Ballerina connector development sample - BallerinaLang

Ballerina is a general purpose, concurrent and strongly typed programming language with both textual and graphical syntaxes, optimized for integration. In this post we will discuss how we can use ballerina swagger connector development tool to develop connector using already designed swagger API.

First download zip file content and unzip it into your local machine. Also you need to download ballerina composer and run time from the ballerinalang web site to try this.

https://drive.google.com/file/d/0B3OmQJfm2Ft8QkRsVHoxTXNfeVE/view?usp=sharing

Now we need to start back end for generated connector.

Goto student-msf4j-server directory and build it.

/swagger-connector-demo/student-msf4j-server>> mvn clean install

Now you will see micro service jar file generated. Then run MSF4J service using following command.

/swagger-connector-demo/student-msf4j-server>> java -jar target/swagger-jaxrs-server-1.0.0.jar starting Micro Services 2017-02-19 21:37:44 INFO  MicroservicesRegistry:55 - Added microservice: io.swagger.api.StudentsApi@25f38edc 2017-02-19 21:37:44 INFO  MicroservicesRegistry:55 - Added microservice: org.wso2.msf4j.internal.swagger.SwaggerDefinitionService@17d99928 2017-02-19 21:37:44 INFO  NettyListener:68 - Starting Netty Http Transport Listener 2017-02-19 21:37:44 INFO  NettyListener:110 - Netty Listener starting on port 8080 2017-02-19 21:37:44 INFO  MicroservicesRunner:163 - Microservices server started in 307ms

Now we can check MSF4J service running or not using CuRL as follows.

curl -v http://127.0.0.1:8080/students *   Trying 127.0.0.1... * Connected to 127.0.0.1 (127.0.0.1) port 8080 (#0) > GET /students HTTP/1.1 > Host: 127.0.0.1:8080 > User-Agent: curl/7.43.0 > Accept: */* > < HTTP/1.1 200 OK < Connection: keep-alive < Content-Length: 41 < Content-Type: application/json < * Connection #0 to host 127.0.0.1 left intact {"code":4,"type":"ok","message":"magic!"}

Please use following sample swagger definition to generate connector(this is available in zip file attached).

swagger: '2.0' info:  version: '1.0.0'  title: Swagger School (Simple)  description: A sample API that uses a school as an example to demonstrate features in the swagger-2.0 specification  termsOfService: http://helloreverb.com/terms/  contact:     name: Swagger API team     email: foo@example.com     url: http://swagger.io  license:     name: MIT     url: http://opensource.org/licenses/MIT host: schol.swagger.io basePath: /api schemes:  - http consumes:  - application/json produces:  - application/json paths:  /students:     get:      description: Returns all students from the system that the user has access to      operationId: findstudents      produces:        - application/json        - application/xml        - text/xml        - text/html      parameters:        - name: limit          in: query          description: maximum number of results to return          required: false          type: integer          format: int32      responses:        '200':          description: student response          schema:            type: array            items:              $ref: '#/definitions/student'        default:          description: unexpected error          schema:            $ref: '#/definitions/errorModel'     post:      description: Creates a new student in the school.  Duplicates are allowed      operationId: addstudent      produces:        - application/json      parameters:        - name: student          in: body          description: student to add to the school          required: true          schema:            $ref: '#/definitions/newstudent'      responses:        '200':          description: student response          schema:            $ref: '#/definitions/student'        default:          description: unexpected error          schema:            $ref: '#/definitions/errorModel'  /students/{id}}:     get:      description: Returns a user based on a single ID, if the user does not have access to the student      operationId: findstudentById      produces:        - application/json        - application/xml        - text/xml        - text/html      parameters:        - name: id          in: path          description: ID of student to fetch          required: true          type: integer          format: int64        - name: ids          in: query          description: ID of student to fetch          required: false          type: integer          format: int64      responses:        '200':          description: student response          schema:            $ref: '#/definitions/student'        default:          description: unexpected error          schema:            $ref: '#/definitions/errorModel'     delete:      description: deletes a single student based on the ID supplied      operationId: deletestudent      parameters:        - name: id          in: path          description: ID of student to delete          required: true          type: integer          format: int64      responses:        '204':          description: student deleted        default:          description: unexpected error          schema:            $ref: '#/definitions/errorModel' definitions:  student:     type: object     required:      - id      - name     properties:      id:        type: integer        format: int64      name:        type: string      tag:        type: string  newstudent:     type: object     required:      - name     properties:      id:        type: integer        format: int64      name:        type: string      tag:        type: string  errorModel:     type: object     required:      - code      - textMessage     properties:      code:        type: integer        format: int32      textMessage:        type: string

