Cassandra Codegen

Generate TypeScript type definitions from a Cassandra (or ScyllaDB) database, as well as type-safe mappers.

Inspired by kysely-codegen.

Example output

Existing Cassandra table	Resulting TypeScript type
CREATE TABLE cyclist_category ( category text, points int, id UUID, last_name text, PRIMARY KEY (category, points) ) WITH CLUSTERING ORDER BY (points DESC);	export interface CyclistCategoryRow { category: PartitionKey<string>; points: Clustering<number, 'desc'>; id?: types.Uuid | null; lastName?: string | null; }

Additionally, a mapper named cyclistCategoryMapper is generated, which is similar to the mapper provided by cassandra-driver, but is more type-safe due to the type annotations specifying partition key & clustering columns.

Usage instructions

1. Install using npm install cassandra-codegen.

2. In your project, run:

   cassandra-codegen --host <host> --port <port> --datacenter <datacenter> --username <username> --password <password> --keyspace <keyspace>
   

   Notes:

   • Run cassandra-codegen -h for extra CLI options.
   • You may have to run npm exec cassandra-codegen -- <args>, depending on your environment.

3. In your code (usually inside some init function), add the following call:

   import { initMappers } from "cassandra-codegen";
   
   // The argument should be a connected `cassandra-driver` client. 
   await initMappers(cassandra);

4. You can now use the generated mappers wherever you need them:

   import { cyclistCategoryMapper } from "cassandra-codegen";
   
   const cyclistCategory = await cyclistCategoryMapper.get({...});

Additional instructions

Using query operators

You can use the query operators available in cassandra-driver in a type-safe manner. For example:

   import { cyclistCategoryMapper, queryOperator } from "cassandra-codegen";

   await cyclistCategoryMapper.find({
      category: 'GC',
      points: queryOperator.gte(42),
   });