Apache Airflow is a workflow orchestration platform for authoring, scheduling, and monitoring data pipelines. The system uses a modular architecture with core components, extensible providers, a React/TypeScript web UI, and a FastAPI-based REST API. Key entry points include the CLI (`airflow` command), web server, scheduler, and triggerer. Data flows involve DAG parsing, task scheduling via executors, and state persistence in a metadata database. External dependencies include PostgreSQL/MySQL, Redis/RabbitMQ for Celery, and various provider-specific integrations. The codebase demonstrates strong engineering practices with version compatibility patterns, plugin systems, and well-structured API layers.
Flowcraft is a workflow orchestration framework for building, executing, and monitoring durable workflows. It provides a type-safe, composable API for defining workflows as directed graphs of nodes and edges, supporting both programmatic (fluent) and declarative (JSON) definitions. The framework enables progressive scaling from in-memory execution to distributed systems via adapters for message queues and cloud services, with built-in support for patterns like retries, timeouts, human-in-the-loop, batch processing, and subflows. Key architectural pieces include a dependency-free core runtime, a sophisticated context tracking system for efficient state persistence, a plugin-based adapter architecture for distributed execution, and LLM tooling for workflow introspection and control via natural language.
ngx-graph is an Angular library for rendering directed acyclic graphs (DAG) and other graph structures using SVG. It provides a standalone GraphComponent with signal-based inputs and outputs, supporting multiple built-in layout engines (Dagre, DagreCluster, DagreNodesOnly, D3 force-directed, Cola force-directed) and custom layouts via a Layout interface. The component handles viewport transformations (pan, zoom), node dragging, minimap, and rich layout morph animations between graph updates. The architecture centers on a flexible layout service pattern where each layout is a class implementing run/updateEdge/hooks, and the GraphComponent orchestrates layout calculations, SVG rendering, and interaction. The codebase demonstrates modern Angular practices (signals, standalone components, OnPush change detection) and includes comprehensive test coverage. It is maintained by Swimlane with regular releases and extensive documentation via Storybook.
pgflow is a PostgreSQL/Supabase-native workflow orchestration engine for defining and executing typed DAGs as background jobs. The system is split into six coordinated packages: a PL/pgSQL core (pkgs/core) that implements the complete workflow state machine in the database — flows, steps, runs, step states, tasks, retries with exponential backoff, map/reduce fan-out, conditional step execution, skip-cascade propagation, and realtime event broadcasting — plus a type-safe TypeScript DSL (pkgs/dsl) for declaring flows with compile-time-enforced inputs/outputs, a Deno/edge worker runtime (pkgs/edge-worker) that consumes PGMQ messages and executes step handlers via platform adapters (Supabase vs. plain process), a realtime-subscription client library (pkgs/client), and a CLI (pkgs/cli) for scaffolding new Supabase projects. Execution relies on pgmq for task queues, pg_cron for stalled-task recovery and worker health, pg_net for HTTP worker invocation, supabase_vault for credentials, and Supabase Realtime for atomic state-transition broadcasts.
This repository is the `lingam` Python package, a comprehensive, research-oriented library for causal discovery from observational data using LiNGAM (Linear Non-Gaussian Acyclic Model) and its numerous extensions. It implements over 20 algorithms, including DirectLiNGAM, ICALiNGAM, VAR-LiNGAM, RCD, CAM-UV, RESIT, LiM, mLiNGAM, GroupLiNGAM, MultiGroup variants, and more. The library provides a consistent API where each algorithm exposes `fit()` on a data matrix, followed by properties like `causal_order_` and `adjacency_matrix_`, and all support bootstrap-based stability analysis via a shared `BootstrapMixin`. Key contributions include handling of latent confounders, time series, missing data, mixed data types, and multiple datasets, alongside utilities for causal effect estimation, visualization, model evaluation, and synthetic data generation. The code is well-structured, uses standard scientific Python dependencies (numpy, scipy, scikit-learn, graphviz), and includes a thorough test suite and extensive Jupyter notebook tutorials.