Add support for generating protobuf3 definition #166

[kapilreddy]

Closes #166

Contribution checklist

• Tests verified by ./bin/kaocha and ./bin/node
• malli.perf.core/quick-bench on malli.protobuf3-schema/transform with a fairly complex schema takes 28.656211 µs

Overview of change

1. Add malli.protobuf3-schema which converts malli schema to protobuf3 defintions
2. Add tests covering nested data structures
3. Add perf test for protobuf3-schema
4. Add fixes for bin/node and malli.perf.core

[ikitommi]

Hi, and thanks for the PR! Quick comments:

1. the solution should be extendable, multimethods are a great way for doing this
2. There could be a property-based way to define the mappings, e.g. [:fn {:protobuf/type "double"} #(double? %)]
3. all default schemas should be mapped if they have protobuf3 counterpart, e.g. (protobuf/transform :keyword) fails currently

I think the solution could look much like the JSON Schema transformation:

• code: https://github.com/metosin/malli/blob/master/src/malli/json_schema.cljc
• tests: https://github.com/metosin/malli/blob/master/test/malli/json_schema_test.cljc

what do you think?

[kapilreddy]

Makes sense. I'll address these comments.

[ikitommi]

for perf testing, most of the time goes in constructing the schema. It can be cached to check the actual transformation code perf. So:

(def schema
  (m/schema
   [:map
    [:id string?]
    [:metadata [:map
                [:created_at inst?]
                [:tags [:vector string?]]]]
    [:data [:vector [:map
                     [:name string?]
                     [:details [:map
                                [:type [:enum :type-a :type-b :type-c]]
                                [:properties [:vector [:map
                                                       [:key string?]
                                                       [:value [:or string? int? boolean?]]
                                                       [:nested [:vector [:map
                                                                          [:sub_key string?]
                                                                          [:sub_value any?]]]]]]]]]]]]]))

(defn transform-perf []
  ;; 28.656211 µs -> 640ns
  (p/bench (protobuf/transform schema)))

[kapilreddy]

That's a good catch! I'll fix the perf namespace as well.