Hasura NDC SDK for Rust

This repository provides a Rust crate to aid development of Hasura Native Data Connectors. Developers can implement a trait, and derive an executable which can be used to run a connector which is compatible with the specification.

In addition, this library adopts certain conventions which are not covered by the current specification:

• Connector configuration
• State management
• Trace collection

Getting Started with the SDK

cargo build

Run the example connector

mkdir empty
cargo run --bin ndc_hub_example serve --configuration ./empty

Inspect the resulting (empty) schema:

curl http://localhost:8080/schema

(The default port, 8080, can be changed using --port.)

Tracing

The serve command emits OTLP trace information. This can be used to see details of requests across services.

To enable tracing you must:

• use the SDK option --otlp-endpoint e.g. http://localhost:4317,
• set the SDK environment variable OTEL_EXPORTER_OTLP_ENDPOINT, or
• set the tracing environment variable OTEL_EXPORTER_OTLP_TRACES_ENDPOINT.

The exporter uses gRPC protocol by default. To use HTTP protocol you must set OTEL_EXPORTER_OTLP_PROTOCOL=http/protobuf.

For additional service information you can:

• Set OTEL_SERVICE_NAME e.g. ndc_hub_example
• Set OTEL_RESOURCE_ATTRIBUTES e.g. key=value, k = v, a= x, a=z

To view trace information during local development you can run a Jaeger server via Docker:

docker run --name jaeger -e COLLECTOR_OTLP_ENABLED=true -p 16686:16686 -p 4317:4317 -p 4318:4318 jaegertracing/all-in-one