Databricks SDK for Java

Stability: Beta

The Databricks SDK for Java includes functionality to accelerate development with Java for the Databricks Lakehouse. It covers all public Databricks REST API operations. The SDK's internal HTTP client is robust and handles failures on different levels by performing intelligent retries.

Contents

• Getting started
• Authentication
• Code examples
• Long-running operations
• Paginated responses
• Single-sign-on with OAuth
• Error handling
• Logging
• Proxy
• Interface stability
• Disclaimer

Getting started

You can install Databricks SDK for Java by adding the following to your pom.xml:

<dependency>
  <groupId>com.databricks</groupId>
  <artifactId>databricks-sdk-java</artifactId>
  <version>0.0.1</version>
</dependency>

Using the SDK is as simple as instantiating the WorkspaceClient class:

import com.databricks.sdk.WorkspaceClient;
import com.databricks.sdk.AccountClient;
import com.databricks.sdk.core.DatabricksConfig;
import com.databricks.sdk.service.compute.ClusterInfo;
import com.databricks.sdk.service.compute.ListClustersRequest;

public class App {
   public static void main(String[] args) {
      WorkspaceClient workspace = new WorkspaceClient();
      for (ClusterInfo c : workspace.clusters().list(new ListClustersRequest())) {
         System.out.println(c.getClusterName());
      }
   }
}

To access account-level APIs, you can instantiate the AccountClient class:

import com.databricks.sdk.WorkspaceClient;
import com.databricks.sdk.AccountClient;
import com.databricks.sdk.core.DatabricksConfig;
import com.databricks.sdk.service.compute.ClusterInfo;
import com.databricks.sdk.service.compute.ListClustersRequest;

public class App {
   public static void main(String[] args) {
      AccountClient account = new AccountClient();
      for (Workspace w : account.workspaces().list()) {
         System.out.println(w.getWorkspaceName());
      }
   }
}

Databricks SDK for Java is compatible with Java 8 and higher. CI testing runs on Java versions 8, 11, 17, and 20.

Authentication

If you use Databricks configuration profiles or Databricks-specific environment variables for Databricks authentication, the only code required to start working with a Databricks workspace is the following code snippet, which instructs the Databricks SDK for Java to use its default authentication flow:

import com.databricks.sdk.WorkspaceClient;
...
WorkspaceClient workspace = new WorkspaceClient();
workspace. // press <TAB> for autocompletion

In this section

• Default authentication flow
• Databricks native authentication
• Azure native authentication
• Overriding .databrickscfg
• Additional authentication configuration options

Default authentication flow

If you run the Databricks Terraform Provider, the Databricks SDK for Go, the Databricks SDK for Python, the Databricks CLI, or applications that target the Databricks SDKs for other languages, most likely they will all interoperate nicely together. By default, the Databricks SDK for Java tries the following authentication methods, in the following order, until it succeeds:

1. Databricks native authentication
2. Azure native authentication
3. If the SDK is unsuccessful at this point, it returns an authentication error and stops running.

You can instruct the Databricks SDK for Java to use a specific authentication method by instantiating the DatabricksConfig class and setting the auth_type as described in the following sections.

For each authentication method, the SDK searches for compatible authentication credentials in the following locations, in the following order. Once the SDK finds a compatible set of credentials that it can use, it stops searching:

1. Credentials that are hard-coded into configuration arguments.

   :warning: Caution: Databricks does not recommend hard-coding credentials into arguments, as they can be exposed in plain text in version control systems. Use environment variables or configuration profiles instead.

2. Credentials in Databricks-specific environment variables.

3. For Databricks native authentication, credentials in the .databrickscfg file's DEFAULT configuration profile from its default file location (~ for Linux or macOS, and %USERPROFILE% for Windows).

4. For Azure native authentication, the SDK searches for credentials through the Azure CLI as needed.

5. For Bricks CLI authentication, the SDK reuses OAuth credentials obtained by running bricks auth login.

Depending on the Databricks authentication method, the SDK uses the following information. Presented are the WorkspaceClient and AccountClient arguments (which have corresponding .databrickscfg file fields), their descriptions, and any corresponding environment variables.

Databricks native authentication

By default, the Databricks SDK for Java initially tries Databricks token authentication (auth_type='pat' argument). If the SDK is unsuccessful, it then tries Databricks basic (username/password) authentication (auth_type="basic" argument).

• For Databricks token authentication, you must provide host and token; or their environment variable or .databrickscfg file field equivalents.
• For Databricks basic authentication, you must provide host, username, and password (for AWS workspace-level operations); or host, account_id, username, and password (for AWS, Azure, or GCP account-level operations); or their environment variable or .databrickscfg file field equivalents.

