Data Connector Agent for Couchbase

This directory contains a Couchbase implementation of a data connector agent. It can use a Couchbase cluster and consume documents of a bucket as referenced by the "DB" config field.

Capabilities

The Couchbase agent currently supports the following capabilities:

• GraphQL Schema
• GraphQL Queries
• Prometheus Metrics
• Exposing Foreign-Key Information
• Mutations
• Subscriptions
• Streaming Subscriptions

Note: You can get detailed metadata about the agent's capabilities by GETting the /capabilities endpoint of the running agent.

Requirements

• NodeJS 16
• "Couchbase": "^3.2.4"
• Note: NPM is used for the TS Types for the DC-API protocol
• Copy .env.example to .env and define your values to environment vars

Options / Environment Variables

Note: Boolean flags {FLAG} can be provided as 1, true, yes, or omitted and default to false.

ENV Variable Name	Format	Default	Info
PORT	INT	8100	Port for agent to listen on.
PERMISSIVE_CORS	{FLAG}	false	Allows all requests - Useful for testing with SwaggerUI. Turn off on production.
DEBUGGING_TAGS	{FLAG}	false	Outputs xml style tags in query comments for deugging purposes.
LOG_LEVEL	fatal | error | info | debug | trace | silent	info	The minimum log level to output
METRICS	{FLAG}	false	Enables a /metrics prometheus metrics endpoint.

Agent usage

The agent is configured as per the configuration schema. The valid configuration properties are:

Property	Type	Default	Info
db	string		Connection string to couchbase cluster
username	string		User that will be used to connect with cluster
password	string		Password that will be used to connect with cluster
bucket	string		Bucket that will be used from DC Agent
scope	string	default	Scope that will be used from DC Agent
collection	string	default	Collection that will be used from DC Agent
healtCheckStrategy	string	null	Strategic to check health of cluster ping or diagnostic

The schema is exposed via introspection, but you can limit which documents are referenced by

Dataset

The dataset used for testing the couchbase agent is sample buckets

• Travel-sample

Get started with Couchbase agent

Testing Changes to the Agent

Run:

cabal run dc-api:test:tests-dc-api -- test --agent-base-url http://localhost:8100 --agent-config '{"bucket": "travel-sample", "healtCheckStrategy": "ping"}'

From the HGE repo.

TODO

• Prometheus metrics hosted at /metrics
• Pull reference types from a package rather than checked-in files
• Health Check
• DB Specific Health Checks
• Schema
• Capabilities
• Query

Known Bugs

Tricky Aggregates may have logic bug

Replicate by running the agent test-suite.