Generate connector
./ballerina swagger connector /home/sanjeewa/Desktop/sample.yaml  -p org.wso2 -d ./test

Then add connector to composer and expose it as service.

import ballerina.net.http;
@http:BasePath("/testService")
service echo {
    @http:POST
    resource echo(message m) {
    Default defaultConnector = create Default();
    message response1 = Default.employeeIDGet( defaultConnector, m);
    reply response1;
    }
}
connector Default() {
    http:ClientConnector endpoint = create http:ClientConnector("http://127.0.0.1:8080/students");
    action employeeIDDelete(Default c, message msg)(message ) {
        message response;
        response = http:ClientConnector.delete(endpoint, http:getRequestURL(msg), msg);
        return response;     
    }
     action employeeIDGet(Default c, message msg)(message ) {
        message response;
        response = http:ClientConnector.get(endpoint, http:getRequestURL(msg), msg);
        return response;
    }
     action employeeIDPut(Default c, message msg)(message ) {
        message response;
        response = http:ClientConnector.put(endpoint, http:getRequestURL(msg), msg);
        return response;
    }
     action rootGet(Default c, message msg)(message ) {
        message response;
        response = http:ClientConnector.get(endpoint, http:getRequestURL(msg), msg);
        return response;
    }
     action rootPost(Default c, message msg)(message ) {
        message response;
        response = http:ClientConnector.post(endpoint, http:getRequestURL(msg), msg);
        return response;     
    } 
}

Then you will see relevant files in output directory.

├── test

  └── org

      └── wso2

          ├── default.bal

          ├── LICENSE

          ├── README.md

          └── types.json

Then you can copy generated connector code into composer and start your service development. How its appear in composer source view.

How its loaded in composer UI.

Then run it.
 ./ballerina run service ./testbal.bal

Now invoke ballerina service as follows.

curl -v -X POST http://127.0.0.1:9090/testService

*   Trying 127.0.0.1...
* Connected to 127.0.0.1 (127.0.0.1) port 9090 (#0)
> POST /testService HTTP/1.1
> Host: 127.0.0.1:9090
> User-Agent: curl/7.43.0
> Accept: */*
>
< HTTP/1.1 200 OK
< Connection: keep-alive
< Content-Length: 49
< Content-Type: application/json
<
* Connection #0 to host 127.0.0.1 left intact
{"code":4,"type":"ok","message":"test-ballerina"}

How to use Ballerina code generator tools to generate connector from swagger definition - BallerinaLang

Download samples and resource required for this project from this location.

https://drive.google.com/file/d/0B3OmQJfm2Ft8ZVJXZi02S19KQ3M/view?usp=sharing

Goto ballerina distribution   

/ballerina-0.8.0-SNAPSHOT/bin

Then it will generate connector as well.

Then run following command. For this we need to pass swagger input file to generate swagger.

Sample command

Example commands for connector, skeleton and mock service generation is as follows in order. ballerina swagger connector /tmp/testSwagger.json -d /tmp  -p wso2.carbon.test ballerina swagger skeleton /tmp/testSwagger.json -d /tmp  -p wso2.carbon.test ballerina swagger mock /tmp/testSwagger.json -d /tmp  -p wso2.carbon.test

Command:

>>./ballerina swagger connector /home/sanjeewa/Desktop/student.yaml -p org.wso2 -d ./test

Please use following sample swagger definition for this.

swagger: '2.0' info:  version: '1.0.0'  title: Swagger School (Simple)  description: A sample API that uses a school as an example to demonstrate features in the swagger-2.0 specification  termsOfService: http://helloreverb.com/terms/  contact:     name: Swagger API team     email: foo@example.com     url: http://swagger.io  license:     name: MIT     url: http://opensource.org/licenses/MIT host: schol.swagger.io basePath: /api schemes:  - http consumes:  - application/json produces:  - application/json paths:  /students:     get:      description: Returns all students from the system that the user has access to      operationId: findstudents      produces:        - application/json        - application/xml        - text/xml        - text/html      parameters:        - name: limit          in: query          description: maximum number of results to return          required: false          type: integer          format: int32      responses:        '200':          description: student response          schema:            type: array            items:              $ref: '#/definitions/student'        default:          description: unexpected error          schema:            $ref: '#/definitions/errorModel'     post:      description: Creates a new student in the school.  Duplicates are allowed      operationId: addstudent      produces:        - application/json      parameters:        - name: student          in: body          description: student to add to the school          required: true          schema:            $ref: '#/definitions/newstudent'      responses:        '200':          description: student response          schema:            $ref: '#/definitions/student'        default:          description: unexpected error          schema:            $ref: '#/definitions/errorModel'  /students/{id}}:     get:      description: Returns a user based on a single ID, if the user does not have access to the student      operationId: findstudentById      produces:        - application/json        - application/xml        - text/xml        - text/html      parameters:        - name: id          in: path          description: ID of student to fetch          required: true          type: integer          format: int64        - name: ids          in: query          description: ID of student to fetch          required: false          type: integer          format: int64      responses:        '200':          description: student response          schema:            $ref: '#/definitions/student'        default:          description: unexpected error          schema:            $ref: '#/definitions/errorModel'     delete:      description: deletes a single student based on the ID supplied      operationId: deletestudent      parameters:        - name: id          in: path          description: ID of student to delete          required: true          type: integer          format: int64      responses:        '204':          description: student deleted        default:          description: unexpected error          schema:            $ref: '#/definitions/errorModel' definitions:  student:     type: object     required:      - id      - name     properties:      id:        type: integer        format: int64      name:        type: string      tag:        type: string  newstudent:     type: object     required:      - name     properties:      id:        type: integer        format: int64      name:        type: string      tag:        type: string  errorModel:     type: object     required:      - code      - textMessage     properties:      code:        type: integer        format: int32      textMessage:        type: string

