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DataHub Frontend

DataHub frontend is a Play service written in Java. It is served as a mid-tier between DataHub GMS which is the backend service and DataHub Web.

Pre-requisites#

  • You need to have JDK8 installed on your machine to be able to build DataHub Frontend.
  • You need to have Chrome web browser installed to be able to build because UI tests have a dependency on Google Chrome.

Build#

DataHub Frontend is already built as part of top level build:

./gradlew build

However, if you only want to build DataHub Frontend specifically:

./gradlew :datahub-frontend:build

Dependencies#

Before starting DataHub Frontend, you need to make sure that DataHub GMS and all its dependencies have already started and running.

Also, user information should already be registered into the DB, otherwise user will not be able to sign in. To do that, first create a file named user.dat containing below line and filling the parts <<something>> with your information:

{"auditHeader": None, "proposedSnapshot": ("com.linkedin.pegasus2avro.metadata.snapshot.CorpUserSnapshot", {"urn": "urn:li:corpuser:<<username>>", "aspects": [{"active": True, "fullName": "<<Full Name>>", "email": "<<e-mail address>>"}, {}]}), "proposedDelta": None}

And run mce producer script as below:

python metadata-ingestion/mce_cli.py produce -d user.dat

Or, you can run the script without providing any data file. In this case, the script will use bootstrap_mce.dat file to bootstrap some sample users and datasets:

python metadata-ingestion/mce_cli.py produce

This will create a default user with username datahub. You can sign in to the app using datahub as your username.

Start via Docker image#

Quickest way to try out DataHub Frontend is running the Docker image.

Start via command line#

If you do modify things and want to try it out quickly without building the Docker image, you can also run the application directly from command line after a successful build:

cd datahub-frontend/run && ./run-local-frontend

Checking out DataHub UI#

After starting your application in one of the two ways mentioned above, you can connect to it by typing below into your favorite web browser:

http://localhost:9001

To be able to sign in, you need to provide your user name. You don't need to type any password.

Sample API calls#

All APIs for the application are defined in routes file. Below, you can find sample curl calls to these APIs and their responses.

Browse APIs#

Getting current browse path#

http://localhost:9001/api/v2/browsePaths?type=dataset&urn=urn:li:dataset:(urn:li:dataPlatform:kafka,pageviews,PROD)
[
"/PROD/kafka/pageviews"
]

Browsing datasets#

http://localhost:9001/api/v2/browse?type=dataset&path=/prod
{
"elements": [],
"start": 0,
"count": 0,
"total": 1,
"metadata": {
"totalNumEntities": 1,
"path": "",
"groups": [{
"name": "prod",
"count": 1
}]
}
}

Search APIs#

Search query#

http://localhost:9001/api/v2/search?type=dataset&input=page
{
"elements": [{
"origin": "PROD",
"name": "pageviews",
"platform": "urn:li:dataPlatform:kafka"
}],
"start": 0,
"count": 10,
"total": 1,
"searchResultMetadatas": [{
"name": "platform",
"aggregations": {
"kafka": 1
}
}, {
"name": "origin",
"aggregations": {
"prod": 1
}
}]
}

Autocomplete query#

http://localhost:9001/api/v2/autocomplete?type=dataset&field=name&input=page
{
"query": "page",
"suggestions": ["pageviews"]
}

Dataset APIs#

Getting basic dataset metadata#

http://localhost:9001/api/v2/datasets/urn:li:dataset:(urn:li:dataPlatform:kafka,pageviewsevent,PROD)
{
"dataset": {
"platform": "kafka",
"nativeName": "pageviewsevent",
"fabric": "PROD",
"uri": "urn:li:dataset:(urn:li:dataPlatform:kafka,pageviewsevent,PROD)",
"description": "",
"nativeType": null,
"properties": null,
"tags": [],
"removed": null,
"deprecated": null,
"deprecationNote": null,
"decommissionTime": null,
"createdTime": null,
"modifiedTime": null
}
}

Getting dataset schema#

http://localhost:9001/api/v2/datasets/urn:li:dataset:(urn:li:dataPlatform:kafka,pageviews,PROD)/schema
{
"schema": {
"schemaless": false,
"rawSchema": "{\"type\":\"record\",\"name\":\"MetadataChangeEvent\",\"namespace\":\"com.linkedin.pegasus2avro.mxe\",\"doc\":\"Kafka event for proposing a metadata change for an entity.\",\"fields\":[{\"name\":\"auditHeader\",\"type\":{\"type\":\"record\",\"name\":\"KafkaAuditHeader\",\"namespace\":\"com.linkedin.pegasus2avro.avro2pegasus.events\",\"doc\":\"Header\"}}]}",
"keySchema": null,
"columns": [{
"id": null,
"sortID": 0,
"parentSortID": 0,
"fieldName": "foo",
"parentPath": null,
"fullFieldPath": "foo",
"dataType": "string",
"comment": "Bar",
"commentCount": null,
"partitionedStr": null,
"partitioned": false,
"nullableStr": null,
"nullable": false,
"indexedStr": null,
"indexed": false,
"distributedStr": null,
"distributed": false,
"treeGridClass": null
}],
"lastModified": 0
}
}

