequestTimeoutError()
+ {
+ // arrange
+ var retryCount = 3;
+ var mockHttpClientHandler = new MockHttpClientHandler(HttpStatusCode.RequestTimeout);
+ var retryHttpClientHandler = new RetryHttpClientHandler(mockHttpClientHandler)
+ {
+ RetryCount = retryCount,
+ RetryOnHttpRequestException = true,
+ FirstRetryDelay = TimeSpan.FromMilliseconds(100)
+ };
+ var httpClient = new HttpClient(retryHttpClientHandler);
+ var httpRequestMessage = new HttpRequestMessage(HttpMethod.Get, "http://localhost");
+
+ // act
+ var response = await httpClient.SendAsync(httpRequestMessage);
+
+ // asserts
+ Assert.Equal(retryCount, mockHttpClientHandler.SendCallCount - 1);
+ Assert.NotNull(response);
+ Assert.Equal(HttpStatusCode.RequestTimeout, response.StatusCode);
+ }
+
+ [Fact]
+ public async Task Test_RetryHttpClientHandler_RetryOnTooManyRequestsError()
+ {
+ // arrange
+ var retryCount = 3;
+ var mockHttpClientHandler = new MockHttpClientHandler(HttpStatusCode.TooManyRequests);
+ var retryHttpClientHandler = new RetryHttpClientHandler(mockHttpClientHandler)
+ {
+ RetryCount = retryCount,
+ RetryOnHttpRequestException = true,
+ FirstRetryDelay = TimeSpan.FromMilliseconds(100)
+ };
+ var httpClient = new HttpClient(retryHttpClientHandler);
+ var httpRequestMessage = new HttpRequestMessage(HttpMethod.Get, "http://localhost");
+
+ // act
+ var response = await httpClient.SendAsync(httpRequestMessage);
+
+ // asserts
+ Assert.Equal(retryCount, mockHttpClientHandler.SendCallCount - 1);
+ Assert.NotNull(response);
+ Assert.Equal(HttpStatusCode.TooManyRequests, response.StatusCode);
+ }
+
+ [Fact]
+ public async Task Test_RetryHttpClientHandler_NoRetryOnBadRequestError()
+ {
+ // arrange
+ var retryCount = 3;
+ var mockHttpClientHandler = new MockHttpClientHandler(HttpStatusCode.BadRequest);
+ var retryHttpClientHandler = new RetryHttpClientHandler(mockHttpClientHandler)
+ {
+ RetryCount = retryCount,
+ RetryOnHttpRequestException = true,
+ FirstRetryDelay = TimeSpan.FromMilliseconds(100)
+ };
+ var httpClient = new HttpClient(retryHttpClientHandler);
+ var httpRequestMessage = new HttpRequestMessage(HttpMethod.Get, "http://localhost");
+
+ // act
+ var response = await httpClient.SendAsync(httpRequestMessage);
+
+ // asserts
+ Assert.Equal(1, mockHttpClientHandler.SendCallCount);
+ Assert.NotNull(response);
+ Assert.Equal(HttpStatusCode.BadRequest, response.StatusCode);
+ }
+
+ [Fact]
+ public async Task Test_RetryHttpClientHandler_NoRetryOnSuccess()
+ {
+ // arrange
+ var retryCount = 3;
+ var mockHttpClientHandler = new MockHttpClientHandler(HttpStatusCode.OK);
+ var retryHttpClientHandler = new RetryHttpClientHandler(mockHttpClientHandler)
+ {
+ RetryCount = retryCount,
+ RetryOnHttpRequestException = true,
+ FirstRetryDelay = TimeSpan.FromMilliseconds(100)
+ };
+ var httpClient = new HttpClient(retryHttpClientHandler);
+ var httpRequestMessage = new HttpRequestMessage(HttpMethod.Get, "http://localhost");
+
+ // act
+ var response = await httpClient.SendAsync(httpRequestMessage);
+
+ // asserts
+ Assert.Equal(1, mockHttpClientHandler.SendCallCount);
+ Assert.NotNull(response);
+ Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+ }
+
+ [Fact]
+ public async Task Test_RetryHttpClientHandler_RateLimit()
+ {
+ // arrange
+ var rateLimit = 5;
+ var rateLimitPeriod = TimeSpan.FromSeconds(1);
+ var retryCount = 3;
+ var totalRequests = 15;
