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README 

        
# OPA Java SDK



[![License](https://img.shields.io/badge/License-Apache_2.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)

[![Maven Central Version](https://img.shields.io/maven-central/v/com.styra/opa?label=Maven%20Central&logo=apache-maven&color=%2324b6e0)](https://central.sonatype.com/artifact/com.styra/opa)



> [!IMPORTANT]

> The documentation for this SDK lives at https://docs.styra.com/sdk, with reference documentation available at https://styrainc.github.io/opa-java/javadoc, and development documentation at https://styrainc.github.io/opa-java/



You can use the Styra OPA SDK to connect to [Open Policy Agent](https://www.openpolicyagent.org/) and [Enterprise OPA](https://www.styra.com/enterprise-opa/) deployments.



## SDK Installation



This package is published on Maven Central as [`com.styra/opa`](https://central.sonatype.com/artifact/com.styra/opa/overview). The Maven Central page includes up-to-date instructions to add it as a dependency to your Java project, tailored for a variety of build systems including Maven and Gradle.



If you wish to build from source and publish the SDK artifact to your local Maven repository (on your filesystem) then use the following command (after cloning the git repo locally):



On Linux/MacOS:

```bash

./gradlew publishToMavenLocal -Pskip.signing

```



On Windows:

```bash

gradlew.bat publishToMavenLocal -Pskip.signing

```



## SDK Example Usage (high-level)



```java

package org.example;



import com.styra.opa.OPAClient;

import com.styra.opa.OPAException;



import java.util.Map;

import java.util.List;



import static java.util.Map.entry;



public class App {

    public static void main(String[] args) throws Exception {

        // Create an OPA instance, this handles any state needed for interacting

        // with OPA, and can be re-used for multiple requests if needed.

        String opaURL = "http://localhost:8181";

        OPAClient opa = new OPAClient(opaURL);



        // This will be the input to our policy.

        java.util.Map input = java.util.Map.ofEntries(

            entry("subject", "alice"),

            entry("action", "read"),

            entry("resource", "/finance/reports/fy2038_budget.csv")

        );



        // We will read the list of policy violations, and whether the request

        // is allowed or not into these.

        java.util.List violations;

        boolean allowed;



        // Perform the request against OPA.

        try {

            allowed = opa.check("policy/allow", input);

            violations = opa.evaluate("policy/violations", input);

        } catch (OPAException e ) {

            // Note that OPAException usually wraps other exception types, in

            // case you need to do more complex error handling.

            System.out.println("exception while making request against OPA: " + e);

            throw e; // crash the program

        }



        System.out.println("allowed: " + allowed);

        System.out.println("violations: " + violations);

    }

}

```



> [!NOTE]

> For low-level SDK usage, see the sections below.



---



# OPA OpenApi SDK (low-level)



## Summary



For more information about the API: [Enterprise OPA documentation](https://docs.styra.com/enterprise-opa)



## Table of Contents



* [SDK Installation](#sdk-installation)

* [SDK Example Usage](#sdk-example-usage)

* [Available Resources and Operations](#available-resources-and-operations)

* [Error Handling](#error-handling)

* [Server Selection](#server-selection)

* [Authentication](#authentication)



## SDK Example Usage



### Example 1



```java

package hello.world;



import com.styra.opa.openapi.OpaApiClient;

import com.styra.opa.openapi.models.errors.ClientError;

import com.styra.opa.openapi.models.errors.ServerError;

import com.styra.opa.openapi.models.operations.ExecuteDefaultPolicyWithInputResponse;

import com.styra.opa.openapi.models.shared.GzipAcceptEncoding;

import com.styra.opa.openapi.models.shared.Input;

import com.styra.opa.openapi.models.shared.Security;

import java.lang.Exception;



public class Application {



    public static void main(String[] args) throws ClientError, ServerError, Exception {



        OpaApiClient sdk = OpaApiClient.builder()

                .security(Security.builder()

                    .bearerAuth("")

                    .build())

            .build();



        ExecuteDefaultPolicyWithInputResponse res = sdk.executeDefaultPolicyWithInput()

                .pretty(false)

                .acceptEncoding(GzipAcceptEncoding.GZIP)

                .input(Input.of(4963.69d))

                .call();



        if (res.result().isPresent()) {

            // handle response

        }

    }

}

```



### Example 2



```java

package hello.world;



import com.styra.opa.openapi.OpaApiClient;

import com.styra.opa.openapi.models.errors.ClientError1;

import com.styra.opa.openapi.models.errors.ServerError;

import com.styra.opa.openapi.models.operations.ExecutePolicyWithInputRequest;

import com.styra.opa.openapi.models.operations.ExecutePolicyWithInputRequestBody;

import com.styra.opa.openapi.models.operations.ExecutePolicyWithInputResponse;

import com.styra.opa.openapi.models.shared.Input;

import com.styra.opa.openapi.models.shared.Security;

import java.lang.Exception;



public class Application {



    public static void main(String[] args) throws ClientError1, ServerError, Exception {



        OpaApiClient sdk = OpaApiClient.builder()

                .security(Security.builder()

                    .bearerAuth("")

                    .build())

            .build();



        ExecutePolicyWithInputRequest req = ExecutePolicyWithInputRequest.builder()

                .path("app/rbac")

                .requestBody(ExecutePolicyWithInputRequestBody.builder()

                    .input(Input.of(false))

                    .build())

                .build();



        ExecutePolicyWithInputResponse res = sdk.executePolicyWithInput()

                .request(req)

                .call();



        if (res.successfulPolicyResponse().isPresent()) {

            // handle response

        }

    }

}

