Introductions to Adaptors can be found on the Introduction to YOUnite page and the Adaptors page.

Developing adaptors can be found on the YOUnite Adaptor Guide for Java Developers page.

The YOUnite API Documentation can be found at https://younite.us/api

Adaptor Workflow

Follow this workflow to get an adaptor fully operational:

1. Add an Adaptor Type using the YOUnite UI's Adaptor Types page (or YOUnite API endpoint /adaptorTypes). Adaptor types are not required since all adaptor will default to the "default" adaptor type. Adaptor types are designed to make configuring an adaptor easier especially for deployments that will be deploying many adaptors of the same type.
2. Follow the adaptor's README on where to load the adaptor software on the instance (e.g. docker image, VM, cloud instance, local system). It must be on an instance that can connect to the YOUnite message bus.
3. In the YOUnite UI Adaptor's page (or YOUnite API endpoint /zones/<target-zone-uuid>/adaptors ) add the adaptor to the target zone specifying the adaptor's type (or just specify the "default" type).
4. The prior step will generates then necessary configuration (Adaptor UUID, clientId and clientSecret for connecting to the YOUnite message bus),  the Adaptor will need these at startup. Typically, these can be added to the adaptor's adaptor.yml file, the adaptor's property file or set in the adaptor's environment variables if using a staging tools such as Kubernetes.
5. Set the adaptor capabilities and/or configuration (metadata) in the YOUnite UI's adaptor page or the API (PUT /zones/<target-zone-uuid>/adaptors/<adaptor-uuid>). See the adaptor README for capability and metadata settings.
6. Deploy the adaptor. Once it is running you can:
   
   1. Change an adaptor's state.
      1. Pause
      2. Play
   2. Manage the adaptor.
      1. Delete an Adaptor
      2. Get new Credentials for an adaptor 

A. Develop an adaptor in your development environment using a YOUnite Adaptor SDK (see YOUnite Adaptor Guide for Java Developers).

B. Create an AdaptorType in the Adaptor Type page in the YOUnite UI or using the API (see the /adaptorTypes endpoint in the YOUnite API)

1. Adding an Adaptor

Adding an adaptor merely informs the Data Hub that there is an intention to add an adaptor to a zone. Only users with POST /zones/zone-uuid/adaptors permissions can add in adaptor to a zone. By default only the Zone Data Steward (ZDS) has this permission.

An adaptor name is all that is required to POST an adaptor. If the request succeeds, an adaptor UUID and security credentials are returned. 

POST /zones/3c9000a9-3eb6-41fe-a11b-5a5859020c65/adaptors

{
	"name": "My First Adaptor"
}

4. Copy the Adaptor Credentials

The response would look similar to:

{
    "uuid": "3dfcc03d-e5d4-4d57-9e9b-5c5d2db32f9a",
    "zoneUuid": "3c9000a9-3eb6-41fe-a11b-5a5859020c65",
    "clientId": "8c9167a6-bb83-4f77-bdfc-1947a946f77b",
    "clientSecret": "de02e3fa-4b23-46cb-aed6-5665a16e73d3"
}

The metadata and adaptor capabilities can be updated with a PUT request.

WARNING: HTTP PUT stipulates that all properties defined in the PUT request body must be provided. Any properties omitted or left blank will overwrite the resource with a null value.

5. Modify the Adaptor Configuration

Adaptor configuration (metadata) and capabilities can be added to the POST request body.  The metadata must be in JSON format and the capabilities JSON schema can be seen below (TODO - More on capabilities):

{
	"name": "My First Adaptor",
	"description": "Our very first adaptor",
	"metadata": {
		"jdbcDriver": "com.mysql.jdbc.Driver",
		"dbUrl": "jdbc: mysql: //localhost/EMP"
	},
	"capabilities": [{
		"action": "GET",
		"direction": "IN",
		"domainVersionUuid": "cf7a0ad4-efe5-4618-8590-ae9c670da9c6"
	}, {
		"action": "PUT",
		"direction": "IN",
		"domainVersionUuid": "cf7a0ad4-efe5-4618-8590-ae9c670da9c6"
	}, {
		"action": "PUT",
		"direction": "IN",
		"domainVersionUuid": "cf7a0ad4-efe5-4618-8590-ae9c670da9c6"
	}, {
		"action": "GET",
		"direction": "OUT",
		"domainVersionUuid": "cf7a0ad4-efe5-4618-8590-ae9c670da9c6"
	}, {
		"action": "PUT",
		"direction": "OUT",
		"domainVersionUuid": "cf7a0ad4-efe5-4618-8590-ae9c670da9c6"
	}, {
		"action": "POST",
		"direction": "OUT",
		"domainVersionUuid": "cf7a0ad4-efe5-4618-8590-ae9c670da9c6"
	}, {
		"action": "DELETE",
		"direction": "OUT",
		"domainVersionUuid": "cf7a0ad4-efe5-4618-8590-ae9c670da9c6"
	}]
}

