Applying Metadata to HDFS and Hive Entities using the API

When you call an API to update or add metadata to existing Navigator entities, the call replaces the metadata of a given type with the metadata provided in the API call. Therefore when you update an entity, you must supply the existing metadata as well as the new metadata in the call payload.

Typically, you would call the GET /entities API to retrieve the existing metadata for the entities you want to update. The GET call returns a JSON object that includes all the metadata for the entities you request. You can then strip the technical metadata from the JSON, augment the remaining metadata with the values you want to update, then use the JSON as the payload for the PUT or POST call.

The GET /entities API allows you to retrieve entity metadata using an entity identifier or by using a search query. The search query uses the same syntax and field names as the full query text in the Navigator console Search tab. There are many examples of useful GET /entity calls in GET Existing Metadata Examples.

Navigator provides an API to create new entities without a metadata extraction process. Use this API to insert entities in Navigator from sources that do not have an extractor plugin or when you want to store metadata during ingest or other processes that occur before extraction would run. The API generates the appropriate internal identifier for the entity. If you call the API before the metadata for an entity is extracted, the user-defined metadata is stored with the following entity properties:

• Identity
• Source ID
• Metadata fields (name, description, tags, properties)
• Fields relevant to the identifier

Other fields (attributes) for the entity, such as Type, are not present when the entity is generated and are filled in later by an automated metadata extraction process.

Use the following cURL syntax to call the POST /entities API:

POST curl http://fqdn-n.example.com:port/api/APIversion/entities/ \
-u username:password \
-X POST \
-H "Content-Type: application/json" \
-d '{properties}'

where properties are:

• sourceId (required) — The identifier value from an existing source entity. See the GET /entities example to find the existing sources.
• parentPath — The path of the parent entity, defined as:
  • HDFS file or directory — fileSystemPath of the parent directory. (Do not provide this field if the entity affected is the root directory.) The parentPath for /user/admin/input_dir is /user/admin.

    If you add metadata to a directory, the metadata does not propagate to any files or folders in that directory.

  • Hive database — If you are updating database metadata, do not specify this field.
  • Hive table or view — The name of database containing the table or view. The parentPath for a table in the default database is default.
  • Hive column — database name/table name/view name. The parentPath for a column in the sample_07 table is default/sample_07.
• originalName (required) — The name as defined by the source system.
  • HDFS file or directory — Name of file or directory (ROOT if the entity is the root directory). The originalName for /user/admin/input_dir is input_dir.
  • Hive database, table, view, or column — The name of the database, table, view, or column.
    • Example for default database: default
    • Example for sample_07 table: sample_07
• Metadata fields (name, description, tags, user-defined properties, managed properties) that describe the final entity, including existing metadata.

All existing naming rules apply, and if any value is invalid, the entire request is denied. The call adds the entity to Navigator with the provided metadata and generates the entity identity:

identity — The ID assigned to an entity by Navigator. This value is generated by Navigator based on the originalName, parentPath, and sourceId.

You can use the PUT /entity/{id} API to update the metadata for a single entity.

User-defined metadata provided through the API overwrites existing metadata. In addition, null values for some metadata overwrites existing metadata. For example, passing empty or no name and description fields with an empty array for tags and empty property dictionary with the API call removes the existing metadata. If you omit the tags or properties fields, the existing tags or properties values remain unchanged. If you want to add a tag to a list of existing tags, you must include the existing tags in your update.

Use the following cURL syntax to make a PUT /entities call:

PUT curl http://fqdn-n.example.com:port/api/APIversion/entities/identity \
-u username:password \
-X PUT \
-H "Content-Type: application/json" \
-d '{properties}'

where identity is an entity ID and properties are:

• name — The name for the entity. This "name" is used in Navigator and is distinct from the "originalName" that Navigator extracted from the source. If there is already a name applied, you must supply the existing name to prevent the call from overwriting the name with a null value.
• description — The description for the entity. If you are not updating the description, you much supply the existing description to avoid overwriting a description with a null value.
• tags — Tag metadata. If you provide any tags, you must also supply existing tags to avoid removing existing tags.
• properties — User-defined properties. The format is {key: value}. Again, if you are adding a user-defined property, you must also supply the existing user-defined properties associated with this entity to avoid overwriting them.
• customProperties — Managed properties. The format is {namespace: {key: value}}. If a property is assigned a value that does not conform to type constraints, the call returns an error. If you are associating a managed property with an entity, you must also supply the existing managed properties associated with this entity to avoid overwriting them.

