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If mismatches are found, xApp onboarding will return failure.

Most of the schema sections The schema file consists of two parts: sections that are static and cannot be changed for different xApp. However, the xApp developer can define their own and xApp specific controls section.

When an operator is onboarding an xApp, he/she will provide the controls section schema with $id "#controls"  together with the xApp descriptor.

The main schema xapp_onboarder will combine and refer to the controls schema with  id "#controls".

The following is the main schema that the xApp onboarder will use to validate the xApp descritor.  

Structure

schema files into one.

How to Create Schema for the Controls Section

You can submit arbitrary schema for the controls section. However, if the xApp descriptor contains a controls section, you have to provide the correct schema that describes it.

If the xApp does not require a control section, you can ignore the control section schema.

It is highly recommended to use draft-07 schema. The following is a skeleton schema that you can use

{
	"$schema": "http://json-schema.org/draft-07/schema#",
	"$id": "#/controls",
	"type": "object",
	"title": "Controls Section Schema",
	"required": [
		"REQUIRED_ITEM_1",
		"REQUIRED_ITEM_2"
	],
	"properties": {
		"REQUIRED_ITEM_1": {REQUIRED_ITEM_1_SUB_SCHEMA},
		"REQUIRED_ITEM_2": {REQUIRED_ITEM_2_SUB_SCHEMA}
	}
}

Please include the list of required items in the required section, and provide the corresponding sub_schema in the properties section.

You can download the skeleton schema file here 

xApp Descriptor Schema

The overall schema file includes the following sectionsThe schema file includes the following sections.

• xapp_name: xapp_name is a string variable. properties are as follows.

  Code Block
  "xapp_name": { "$id": "#/properties/xapp_name", "type": "string", "title": "The xApp Name", "default": "xapp", "examples": [ "example_xapp" ] },

  
  

• version: version is a string variable that follows the semantic versioning syntax.

  Code Block
  "version": { "$id": "#/properties/version", "type": "string", "title": "The xApp version", "default": "1.0.0", "examples": [ "1.0.0" ], "pattern": "^(0|[1-9]\\d*)\\.(0|[1-9]\\d*)\\.(0|[1-9]\\d*)(?:-((?:0|[1-9]\\d*|\\d*[a-zA-Z-][0-9a-zA-Z-]*)(?:\\.(?:0|[1-9]\\d*|\\d*[a-zA-Z-][0-9a-zA-Z-]*))*))?(?:\\+([0-9a-zA-Z-]+(?:\\.[0-9a-zA-Z-]+)*))?$" },

  
  

• containers: containers is a list of container objects that includes name of the container, container image name, registry, tag, and entry command . It has a structure of

  Code Block
  "containers": [ { "name": "example_container_1", "image": { "registry": "example_image_registry_1", "name": "example_image_name_1", "tag": "example_image_tag_1" }, "command": "example_command_1" }, { "name": "example_container_2", "image": { "registry": "example_image_registry_2", "name": "example_image_name_2", "tag": "example_image_tag_2" } } ]

  The following schema defines the above structure 

  Code Block

  "containers": { "$id": "#/properties/containers", "type": "array", "title": "The Container Schema", "items": { "$id": "#/properties/containers/items", "type": "object", "title": "The Container Items Schema", "required": [ "name", "image" ], "properties": { "name": { "$id": "#/properties/containers/items/properties/name", "type": "string", "title": "The xApp Container Name", "default": "xapp", "examples": [ "xapp" ] }, "image": { "$id": "#/properties/containers/items/properties/image", "type": "object", "title": "The Container Image", "required": [ "registry", "name", "tag" ], "properties": { "registry": { "$id": "#/properties/containers/items/properties/image/properties/registry", "type": "string", "title": "The xApp Image Registry", "default": "nexus3.o-ran-sc.org:10002", "examples": [ "nexus3.o-ran-sc.org:10002" ], "pattern": "^[A-Za-z0-9\\.-]{1,}\\.[A-Za-z]{1,}(?:\\:\\d+)?$" }, "name": { "$id": "#/properties/containers/items/properties/image/properties/name", "type": "string", "title": "The xApp Image Name", "default": "xapp", "examples": [ "xapp" ] }, "tag": { "$id": "#/properties/containers/items/properties/image/properties/tag", "type": "string", "title": "The xApp Image Tag", "default": "latest", "examples": [ "latest" ] } } }, "command": { "$id": "#/properties/containers/items/properties/command", "type": "string", "title": "Command To Run The xApp Container", "default": "command", "examples": [ "command" ] } } } },