+ var expectedDuration = rateLimitPeriod * (totalRequests - rateLimit) / rateLimit;
+
+ var mockHttpClientHandler = new MockHttpClientHandler(HttpStatusCode.OK);
+ var retryHttpClientHandler = new RetryHttpClientHandler(mockHttpClientHandler)
+ {
+ RetryCount = retryCount,
+ RetryOnHttpRequestException = true,
+ FirstRetryDelay = TimeSpan.FromMilliseconds(100),
+ RateGate = new RateGate(
+ occurrences: rateLimit,
+ timeUnit: rateLimitPeriod)
+ };
+ var httpClient = new HttpClient(retryHttpClientHandler);
+
+ var responses = new HttpResponseMessage[totalRequests];
+ var stopWatch = Stopwatch.StartNew();
+
+ // act
+ for (var i = 0; i < totalRequests; ++i)
+ {
+ var httpRequestMessage = new HttpRequestMessage(HttpMethod.Get, "http://localhost");
+ responses[i] = await httpClient.SendAsync(httpRequestMessage);
+ }
+
+ stopWatch.Stop();
+
+ // asserts
+ Assert.Equal(totalRequests, mockHttpClientHandler.SendCallCount);
+ Assert.True(stopWatch.Elapsed >= expectedDuration);
+
+ foreach (var response in responses)
+ {
+ Assert.NotNull(response);
+ Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+ }
+ }
+ }
+}
diff --git a/Incendium.sln b/Incendium.sln
new file mode 100644
index 0000000..55eb4a7
--- /dev/null
+++ b/Incendium.sln
@@ -0,0 +1,37 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.9.34607.119
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Incendium.Result", "Incendium.Result\Incendium.Result.csproj", "{57B0A352-4FE6-4ECC-87C1-066966429B90}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Incendium.Tests", "Incendium.Tests\Incendium.Tests.csproj", "{53D9492E-9EE9-48F7-9CB9-642AAB2E8D1D}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Incendium.RetryPolicy", "Incendium.RetryPolicy\Incendium.RetryPolicy.csproj", "{9B2DCBEC-61F3-4484-9426-98E280FCF7DB}"
+EndProject
+Global
+ GlobalSection(SolutionConfigurationPlatforms) = preSolution
+ Debug|Any CPU = Debug|Any CPU
+ Release|Any CPU = Release|Any CPU
+ EndGlobalSection
+ GlobalSection(ProjectConfigurationPlatforms) = postSolution
+ {57B0A352-4FE6-4ECC-87C1-066966429B90}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+ {57B0A352-4FE6-4ECC-87C1-066966429B90}.Debug|Any CPU.Build.0 = Debug|Any CPU
+ {57B0A352-4FE6-4ECC-87C1-066966429B90}.Release|Any CPU.ActiveCfg = Release|Any CPU
+ {57B0A352-4FE6-4ECC-87C1-066966429B90}.Release|Any CPU.Build.0 = Release|Any CPU
+ {53D9492E-9EE9-48F7-9CB9-642AAB2E8D1D}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+ {53D9492E-9EE9-48F7-9CB9-642AAB2E8D1D}.Debug|Any CPU.Build.0 = Debug|Any CPU
+ {53D9492E-9EE9-48F7-9CB9-642AAB2E8D1D}.Release|Any CPU.ActiveCfg = Release|Any CPU
+ {53D9492E-9EE9-48F7-9CB9-642AAB2E8D1D}.Release|Any CPU.Build.0 = Release|Any CPU
+ {9B2DCBEC-61F3-4484-9426-98E280FCF7DB}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+ {9B2DCBEC-61F3-4484-9426-98E280FCF7DB}.Debug|Any CPU.Build.0 = Debug|Any CPU
+ {9B2DCBEC-61F3-4484-9426-98E280FCF7DB}.Release|Any CPU.ActiveCfg = Release|Any CPU
+ {9B2DCBEC-61F3-4484-9426-98E280FCF7DB}.Release|Any CPU.Build.0 = Release|Any CPU
+ EndGlobalSection
+ GlobalSection(SolutionProperties) = preSolution
+ HideSolutionNode = FALSE
+ EndGlobalSection
+ GlobalSection(ExtensibilityGlobals) = postSolution
+ SolutionGuid = {41448C2A-C2BA-400E-BD92-BAC6E3A50BF8}
+ EndGlobalSection
+EndGlobal
diff --git a/LICENSE.txt b/LICENSE.txt
new file mode 100644
index 0000000..6ba5eae
--- /dev/null
+++ b/LICENSE.txt
