Merge pull request #1169 from redis/DOC-4819-amr-lettuce

DOC-4819 added Lettuce AMR example

Author: andy-stark-redis

content/develop/clients/lettuce/amr.md

@@ -0,0 +1,219 @@
+---
+categories:
+- docs
+- develop
+- stack
+- oss
+- rs
+- rc
+- oss
+- kubernetes
+- clients
+description: Learn how to authenticate to an Azure Managed Redis (AMR) database
+linkTitle: Connect to AMR
+title: Connect to Azure Managed Redis
+weight: 2
+---
+
+The [`redis-authx-entraid`](https://github.com/redis/jvm-redis-authx-entraid) package
+lets you authenticate your app to
+[Azure Managed Redis (AMR)](https://azure.microsoft.com/en-us/products/managed-redis)
+using [Microsoft Entra ID](https://learn.microsoft.com/en-us/entra/identity/).
+You can authenticate using a system-assigned or user-assigned
+[managed identity](https://learn.microsoft.com/en-us/entra/identity/managed-identities-azure-resources/overview)
+or a [service principal](https://learn.microsoft.com/en-us/entra/identity-platform/app-objects-and-service-principals),
+letting `redis-authx-entraid` fetch and renew the authentication tokens for you automatically.
+
+See
+[Use Microsoft Entra for cache authentication](https://learn.microsoft.com/en-us/azure/azure-cache-for-redis/cache-azure-active-directory-for-authentication)
+in the Microsoft docs to learn how to configure Azure to use Entra ID authentication.
+
+## Install
+
+Install [`Lettuce`]({{< relref "/develop/clients/lettuce" >}}) first,
+if you have not already done so.
+
+If you are using Maven, add
+the following dependency to your `pom.xml` file:
+
+```xml
+<dependency>
+    <groupId>redis.clients.authentication</groupId>
+    <artifactId>redis-authx-entraid</artifactId>
+    <version>0.1.1-beta1</version>
+</dependency>
+```
+
+If you are using Gradle, add the following dependency to your
+`build.gradle` file:
+
+```bash
+implementation 'redis.clients.authentication:redis-authx-entraid:0.1.1-beta1'
+```
+
+## Create a `TokenBasedRedisCredentialsProvider` instance
+
+The `TokenBasedRedisCredentialsProvider` class contains the authentication details that you
+must supply when you connect to Redis. Chain the methods of the
+`EntraIDTokenAuthConfigBuilder` class together (starting with the `builder()`
+method) to include the details you need, as shown in the following example:
+
+```java
+TokenBasedRedisCredentialsProvider credentials;
+
+try ( EntraIDTokenAuthConfigBuilder builder = EntraIDTokenAuthConfigBuilder.builder()) {
+        builder.clientId(CLIENT_ID)
+                .secret(CLIENT_SECRET)
+                .authority(AUTHORITY) // "https://login.microsoftonline.com/{YOUR_TENANT_ID}";
+                .scopes(SCOPES);      // "https://redis.azure.com/.default";
+
+        credentials = TokenBasedRedisCredentialsProvider.create(builder.build());
+}
+```
+
+Some of the details you can supply are common to different use cases:
+
+-   `secret()`: A string containing the [authentication secret](https://learn.microsoft.com/en-us/purview/sit-defn-azure-ad-client-secret).
+-   `authority()`: A string containing the [authority](https://learn.microsoft.com/en-us/entra/identity-platform/msal-client-application-configuration#authority)
+    URL.
+-   `scopes()`: A set of strings defining the [scopes](https://learn.microsoft.com/en-us/entra/identity-platform/scopes-oidc)
+    you want to apply. Configure your client application to acquire a Microsoft Entra token for scope, `https://redis.azure.com/.default` or `acca5fbb-b7e4-4009-81f1-37e38fd66d78/.default`
+    with the
+    [Microsoft Authentication Library (MSAL)](https://learn.microsoft.com/en-us/entra/identity-platform/msal-overview)
+
+You can also add configuration to authenticate with a [service principal](#serv-principal)
+or a [managed identity](#mgd-identity) as described in the sections below.
+
+When you have created your `TokenBasedRedisCredentialsProvider` instance, you may want to
+test it by obtaining a token, as shown in the folowing example:
+
+```java
+// Test that the Entra ID credentials provider can resolve credentials.
+credentials.resolveCredentials()
+        .doOnNext(c-> System.out.println(c.getUsername()))
+        .block();
+```
+
+### Configuration for a service principal {#serv-principal}
+
+Add `clientId()` to the `EntraIDTokenAuthConfigBuilder` chain to specify
+authentication via a service principal, passing the ID token string as
+a parameter. (See the
+[Microsoft EntraID docs](https://learn.microsoft.com/en-us/entra/identity-platform/app-objects-and-service-principals)
+for more information about service principals.)
+
+```java
+TokenBasedRedisCredentialsProvider credentials;
+
+try ( EntraIDTokenAuthConfigBuilder builder = EntraIDTokenAuthConfigBuilder.builder()) {
