Install and Start Using the Scala SDK with Couchbase Server

  • how-to
    +
    Get up and running quickly, installing the Couchbase Scala SDK, and running our Hello World example.

    The Couchbase Scala SDK allows Scala applications to access a Couchbase cluster.

    Hello Couchbase

    On this page we show you how to quickly get up and running — installing the Couchbase Scala SDK, and trying out the Hello World code example against Couchbase Capella, or against a local Couchbase cluster.

    We will go through the code sample step by step, but for those in a hurry to see it, here it is:

    • Couchbase Capella Sample

    • Local Couchbase Server

    /*
     * Copyright (c) 2022 Couchbase, Inc.
     *
     * Licensed under the Apache License, Version 2.0 (the "License");
     * you may not use this file except in compliance with the License.
     * You may obtain a copy of the License at
     *
     *    http://www.apache.org/licenses/LICENSE-2.0
     *
     * Unless required by applicable law or agreed to in writing, software
     * distributed under the License is distributed on an "AS IS" BASIS,
     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     * See the License for the specific language governing permissions and
     * limitations under the License.
     */
    
    import com.couchbase.client.scala.durability.Durability
    import com.couchbase.client.scala.env.{
      ClusterEnvironment,
      SecurityConfig,
      TimeoutConfig
    }
    import com.couchbase.client.scala.json.{JsonObject, JsonObjectSafe}
    import com.couchbase.client.scala.kv.ReplaceOptions
    import com.couchbase.client.scala.{Cluster, ClusterOptions}
    import io.netty.handler.ssl.util.InsecureTrustManagerFactory
    
    import java.nio.file.Path
    import java.util.UUID
    import scala.concurrent.duration._
    import scala.util.{Failure, Success, Try}
    
    object Cloud {
      def main(args: Array[String]): Unit = {
        // Update this to your cluster
        val endpoint = "cb.<your-endpoint>.cloud.couchbase.com"
        val username = "username"
        val password = "Password123!"
        val bucketName = "travel-sample"
    
        val env = ClusterEnvironment.builder
          .securityConfig(
            SecurityConfig()
              .enableTls(true)
          )
          .timeoutConfig(
            TimeoutConfig()
              .kvTimeout(10.seconds)
          )
          .build
          .get
    
        val cluster = Cluster
          .connect(
            "couchbases://" + endpoint,
            ClusterOptions
              .create(username, password)
              .environment(env)
          )
          .get
    
        val bucket = cluster.bucket(bucketName)
        bucket.waitUntilReady(30.seconds).get
    
        // get a reference to the default collection, required for Couchbase server 6.5 or earlier
        // val collection = bucket.defaultCollection
    
        val collection = bucket.scope("inventory").collection("airport")
    
        val json = JsonObject("status" -> "awesome")
    
        val docId = UUID.randomUUID().toString
        collection.upsert(docId, json) match {
          case Success(result)    =>
          case Failure(exception) => println("Error: " + exception)
        }
    
        // Get a document
        collection.get(docId) match {
          case Success(result) =>
            // Convert the content to a JsonObjectSafe
            result.contentAs[JsonObjectSafe] match {
              case Success(json) =>
                // Pull out the JSON's status field, if it exists
                json.str("status") match {
                  case Success(hello) => println(s"Couchbase is $hello")
                  case _              => println("Field 'status' did not exist")
                }
              case Failure(err) => println("Error decoding result: " + err)
            }
          case Failure(err) => println("Error getting document: " + err)
        }
    
        def getFor() {
          val result: Try[String] = for {
            result <- collection.get(docId)
            json <- result.contentAs[JsonObjectSafe]
            status <- json.str("status")
          } yield status
    
          result match {
            case Success(status) => println(s"Couchbase is $status")
            case Failure(err)    => println("Error: " + err)
          }
        }
    
        def getMap() {
          val result: Try[String] = collection
            .get(docId)
            .flatMap(_.contentAs[JsonObjectSafe])
            .flatMap(_.str("status"))
    
