go-puppet / puppet

The Puppet language in pure Go — lexer, parser and Puppet::Pops AST, no cgo.

go-puppet/puppet is a pure-Go (no cgo) implementation of the Puppet language. It parses Puppet 8 manifests into a faithful Puppet::Pops-style abstract-syntax model that an evaluator and catalog compiler build on. The type system is delegated to go-pcore, data binding to go-hiera, and facts to go-facter — this repository never reimplements them.

prog, _ := puppet.Parse(`
  class nginx (String $vhost = 'localhost', Integer[1,65535] $port = 80) {
    package { 'nginx': ensure => installed }
    -> service { 'nginx': ensure => running, require => Package['nginx'] }
  }
  include nginx
`)
fmt.Println(cat.JSON()) // Puppet catalog JSON: resources + containment/ordering edges
_ = logs                // notice/info/warning/err messages

Status

Milestones 1 & 2 complete — the lexer + parser + AST and the evaluator + catalog compiler — at 100 % test coverage (enforced as a CI gate, including every parse- and eval-error path), gofmt + go vet clean, and green across all six 64-bit Go targets (amd64, arm64, riscv64, loong64, ppc64le, s390x). The type system is delegated to go-pcore, data binding to go-hiera, and facts to an injectable provider backed by go-facter.

What it parses

The lexer and parser cover the Puppet 8 grammar:

What it evaluates

The evaluator compiles a manifest to a catalog:

The registry seam

Evaluator.RegisterFunction(name, fn) adds or overrides a function at runtime. This is the seam go-ruby-puppet plugs into to contribute Ruby-defined custom functions and types without this repository depending on the Ruby VM.

Packages

Roadmap

• v0.1 (this release): lexer, parser, AST, evaluator, catalog compiler, built-in function set, iteration, Hiera-backed lookup(), facts, and the function/type registry seam.
• Staged for v0.2 (parsed but not yet evaluated — no fake stubs): EPP/ERB templates, resource defaults/overrides/collectors, exported resources / PuppetDB, the full stdlib module, and the plan/apply language. Evaluating these today returns a clear "staged for v0.2" error.

Principles

• Pure Go, zero cgo. Cross-compiles anywhere; static binary by default.
• Faithful to Puppet 8 / Pops. Node kinds, grammar and precedence track the Puppet specification.
• No reinvention. Types → go-pcore, data → go-hiera, facts → go-facter.
• 100 % test coverage, enforced in CI, including every parse- and eval-error branch, on all six 64-bit Go arches.

BSD-3-Clause.