Service Manager is a Go implementation of a service that calls the CAPIF Core function. When publishing a service we create a Kong route and Kong service, https://konghq.com/. The InterfaceDescription that we return 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. This allows the rApp's API call to be re-directed through Kong.
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.
See CAPIF Core
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.
./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.
To fix the specifications there are three tools.
commoncollector, collects type definitions from peripheral specifications to keep down the number of dependencies to other specifications. The types to collect are listed in the definitions.txt file. Some fixes are hard-coded.enumfixer, fixes enumeration definitions so they can be properly generated.specificationfixer, fixes flaws in the specifications so they can be properly generated. All fixes are hard-coded.First, we need to run generate.sh as described above to generate our API code from the 3GPP spec.
Before we can test or run Service Manager, we need to configure a .env file with the required parameters. Please see the template .env.example in the servicemanager directory.
You can set the environmental variable SERVICE_MANAGER_ENV to specify the .env file. For example, the following command specifies to use the config file .env.development. If this flag is not set, first we try .env.development and then .env.
export SERVICE_MANAGER_ENV=development
We also need Kong and CAPIFcore to be running. Please see the examples in the deploy folder. You can also use https://gerrit.o-ran-sc.org/r/it/dep for deployment. Please see the notes at https://wiki.o-ran-sc.org/display/RICNR/Release+J%3A+Service+Manager
After generating the API code, we can build the application with the following command.
go build
To run the unit tests for the application, first ensure that the .env file is configured. In the following example, we specify .env.test.
export SERVICE_MANAGER_ENV=test go test ./...
To run as a local app, first ensure that the .env file is configured. In the following example, we specify .env.development.
export SERVICE_MANAGER_ENV=development ./servicemanager
Service Manager is then available on the port configured in .env.
The application can also be built as a Docker image, by using the following command. We build the image without a .env file. This is supplied by volume mounting at container run-time. Because we need to include CAPIFcore in the Docker build context, we build from the git repo's root directory, sme.
docker build -t servicemanager -f servicemanager/Dockerfile .
Please note that a special executable has been provided for deleting Kong routes and services that have been created by Service Manager in Kong. This executable is called kongclearup and is found in the working directory of the Service Manger Docker image, at /app/servicemanager. When we create a Kong route or service, we add Kong tags with information as follows.
When we delete Kong routes and services using kongclearup, we check for the existance of these tags, specifically, apfId, apiId and aefId. Only if these tags exist and have values do we proceed to delete the Kong service or route. The executable kongclearup uses the volume-mounted .env file to load the configuration giving the location of Kong. Please refer to sme/servicemanager/internal/kongclearup.go.
For a stand-alone deployment, please see the deploy folder for configurations to deploy to Service Manager to Kubernetes. We need the following steps.
We consolidate the above steps into the script deploy-to-k8s.sh. To delete the full deployment, you can use delete-from-k8s.sh. The deploy folder has the following structure.
We store the Kubernetes manifests files in the manifests in the subfolder. We store the shell scripts in the src folder.
In deploy-to-k8s.sh, we copy .env.example and use sed to replace the template values with values for running the Service Manager container. You will need to update this part of the script with your own values. There is an example sed replacement in function substitute_manifest() in deploy-to-k8s.sh. Here, you can substitute your own Docker images for CAPIFcore and Service Manager for local development.
In addition there are 2 switches that are added for developer convenience.
The additional env file needs to exist in the sme/servicemanager folder so that kongclearup can access is. It is specified by its filename. The relative path ../.. is added in the deploy-to-k8s.sh script. For example, to use
./deploy-to-k8s.sh --env .env.development
../../.env.development needs to exist.
A Postman collection has been included in this repo at sme/postman/ServiceManager.postman_collection.json.
To distinguish between multiple interface descriptions, Service Manager prepends the port number and a hash code to the URL path.
We can specify either static or dynamic routes. Static routing defines a route when there is a single route for traffic to reach a destination. Dynamic routing allows us to specify path parameters. In this config file, we specify path parameters using regular expressions.
Kong uses the regex definition from the Rust programming language to specify the regular expression (regex) that describes the path parameters, Kong regex.
An example of a static path is as follows. This is the straightforward case.
/rapps
An example of a dynamic path is
~/rapps/(?<rappId>[a-zA-Z0-9]+([-_][a-zA-Z0-9]+)*)
Our dynamic path starts with a ~ character. In this example, we have a path parameter that is described by a regex capture group called rappId. The regex describes a word made of mixed-case alphanumeric characters optionally followed by one or more sets of a dash or underscore together with another word.
When the Service Manager client calls a dynamic API, we call the URL without the '~'. Kong substitutes the path parameter according to the rules specified in the regex. Therefore, we can call the above example by using
/rapps/my-rApp-id
as the URL where my-rApp-id is the rApp id of in the rApp Manager. The name my-rApp-id has to match the regex shown above.
It is required to name the capture group in this YAML config file. The capture group name is used by Service Manager when creating a Kong Request Transformer plugin. We can specify multiple capture groups in a URL if there are multiple path parameters in the API path.
We create a Kong Request Transformer plugin with .data[].config.replace, as in the following example curl with abridged response.
curl -X GET http://oran-nonrtric-kong-admin.nonrtric.svc.cluster.local:8001/plugins
{ "body": [], "uri": "/rapps/$(uri_captures[\"rappId\"])", "headers": [], "querystring": [] }
In our example, this allows Kong to match /rapps/my-rApp-id.
The Service Manager uses the following regex to search and replace the YAML file regexes.
/\(\?<([^>]+)>([^\/]+)/
Please note that the example path, /rapps/my-rApp-id, is not terminated by a '/'. Service Manager adds a '/' for internal matching. This made the regex easier to develop. Service Manager will match on /rapps/my-rApp-id/ for this case.