Flow control patterns

Polly is a resilience and transient-fault-handling library for .NET applications. It provides a framework for defining and executing stability patterns that manage failures and resource exhaustion during operation execution. The library enables developers to compose complex resilience strategies through a fluent builder pattern, wrapping target operations in functional decorators. These policies intercept execution flow to apply automated recovery mechanisms, such as retries for temporary errors or circuit breakers that isolate unstable components by blocking requests. The framework supports

Tenacity is a Python retry library and fault tolerance framework designed to automatically re-execute failing functions based on custom conditions, wait intervals, and stop criteria. It provides a mechanism to apply retry logic to both synchronous functions and asynchronous coroutines. The library implements exponential backoff to increase delays between retries, helping to manage transient network failures and prevent the overloading of services. Its capabilities cover the definition of retry conditions based on exception types or return values, as well as the enforcement of duration limits

Resilience4j is a fault tolerance library for Java 8 applications designed to handle failures in distributed systems. It provides a comprehensive suite of resilience patterns including resource isolation, request throttling, retries, and timeouts. The project implements specific stability mechanisms such as circuit breakers to prevent cascading failures, bulkheads for system resource isolation, and rate limiters to cap execution rates. It also includes a retry framework with backoff policies and timeout enforcement to manage transient faults and maximum execution durations. Additional capabi

Failsafe is a JVM resilience library providing a collection of fault tolerance patterns for Java applications. It functions as an asynchronous execution wrapper that runs tasks in the background and returns futures to prevent thread blocking. The library allows for the composition of resilience policies, enabling multiple patterns to be stacked into a sequential pipeline. It includes specific implementations for circuit breaking to prevent system overload, rate limiting to control traffic flow, and a framework for managing retries and fallbacks. Capability areas cover traffic management thro

Sentinel is a microservice flow control framework designed for managing traffic limits, distributed circuit breaking, and adaptive overload protection. It serves as a traffic shaping component that defines resource boundaries to regulate request flow and ensure reliability across distributed systems. The project provides a real-time monitoring dashboard for tracking resource metrics and performance bottlenecks across service clusters. It includes a visual interface for the real-time management of flow control and circuit breaking rules, allowing parameters to be updated without restarting the

RxJava is a reactive stream processing framework and JVM reactive extensions library. It serves as an asynchronous dataflow orchestrator used to compose event-based programs by transforming, combining, and consuming real-time data flows on the Java Virtual Machine. The project distinguishes itself through integrated backpressure flow control, which manages the emission rate between producers and consumers to prevent memory exhaustion. It further provides mechanisms for concurrent thread management and parallel data processing to offload blocking operations and maintain application responsiven

Reactor Core is a reactive programming toolkit and non-blocking foundation for composing asynchronous data pipelines on the JVM. It serves as an asynchronous stream processing framework and a backpressure management system, allowing developers to transform, filter, and combine sequences of events while regulating data flow between producers and consumers to prevent resource exhaustion. The library differentiates itself through a sophisticated concurrency scheduling system and demand-based flow control. It decouples signal processing from specific threads using a scheduler registry and provide

Async is a JavaScript asynchronous flow library designed to manage the execution and coordination of asynchronous tasks in Node.js and the browser. It provides functional utilities to wrap, process, and orchestrate complex asynchronous workflows. The library distinguishes itself through a comprehensive task orchestrator that handles dependency graphs to resolve circular references and manages concurrent task queues. It includes a unification bridge that allows callback-style and promise-based functions to operate within the same execution interface. The project covers several primary capabil

Tokio is an asynchronous runtime for the Rust programming language, designed to manage and execute concurrent tasks efficiently. It provides a multi-threaded execution environment that schedules lightweight tasks across available processor cores, utilizing a work-stealing scheduler to balance computational load. By employing a poll-based execution model and waker-based notifications, the runtime drives asynchronous operations forward without requiring active polling loops, ensuring efficient resource utilization. The project distinguishes itself through a comprehensive suite of tools for high

RxGo is a functional reactive programming library and an implementation of ReactiveX for the Go language. It serves as an asynchronous stream processing toolkit designed to coordinate event-based programs and data flows using the observable pattern. The library enables the construction of asynchronous processing pipelines that transform, filter, and combine event sequences. It distinguishes itself through the use of functional operators to compose these pipelines and provides mechanisms for managing concurrent execution. The toolkit covers a broad range of stream orchestration capabilities,

