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Reading Tags On Datasets/Columns

Why Would You Read Tags?​

Tags are informal, loosely controlled labels that help in search & discovery. They can be added to datasets, dataset schemas, or containers, for an easy way to label or categorize entities – without having to associate them to a broader business glossary or vocabulary.

For more information about tags, refer to About DataHub Tags.

Goal Of This Guide​

This guide will show you how to read tags attached to a dataset SampleHiveDataset.

Prerequisites​

For this tutorial, you need to deploy DataHub Quickstart and ingest sample data. For detailed steps, please refer to Datahub Quickstart Guide.

note

Before reading tags, you need to ensure the targeted dataset and the tag are already present in your datahub. If you attempt to manipulate entities that do not exist, your operation will fail. In this guide, we will be using data from a sample ingestion. If you want to know how to create tags using APIs & SDKs, please refer to Creating Tags and Adding Tags.

Read Tags With GraphQL​

note

Please note that there are two available endpoints (:8000, :9002) to access GraphQL. For more information about the differences between these endpoints, please refer to DataHub Metadata Service

GraphQL Explorer​

GraphQL Explorer is the fastest way to experiment with GraphQL without any dependencies. Navigate to GraphQL Explorer (http://localhost:9002/api/graphiql) and run the following query.

query {
  dataset(urn: "urn:li:dataset:(urn:li:dataPlatform:hive,SampleHiveDataset,PROD)") {
    tags {
      tags {
        tag {
          name
          urn
            properties {
              description
              colorHex
            }
        }
      }
    }
  }
}

If you see the following response, the operation was successful:

{
  "data": {
    "dataset": {
      "tags": {
        "tags": [
          {
            "tag": {
              "name": "Legacy",
              "urn": "urn:li:tag:Legacy",
              "properties": {
                "description": "Indicates the dataset is no longer supported",
                "colorHex": null,
                "name": "Legacy"
              }
            }
          }
        ]
      }
    }
  },
  "extensions": {}
}

CURL​

With CURL, you need to provide tokens. To generate a token, please refer to Access Token Management. With accessToken, you can run the following command.

curl --location --request POST 'http://localhost:8080/api/graphql' \
--header 'Authorization: Bearer <my-access-token>' \
--header 'Content-Type: application/json' \
--data-raw '{ "query": "{dataset(urn: \"urn:li:dataset:(urn:li:dataPlatform:hive,SampleHiveDataset,PROD)\") {tags {tags {tag {name urn properties { description colorHex } } } } } }", "variables":{}}'

Expected Response:

{
  "data": {
    "dataset": {
      "tags": {
        "tags": [
          {
            "tag": {
              "name": "Legacy",
              "urn": "urn:li:tag:Legacy",
              "properties": {
                "description": "Indicates the dataset is no longer supported",
                "colorHex": null
              }
            }
          }
        ]
      }
    }
  },
  "extensions": {}
}

Read Tags With Python SDK​

The following code reads tags attached to a dataset SampleHiveDataset.

Coming Soon!

We're using the MetdataChangeProposalWrapper to change entities in this example. For more information about the MetadataChangeProposal, please refer to MetadataChangeProposal & MetadataChangeLog Events