consul-template is a HashiCorp-maintained daemon that renders filesystem templates using data from Consul, Vault, and Nomad. It watches template files, fetches dependency data via blocking queries or polling, then atomically writes rendered output and optionally executes a command (e.g., restart a service) on changes. The architecture is a single binary CLI with a manager that orchestrates dependency fetching (via a watcher), template execution (with a rich function library), and child process supervision. It supports multiple modes including once, de-duplication across instances, and exec. The code is well-structured with clear separation into packages: config, dependency, template, renderer, child, watch, manager, and logging. Each package implements reusable patterns (e.g., config copy/merge/finalize, dependency interface, atomic file writer, process manager). The tool is heavily tested with integration tests against real Consul/Vault/Nomad instances. It is actively maintained and widely used in production for dynamic configuration generation.