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) Igor Matsak
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..b3226c8
--- /dev/null
+++ b/README.md
@@ -0,0 +1,94 @@
+# Incendium
+[![License: MIT](https://img.shields.io/github/license/matsakiv/incendium)](https://opensource.org/licenses/MIT)
+Incendium.Result
+![NuGet Version](https://img.shields.io/nuget/v/Incendium.Result)![NuGet Downloads](https://img.shields.io/nuget/dt/Incendium.Result)
+Incendium.RetryPolicy
+![NuGet Version](https://img.shields.io/nuget/v/Incendium.RetryPolicy)![NuGet Downloads](https://img.shields.io/nuget/dt/Incendium.RetryPolicy)
+
+Incendium is a small set of useful cross-platform .NET standard 2.1 libraries for .NET developers.
+
+| Package | Description |
+| --------- | ----------- |
+| Incendium.Result | Contains `Error`, `Result` and `NullableResult` types which allows to return a success value or an error (something vaguely similar to the Rust style) |
+| Incendium.RetryPolicy | Provides `RetryHttpClientHandler` to easily retry HTTP requests in case of errors, as well as `RateGate` to control rate limiting |
+
+## Getting started
+
+### Installation
+
+`PM> Install-Package Incendium.Result`
+
+`PM> Install-Package Incendium.RetryPolicy`
+
+### Result and NullableResult
+
+The method can be synchronous or asynchronous and can return a value without explicitly creating a `Result` type:
+
+```cs
+public async Result GetStringAsync() {
+ // ...
+ if (condition1) {
+ return "Test string result";
+ } else {
+ return new Error(code: 123, message: "Test error");
+ }
+
+ try {
+ // ...
+ } catch (Exception e) {
+ return new Error(code: 321, message: "Test error", exception: e);
+ }
+}
+```
+Then processing the result might look like this:
+
+```cs
+var (str, error) = await GetStringAsync();
+
+if (error != null) {
+ log.LogError(
+ error.Exception(),
+ "Error with code {@code} and message {@message}",
+ error.Code(),
+ error.Message());
+}
+```
+### RetryHttpClientHandler
+
+Сan be used as a handler for `HttpClient` and allows you to easily (compared to Polly) set up repeated requests in the following cases:
+* `HttpNetworkException`
+* Server errors (`5xx`)
+* Request timeout error (`408`)
+* Too many requests (`429`)
+
+and also allows you to configure rate limiting with exponential delays for outgoing requests using `RateGate`:
+
+```cs
+var innerHttpClientHandler = new HttpClientHandler(); // can be easily mocked
+var retryHttpClientHandler = new RetryHttpClientHandler(innerHttpClientHandler)
+{
+ RetryCount = 5, // sets 5 retry attempts
+ RetryOnHttpRequestException = true, // sets the retry flag in case of an HttpRequestException
+ FirstRetryDelay = TimeSpan.FromMilliseconds(100), // sets the median starting delay between requests
+ RateGate = new RateGate(
+ occurrences: 10, // sets rate limit to 10 request per 60 seconds
+ timeUnit: TimeSpan.FromSeconds(60))
+}
+var httpClient = new HttpClient(retryHttpClientHandler);
+```
+
+There are several ready-made delay algorithms that can be used:
+* Constant
+* Exponential
+* DecorrelatedJitterBackoffV2 (default)
+
+```cs
+var retryHttpClientHandler = new RetryHttpClientHandler(innerHttpClientHandler)
+{
+ RetryDelaysFactory = () => Delays.Exponential(
+ firstDelay: TimeSpan.FromMilliseconds(100),
+ count: 10)
+}
+```
+
+You can also pass your own delay algorithm in the `RetryDelaysFactory` property, which should return `IEnumerable`.