smithy_beam

Hex package for the smithy-beam code generator.

Generates Elixir and Erlang code from Smithy models (client and server).

Mix and rebar3 helper that runs the Smithy CLI to generate Elixir and Erlang code from Smithy models.

The Java codegen plugins are resolved from Maven Central. This Hex package is the BEAM-native compile-time glue.

Generation runs at compile time in the consumer project. Compiling smithy_beam itself as a dependency does not generate code.

Prerequisites

Smithy CLI on PATH
- macOS: brew tap smithy-lang/tap && brew install smithy-cli
- Verify: smithy --help
A JVM that can load the published codegen JARs (Java 21+)
Network access on first build so the CLI can download Maven dependencies

Elixir (Mix)

def project do
  [
    compilers: [:smithy_beam] ++ Mix.compilers(),
    elixirc_paths: ["lib", "lib/generated"],
    smithy_beam: [
      models: "model",
      output: "lib/generated",
      language: :elixir,
      kind: :client,
      edition: "2026"
    ],
    deps: [
      {:smithy_beam, "~> 0.1", runtime: false}
    ]
  ]
end

Explicit task:

mix smithy_beam.generate
mix smithy_beam.generate --force

Erlang (rebar3)

{project_plugins, [smithy_beam]}.

{provider_hooks, [
  {pre, [{compile, {smithy_beam, generate}}]}
]}.

{smithy_beam, [
  {models, "model"},
  {output, "src/generated"},
  {language, erlang},
  {kind, client},
  {edition, "2026"}
]}.

Explicit task:

rebar3 smithy_beam generate

Configuration reference

Key	Required	Default	Notes
`models`	yes (unless `config_file`)		Model file or directory
`output`	no	`lib/generated` / `src/generated`	Destination for generated sources
`language`	yes		`:elixir` or `:erlang`
`kind`	yes		`:client`, `:server`, or `:types`
`edition`	yes (auto config)		Plugin edition, e.g. `"2026"`
`service`	no		Shape id when the model has multiple services
`name`	no		Optional module/file name stem
`codegen_version`	no	`0.3.1`	Maven codegen artifact version
`maven_deps`	no	`[]`	Extra GAV strings appended after defaults
`config_file`	no		Escape hatch: use an existing `smithy-build.json`
`plugin`	with `config_file`	derived	Plugin id when using `config_file`

Default Maven dependencies always include the matching codegen-elixir or codegen-erlang coordinate plus common Smithy AWS-related artifacts. Consumer maven_deps are appended.

Versioning

Hex package version (smithy_beam) and Maven codegen versions are independent. Override the generator with codegen_version when needed.

Generated sources and git

Whether lib/generated / src/generated is committed is a consumer choice.