On startup an adaptor consults either a properties file (e.g. adaptor.yml) or configuration object (TODO Kevin) for its configuration information. The properties file resides on the same system as the adaptor. The list below explains the minimum properties needed by an adaptor. Consult the adaptors documentation for a definitive list and property names since they can change from adaptor to adaptor???:

Example:

# Configuration
# Transport implementation class
className: com.younite.adaptor.sdk.transport.amq.AMQConnect

# UUID of the zone this adaptor belongs to
zoneUuid: 6ab9380f-d7f2-477c-b93c-3a762e70095e

# Adaptor UUID
adaptorUuid: 3dfcc03d-e5d4-4d57-9e9b-5c5d2db32f9a

# ClientID and Secret to be used by JMS to verify adaptor has valid access to message bus (and API)
clientId: 8c9167a6-bb83-4f77-bdfc-1947a946f77b
clientSecret: de02e3fa-4b23-46cb-aed6-5665a16e73d3

# Message Broker URL
brokerUrl: nio+ssl://192.2.200.25:61617

# OAUTH Server to validate adaptor access credentials
oauthServerUrl: http://192.2.200.15:8080

6. Start the Adaptor - Connect to the Hub

Once the adaptor has been added (posted) and configured, it can be launched. It should successfully connect to the hub and move briefly into the "Configured" state and then into the "Play" state unless otherwise configured.

Once an adaptor is in the PLAY state, messages can be passed an adaptor to the datahub, and vice versa. Two situations may occur that cause the adaptor to no longer send/receive messages. The first is if the API is used to change the state to PAUSE. The second is in the rare case something goes awry between the datahub and adaptor. This could be the message bus service itself is down/restarting, the queue used for communication has an issue, or possibly something else. In the latter cases, usually the adaptor will auto restart and that will start the Datahub startup sequence again and communications should be re-established. If that does not occur, it may be required to dig further in to the YOUnite logs and possibly the adaptor logs to determine what might have happened.

6a. Change an Adaptor's State

Once an adaptor is added (step 1, above) it is in the "Posted" state. The states normally set by the YOUnite Data Hub are: POSTED, CONFIGURED, and DOWN.

The adaptor moves between states as follows:

Adaptor States

An adaptor state can be changed using the request including JSON request body:

PATCH /zones/zone-uuid/adaptors/adaptor-uuid

Request body to pause:
{
    "state": "ADAPTOR_PAUSE"
}

Request body to resume:
{
    "state": "ADAPTOR_PLAY"
}

6b. Manage an Adaptor

See the YOUnite API documentation (https://younite.us/api) for more requests that can be made to the adaptors endpoint.

A few common requests include:

Deleting an Adaptor

DELETE /zones/661f5d76-6bc7-4fc0-97fd-f331ab683379/adaptors/3dfcc03d-e5d4-4d57-9e9b-5c5d2db32f9a

Note: When you delete an adaptor it is a soft delete (meaning the adaptor's "active" setting will be set to false). A soft-delete for entities avoids purging important information, including that which can be used to associate past activity in the system, such as logged events, zone, and adaptor type.

However, the linking (mapping) between the (YOUnite) Data Record and the source entities in the source system attached to the deleted adaptor will be hard deletes. Linking for deleted adaptors is hard-deleted as this particular data carries no useful additional data or metadata (the link entities are just an adaptorUuid and a drUuid).  Post-delete, an adaptor's linking history can still be viewed in system logs that should include all the relevant details about that link, as well as a log timestamp.

Get Credentials for an Adaptor

By default only the Zone Data Steward can retrieve the credentials for an adaptor:

GET /zones/661f5d76-6bc7-4fc0-97fd-f331ab683379/adaptors/3dfcc03d-e5d4-4d57-9e9b-5c5d2db32f9a/registration

The response would look similar to:

{
    "uuid": "3dfcc03d-e5d4-4d57-9e9b-5c5d2db32f9a",
    "zoneUuid": "661f5d76-6bc7-4fc0-97fd-f331ab683379",
    "clientId": "64ed6954-3987-4020-9553-54d9e4e7d258",
    "clientSecret": "76e33a67-8e8c-4209-ae38-5e4fa59fd452"
}