Schema Stitching Configuration

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$id": "https://schema-stitching.dev/schema-stitching-config-schema.json",
  "title": "Schema Stitching Configuration",
  "description": "JSON Schema for configuring a GraphQL schema stitching gateway, defining subschemas, type merging, and field delegation.",
  "type": "object",
  "properties": {
    "subschemas": {
      "type": "array",
      "description": "Array of subschemas to stitch together into a unified gateway schema.",
      "items": {
        "$ref": "#/definitions/SubschemaConfig"
      }
    },
    "typeDefs": {
      "type": "string",
      "description": "Additional GraphQL type definitions to extend the stitched schema with extra fields or types."
    },
    "resolvers": {
      "type": "object",
      "description": "Additional resolver functions for types and fields added via typeDefs.",
      "additionalProperties": true
    },
    "mergeTypes": {
      "type": "boolean",
      "default": true,
      "description": "Whether to automatically merge types with the same name across subschemas."
    }
  },
  "definitions": {
    "SubschemaConfig": {
      "type": "object",
      "required": ["schema"],
      "properties": {
        "schema": {
          "type": "string",
          "description": "The GraphQL schema SDL string or reference to a remote schema."
        },
        "url": {
          "type": "string",
          "format": "uri",
          "description": "URL of the remote GraphQL service endpoint."
        },
        "batch": {
          "type": "boolean",
          "default": false,
          "description": "Whether to batch queries to this subschema using DataLoader-style batching."
        },
        "merge": {
          "type": "object",
          "description": "Type merging configuration for this subschema.",
          "additionalProperties": {
            "$ref": "#/definitions/MergeTypeConfig"
          }
        },
        "transforms": {
          "type": "array",
          "description": "Schema transforms to apply to this subschema before stitching.",
          "items": {
            "$ref": "#/definitions/SchemaTransform"
          }
        },
        "executor": {
          "type": "string",
          "description": "Custom executor function name for this subschema."
        }
      }
    },
    "MergeTypeConfig": {
      "type": "object",
      "properties": {
        "selectionSet": {
          "type": "string",
          "description": "GraphQL selection set for fetching the key fields required to merge this type.",
          "example": "{ id }"
        },
        "fieldName": {
          "type": "string",
          "description": "The query field name used to fetch a single merged type by key."
        },
        "argsFromKeys": {
          "type": "string",
          "description": "Function expression mapping key values to query arguments."
        },
        "key": {
          "type": "string",
          "description": "Function expression extracting the merge key from a type object."
        },
        "dataLoaderOptions": {
          "type": "object",
          "description": "DataLoader configuration for batched type merging.",
          "properties": {
            "maxBatchSize": {
              "type": "integer",
              "description": "Maximum number of keys per batch request."
            }
          }
        }
      }
    },
    "SchemaTransform": {
      "type": "object",
      "description": "A schema transformation to apply to a subschema.",
      "properties": {
        "type": {
          "type": "string",
          "enum": [
            "FilterRootFields",
            "FilterObjectFields",
            "RenameTypes",
            "RenameRootFields",
            "RenameObjectFields",
            "WrapQuery",
            "HoistField",
            "PruneSchema"
          ],
          "description": "The type of transformation to apply."
        },
        "config": {
          "type": "object",
          "description": "Configuration specific to the transform type.",
          "additionalProperties": true
        }
      }
    },
    "StitchingDirectivesConfig": {
      "type": "object",
      "description": "Configuration for stitching directives SDL approach.",
      "properties": {
        "keyDirective": {
          "type": "string",
          "default": "key",
          "description": "Name of the directive used to specify merge keys."
        },
        "mergeDirective": {
          "type": "string",
          "default": "merge",
          "description": "Name of the directive used to configure type merging."
        },
        "computedDirective": {
          "type": "string",
          "default": "computed",
          "description": "Name of the directive used to specify computed fields."
        }
      }
    }
  }
}