Discover the Microservice Bus

Microservice Bus provides a service registration/discovery and routing mechanism to simply the communications between services, The service consumers only need to talk with Microservice Bus without any address information of individual service providers. However, all the service consumers/providers must know the IP and service port of Microservice Bus. MSB suggests the following approach to discover the Microservice Bus.
Each service provider/consumer implementation can get the address of the Microservice Bus from a local config file via the key 'msb.address', the default value consists of a hostname and a service port. The hostname is 'msb.onap.org', which can be resolved by a DNS server in the local network, and the default port is 80. If a DNS server is not available in some deployments, an IP should be used instead.

Examples:

Default config when a DNS server is available

msb.address: msb.onap.org:80

An IP if a DNS server is not available

msb.address: 10.74.205.123:80

API Definition and Swagger-UI

ONAP intends to be a microservices-based architecture and every individual service is exposed as a restful API. Microservice Bus provide mechanisms to collect and display the API description(swagger UI) and metrics of services centrally.
The services should provide the information to Microservice Bus by the below approaches:

Swagger

REST APIs should be described in a swagger.json file according to Open API Initiative.
The swagger.json file should be put at the root path of the service url, such as: http(s)://[hostname][:port]/[ServiceType]/[ServiceName]/[Service Version]/Swagger.json
The swagger.json can be automatically generated by JAVA notation, more information can be find at Swagger Annotations.

For example, the swagger description and UI of the services provided by Microservice Bus:
Service: /api/microservices/v1/
Swagger: /api/microservices/v1/swagger.json

Register service to the Microservice Bus

Operation

URL

/api/microservices/v1/services

Verb

POST

Request

Parameter

Mandatory

Parameter type

Data Type

Default

example

Description

Body

JSON String

{
  "serviceName": "aai",
  "version": "v8",
  "url": "/aai/v8",
  "protocol": "REST",
  "visualRange": "1",
  "path":"/aai/v8"
  "nodes": [

    {
      "ip": "10.74.56.36",
      "port": "8988",
      "ttl": 0
    }
  ]
}

Described in the below table

createOrUpdate

Query

boolean

true

true: create new instances or replace the old instances if the instance with the same service name, ipandportexist

false: create new instances and remove all the old instances with the same service name

Parameter	Mandatory	Data Type	Default	Description
serviceName	Y	String		Service Name, must comply with RFC 1123, only allowsthe ASCII letters 'a' through 'z' , the digits '0' through '9', and the minus sign ('-').
version	Y	String		Service Version
url	Y if protocol is 'REST' or 'UI' or 'HTTP'	String		the actual URL of the service to be registered
protocol	Y	String		supported protocols: 'REST', 'UI', 'HTTP','TCP'
visualRange	N	String	1	Visibility of the service. External(can be accessed by external systems):0 Internal(can only be accessed by ONAP microservices):1
path	N	String		Thecustomizedpublish path of this service. If path parameter is specified when registering the service, the service will be published to apigateway under this path. Otherwise, the service will be published to apigateway using a fixed format: api/{serviceName}/{version}. The customized publish path should only be used for back-compatible.
enable_ssl	N	boolean	False	True if the registered service is based on https. False if the registered service is based on http.
nodes	Y	List		ip: the ipoftheservice instance node, it could also be a hostname like catalog.onap.org port: the port of the service instance node ttl: time to live, this parameter is reserved for later use

Response

example

Description

{
  "serviceName": "catalog",
  "version": "v1",
  "url": "/api/catalog/v1",
  "protocol": "REST",
  "visualRange": "1",
 "lb_policy":"ip_hash",

