NDC Cassandra

This repository contains an adapter that is metadata configurable to support approximately 40 data sources.

Approximately 15 files-based data sources, and 25 JDBC based data sources.

Temporary Instructions - For Getting Started as a Developer with this repo.

Clone the repo && the subrepo

This adapter is based on a forked version of Cassandra (the sub-repo)

 git clone https://github.com/hasura/ndc-cassandra.git
 cd ndc-cassandra
 git checkout main

Note - this is somewhat simplified - because everything is in the "main" branch. I'll let you research how to manage the primary and sub-branch on your own!

Build the Java project

The project will require jdk 21 and maven. You need to have those installed first.

This is the JNI for cassandra. It handles the Cassandra to Rust handoff.

You can build it like this.

cd calcite-rs-jni
chmod +x build.sh
./build.sh

This will build the Java jars that the Rust project (at the root of this mono-repo) requires.

Build the Connector and CLI Plugin

cd ..
cargo build --bin ndc-calcite --bin ndc-calcite-cli

Test the file adapter

Note - the test requires "metadata" to be added to configuration.json. It should do it on first pass, but for now - you may to run it once to populate. Then run it again to actually perform the test.

chmod +x test.sh
./test.sh # populate metadata
./test.sh # run the tests

Build the docker image

chmod +x build-local.sh
./build-local.sh

Create a supergraph

ddn supergraph init test-connector
cd test-connector

Create a connector under default subgraph "app"

mkdir ./app/connector
ddn connector-link add cassandra --configure-connector-token secret --configure-host http://local.hasura.dev:8081 --subgraph app/subgraph.yaml --target-env-file .env

Add metadata to the connector

This script is one-and-done, you can't redo without resetting back to prior state. You might consider, committing before running this, to facilitate a rollback.

chmod +x ../cli.sh
../cli.sh ./app/connector/cassandra 8081 secret

Optional Revise Cassandra Adapter

This will setup a SQLite connector. If you want to change the connector DO IT NOW. Go to app/connector/cassandra/models/model.json and revise the schema(s). Look at the sample models for ideas, or, get more details from Apache Cassandra.

chmod +x ../cli-update-model.sh
../cli-update-model.sh ./app/connector/cassandra

Start supergraph

This is to facilitate the introspection. Introspection will not work offline with ddn connect-link add-all, without the connector being in connector hub. (That's a guess, since I can't prove it.)

HASURA_DDN_PAT=$(ddn auth print-pat) docker compose --env-file .env up --build --watch

Introspect

ddn connector-link update cassandra --add-all-resources --subgraph app/subgraph.yaml

Build supergraph

ddn supergraph build local

View in console

Click here to launch Console View

Execute a query

query MyQuery {
  albums(limit: 10) {
    title
    artist {
      name
    }
  }
}

And you should see this:

{
  "data": {
    "albums": [
      {
        "title": "For Those About To Rock We Salute You",
        "artist": {
          "name": "AC/DC"
        }
      },
      {
        "title": "Balls to the Wall",
        "artist": {
          "name": "Accept"
        }
      },
      {
        "title": "Restless and Wild",
        "artist": {
          "name": "Accept"
        }
      },
      {
        "title": "Let There Be Rock",
        "artist": {
          "name": "AC/DC"
        }
      },
      {
        "title": "Big Ones",
        "artist": {
          "name": "Aerosmith"
        }
      },
      {
        "title": "Jagged Little Pill",
        "artist": {
          "name": "Alanis Morissette"
        }
      },
      {
        "title": "Facelift",
        "artist": {
          "name": "Alice In Chains"
        }
      },
      {
        "title": "Warner 25 Anos",
        "artist": {
          "name": "Antônio Carlos Jobim"
        }
      },
      {
        "title": "Plays Metallica By Four Cellos",
        "artist": {
          "name": "Apocalyptica"
        }
      },
      {
        "title": "Audioslave",
        "artist": {
          "name": "Audioslave"
        }
      }
    ]
  }
}