          result match {
            case Success(status) => println(s"Couchbase is $status")
            case Failure(err)    => println("Error: " + err)
          }
        }
    
        def replaceOptions() {
          collection.replace(
            docId,
            json,
            ReplaceOptions()
              .expiry(10.seconds)
              .durability(Durability.Majority)
          ) match {
            case Success(status) =>
            case Failure(err)    => println("Error: " + err)
          }
        }
    
        def replaceNamed() {
          collection.replace(docId, json, durability = Durability.Majority) match {
            case Success(status) =>
            case Failure(err)    => println("Error: " + err)
          }
        }
      }
    }
    /*
     * Copyright (c) 2022 Couchbase, Inc.
     *
     * Licensed under the Apache License, Version 2.0 (the "License");
     * you may not use this file except in compliance with the License.
     * You may obtain a copy of the License at
     *
     *    http://www.apache.org/licenses/LICENSE-2.0
     *
     * Unless required by applicable law or agreed to in writing, software
     * distributed under the License is distributed on an "AS IS" BASIS,
     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     * See the License for the specific language governing permissions and
     * limitations under the License.
     */
    
    import com.couchbase.client.scala.durability.Durability
    import com.couchbase.client.scala.env.{
      ClusterEnvironment,
      SecurityConfig,
      TimeoutConfig
    }
    import com.couchbase.client.scala.json.{JsonObject, JsonObjectSafe}
    import com.couchbase.client.scala.kv.ReplaceOptions
    import com.couchbase.client.scala.{Cluster, ClusterOptions}
    import io.netty.handler.ssl.util.InsecureTrustManagerFactory
    
    import java.nio.file.Path
    import java.util.UUID
    import scala.concurrent.duration._
    import scala.util.{Failure, Success, Try}
    
    object StartUsing {
      def main(args: Array[String]): Unit = {
        // Update this to your cluster
        val username = "Administrator"
        val password = "password"
        val bucketName = "travel-sample"
    
        val env = ClusterEnvironment.builder
          // You should uncomment this if running in a production environment.
          // .securityConfig(
          //   SecurityConfig()
          //     .enableTls(true)
          //     .trustCertificate(Path.of("/path/to/cluster-root-certificate.pem"))
          // )
          .timeoutConfig(
            TimeoutConfig()
              .kvTimeout(10.seconds)
          )
          .build
          .get
    
        val cluster = Cluster
          .connect(
            "couchbase://localhost",
            ClusterOptions
              .create(username, password)
              .environment(env)
          )
          .get
    
        val bucket = cluster.bucket(bucketName)
        bucket.waitUntilReady(30.seconds).get
    
        val collection = bucket.defaultCollection
    
        val json = JsonObject("status" -> "awesome")
    
        val docId = UUID.randomUUID().toString
        collection.upsert(docId, json) match {
          case Success(result)    =>
          case Failure(exception) => println("Error: " + exception)
        }
    
        // Get a document
        collection.get(docId) match {
          case Success(result) =>
            // Convert the content to a JsonObjectSafe
            result.contentAs[JsonObjectSafe] match {
              case Success(json) =>
                // Pull out the JSON's status field, if it exists
                json.str("status") match {
                  case Success(hello) => println(s"Couchbase is $hello")
                  case _              => println("Field 'status' did not exist")
                }
              case Failure(err) => println("Error decoding result: " + err)
            }
          case Failure(err) => println("Error getting document: " + err)
        }
    
        def getFor() {
          val result: Try[String] = for {
            result <- collection.get(docId)
            json <- result.contentAs[JsonObjectSafe]
            status <- json.str("status")
          } yield status
    
          result match {
            case Success(status) => println(s"Couchbase is $status")
            case Failure(err)    => println("Error: " + err)
          }
        }
    
        def getMap() {
          val result: Try[String] = collection
            .get(docId)
            .flatMap(_.contentAs[JsonObjectSafe])
            .flatMap(_.str("status"))
    
          result match {
            case Success(status) => println(s"Couchbase is $status")
            case Failure(err)    => println("Error: " + err)
          }
        }
    
        def replaceOptions() {
          collection.replace(
            docId,
            json,
            ReplaceOptions()
              .expiry(10.seconds)
              .durability(Durability.Majority)
          ) match {
            case Success(status) =>
            case Failure(err)    => println("Error: " + err)
          }
        }
    
        def replaceNamed() {
          collection.replace(docId, json, durability = Durability.Majority) match {
            case Success(status) =>
            case Failure(err)    => println("Error: " + err)
          }
        }
      }
    }

