NATS

NATS event provider support for EDFS

Minimum requirements

PackageMinimum version

controlplane

0.88.3

router

0.88.0

wgc

0.55.0

Full schema example

Here is a comprehensive example of how to use NATS with EDFS. This guide covers request, publish, subscribe directive. All examples can be modified to suit your specific needs. The schema directives and edfs__* types belong to the EDFS schema contract and must not be modified.

# EDFS

directive @edfs__natsRequest(subject: String!, providerId: String! = "default") on FIELD_DEFINITION
directive @edfs__natsPublish(subject: String!, providerId: String! = "default") on FIELD_DEFINITION
directive @edfs__natsSubscribe(subjects: [String!]!, providerId: String! = "default", streamConfiguration: edfs__NatsStreamConfiguration) on FIELD_DEFINITION

type edfs__PublishResult {
    success: Boolean!
}

input edfs__NatsStreamConfiguration {
    consumerName: String!
    streamName: String!
}

# Custom

type Query {
    employeeFromEvent(id: Int!): Employee! @edfs__natsRequest(subject: "getEmployee.{{ args.id }}", providerId: "my-nats")
    employeeFromEventMyNats(employeeID: Int!): Employee! @edfs__natsRequest(subject: "getEmployeeMyNats.{{ args.employeeID }}", providerId: "my-nats")
}

input UpdateEmployeeInput {
    name: String
    email: String
}

type Mutation {
    updateEmployeeMyNats(employeeID: Int!, update: UpdateEmployeeInput!): edfs__PublishResult! @edfs__natsPublish(subject: "employeeUpdatedMyNats.{{ args.employeeID }}", providerId: "my-nats")
}

type Subscription {
    employeeUpdated(employeeID: Int!): Employee! @edfs__natsSubscribe(subjects: ["employeeUpdated.{{ args.employeeID }}"])
    employeeUpdatedMyNats(id: Int!): Employee! @edfs__natsSubscribe(subjects: ["employeeUpdatedMyNats.{{ args.id }}", "employeeUpdatedMyNatsTwo.{{ args.id }}"], providerId: "my-nats")
    employeeUpdatedNatsStream(id: Int!): Employee! @edfs__natsSubscribe(subjects: ["employeeUpdated.{{ args.id }}"], streamConfiguration: { consumerName: "consumerName", streamName: "streamName"}, providerId: "my-nats")
}

# Subgraph schema

type Employee @key(fields: "id", resolvable: false) {
  id: Int! @external
}

You can create the abstract subgraph with the following wgc command:

wgc subgraph publish employee --namespace default --schema edfs-graph.graphqls --routing-url http://localhost:4004/graphql

The routing url is still mandatory due a limitation. You can specify anything to make it pass.

Router config

Based on the example above, you will need a compatible router configuration.

config.yaml
events:
  providers:
    nats:
      - id: my-nats
        url: "nats://localhost:4222"
        authentication: 
          token: "token" # or
          user_info: 
            username: "username"
            password: "password"

Example Query

This query assumes that your implemented employee subgraph can resolve the fields.

subscription {
  employeeUpdated(employeeID: 1) {
    id
    tag
    details {
      surname
    }
  }
}

System diagram

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