clanLib.jsonschema: move tests from pkgs/clan-cli

lib/jsonschema/default.nix

@@ -0,0 +1,153 @@
+{ lib ? (import <nixpkgs> { }).lib }:
+let
+
+  # from nixos type to jsonschema type
+  typeMap = {
+    bool = "boolean";
+    float = "number";
+    int = "integer";
+    str = "string";
+  };
+
+  # remove _module attribute from options
+  clean = opts: builtins.removeAttrs opts [ "_module" ];
+
+  # throw error if option type is not supported
+  notSupported = option: throw
+    "option type '${option.type.description}' not supported by jsonschema converter";
+
+in
+rec {
+
+  # parses a nixos module to a jsonschema
+  parseModule = module:
+    let
+      evaled = lib.evalModules {
+        modules = [ module ];
+      };
+    in
+    parseOptions evaled.options;
+
+  # parses a set of evaluated nixos options to a jsonschema
+  parseOptions = options':
+    let
+      options = clean options';
+      # parse options to jsonschema properties
+      properties = lib.mapAttrs (_name: option: parseOption option) options;
+      isRequired = prop: ! (prop ? default || prop.type == "object");
+      requiredProps = lib.filterAttrs (_: prop: isRequired prop) properties;
+      required = lib.optionalAttrs (requiredProps != { }) {
+        required = lib.attrNames requiredProps;
+      };
+    in
+    # return jsonschema
+    required // {
+      type = "object";
+      inherit properties;
+    };
+
+  # parses and evaluated nixos option to a jsonschema property definition
+  parseOption = option:
+    let
+      default = lib.optionalAttrs (option ? default) {
+        inherit (option) default;
+      };
+      description = lib.optionalAttrs (option ? description) {
+        inherit (option) description;
+      };
+    in
+    if option._type != "option"
+    then throw "parseOption: not an option"
+
+    # parse nullOr
+    else if option.type.name == "nullOr"
+    # return jsonschema property definition for nullOr
+    then default // description // {
+      type = [
+        "null"
+        (typeMap.${option.type.functor.wrapped.name} or (notSupported option))
+      ];
+    }
+
+    # parse bool
+    else if option.type.name == "bool"
+    # return jsonschema property definition for bool
+    then default // description // {
+      type = "boolean";
+    }
+
+    # parse float
+    else if option.type.name == "float"
+    # return jsonschema property definition for float
+    then default // description // {
+      type = "number";
+    }
+
+    # parse int
+    else if option.type.name == "int"
+    # return jsonschema property definition for int
+    then default // description // {
+      type = "integer";
+    }
+
+    # parse string
+    else if option.type.name == "str"
+    # return jsonschema property definition for string
+    then default // description // {
+      type = "string";
+    }
+
+    # parse enum
+    else if option.type.name == "enum"
+    # return jsonschema property definition for enum
+    then default // description // {
+      enum = option.type.functor.payload;
+    }
+
+    # parse listOf submodule
+    else if option.type.name == "listOf" && option.type.functor.wrapped.name == "submodule"
+    # return jsonschema property definition for listOf submodule
+    then default // description // {
+      type = "array";
+      items = parseOptions (option.type.functor.wrapped.getSubOptions option.loc);
+    }
+
+    # parse list
+    else if
+      (option.type.name == "listOf")
+      && (typeMap ? "${option.type.functor.wrapped.name}")
+    # return jsonschema property definition for list
+    then default // description // {
+      type = "array";
+      items = {
+        type = typeMap.${option.type.functor.wrapped.name};
+      };
+    }
+
+    # parse attrsOf submodule
+    else if option.type.name == "attrsOf" && option.type.nestedTypes.elemType.name == "submodule"
+    # return jsonschema property definition for attrsOf submodule
+    then default // description // {
+      type = "object";
+      additionalProperties = parseOptions (option.type.nestedTypes.elemType.getSubOptions option.loc);
+    }
+
+    # parse attrs
+    else if option.type.name == "attrsOf"
+    # return jsonschema property definition for attrs
+    then default // description // {
+      type = "object";
+      additionalProperties = {
+        type = typeMap.${option.type.nestedTypes.elemType.name} or (notSupported option);
+      };
+    }
+
+    # parse submodule
+    else if option.type.name == "submodule"
+    # return jsonschema property definition for submodule
+    # then (lib.attrNames (option.type.getSubOptions option.loc).opt)
+    then parseOptions (option.type.getSubOptions option.loc)
+
+    # throw error if option type is not supported
+    else notSupported option;
+}