BullMQ is a Redis-backed message queue library and background processor designed for distributed task queueing. It functions as a distributed queue manager and task scheduler, utilizing Redis to manage asynchronous job processing and persistence. The system distinguishes itself through its role as a job workflow orchestrator, enabling the definition of complex parent-child job dependencies and hierarchies for multi-step workflows. It provides sandboxed process execution to isolate heavy workloads and prevent event loop blocking, alongside distributed rate limiting to protect downstream servic

Inngest is a durable execution framework and event-driven automation engine designed to orchestrate background workflows. It enables developers to build resilient, stateful processes by memoizing function steps, ensuring that long-running tasks can automatically resume from the last successful operation after failures, timeouts, or infrastructure restarts. The platform distinguishes itself through its event-driven architecture, which uses a schema-validated bus to trigger functions and coordinate complex, multi-step logic. It employs an onion-model middleware approach for cross-cutting concer

RxSwift is a reactive programming library for Swift that provides a framework for managing push-based data flows and composing asynchronous, event-based programs. It utilizes observable sequences and functional operators to transform and filter asynchronous sequences through a declarative approach. The library is distinguished by its ability to link asynchronous data streams directly to user interface elements, automating view updates via reactive data binding. It includes specialized tools for tracking UI control properties and events on the main thread, as well as the ability to encapsulate

RxKotlin is a reactive programming library and asynchronous stream processor that provides Kotlin language extensions for composing event-based data streams. It serves as a set of Kotlin bindings for RxJava, allowing developers to transform, filter, and flatten sequences of data emitted over time. The library focuses on integrating RxJava patterns into Kotlin projects by applying language-specific conventions and idioms. It utilizes extension functions to simplify reactive programming patterns, reduce boilerplate, and optimize workflows within the reactive ecosystem. The toolkit covers a bro

RxPY is a functional reactive programming library and a ReactiveX observable library for Python. It serves as an asynchronous stream processor and event-driven coordination framework used to build data pipelines that react to changes in state or streams of events over time. The library provides a toolkit for composing asynchronous and event-based programs using observable sequences and operators. It distinguishes itself through the use of configurable schedulers to manage concurrency, timing, and subscription lifecycles. The project covers a wide range of stream processing capabilities, incl

Reactive extensions for PHP

Node-rate-limiter is a utility library for Node.js designed to throttle both incoming and outgoing traffic using configurable time intervals and token bucket limits. It protects server capacity and backend APIs by capping the number of requests an individual client can make within a specified time window, while also controlling the frequency of outbound API calls and web crawling tasks to avoid triggering remote rate limit violations. The library implements a token-bucket rate limiting algorithm with continuous replenishment, allowing administrators to configure specific burst and drip rates.

Retry-go is a utility library for Go that automates the re-execution of failing code blocks and operations until they succeed or exhaust configured attempt limits. It provides mechanisms for handling transient failures, capturing both computed results and final errors from repeatedly executed functions. The library supports configurable retry timing through fixed intervals, exponential backoff strategies, and randomized jitter to control recovery speed and prevent overwhelming recovering services. It also includes error filtering rules that trigger retries on specific error conditions while h

Spring Retry is a Java library that provides exception handling, automated operation reattempts, backoff strategies, and recovery mechanisms for application workflows. It handles transient operation failures through declarative annotations, programmatic templates, stateful context storage, and fallback recovery paths. The library controls retry behavior by specifying attempt counts, timeouts, and inclusion or exclusion rules for specific exception types. It pauses execution between attempts using fixed, exponential, or randomized backoff intervals, and caches retry state outside the call stac

Computational parallel flows on top of GenStage

Taskflow is a C++ task-parallel framework designed to build high-performance parallel workflows and complex dependency graphs. It provides a programming model that organizes computational work into directed acyclic graphs, enabling developers to manage concurrency, resource scheduling, and task dependencies across multi-core CPUs and GPU accelerators. The framework distinguishes itself through its ability to orchestrate heterogeneous systems, allowing for the integration of hardware-accelerated kernels and memory operations into unified execution pipelines. It supports dynamic runtime subflow