  
  

• livenessProbe: livenessProbe defines the k8s liveness probe for the xApp pod. It follows the following schema

  Code Block

  "livenessProbe": { "$id": "#/properties/livenessprobe", "type": "object", "title": "The Liveness Probe Definition", "properties": { "exec": { "$id": "#/properties/livenessprobe/exec", "type": "object", "title": "Script of Liveness Probe", "properties": { "command": { "$id": "#/properties/livenessprobe/exec/command", "type": "array", "items": [ { "$id": "#/properties/livenessprobe/exec/command/item", "type": "string", "title": "The Command Item", "default": "/bin/sh", "examples": [ "/bin/sh" ] } ] } }, "required": [ "command" ] }, "httpGet": { "$id": "#/properties/livenessprobe/httpget", "type": "object", "title": "Http of Liveness Probe", "properties": { "path": { "$id": "#/properties/livenessprobe/httpget/path", "type": "string", "title": "The Path of Http Liveness Probe", "default": "/health", "examples": [ "/health" ] }, "port": { "$id": "#/properties/livenessprobe/httpget/port", "type": "integer", "title": "The Port of Http Liveness Probe", "default": 80, "examples": [ 80 ] } }, "required": [ "path", "port" ] }, "initialDelaySeconds": { "$id": "#/properties/livenessprobe/initialdelayseconds", "type": "integer", "title": "Initial Delay of Liveness Probe", "default": 5, "examples": [ 5 ] }, "periodSeconds": { "$id": "#/properties/livenessprobe/periodseconds", "type": "integer", "title": "Period of Liveness Probe", "default": 15, "examples": [ 15 ] } }, "oneOf": [ { "$id": "#/properties/livenessprobe/oneof/exec", "required": ["exec", "initialDelaySeconds", "periodSeconds"] }, { "$id": "#/properties/livenessprobe/oneof/httpget", "required": ["httpGet", "initialDelaySeconds", "periodSeconds"] } ] },

  
  

• readinessProbe: readinessProbe defines the k8s readiness probe for the xApp pod. It follows the following schema

  Code Block

  "readinessProbe": { "$id": "#/properties/readinessprobe", "type": "object", "title": "The Readiness Probe Definition", "properties": { "exec": { "$id": "#/properties/readinessprobe/exec", "type": "object", "title": "Script of Readiness Probe", "properties": { "command": { "$id": "#/properties/readinessprobe/exec/command", "type": "array", "items": [ { "type": "string" } ] } }, "required": [ "command" ] }, "httpGet": { "$id": "#/properties/readinessprobe/httpget", "type": "object", "title": "Http of Readiness Probe", "properties": { "path": { "$id": "#/properties/readinessprobe/httpget/path", "type": "string", "title": "The Path of Http Readiness Probe", "default": "/health", "examples": [ "/health" ] }, "port": { "$id": "#/properties/readinessprobe/httpget/port", "type": "integer", "title": "The Port of Http Readiness Probe", "default": 80, "examples": [ 80 ] } }, "required": [ "path", "port" ] }, "initialDelaySeconds": { "$id": "#/properties/readinessprobe/initialdelayseconds", "type": "integer", "title": "Initial Delay of Readiness Probe", "default": 5, "examples": [ 5 ] }, "periodSeconds": { "$id": "#/properties/readinessprobe/periodseconds", "type": "integer", "title": "Period of Readiness Probe", "default": 15, "examples": [ 15 ] } }, "oneOf": [ { "$id": "#/properties/readinessprobe/oneof/exec", "required": ["exec", "initialDelaySeconds", "periodSeconds"] }, { "$id": "#/properties/readinessprobe/oneof/httpget", "required": ["httpGet", "initialDelaySeconds", "periodSeconds"] } ] },

  
  

...

