@apollo/federation-internals/src/specs/costSpec.ts

Apollo Federation internal utilities

import { DirectiveLocation } from 'graphql';
import { createDirectiveSpecification } from '../directiveAndTypeSpecification';
import { FeatureDefinition, FeatureDefinitions, FeatureUrl, FeatureVersion } from './coreSpec';
import { DirectiveDefinition, ListType, NonNullType, Schema } from '../definitions';
import { registerKnownFeature } from '../knownCoreFeatures';
import { ARGUMENT_COMPOSITION_STRATEGIES } from '../argumentCompositionStrategies';

export const costIdentity = 'https://specs.apollo.dev/cost';

export class CostSpecDefinition extends FeatureDefinition {
  constructor(version: FeatureVersion, readonly minimumFederationVersion: FeatureVersion) {
    super(new FeatureUrl(costIdentity, 'cost', version), minimumFederationVersion);

    this.registerDirective(createDirectiveSpecification({
      name: 'cost',
      locations: [
        DirectiveLocation.ARGUMENT_DEFINITION,
        DirectiveLocation.ENUM,
        DirectiveLocation.FIELD_DEFINITION,
        DirectiveLocation.INPUT_FIELD_DEFINITION,
        DirectiveLocation.OBJECT,
        DirectiveLocation.SCALAR
      ],
      args: [{ name: 'weight', type: (schema) => new NonNullType(schema.intType()), compositionStrategy: ARGUMENT_COMPOSITION_STRATEGIES.MAX }],
      composes: true,
      repeatable: false,
      supergraphSpecification: (fedVersion) => COST_VERSIONS.getMinimumRequiredVersion(fedVersion),
    }));

    this.registerDirective(createDirectiveSpecification({
      name: 'listSize',
      locations: [DirectiveLocation.FIELD_DEFINITION],
      args: [
        { name: 'assumedSize', type: (schema) => schema.intType(), compositionStrategy: ARGUMENT_COMPOSITION_STRATEGIES.NULLABLE_MAX },
        { name: 'slicingArguments', type: (schema) => new ListType(new NonNullType(schema.stringType())), compositionStrategy: ARGUMENT_COMPOSITION_STRATEGIES.NULLABLE_UNION },
        { name: 'sizedFields', type: (schema) => new ListType(new NonNullType(schema.stringType())), compositionStrategy: ARGUMENT_COMPOSITION_STRATEGIES.NULLABLE_UNION },
        { name: 'requireOneSlicingArgument', type: (schema) => schema.booleanType(), defaultValue: true, compositionStrategy: ARGUMENT_COMPOSITION_STRATEGIES.NULLABLE_AND },
      ],
      composes: true,
      repeatable: false,
      supergraphSpecification: (fedVersion) => COST_VERSIONS.getMinimumRequiredVersion(fedVersion)
    }));
  }

  costDirective(schema: Schema): DirectiveDefinition<CostDirectiveArguments> | undefined {
    return this.directive(schema, 'cost');
  }

  listSizeDirective(schema: Schema): DirectiveDefinition<ListSizeDirectiveArguments> | undefined {
    return this.directive(schema, 'listSize');
  }
}

export const COST_VERSIONS = new FeatureDefinitions<CostSpecDefinition>(costIdentity)
  .add(new CostSpecDefinition(new FeatureVersion(0, 1), new FeatureVersion(2, 9)));

registerKnownFeature(COST_VERSIONS);

export interface CostDirectiveArguments {
  weight: number;
}

export interface ListSizeDirectiveArguments {
  assumedSize?: number;
  slicingArguments?: string[];
  sizedFields?: string[];
  requireOneSlicingArgument?: boolean;
}