+        builder.clientId(CLIENT_ID)
+                .secret(CLIENT_SECRET)
+                .authority(AUTHORITY) // "https://login.microsoftonline.com/{YOUR_TENANT_ID}";
+                .scopes(SCOPES);      // "https://redis.azure.com/.default";
+
+        credentials = TokenBasedRedisCredentialsProvider.create(builder.build());
+}
+```
+
+### Configuration for a managed identity {#mgd-identity}
+
+You can also authenticate to AMR using a managed identity (see the
+[Microsoft documentation](https://learn.microsoft.com/en-us/entra/identity/managed-identities-azure-resources/overview) to learn more about managed identities).
+
+For a system assigned managed identity, simply add the `systemAssignedManagedIdentity()`
+method to the `EntraIDTokenAuthConfigBuilder` chain:
+
+```java
+TokenBasedRedisCredentialsProvider credentials;
+
+try ( EntraIDTokenAuthConfigBuilder builder = EntraIDTokenAuthConfigBuilder.builder()) {
+        builder.clientId(CLIENT_ID)
+                // ...
+                .systemAssignedManagedIdentity();
+
+        credentials = TokenBasedRedisCredentialsProvider.create(builder.build());
+}
+```
+
+For a user assigned managed identity, add `userAssignedManagedIdentity()`. This
+requires a member of the `UserManagedIdentityType` enum (to select a
+`CLIENT_ID`, `OBJECT_ID`, or `RESOURCE_ID`) as well as the `id` string itself:
+
+```java
+TokenBasedRedisCredentialsProvider credentials;
+
+try ( EntraIDTokenAuthConfigBuilder builder = EntraIDTokenAuthConfigBuilder.builder()) {
+        builder.clientId(CLIENT_ID)
+                // ...
+                .userAssignedManagedIdentity(
+                        UserManagedIdentityType.CLIENT_ID,
+                        "<ID>"
+                );
+
+        credentials = TokenBasedRedisCredentialsProvider.create(builder.build());
+}
+```
+
+## Connect using the `withAuthentication()` option
+
+When you have created your `TokenBasedRedisCredentialsProvider` instance, you are ready to
+connect to AMR.
+The example below shows how to include the authentication details in a
+`TokenBasedRedisCredentialsProvider` instance and pass it to the `RedisURI.Builder`
+using the `withAuthentication()` option. It also uses a `ClientOptions` object to
+enable automatic re-authentication.
+
+The connection uses
+[Transport Layer Security (TLS)](https://en.wikipedia.org/wiki/Transport_Layer_Security),
+which is recommended and enabled by default for managed identities. See
+[TLS connection]({{< relref "/develop/clients/lettuce/connect#tls-connection" >}}) for more information.
+
+{{< note >}} The `Lettuce` client library doesn't manage the lifecycle of
+the `TokenBasedRedisCredentialsProvider` instance for you. You can reuse the
+same instance for as many clients and connections as you want. When you have
+finished using the credentials provider, call its `close()` method, as shown
+at the end of the example.
+{{< /note >}}
+
+```java
+// Entra ID credentials provider for Service Principal Identity with Client Secret.
+TokenBasedRedisCredentialsProvider credentialsSP;
+try (EntraIDTokenAuthConfigBuilder builder = EntraIDTokenAuthConfigBuilder.builder()) {
+        builder
+                .clientId(CLIENT_ID)
+                .secret(CLIENT_SECRET).authority(AUTHORITY) // "https://login.microsoftonline.com/{YOUR_TENANT_ID}"
+                .scopes(SCOPES); // "https://redis.azure.com/.default"
+
+        credentialsSP = TokenBasedRedisCredentialsProvider.create(builder.build());
+}
+
+// Optionally test the credentials provider.
+// credentialsSP.resolveCredentials().doOnNext(c -> System.out.println("SPI ID :" + c.getUsername())).block();
+
+// Enable automatic re-authentication.
+ClientOptions clientOptions = ClientOptions.builder()
+        .reauthenticateBehavior(
+                ClientOptions.ReauthenticateBehavior.ON_NEW_CREDENTIALS
+        ).build();
+
+// Use the Entra ID credentials provider.
+RedisURI redisURI = RedisURI.builder()
+        .withHost(HOST)
+        .withPort(PORT)
+        .withAuthentication(credentialsSP)
+        .withSsl(true)
+        .build();
+
+// Create the RedisClient and set the re-authentication options.
+RedisClient redisClient = RedisClient.create(redisURI);
+redisClient.setOptions(clientOptions);
+
+// Connect with the credentials provider.
+try (StatefulRedisConnection<String, String> user1 = redisClient.connect(StringCodec.UTF8)) {
+        System.out.println("Connected to redis as :" + user1.sync().aclWhoami());
+        System.out.println("Db size :" + user1.sync().dbsize());
+} finally {
+        redisClient.shutdown();  // Shutdown Redis client and close connections.
+        credentialsSP.close(); // Shutdown Entra ID Credentials provider.
+}
+```