```



### Example 3



```java

package hello.world;



import com.styra.opa.openapi.OpaApiClient;

import com.styra.opa.openapi.models.errors.BatchServerError;

import com.styra.opa.openapi.models.errors.ClientError1;

import com.styra.opa.openapi.models.operations.ExecuteBatchPolicyWithInputRequest;

import com.styra.opa.openapi.models.operations.ExecuteBatchPolicyWithInputRequestBody;

import com.styra.opa.openapi.models.operations.ExecuteBatchPolicyWithInputResponse;

import com.styra.opa.openapi.models.shared.Input;

import com.styra.opa.openapi.models.shared.Security;

import java.lang.Exception;

import java.util.Map;



public class Application {



    public static void main(String[] args) throws ClientError1, BatchServerError, Exception {



        OpaApiClient sdk = OpaApiClient.builder()

                .security(Security.builder()

                    .bearerAuth("")

                    .build())

            .build();



        ExecuteBatchPolicyWithInputRequest req = ExecuteBatchPolicyWithInputRequest.builder()

                .path("app/rbac")

                .requestBody(ExecuteBatchPolicyWithInputRequestBody.builder()

                    .inputs(Map.ofEntries(

                        Map.entry("key", Input.of(""))))

                    .build())

                .build();



        ExecuteBatchPolicyWithInputResponse res = sdk.executeBatchPolicyWithInput()

                .request(req)

                .call();



        if (res.batchSuccessfulPolicyEvaluation().isPresent()) {

            // handle response

        }

    }

}

```



## Available Resources and Operations



Available methods



### [OpaApiClient SDK](docs/sdks/opaapiclient/README.md)



* [executeDefaultPolicyWithInput](docs/sdks/opaapiclient/README.md#executedefaultpolicywithinput) - Execute the default decision  given an input

* [executePolicy](docs/sdks/opaapiclient/README.md#executepolicy) - Execute a policy

* [executePolicyWithInput](docs/sdks/opaapiclient/README.md#executepolicywithinput) - Execute a policy given an input

* [executeBatchPolicyWithInput](docs/sdks/opaapiclient/README.md#executebatchpolicywithinput) - Execute a policy given a batch of inputs

* [health](docs/sdks/opaapiclient/README.md#health) - Verify the server is operational



## Server Selection



### Select Server by Index



You can override the default server globally by passing a server index to the `serverIndex` builder method when initializing the SDK client instance. The selected server will then be used as the default on the operations that use it. This table lists the indexes associated with the available servers:



| # | Server | Variables |

| - | ------ | --------- |

| 0 | `http://localhost:8181` | None |



#### Example



```java

package hello.world;



import com.styra.opa.openapi.OpaApiClient;

import com.styra.opa.openapi.models.errors.ClientError;

import com.styra.opa.openapi.models.errors.ServerError;

import com.styra.opa.openapi.models.operations.ExecuteDefaultPolicyWithInputResponse;

import com.styra.opa.openapi.models.shared.GzipAcceptEncoding;

import com.styra.opa.openapi.models.shared.Input;

import com.styra.opa.openapi.models.shared.Security;

import java.lang.Exception;



public class Application {



    public static void main(String[] args) throws ClientError, ServerError, Exception {



        OpaApiClient sdk = OpaApiClient.builder()

                .serverIndex(0)

                .security(Security.builder()

                    .bearerAuth("")

                    .build())

            .build();



        ExecuteDefaultPolicyWithInputResponse res = sdk.executeDefaultPolicyWithInput()

                .pretty(false)

                .acceptEncoding(GzipAcceptEncoding.GZIP)

                .input(Input.of(4963.69d))

                .call();



        if (res.result().isPresent()) {

            // handle response

        }

    }

}

```



### Override Server URL Per-Client



The default server can also be overridden globally by passing a URL to the `serverURL` builder method when initializing the SDK client instance. For example:

```java

package hello.world;



import com.styra.opa.openapi.OpaApiClient;

import com.styra.opa.openapi.models.errors.ClientError;

import com.styra.opa.openapi.models.errors.ServerError;

import com.styra.opa.openapi.models.operations.ExecuteDefaultPolicyWithInputResponse;

import com.styra.opa.openapi.models.shared.GzipAcceptEncoding;

import com.styra.opa.openapi.models.shared.Input;

import com.styra.opa.openapi.models.shared.Security;

import java.lang.Exception;



public class Application {



    public static void main(String[] args) throws ClientError, ServerError, Exception {



        OpaApiClient sdk = OpaApiClient.builder()

                .serverURL("http://localhost:8181")

                .security(Security.builder()

                    .bearerAuth("")

                    .build())

            .build();



        ExecuteDefaultPolicyWithInputResponse res = sdk.executeDefaultPolicyWithInput()

                .pretty(false)

                .acceptEncoding(GzipAcceptEncoding.GZIP)

                .input(Input.of(4963.69d))

                .call();



        if (res.result().isPresent()) {

            // handle response

        }

    }

}

```



## Error Handling



Handling errors in this SDK should largely match your expectations. All operations return a response object or raise an exception.