If any value is invalid, the entity is not updated.

curl http://node1.example.com:7187/api/v13/entities/e461de8de38511a3ac6740dd7d51b8d0 \
-u username:password \
-X PUT \
-H "Content-Type: application/json"\
-d '{"name":"my_name",
   "description":"My description",
   "tags":["tag1","tag2"],
   "properties":{"property1":"value1","property2":"value2"}}'

curl http://node1.example.com:7187/api/v13/entities/ \
-u username:password \
-X POST \
-H "Content-Type: application/json" \
-d '{"sourceId":"a09b0233cc58ff7d601eaa68673a20c6",
     "parentPath":"/user/admin",
     "originalName":"input_dir",
     "name":"my_name",
     "description":"My description",
     "tags":["tag1","tag2"],
     "properties":{"property1":"value1","property2":"value2"}}'

curl http://node1.example.com:7187/api/v13/entities/\
-u username:password \
-X POST \
-H "Content-Type: application/json" \
-d '{"sourceId":"4fbdadc6899638782fc8cb626176dc7b",
     "parentPath":"default/sample_07",
     "originalName":"total_emp",
     "name":"my_name",
     "description":"My description",
     "tags":["tag1","tag2"],
     "properties":{"property1":"value1","property2":"value2"}}'

This section shows some examples of useful GET /entity calls:

To retrieve a specific entity:

curl https://node1.example.com:7187/api/v14/entities/21302 \
-X GET -b NavCookie

curl https://node1.example.com:7187/api/v14/entities/?query=type%3ASOURCE \
-b NavCookie -X GET

{
  "originalName" : "HIVE-1",
  "originalDescription" : null,
  "sourceId" : null,
  "firstClassParentId" : null,
  "parentPath" : null,
  "deleteTime" : null,
  "extractorRunId" : null,
  "customProperties" : null,
  "name" : "HIVE-1",
  "description" : null,
  "tags" : null,
  "properties" : null,
  "technicalProperties" : null,
  "clusterName" : "Cluster 1",
  "sourceUrl" : "thrift://node2.example.com:9083",
  "sourceType" : "HIVE",
  "sourceExtractIteration" : 15,
  "sourceTemplate" : true,
  "hmsDbHost" : "node1.example.com",
  "hmsDbName" : "hive1",
  "hmsDbPort" : "3306",
  "hmsDbUser" : "hive1",
  "type" : "SOURCE",
  "userEntity" : false,
  "deleted" : null,
  "metaClassName" : "source",
  "packageName" : "nav",
  "identity" : "6",
  "internalType" : "source"
}

To retrieve all entities from a single source:

Run the previous call to determine the identity of the source, then use that value as the sourceId in the query. This example uses sourceId of 6.

curl https://node1.example.com:7187/api/v14/entities/?query=sourceId%3A6 \
-b NavCookie -X GET

To retrieve all entities marked with a specific tag:

Use quotes around the tag name. This example retrieves metadata for entities tagged with "sensitive".

curl https://node1.example.com:7187/api/v14/entities/?query=tags%3A%22sensitive%22 \
-b NavCookie -X GET

To retrieve all entities from a single source and marked with a tag:

This example includes a plus sign (+) before each of the query components to ensure they are treated as an AND relation. Note that this is a case where the query returns the correct results only with the ASCII codes.

curl https://node1.example.com:7187/api/v14/entities/?query=%2btags%3A%22sensitive%22%20%2bsourceId%3A6 \
-b cookie -X GET

To search for pre-registered entities:

This example shows how to get metadata for pre-registered entities, which do not include an internal type:

curl http://node1.example.com:7187/api/v13/entities/?query=-internalType:* \
-b cookie -X GET