Version 1.0.1

Cassandra to Cloud Spanner Proxy Adapter is designed to forward your application's CQL traffic to Spanner database service. It listens on a local address and securely forwards that traffic.

• When to use cassandra-to-spanner-proxy?
• Prerequisites
• Cloud Spanner Instructions
• Getting started
  • Locally build and run
  • Run a cassandra-to-spanner-proxy via docker
  • Use Kubernetes
• Infrastructure Provisioning on GCP using Terraform
• CQLSH support
• Stale Read Support
• Configuration Options
• Limitations for Proxy Application
• Setting Up systemd
• Instrument with OpenTelemetry
• Differences from Cassandra
• Run Unit/Integration tests locally
• Generating Mock Files Using Mockery
• Frequently Asked Questions

cassandra-to-spanner-proxy enables applications that are currently using Apache Cassandra or DataStax Enterprise (DSE) and would like to switch to use Cloud Spanner. This Proxy Adapter can be used as Plug-N-Play for the Client Application without the need of any code changes in the Client Application.

You will need a Google Cloud Platform Console project with the Cloud Spanner API enabled. You will need to enable billing to use Google Cloud Spanner. Follow these instructions to get your project set up.

Ensure that you run

gcloud auth application-default login

to set up your local development environment with authentication credentials.

Set the GCLOUD_PROJECT environment variable to your Google Cloud project ID:

gcloud config set project [MY_PROJECT_NAME]

• Database and all the tables should be created in advance before executing the queries using the adapter.

• A table should be created as below which will have the metadata information of the cassandra tables and its columns.

      CREATE TABLE IF NOT EXISTS TableConfigurations (
          `KeySpaceName` STRING(MAX),
          `TableName` STRING(MAX),
          `ColumnName` STRING(MAX),
          `ColumnType` STRING(MAX),
          `IsPrimaryKey` BOOL,
          `PK_Precedence` INT64,
      ) PRIMARY KEY (TableName, ColumnName, KeySpaceName);

• Make sure to insert all the table and column information into the above table before running the application.

We can setup the cassandra-to-spanner-proxy adapter via 3 different methods as mentioned below

• Locally build and run cassandra-to-spanner-proxy
• Run a docker image that has cassandra-to-spanner-proxy installed
• Use a Kubernetes container to run cassandra-to-spanner-proxy

Steps to run the adapter locally are as mentioned below:

• Clone the repository (https://github.com/cloudspannerecosystem/cassandra-to-spanner-proxy.git)

• Update config.yaml (or set up the CONFIG_FILE environment variable with the appropriate config file path), to specify listeners, project, instance, database details as well as additional configuration like enabling/disabling OTEL, keyspace flattening , Spanner session related configuration etc. See advanced config options for more details.

  cassandra_to_spanner_configs:
  projectId: YOUR_PROJECT_ID
  configTableName: YOUR_CONFIG_TABLE_NAME
  keyspaceFlatter: True
  
  listeners:
  - name: YOUR_CLUSTER_NAME_1
      port: PORT_1
      spanner:
          instanceId: YOUR_SPANNER_INSTANCE_ID
          databaseId: YOUR_SPANNER_DATABASE
  

• Build the proxy application by running the below command on the root directory.

  CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o cassandra-to-spanner-proxy .

• Run the Application

  ./cassandra-to-spanner-proxy

• Optional Arguments with the default values.

  • cql-version: CQL version, default value: "3.4.5"
  • partitioner: Partitioner, default value: "org.apache.cassandra.dht.Murmur3Partitioner"
  • release-version: Release Version, default value: "4.0.0.6816"
  • data-center: Data center, default value: "datacenter1"
  • protocol-version: Initial protocol version to use when connecting to the backend cluster, default value: v4
  • log-level: , set log level - [info/debug/error/warn] default value: info

• Run the Application with the arguments example

  ./cassandra-to-spanner-proxy --log-level error

• Application will be listening on PORT 9042.

• Build the docker image

  docker run -p 9042:9042 \
  -e GOOGLE_APPLICATION_CREDENTIALS="/var/run/secret/cloud.google.com/spanner-adaptor-service-account.json" \
  -v <<path to service account>>/spanner-adaptor-service-account.json:/var/run/secret/cloud.google.com/ \
  -d cassandra-spanner-proxy
  

• Deployment via k8

• Infrastructure provisioning on GCP

Users can connect and use cqlsh with the proxy. Detailed document - cqlsh.md

Detailed document - Limitations

Why systemd? - It can automatically restart crashed services, which is crucial for maintaining the availability of applications and system functions. systemd also provides mechanisms for service sandboxing and security.

Go through this document for setting up systemd for this project in your linux system - Setting Up systemd

The Proxy Adapter supports OpenTelemetry metrics and traces, which gives insight into the adapter internals and aids in debugging/troubleshooting production issues.

See OpenTelemetry for integrating OpenTelemetry (OTEL) with Your Application

See Frequently Asked Questions for answers to frequently asked questions.

Apache License 2.0

The Cassandra to Cloud Spanner Proxy Adapter is a Cloud Spanner Ecosystem project is maintained by the Google Spanner team. We'd love for you to report issues, file feature requests, and send pull requests (see Contributing). You may file bugs and feature requests using GitHub's issue tracker or using the existing Cloud Spanner support channels.