Concourse CI/CD Pipeline

Concourse is a free and open-source continuous integration and continuous delivery (CI/CD) system designed to be simple, composable, and transparent. Originally developed by Alex Suraci and Pivotal Software (now part of VMware/Broadcom) in 2014, Concourse is written in Go and addresses the complexity, opacity, and vendor lock-in issues of other CI/CD tools like Jenkins. Key features: pipeline as code: the entire CI/CD pipeline is defined in YAML configuration files, version-controlled alongside the application code. This makes pipelines reproducible, reviewable, and auditable. Resources: the core abstraction is resources — versioned artifacts (Git repos, Docker images, S3 buckets, time-based triggers, semver tags). Each resource type defines how to check for new versions, fetch (get), and publish (put). Tasks: self-contained scripts that run in Docker containers with defined inputs and outputs. Tasks are idempotent and can be run locally with the fly CLI for debugging. Jobs: connect resources and tasks into a directed acyclic graph (DAG), defining the flow of artifacts through the pipeline with passed and trigger constraints. Everything in containers: every task and resource operation runs in an isolated Docker container, ensuring reproducibility and eliminating the 'works on my machine' problem. No persistent state on workers. Fly CLI: command-line interface for pipeline management, task execution, resource checking, and log streaming. Visibility: every build, input, output, and log is visible in the web UI with full traceability. Reusable pipelines via instance variables for multi-branch and multi-environment pipelines. RBAC, credential management via Vault and Credhub. Apache-2.0.