Modify your Absinthe.Plug pipeline for Opencensus.Absinthe:

Installation

Specify traced_pipeline/2 as your pipeline in your Absinthe.Plug.opts/0, e.g. via Phoenix.Router.forward/4:

forward "/graphql", Absinthe.Plug,
  schema: MyApp.Schema,
  pipeline: {Opencensus.Absinthe.Plug, :traced_pipeline}

WARNING: traced_pipeline/2 will be present only if Absinthe.Plug is loaded. Don't forget your absinthe_plug dependency in mix.exs!