Swagger helps on following aspects:
Define REST API based on OAS standard, as swagger.json
Auto generate the REST service code, using swagger.json with swagger annotations.
Auto generate the client sdk code, using swagger.json in different language
Provides readable REST API document using swagger.json
And for implementing mirco-services, swagger is being an default technology.
Problems in mirco-services development
Following problem occurs in micro-service based products as there is no process exist to govern them:
Most of the time, developers manually authors the swagger REST API document, and it leads to inconsistent between the actual REST API implementation and API defined the document.
For mirco-services, developer starts to write the client sdk manually and which will also brings inconsistent between actual REST API provided by mirco-service and the client SDK implementation.
Client SDK in different languages become an huge effort involved and most of time, teams do not provide the client SDK in required languages of different micro-service, dependenting on another micro-service.
When depending services (B) changes the REST API, its only detected at system testing and integration testing phase of dependent service (A). Because client SDK of B is implemented by service A team, because service A does not provide the client SDK in required language as mentioned above.
To address these problems, Swagger-SDK is brought into ONAP, as ONAP is mirco-service based architecture.
What does Swagger-SDK provide:
It provides feature in build-time and run-time.
Generate the java client SDK for those services, which provides swagger.json already and deploy it in nexus in following package
[ Project Maven Group-id] ::[ Project maven artifact-id]-java-sdk :: [project maven version]
Generate the swagger.json for those services, which is already annotated with swagger java annotations. Also it deploy it in nexus in following package
[ Project Maven Group-id] ::[ Project maven artifact-id]-swagger-schema :: [project maven version]
MSB is already supported with this feature.
Provides an RESP API controller for reporting swagger.json at pre-defined URI. And it helps to maintain the same URI across different servicse in ONAP, by making use of it. Also it helps to generate swagger.json at run-time if a given service is already annotated with swagger annotations.
It does support only for java based swagger enabled RESTful services.