For example, to use Databricks token authentication:

import com.databricks.sdk.WorkspaceClient;
import com.databricks.sdk.core.DatabricksConfig;
...
        DatabricksConfig config=new DatabricksConfig()
        .setAuthType("pat")
        .setHost("https://my-databricks-instance.com")
        .setToken("my-token");
        WorkspaceClient workspace=new WorkspaceClient(config);

Azure native authentication

By default, the Databricks SDK for Java first tries Azure client secret authentication (auth_type='azure-client-secret' argument). If the SDK is unsuccessful, it then tries Azure CLI authentication (auth_type='azure-cli' argument). See Manage service principals.

The Databricks SDK for Java picks up an Azure CLI token, if you've previously authenticated as an Azure user by running az login on your machine. See Get Azure AD tokens for users by using the Azure CLI.

To authenticate as an Azure Active Directory (Azure AD) service principal, you must provide one of the following. See also Add a service principal to your Azure Databricks account:

• azure_resource_id, azure_client_secret, azure_client_id, and azure_tenant_id; or their environment variable or .databrickscfg file field equivalents.
• azure_resource_id and azure_use_msi; or their environment variable or .databrickscfg file field equivalents.

For example, to use Azure client secret authentication:

import com.databricks.sdk.WorkspaceClient;
import com.databricks.sdk.core.DatabricksConfig;
...
        DatabricksConfig config=new DatabricksConfig()
        .setAuthType("azure-client-secret")
        .setHost("https://my-databricks-instance.com")
        .setAzureTenantId("tenant-id")
        .setAzureClientId("client-id")
        .setAzureClientSecret("client-secret");
        WorkspaceClient workspace=new WorkspaceClient(config);

Google Cloud Platform native authentication

By default, the Databricks SDK for Java first tries GCP credentials authentication (auth_type='google-credentials', argument). If the SDK is unsuccessful, it then tries Google Cloud Platform (GCP) ID authentication (auth_type='google-id', argument).

The Databricks SDK for Java picks up an OAuth token in the scope of the Google Default Application Credentials (DAC) flow. This means that if you have run gcloud auth application-default login on your development machine, or launch the application on the compute, that is allowed to impersonate the Google Cloud service account specified in google_service_account. Authentication should then work out of the box. See Creating and managing service accounts.

To authenticate as a Google Cloud service account, you must provide one of the following:

• host and google_credentials; or their environment variable or .databrickscfg file field equivalents.
• host and google_service_account; or their environment variable or .databrickscfg file field equivalents.

For example, to use Google ID authentication:

import com.databricks.sdk.WorkspaceClient;
import com.databricks.sdk.core.DatabricksConfig;
...
        DatabricksConfig config=new DatabricksConfig()
        .setAuthType("google-credentials")
        .setHost("https://my-databricks-instance.com")
        .setGoogleServiceAccgount("google-service-account");
        WorkspaceClient workspace=new WorkspaceClient(config);

Overriding .databrickscfg

For Databricks native authentication, you can override the default behavior for using .databrickscfg as follows:

For example, to use a profile named MYPROFILE instead of DEFAULT:

import com.databricks.sdk.WorkspaceClient;
import com.databricks.sdk.core.DatabricksConfig;
...
        DatabricksConfig config=new DatabricksConfig()
        .setProfile("MYPROFILE");
        WorkspaceClient workspace=new WorkspaceClient(config);

Additional authentication configuration options

For all authentication methods, you can override the default behavior in client arguments as follows:

For example, to turn on debug HTTP headers:

import com.databricks.sdk.WorkspaceClient;
import com.databricks.sdk.core.DatabricksConfig;
...
        DatabricksConfig config=new DatabricksConfig()
        .setDebugHeaders(true);
        WorkspaceClient workspace=new WorkspaceClient(config);

Code examples

To find code examples that demonstrate how to call the Databricks SDK for Java, see the top-level examples folder within this repository.

Long-running operations

When you invoke a long-running operation, the SDK provides a high-level API to trigger these operations and wait for the related entities to reach the correct state or return the error message in case of failure. All long-running operations return generic Wait instance with a get() method to get a result of long-running operation, once it's finished. Databricks SDK for Java picks the most reasonable default timeouts for every method, but sometimes you may find yourself in a situation, where you'd want to provide a custom Duration as the value of timeout argument to the get() method.

There are a number of long-running operations in Databricks APIs, including:

• Clusters
• Command execution
• Jobs
• Libraries
• Delta Live Tables pipelines
• SQL warehouses

For example, in the Clusters API, once you create a cluster, you receive a cluster ID, and the cluster is in the PENDING state Meanwhile Databricks takes care of provisioning virtual machines from the cloud provider in the background. The cluster is only usable in the RUNNING state and so you have to wait for that state to be reached.

