Dynamic Connection Plugin for Hasura

This repository contains a dynamic connection plugin for Hasura. The plugin is built using Node.js and Express.js. It provides dynamic connection routing for pre-NDC requests, routing mutations to the primary database and queries to read replicas using round-robin.

A sample hml file for the plugin:

kind: LifecyclePluginHook
version: v1
definition:
  pre: ndcRequest
  name: dynamic_routing
  url:
    valueFromEnv: APP_PRE_NDC_WEBHOOK_URL
  connectors:
    - postgres
  config:
    request:
      headers:
        "hasura-m-auth":
          valueFromEnv: APP_PRE_NDC_WEBHOOK_TOKEN
        "hasura-replica-connection-names":
          valueFromEnv: APP_REPLICA_CONNECTION_NAMES
        "hasura-primary-connection-name":
          valueFromEnv: APP_PRIMARY_CONNECTION_NAME
      session: {}
      ndcRequest: {}

The environment variables to be set are:

• APP_PRE_NDC_WEBHOOK_URL: The URL of the plugin. Eg. http://localhost:8787/pre/ndc
• APP_PRE_NDC_WEBHOOK_TOKEN: The token to authenticate requests to the plugin. Eg. zZkhKqFjqXR4g5MZCsJUZCnhCcoPyZ
• APP_REPLICA_CONNECTION_NAMES: A comma-separated list of replica connection names. Eg. replica1,replica2,replica3
• APP_PRIMARY_CONNECTION_NAME: The name of the primary connection. Eg. primary