Render SDL

[binaryseed]

This PR adds the ability to render out Blueprint structs as GraphQL SDL.

If you have a blueprint struct, you may view it's SDL by inspecting it with the :pretty flag:

IO.inspect(blueprint, pretty: true)

From the command line, you can invoke a Mix Task generate a .graphql file:

mix absinthe.schema.sdl --schema MySchema

[binaryseed]

• multi-line descriptions need correct indentation

[benwilson512]

Dude, this is awesome. 😍

[binaryseed]

• directive locations can break to multiline

[bruce]

@binaryseed I think you're unblocked by the directive args issue now. 🎉

[binaryseed]

I don't think it's quite there, I pushed a commit with enum_value missing in one location, and I'm not seeing the deprecation getting attached to the schema node...

Looks like some of the functions in AttachDirectives aren't actually used?

[bruce]

AttachDirectives shouldn't actually be necessary at all, now that Absinthe.Phase.Schema is being used to apply schema_node entries. I've pushed a commit to master removing it from the pipeline.

That said, this test was even passing before, and I'm seeing the deprecation attached as I expect:

%Absinthe.Type.Field{
  __private__: [],
  __reference__: %{
    location: %{
      file: "/Users/bruce/code/absinthe-graphql/absinthe/test/absinthe/schema/notation/experimental/import_sdl_test.exs",
      line: 23
    },
    module: Absinthe.Schema.Notation.Experimental.ImportSdlTest.Definition
  },
  args: %{},
  complexity: nil,
  config: nil,
  default_value: nil,
  definition: Absinthe.Schema.Notation.Experimental.ImportSdlTest.Definition,
  deprecation: %Absinthe.Type.Deprecation{reason: "Reason"},
  description: nil,
  identifier: :deprecated_field_with_reason,
  middleware: [{Absinthe.Middleware.MapGet, :deprecated_field_with_reason}],
  name: "deprecatedFieldWithReason",
  triggers: [],
  type: :string
}
.....

[binaryseed]

I think the default_value SDL support still needs work...

Macro based schemas get raw elixir values for default_value, while SDL schemas get structs like Absinthe.Blueprint.Input.Enum when it goes through Blueprint.Draft.convert

This is easy to see when an Enum is used, since it causes a failure in a schema phase:

#754

[bruce]

This is good to merge when you're ready, I just left a couple comments.

Might just want to pull that comment out to an issue, and it looks like you still have one unfinished checkbox on the PR.

[binaryseed]

Ready to go!