Thrift Utilities for Elixir

This package contains a handful of useful utilities for working with Thrift in Elixir.

In particular, it includes a copy of the Erlang Thrift runtime library.

Setup

Start by adding this package to your project as a dependency:

{:thrift, "~> 1.3"}

Or to track the GitHub master branch:

{:thrift, github: "pinterest/elixir-thrift", submodules: true}

Mix

This package includes a Mix compiler task that can be used to automate Thrift code generation. Start by adding :thrift to your project's :compilers list. For example:

compilers: [:thrift | Mix.compilers]

It's important to add :thrift before the :erlang entry. The Thrift compiler will generate Erlang source files, and we currently rely on this ordering to ensure those generated source files get compiled.

Next, define the list of :thrift_files that should be compiled. In this example, we gather all of the .thrift files under the thrift directory:

thrift_files: Mix.Utils.extract_files(["thrift"], [:thrift])

By default, the generated source files will be written to the src directory, but you can change that using the thrift_output option.

You can also pass additional options to the Thrift compiler by listing them in the thrift_options option:

thrift_options: ~w[-I my/include/dir]

If you require a specific version of the Thrift compiler, you can specify a version requirement using the thrift_version option. Version requirements use the SemVer 2.0 schema. For example:

thrift_version: ">= 0.9.3"  # Erlang maps support

You can also override the name of the Thrift compiler executable itself:

thrift_executable: "thrift-0.9.3"

If you get something like type set() undefined when compiling the generated files you can try:

thrift_options: ~w[--gen erl:maps]

Thrift IDL Parsing

This package also contains experimental support for parsing Thrift IDL files. It is built on a low-level Erlang lexer and parser:

{:ok, tokens, _} = :thrift_lexer.string('enum Colors { RED, GREEN, BLUE}')
{:ok,
 [{:enum, 1}, {:ident, 1, 'Colors'}, {:symbol, 1, '{'}, {:ident, 1, 'RED'},
  {:symbol, 1, ','}, {:ident, 1, 'GREEN'}, {:symbol, 1, ','},
  {:ident, 1, 'BLUE'}, {:symbol, 1, '}'}], 1}

{:ok, schema} = :thrift_parser.parse(tokens)
{:ok,
 %Thrift.Parser.Models.Schema{constants: %{},
  enums: %{Colors: %Thrift.Parser.Models.TEnum{name: :Colors,
     values: [RED: 1, GREEN: 2, BLUE: 3]}}, exceptions: %{}, includes: [],
  namespaces: %{}, services: %{}, structs: %{}, thrift_namespace: nil,
  typedefs: %{}, unions: %{}}}

But also provides a high-level Elixir parsing interface:

Thrift.Parser.parse("enum Colors { RED, GREEN, BLUE}")
%Thrift.Parser.Models.Schema{constants: %{},
 enums: %{Colors: %Thrift.Parser.Models.TEnum{name: :Colors,
    values: [RED: 1, GREEN: 2, BLUE: 3]}}, exceptions: %{}, includes: [],
 namespaces: %{}, services: %{}, structs: %{}, thrift_namespace: nil,
 typedefs: %{}, unions: %{}}