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Gerrit https://gerrit.o-ran-sc.org/r/nonrtric/plt/sme
Overview
Service Manager builds on CAPIF and depends on the Kong API Gateway. CAPIF stands for common API framework and it was developed by 3GPP to enable a unified Northbound API framework across 3GPP network functions, and to ensure that there is a single and harmonized approach for API development. Among CAPIF's key features are the following.
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If you only need the above APIs, then Service Manager is a plugin-in replacement for CAPIF.
CAPIF core function APIs
The CAPIF Interfaces
Service Manager is a Go implementation of the CAPIF Core function, which is based on the 3GPP "29.222 Common API Framework for 3GPP Northbound APIs (CAPIF)" interfaces, see https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=3450.
Generation of API Code
The CAPIF APIs are generated from the OpenAPI specifications provided by 3GPP. The `generate.sh` script downloads the specifications from 3GPP, fixes them and then generates the APIs. While these files are checked into the repo, they can be re-generated using generate.sh.
The specifications are downloaded from the following site; https://www.3gpp.org/ftp/Specs/archive/29_series. To see the APIs in swagger format, see the following link; https://github.com/jdegre/5GC_APIs/tree/Rel-17#common-api-framework-capif.
CAPIF core function APIs implemented by Service Manager
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Service Name | Service Operations | Operation Semantics | Consumer(s) |
CAPIF_API_Provider_Management_API | Register_API_Provider | POST /registrations | API Management Function |
Update_API_Provider | PUT /registrations/{registrationId} | API Management Function | |
Deregister_API_Provider | DELETE /registrations/{registrationId} | API Management Function | |
CAPIF_Publish_Service_API | Publish_Service_API | POST /{apfId}//service-apis | API Publishing Function, CAPIF core function |
Unpublish_Service_API | DELETE /{apfId/service-apis/{serviceApiId} | API Publishing Function, CAPIF core function | |
Update_Service_API | PUT /{apfId/service-apis/{serviceApiId} | API Publishing Function, CAPIF core function | |
Get_Service_API | GET /{apfId}/service-apis | API Publishing Function, CAPIF core function | |
CAPIF_API_Invoker_Management_API | Onboard_API_Invoker | POST /onboardedInvokers | API Invoker |
Offboard_API_Invoker | DELETE /onboardedInvokers/{onboardingId} | API Invoker | |
Update_API_Invoker_Details | PUT /onboardedInvokers/{onboardingId} | API Invoker | |
CAPIF_Discover_Service_API | Discover_Service_API | GET /allServiceAPIs | API Invoker, CAPIF core function |
Service Manager
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Integration with Kong
Service Manager is a Go implementation of a service that calls CAPIF Core. When publishing a service through Service Manager, we create a Kong route and Kong service. The InterfaceDescription JSON element that we return in the response body is updated to point to the Kong Data Plane. Therefore, the API interface that we return from Service Discovery has the Kong host and port, and not the original service's host and port. In this way, we use Kong as a reverse proxy. Instead of calling the Publishing service directly, our Invoker's API request is proxied through Kong. This gives us the advantages of using a proxied service, such as providing caching and load balancing.
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