Getting owners of a dataset#

http://localhost:9001/api/v2/datasets/urn:li:dataset:(urn:li:dataPlatform:kafka,pageviews,PROD)/owners
{
"owners": [{
"userName": "ksahin",
"source": "UI",
"namespace": "urn:li:corpuser",
"name": "Kerem Sahin",
"email": "ksahin@linkedin.com",
"isGroup": false,
"isActive": true,
"idType": "USER",
"type": "DataOwner",
"subType": null,
"sortId": null,
"sourceUrl": null,
"confirmedBy": "UI",
"modifiedTime": 0
}, {
"userName": "datahub",
"source": "UI",
"namespace": "urn:li:corpuser",
"name": "Data Hub",
"email": "datahub@linkedin.com",
"isGroup": false,
"isActive": true,
"idType": "USER",
"type": "DataOwner",
"subType": null,
"sortId": null,
"sourceUrl": null,
"confirmedBy": "UI",
"modifiedTime": 0
}],
"fromUpstream": false,
"datasetUrn": "urn:li:dataset:(urn:li:dataPlatform:kafka,pageviews,PROD)",
"lastModified": 0,
"actor": "ksahin"
}

Getting dataset documents#

http://localhost:9001/api/v2/datasets/urn:li:dataset:(urn:li:dataPlatform:kafka,pageviews,PROD)/institutionalmemory
{
"elements": [{
"description": "Sample doc",
"createStamp": {
"actor": "urn:li:corpuser:ksahin",
"time": 0
},
"url": "https://www.linkedin.com"
}]
}

Getting upstreams of a dataset#

http://localhost:9001/api/v2/datasets/urn:li:dataset:(urn:li:dataPlatform:kafka,pageviews,PROD)/upstreams
[{
"dataset": {
"platform": "kafka",
"nativeName": "pageViewsUpstream",
"fabric": "PROD",
"uri": "urn:li:dataset:(urn:li:dataPlatform:kafka,pageViewsUpstream,PROD)",
"description": "",
"nativeType": null,
"properties": null,
"tags": [],
"removed": null,
"deprecated": null,
"deprecationNote": null,
"decommissionTime": null,
"createdTime": null,
"modifiedTime": null
},
"type": "TRANSFORMED",
"actor": "urn:li:corpuser:ksahin",
"modified": null
}]

User APIs#

Getting basic user metadata#

http://localhost:9001/api/v1/user/me
{
"user": {
"id": 0,
"userName": "ksahin",
"departmentNum": 0,
"email": "ksahin@linkedin.com",
"name": "Kerem Sahin",
"pictureLink": "https://content.linkedin.com/content/dam/me/business/en-us/amp/brand-site/v2/bg/LI-Bug.svg.original.svg",
"userSetting": null
},
"status": "ok"
}

Getting all users#

http://localhost:9001/api/v1/party/entities
{
"status": "ok",
"userEntities": [{
"label": "ksahin",
"category": "person",
"displayName": null,
"pictureLink": "https://content.linkedin.com/content/dam/me/business/en-us/amp/brand-site/v2/bg/LI-Bug.svg.original.svg"
}, {
"label": "datahub",
"category": "person",
"displayName": null,
"pictureLink": "https://content.linkedin.com/content/dam/me/business/en-us/amp/brand-site/v2/bg/LI-Bug.svg.original.svg"
}]
}

Authentication#

DataHub frontend leverages Java Authentication and Authorization Service (JAAS) to perform the authentication. By default we provided a DummyLoginModule which will accept any username/password combination. You can update jaas.conf to match your authentication requirement. For example, use the following config for LDAP-based authentication,

WHZ-Authentication {
  com.sun.security.auth.module.LdapLoginModule sufficient
  userProvider="ldaps://<host>:636/dc=<domain>"
  authIdentity="{USERNAME}"
  userFilter="(&(objectClass=person)(uid={USERNAME}))"
  java.naming.security.authentication="simple"
  debug="false"
  useSSL="true";
};

Authentication in React#

The React app supports both JAAS as described above and separately OIDC authentication. To learn about configuring OIDC for React, see the OIDC in React document.

API Debugging#

Most DataHub frontend API endpoints are protected using Play Authentication, which means it requires authentication information stored in the cookie for the request to go through. This makes debugging using curl difficult. One option is to first make a curl call against the /authenticate endpoint and stores the authentication info in a cookie file like this

curl -c cookie.txt -d '{"username":"datahub", "password":"datahub"}' -H 'Content-Type: application/json' http://localhost:9001/authenticate

You can then make all subsequent calls using the same cookie file to pass the authentication check.

curl -b cookie.txt "http://localhost:9001/api/v2/search?type=dataset&input=page"