By default, an API error will throw a `models/errors/SDKError` exception. When custom error responses are specified for an operation, the SDK may also throw their associated exception. You can refer to respective *Errors* tables in SDK docs for more details on possible exception types for each operation. For example, the `executeDefaultPolicyWithInput` method throws the following exceptions:



| Error Type                | Status Code               | Content Type              |

| ------------------------- | ------------------------- | ------------------------- |

| models/errors/ClientError | 400, 404                  | application/json          |

| models/errors/ServerError | 500                       | application/json          |

| models/errors/SDKError    | 4XX, 5XX                  | \*/\*                     |



### Example



```java

package hello.world;



import com.styra.opa.openapi.OpaApiClient;

import com.styra.opa.openapi.models.errors.ClientError;

import com.styra.opa.openapi.models.errors.ServerError;

import com.styra.opa.openapi.models.operations.ExecuteDefaultPolicyWithInputResponse;

import com.styra.opa.openapi.models.shared.GzipAcceptEncoding;

import com.styra.opa.openapi.models.shared.Input;

import com.styra.opa.openapi.models.shared.Security;

import java.lang.Exception;



public class Application {



    public static void main(String[] args) throws ClientError, ServerError, Exception {



        OpaApiClient sdk = OpaApiClient.builder()

                .security(Security.builder()

                    .bearerAuth("")

                    .build())

            .build();



        ExecuteDefaultPolicyWithInputResponse res = sdk.executeDefaultPolicyWithInput()

                .pretty(false)

                .acceptEncoding(GzipAcceptEncoding.GZIP)

                .input(Input.of(4963.69d))

                .call();



        if (res.result().isPresent()) {

            // handle response

        }

    }

}

```



## Authentication



### Per-Client Security Schemes



This SDK supports the following security scheme globally:



| Name         | Type         | Scheme       |

| ------------ | ------------ | ------------ |

| `bearerAuth` | http         | HTTP Bearer  |



You can set the security parameters through the `security` builder method when initializing the SDK client instance. For example:

```java

package hello.world;



import com.styra.opa.openapi.OpaApiClient;

import com.styra.opa.openapi.models.errors.ClientError;

import com.styra.opa.openapi.models.errors.ServerError;

import com.styra.opa.openapi.models.operations.ExecuteDefaultPolicyWithInputResponse;

import com.styra.opa.openapi.models.shared.GzipAcceptEncoding;

import com.styra.opa.openapi.models.shared.Input;

import com.styra.opa.openapi.models.shared.Security;

import java.lang.Exception;



public class Application {



    public static void main(String[] args) throws ClientError, ServerError, Exception {



        OpaApiClient sdk = OpaApiClient.builder()

                .security(Security.builder()

                    .bearerAuth("")

                    .build())

            .build();



        ExecuteDefaultPolicyWithInputResponse res = sdk.executeDefaultPolicyWithInput()

                .pretty(false)

                .acceptEncoding(GzipAcceptEncoding.GZIP)

                .input(Input.of(4963.69d))

                .call();



        if (res.result().isPresent()) {

            // handle response

        }

    }

}

```



## Development



This repository includes components generated by [Speakeasy](https://www.speakeasyapi.dev/) based on [this OpenAPI spec](https://github.com/StyraInc/enterprise-opa/tree/main/openapi), as well as human authored code that simplifies usage. The Speakeasy generated code resides in the [com.styra.opa.sdk](https://styrainc.github.io/opa-java/javadoc/com/styra/opa/sdk/package-summary.html) package and offers the greatest level of control, but is more verbose and complicated. The hand written [com.styra.opa](https://styrainc.github.io/opa-java/javadoc/com/styra/opa/package-summary.html) package offers a simplified API designed to make using the OPA REST API straightforward for common use cases.



### Build Instructions



**To build the SDK**, use `./gradlew build`, the resulting JAR will be placed in `./build/libs/api.jar`.



**To build the documentation** site, including JavaDoc, run `./scripts/build_docs.sh OUTPUT_DIR`. You should replace `OUTPUT_DIR` with a directory on your local system where you would like the generated docs to be placed. You can also preview the documentation site ephemerally using `./scripts/serve_docs.sh`, which will serve the docs on `http://localhost:8000` until you use Ctrl+C to exit the script.



**To run the unit tests**, you can use `./gradlew test`.



**To run the linter**, you can use `./gradlew lint`



## Community



For questions, discussions and announcements related to Styra products, services and open source projects, please join

the Styra community on [Slack](https://communityinviter.com/apps/styracommunity/signup)!