Add support for async service bindings

[gberche-orange]

Supports private issue https://github.com/orange-cloudfoundry/paas-templates/issues/1360

Async service binding is now available in cf java client in https://github.com/cloudfoundry/cf-java-client/releases/tag/v5.9.0.RELEASE thanks to cloudfoundry/cf-java-client#1158

http://v3-apidocs.cloudfoundry.org/version/3.203.0/index.html#asynchronous-operations

Unlike V2, clients cannot opt-in for asynchronous responses from endpoints. Instead, endpoints that require asynchronous processing will return 202 Accepted with a Location header pointing to the job resource to poll. Endpoints that do not require asynchronous processing will respond synchronously.

For clients that want to report the outcome of an asynchronous operation, poll the job in the Location header until its state is no longer PROCESSING. If the job’s state is FAILED, the errors field will contain any errors that occurred during the operation.

Service related endpoints such as service instance, service credential binding and service route binding may create jobs that transition to state POLLING after PROCESSING. This state reflects the polling of the last operation from the service broker. For clients that want to report the outcome of this asynchronous operation, poll the job in the Location header until its state is no longer POLLING.

Protocol mapping outline

https://github.com/cloudfoundry/servicebroker/blob/master/spec.md#request-creating-a-service-binding
https://github.com/cloudfoundry/servicebroker/blob/master/spec.md#polling-last-operation-for-service-bindings
https://github.com/cloudfoundry/servicebroker/blob/master/spec.md#fetching-a-service-binding

http://v3-apidocs.cloudfoundry.org/version/3.203.0/index.html#create-a-service-credential-binding
http://v3-apidocs.cloudfoundry.org/version/3.203.0/index.html#get-a-job
http://v3-apidocs.cloudfoundry.org/version/3.203.0/index.html#get-a-service-credential-binding-details

sequenceDiagram
        actor osb-client
        actor osb-cmdb-broker
        actor cf
        osb-client ->>+ osb-cmdb-broker: PUT /v2/service_instances/:instance_id/service_bindings/:binding_id
        osb-cmdb-broker ->>+ cf: POST /POST /v2/service_bindings<br>name=:binding_id,accepts_incomplete=false
        note right of osb-cmdb-broker: return sync credentials if supported
        cf ->> osb-cmdb-broker: HTTP/1.1 201 created<br>credentials
        osb-cmdb-broker ->> osb-client: returns 201 Created, response contains credentials


        cf ->>- osb-cmdb-broker: HTTP/1.1 4xx Async not supported
        note right of osb-cmdb-broker: continue with new async request if sync not supported
        osb-cmdb-broker ->>+ cf: POST /v3/service_credential_bindings<br>name=:binding_id
        cf ->>- osb-cmdb-broker: HTTP/1.1 202 Accepted, <br/>Location:https://api.../v3/jobs/job-id
        osb-cmdb-broker ->>- osb-client: returns 202 Accepted, body{operation} with operation holding jobid

        osb-client ->>+ osb-cmdb-broker: GET /v2/service_instances/:instance_id/service_bindings/:binding_id/last_operation<br/>with  body{operation}
        osb-cmdb-broker ->>+ cf: GET /v3/jobs/:guid 
        cf ->>- osb-cmdb-broker:  return state
        osb-cmdb-broker ->>- osb-client: If COMPLETE then return {state": "succeeded"}<br/>If not, return {state": "in progress"}


        osb-client ->>+ osb-cmdb-broker: GET /v2/service_instances/:instance_id/service_bindings/:binding_id
        osb-cmdb-broker ->>+ cf: GET /v3/service_credential_bindings?service_instance_names=:instance_id <br> & names=:binding_id & type=key
        cf ->>- osb-cmdb-broker:  200 OK <br/>resources json, with binding guid
        osb-cmdb-broker ->>+ cf: GET /v3/service_credential_bindings/:guid/details
        cf ->>- osb-cmdb-broker:  200 OK <br/>credentials json
        osb-cmdb-broker ->>- osb-client: 200 OK <br/> credentials json

Loading