MyPgContextPlugin.ts

const MyPgContextPlugin: GraphileConfig.Plugin = {
  name: "MyPgContextPlugin",
  description:
    "Extends the runtime GraphQL context with details needed to support your configured pgServices",
  version: "0.0.0",

  grafast: {
    middleware: {
      prepareArgs(next, { args }) {
        if (!args.contextValue) args.contextValue = Object.create(null);
        const { resolvedPreset: { pgServices: [pgService] }, requestContext: ctx } = args;
        const contextValue = args.contextValue as Record<string, any>;

        const { pgSettings } = pgService;
        contextValue.pgSettings = pgSettings(ctx ?? EMPTY_OBJECT);

        const { pgSubscriber, withPgClient } = getContextValuesForTenant(ctx.expressv4.req.tenant_id);
        contextValue.pgSubscriber = pgSubscriber;
        contextValue.withPgClient = withPgClient;

        return next();
      },
    },
  },
};

// Replaces PgContextPlugin with MyPgContextPlugin
export const MultitenantPreset: GraphileConfig.Preset = {
  disablePlugins: ['PgContextPlugin'],
  plugins: [MyPgContextPlugin],
};