  "nodes": [
    {
      "ip": "10.74.55.66",
      "port": "6666",
      "ttl": 0
    },
    {
      "ip": "10.74.56.37",
      "port": "8989",
      "ttl": 0  
    },
    {
      "ip": "10.74.56.36",
      "port": "8988",
      "ttl": 0
    }
  ]
}

serviceName: service name
version: version
url: url of the created service instance
protocol: supported protocols: 'REST', 'UI','HTTP','TCP'
nodes: the service instance nodes list to register
lb_policy: Load balancing method, Currently two LB methods are supported, round-robin and ip-hash.
ip: the ip of the service instance node, it could also be a hostname like catalog.onap.org
port: the port of the service instance node
ttl: time to live, this parameter is reserved for later use

Success Code

201

Error Code

422 Invalid Parameters
500 Internal Server Error

Unregister service from the Microservice Bus

Operation

Unregister service from the Microservice Bus

URL

/api/microservices/v1/services/{serviceName}/version/{version}/nodes/{ip}/{port}

Verb

DELETE

Request

Parameter	Mandatory	Parameter type	Data Type	Description
serviceName	Y	Path	String	Service Name
version	N	Path	String	Service Version
ip	N	Path	String	the IP address of the service instance, it could also be a hostname like catalog.onap.org
port	N	Path	String	the port of the service instance

Response

Success Code

204

Error Code

404 Can't find the service instance
422 Invalid Parameters
500 Internal Server Error

Query service from the Microservice Bus

You can access service by two ways:

First is Point to Point, service consumer can query service instances address from MSB by the following API,and access the service provider directly; - Not recommended, we will lose centralized control capabilities if chose this approach, for example, service call logging, service load balancing policy, etc.

Second is API Gateway, service consumer do not care ip and port of the service provider, it just access the API-Gateway ,and the API-Gateway will route the service call to the appropriate service provider; in this approach, service consumers only need to know the ip and port of API Gateway, it can be stored in a configuration file or an environment property of the service consumer implementation.

MSB support the following access methods:

if the service provider version property is provided when registration, you can use the version before or behind the service name.

/api/[servicename]/v1

/api/v1/[servicename]

if the service did not have version property, you can use the url without version.

/api/[servicename]/

Operation

Query service from the Microservice Bus

URL

/api/microservices/v1/services/{serviceName}/version/{version}

Verb

GET

Request

Parameter	Mandatory	Parameter type	Data Type	Default	example	Description
serviceName	N	Path	String			Service Name
version	N	Path	String			Service Version

Response

example	Description
{ "serviceName": "catalog", "version": "v1", "url": "/api/catalog/v1", "protocol": "REST", "visualRange": "1", "nodes": [ { "ip": "10.74.55.66", "port": "6666", "ttl": 0 }, { "ip": "10.74.56.37", "port": "8989", "ttl": 0 }, { "ip": "10.74.56.36", "port": "8988", "ttl": 0 } ] }	serviceName: service name version: version url: url of the created service instance protocol: supported protocols: 'REST', 'UI', 'HTTP','TCP' nodes: the service instance nodes list to register ip: the ip of the service instance node, it could also be a hostname like catalog.onap.org port: the port of the service instance node ttl: time to live, this parameter is reserved for later use

Success Code

200

Error Code

404 Can't find the service instance
422 Invalid Parameters
500 Internal Server Error

MSB Client SDK

MSBServiceClient : JAVA SDK for MSB service discovery

RestServiceCreater: JAVA SDK for REST service invocation

MSB Client SDK Example

https://gerrit.onap.org/r/gitweb?p=msb/java-sdk.git;a=tree;f=example;h=1c331f86cbcbdb8cc2935d8ac41169da1a523ec5;hb=refs/heads/master

    String MSB_IP="127.0.0.1";
    int MSB_Port=10081;
    
    MSBServiceClient msbClient = new MSBServiceClient(MSB_IP, MSB_Port);
    
    RestServiceCreater restServiceCreater =
        new RestServiceCreater(msbClient);

    AnimalServiceClient implProxy =
        restServiceCreater.createService(AnimalServiceClient.class);
    
    Animal animal = implProxy.queryAnimal("panda").execute().body();
    System.out.println("animal:" + animal);

Note: In order to test the example application, you need to run MSB following this guide MSB Test Environment Setup