Another example is the API for running a job or repairing the run: right after the run starts, the run is in the PENDING state. The job is only considered to be finished when it is in either the TERMINATED or SKIPPED state. Also you would likely need the error message if the long-running operation times out failed with an error code. Other times you may want to configure a custom timeout other than the default of 20 minutes.

In the following example, workspace.clusters().create() returns ClusterInfo only once the cluster is in the RUNNING state, otherwise it will timeout in 10 minutes:

CreateCluster request = new CreateCluster()
   .setClusterName("test-cluster")
   .setSparkVersion("13.0.x-scala2.12")
   .setNodeTypeId("i3.xlarge")
   .setAutoterminationMinutes(10L)
   .setNumWorkers(1L);
ClusterInfo cluster = workspace.clusters().create(request).get(Duration.ofMinutes(10));

Paginated responses

On the platform side the Databricks APIs have different wait to deal with pagination:

• Some APIs follow the offset-plus-limit pagination
• Some start their offsets from 0 and some from 1
• Some use the cursor-based iteration
• Others just return all results in a single response

The Databricks SDK for Java hides this complexity under the Paginator abstraction. Users can iterate over the results of a paginated API, and the SDK will lazily load the next page of results as needed.

Map<Long, BaseJob> allJobs = new HashMap<>();
Map<Long, List<Long>> durations = new HashMap<>();
Map<Long, BaseRun> latestState = new HashMap<>();

WorkspaceClient workspace = new WorkspaceClient();
for (BaseJob job : workspace.jobs().list(new ListJobsRequest())) {
   allJobs.put(job.getJobId(), job);
   for (BaseRun run : workspace.jobs().listRuns(new ListRunsRequest().setJobId(job.getJobId()).setExpandTasks(false))) {
      durations.computeIfAbsent(job.getJobId(), k -> new ArrayList<>()).add(run.getRunDuration());
      if (!latestState.containsKey(job.getJobId())) {
         latestState.put(job.getJobId(), run);
         continue;
      }
      if (run.getEndTime() < latestState.get(job.getJobId()).getEndTime()) {
         continue;
      }
      latestState.put(job.getJobId(), run);
   }
}

// JobSummary is a custom POJO.
List<JobSummary> summary = new ArrayList<>();
for (Map.Entry<Long, BaseRun> entry : latestState.entrySet()) {
   Long jobId = entry.getKey();
   BaseRun run = entry.getValue();
   BaseJob job = allJobs.get(jobId);
   List<Long> jobDurations = durations.get(jobId);

   JobSummary jobSummary = new JobSummary(
           job.getSettings().getName(),
           run.getState().getResultState(),
           ZonedDateTime.ofInstant(Instant.ofEpochMilli(run.getEndTime()), ZoneId.of("UTC")),
           jobDurations.stream().mapToLong(Long::longValue).average().orElse(0)
   );
   summary.add(jobSummary);
}

summary.stream()
   .sorted(Comparator.comparing(JobSummary::getLastFinished).reversed())
   .forEach(jobSummary -> LOGGER.info("Latest: {}", jobSummary));

Single-Sign-On (SSO) with OAuth

Authorization Code flow with PKCE

For a regular web app running on a server, it's recommended to use the Authorization Code Flow to obtain an Access Token and a Refresh Token. This method is considered safe because the Access Token is transmitted directly to the server hosting the app, without passing through the user's web browser and risking exposure.

To enhance the security of the Authorization Code Flow, the PKCE (Proof Key for Code Exchange) mechanism can be employed. With PKCE, the calling application generates a secret called the Code Verifier, which is verified by the authorization server. The app also creates a transform value of the Code Verifier, called the Code Challenge, and sends it over HTTPS to obtain an Authorization Code. By intercepting the Authorization Code, a malicious attacker cannot exchange it for a token without possessing the Code Verifier.

The presented sample is a Spring Boot application that uses the Databricks SDK for Java to demonstrate how to implement the OAuth Authorization Code flow with PKCE security. It can be used to build an app where each user uses their identity to access Databricks resources. The script can be executed with or without client and secret credentials for a custom OAuth app.

Databricks SDK for Java exposes the OAuthClient.initiateConsent() helper to acquire user redirect URL and initiate PKCE state verification. Application developers are expected to persist SessionCredentials in the webapp session using Java serialization. The underlying HttpClient, used for refreshing the access token, is not serializable, so this must be rehydrated by the application on every request.