Then you will see relevant files in output directory.

├── test

  └── org

      └── wso2

          ├── default.bal

          ├── LICENSE

          ├── README.md

          └── types.json

Now copy this connector content to ballerina editor and load it as connector. Please see below image.

import ballerina.lang.messages; import ballerina.lang.system; import ballerina.net.http; import ballerina.lang.jsonutils; import ballerina.lang.exceptions; import ballerina.lang.arrays; connector Default(string text) {    action Addstudent(string msg, string auth)(message ) {       http:ClientConnector rmEP = create http:ClientConnector("http://127.0.0.1:8080");       message request = {};       message requestH;       message response;       requestH = authHeader(request, auth);       response = http:ClientConnector.post(rmEP, "/students", requestH);       return response;          }     action Findstudents(string msg, string auth)(message ) {       http:ClientConnector rmEP = create http:ClientConnector("http://127.0.0.1:8080");       message request = {};       message requestH;       message response;       requestH = authHeader(request, auth);       response = http:ClientConnector.get(rmEP, "/students", requestH);       return response;          }     }

Then goto editor view and see loaded ballerina connector.

Then we can see it's loaded as follows.

Now we can start writing our service by using generated connector. We can add following sample service definition which calls connector and get output. Connect your service with generated connector as follows.

@http:BasePath("/connector-test") service testService {        @http:POST    @http:Path("/student")    resource getIssueFromID(message m) {       StudentConnector studentConnector = create StudentConnector("test");       message response = {};       response = studentConnector.Findstudents(studentConnector, "");       json complexJson = messages:getJsonPayload(response);       json rootJson = `{"root":"someValue"}`;       jsonutils:set(rootJson, "$.root", complexJson);       string tests = jsonutils:toString(rootJson);       system:println(tests);       reply response;          }     }

Please see how it's loaded in editor.

Now we need to start back end for generated connector.

Goto student-msf4j-server directory and build it.

/swagger-connector-demo/student-msf4j-server>> mvn clean install

Now you will see micro service jar file generated. Then run MSF4J service using following command.

/swagger-connector-demo/student-msf4j-server>> java -jar target/swagger-jaxrs-server-1.0.0.jar starting Micro Services 2017-02-19 21:37:44 INFO  MicroservicesRegistry:55 - Added microservice: io.swagger.api.StudentsApi@25f38edc 2017-02-19 21:37:44 INFO  MicroservicesRegistry:55 - Added microservice: org.wso2.msf4j.internal.swagger.SwaggerDefinitionService@17d99928 2017-02-19 21:37:44 INFO  NettyListener:68 - Starting Netty Http Transport Listener 2017-02-19 21:37:44 INFO  NettyListener:110 - Netty Listener starting on port 8080 2017-02-19 21:37:44 INFO  MicroservicesRunner:163 - Microservices server started in 307ms

Now we can check MSF4J service running or not using CuRL as follows.

curl -v http://127.0.0.1:8080/students *   Trying 127.0.0.1... * Connected to 127.0.0.1 (127.0.0.1) port 8080 (#0) > GET /students HTTP/1.1 > Host: 127.0.0.1:8080 > User-Agent: curl/7.43.0 > Accept: */* > < HTTP/1.1 200 OK < Connection: keep-alive < Content-Length: 41 < Content-Type: application/json < * Connection #0 to host 127.0.0.1 left intact {"code":4,"type":"ok","message":"magic!"}

Now we have MSF4J service for student service up and running. We also have connector pointed to that and service which use that connector. So we can start ballerina service with final ballerina file. Then invoke student service as follows.

curl -v http://127.0.0.1:/connector-test/student