• messaging: this schema defines the messaging parameters structure

  Code Block

  "messaging": { "type": "object", "$id": "#/properties/messaging", "title": "The Messaging Schema", "properties": { "ports": { "$id": "#/properties/messaging/ports", "type": "array", "title": "The Ports for Messaging", "items":{ "$id": "#/properties/messaging/ports/items", "type": "object", "title": "The Item of Port", "required": ["name", "container", "port"], "dependencies": { "txMessages": ["rxMessages", "policies"], "rxMessages": ["txMessages", "policies"], "policies": ["rxMessages", "txMessages"] }, "properties": { "name": { "$id": "#/properties/messaging/ports/items/name", "type": "string", "title": "The Name of the Port", "default": "App", "examples": [ "App" ] }, "container": { "$id": "#/properties/messaging/ports/items/container", "type": "string", "title": "The Container of the Port", "default": "xapp", "examples": [ "xapp" ] }, "port": { "$id": "#/properties/messaging/ports/items/port", "type": "integer", "title": "The Port Number", "default": 8080, "examples": [ 8080 ] }, "description": { "$id": "#/properties/messaging/ports/items/description", "type": "string", "title": "The description for the port", "default": "port description", "examples": [ "port description" ] }, "txMessages": { "$id": "#/properties/messaging/ports/items/txmessages", "type": "array", "title": "The txMessage Types", "items":{ "$id": "#/properties/messaging/ports/items//txmessages/item", "type": "string", "title": "The txMessage Types Item", "default": "RIC_SUB", "examples": [ "RIC_SUB" ] } }, "rxMessages": { "$id": "#/properties/messaging/ports/items/rxmessages", "type": "array", "title": "The rxMessage Types", "items":{ "$id": "#/properties/messaging/ports/items/rxmessages/item", "type": "string", "title": "The rxMessage Types Item", "default": "RIC_SUB", "examples": [ "RIC_SUB" ] } }, "policies": { "$id": "#/properties/messaging/ports/items/policies", "type": "array", "title": "The Policies Types", "items":{ "$id": "#/properties/messaging/ports/items/policies/item", "type": "integer", "title": "The Policy Types Item", "default": 1, "examples": [ 1 ] } } } } } }, "required": [ "ports" ] },

  Controls: controls is an xApp specify section. xApp developer shall defines the schema for this section to describe the internal xApp parameter structure. it has a basic structure of 

  Code Block
  "controls": { "type": "object", "$id": "#/properties/controls", "title": "The Controls Schema" },

  
  

  
  

• metrics: this schema defines the metrics structure

  Code Block

  "metrics": { "type": "array", "$id": "#/properties/metrics", "title": "The Metrics Schema", "items": { "$id": "#/properties/metrics/items", "type": "object", "title": "The Metrics Items Schema", "required": [ "objectName", "objectInstance", "name", "type", "description" ], "properties": {": { "objectName": { "$id": "#/properties/metrics/items/objectname", "type": "string", "title": "The Object Name" }, "objectNameobjectInstance": { "$id": "#/properties/metrics/items/objectnameobjectinstance", "type": "string", "title": "The Object NameInstance" }, "objectInstancename": { "$id": "#/properties/metrics/items/objectinstancename", "type": "string", "title": "The Object InstanceName" }, "nametype": { "$id": "#/properties/metrics/items/nametype", "type": "string", "title": "The Object NameType" }, "typedescription": { "$id": "#/properties/metrics/items/typedescription", "type": "string", "title": "The Object Type" }, "descriptionDescription" } } } } },

  
  

• Controls: This section will be replaced by the submitted control section schema. If the controls section schema is not provided, the following will be used to make sure that the xApp onboarder will reject an xApp descriptor with an undefined control section.

  Code Block
  "controls": { "$idrequired": "#/properties/metrics/items/description", [ "type": "string",__empty_control_section__" "title": "The Object Description" } } } } ] }