SSO for local scripts on development machines

For applications, that do run on developer workstations, Databricks SDK for Java provides auth_type='external-browser' utility, that opens up a browser for a user to go through SSO flow. See the CLI app example project for a demo of using this authentication method.

Creating custom OAuth applications

In order to use OAuth with Databricks SDK for Python, you should use AccountClient.customAppIntegration().create() API. Usage of this can be seen in the Spring Boot example project.

Error Handling

The Databricks SDK for Java provides a robust error-handling mechanism that allows developers to catch and handle API errors. When an error occurs, the SDK will raise an exception that contains information about the error, such as the HTTP status code, error message, and error details. Developers can catch these exceptions and handle them appropriately in their code.

import com.databricks.sdk.WorkspaceClient;
import com.databricks.sdk.core.errors.platform.ResourceDoesNotExist;
import com.databricks.sdk.service.compute.ClusterDetails;

public class ErrorDemo {
    public static void main(String[] args) {
        WorkspaceClient w = new WorkspaceClient();
        try {
            ClusterDetails c = w.clusters().get("1234-5678-9012");
        } catch (ResourceDoesNotExist e) {
          System.out.println("Cluster not found: " + e.getMessage());
        }
    }
}

The SDK handles inconsistencies in error responses amongst the different services, providing a consistent interface for developers to work with. Simply catch the appropriate exception type and handle the error as needed. The errors returned by the Databricks API are defined in databricks-sdk-java/src/main/java/com/databricks/sdk/core/error/platform.

Logging

The Databricks SDK for Java seamlessly integrates with the standard SLF4J logging framework. This allows developers to easily enable and customize logging for their Databricks Java projects. To enable debug logging in your Databricks java project, you can add the following to your log4j.properties file:

log4j.logger.com.databricks.sdk=DEBUG

This will enable logging at the debug level and above. Developers can adjust the logging level as needed to control the verbosity of the logging output. The SDK will log all requests and responses to standard error output, using the format > for requests and < for responses. In some cases, requests or responses may be truncated due to size considerations. If this occurs, the log message will include the text ... (XXX additional elements) to indicate that the request or response has been truncated. To increase the truncation limits, developers can set the debug_truncate_bytes configuration property or the DATABRICKS_DEBUG_TRUNCATE_BYTES environment variable. To protect sensitive data, such as authentication tokens, passwords, or any HTTP headers, the SDK will automatically replace these values with **REDACTED** in the log output. Developers can disable this redaction by setting the debug_headers configuration property to True.

2023-03-22 21:19:21,702 [databricks.sdk][DEBUG] GET /api/2.1/clusters/list
< 200 OK
< {
<   "clusters": [
<     {
<       "autotermination_minutes": 60,
<       "cluster_id": "1109-115255-s1w13zjj",
<       "cluster_name": "DEFAULT Test Cluster",
<       ... truncated for brevity
<     },
<     "... (47 additional elements)"
<   ]
< }

Overall, the logging capabilities provided by the Databricks SDK for Java can be a powerful tool for monitoring and troubleshooting your Databricks Java projects. Developers can use the various logging methods and configuration options provided by the SDK to customize the logging output to their specific needs.

Proxy

Databricks SDK for Java supports clients using proxy. Clients can use their proxy setup either by providing the proxy settings in the DatabricksConfig configuration object or by creating a ProxyConfig object and passing it to the constructor of CommonsHttpClient. The following properties can be set in the .databrickscfg file to configure the proxy settings:

Note: when using Kerberos authentication in SPNEGO, the java.security.krb5.conf system property must point to the krb5.conf/krb5.ini file that contains the Kerberos configuration.

Shaded JAR

If you wish to use the latest version of the Databricks SDK for Java on DBR, you'll find that the version that's built into DBR takes precedence.

To use the latest version regardless, you can build and install a JAR with a different namespace for the SDK packages:

cd shaded
mvn package
ls -l target
# The target directory includes a file "shaded-databricks-sdk-X.Y.Z.jar".

Use the SDK in this package by prepending shaded. to all imports:

import shaded.com.databricks.sdk.WorkspaceClient;
import shaded.com.databricks.sdk.AccountClient;
import shaded.com.databricks.sdk.core.DatabricksConfig;
import shaded.com.databricks.sdk.service.compute.ClusterInfo;
import shaded.com.databricks.sdk.service.compute.ListClustersRequest;

// ...

Disclaimer

Databricks is actively working on stabilizing the Databricks SDK for Java's interfaces. API clients for all services are generated from specification files that are synchronized from the main platform. You are highly encouraged to pin the exact dependency version and read the changelog where Databricks documents the changes. Databricks may have minor documented backward-incompatible changes, such as renaming the methods or some type names to bring more consistency.