    The Couchbase Capella free trial version comes with the Travel Sample Bucket, and its Query indexes, loaded and ready.

    Quick Install

    A more detailed guide in our Installation page covers every supported platform, but this section should be enough to get up and running in most cases.

    • SBT

    • Gradle

    • Maven

    libraryDependencies += "com.couchbase.client" %% "scala-client" % "1.3.4"

    This will automatically use the Scala 2.12 or 2.13 builds, as appropriate for your SBT project.

    It can be included in your build.gradle like this for 2.13:

    dependencies {
        compile group: 'com.couchbase.client', name: 'scala-client_2.13', version: '1.3.4'
    }

    For Scala 2.12, refer to the full Installation page.

    It can be included in your Maven pom.xml like this for 2.13:

    <dependencies>
        <dependency>
            <groupId>com.couchbase.client</groupId>
            <artifactId>scala-client_2.13</artifactId>
            <version>1.3.4</version>
        </dependency>
    </dependencies>

    For Scala 2.12, refer to the full Installation page.

    Step by Step

    Here’s the above Hello World example, broken down into individual actions.

    Connecting to a Cluster

    Now you have the Scala client installed, try out the following to connect to a Couchbase cluster.

    First pull in all the imports we’ll be using:

    import com.couchbase.client.scala.durability.Durability
    import com.couchbase.client.scala.env.{
      ClusterEnvironment,
      SecurityConfig,
      TimeoutConfig
    }
    import com.couchbase.client.scala.json.{JsonObject, JsonObjectSafe}
    import com.couchbase.client.scala.kv.ReplaceOptions
    import com.couchbase.client.scala.{Cluster, ClusterOptions}
    import io.netty.handler.ssl.util.InsecureTrustManagerFactory
    
    import java.nio.file.Path
    import java.util.UUID
    import scala.concurrent.duration._
    import scala.util.{Failure, Success, Try}

    The basic connection details that you’ll need are given below — for more background information, refer to the Managing Connections page.

    Now we can connect to the cluster:

    • Couchbase Capella

    • Local Couchbase Server

    You connect to a Couchbase Capella cluster the same as any other cluster, except that the use of TLS and a certificate is mandatory, and the "couchbases://" connection string prefix should be used to allow DNS SRV lookup.

    As of Scala SDK version 1.3.0, the standard certificate required to connect to a Capella cluster is automatically included with no additional configuration.
    // Update this to your cluster
    val endpoint = "cb.<your-endpoint>.cloud.couchbase.com"
    val username = "username"
    val password = "Password123!"
    val bucketName = "travel-sample"
    
    val env = ClusterEnvironment.builder
      .securityConfig(
        SecurityConfig()
          .enableTls(true)
      )
      .timeoutConfig(
        TimeoutConfig()
          .kvTimeout(10.seconds)
      )
      .build
      .get
    
    val cluster = Cluster
      .connect(
        "couchbases://" + endpoint,
        ClusterOptions
          .create(username, password)
          .environment(env)
      )
      .get

    Couchbase Capella uses Roles to control user access to database resources. For the purposes of this example, we can use the Organization Owner role automatically assigned to a user account during installation of the Capella cluster. This role grants full access to a Capella organization, including full data access to all projects and clusters. In a production scenario, we strongly recommend setting up users with more granular access roles as a best practice.

    For the SDK client to access cluster data, you will need to set up credentials for your database by following these steps.

    // Update this to your cluster
    val username = "Administrator"
    val password = "password"
    val bucketName = "travel-sample"
    
    val env = ClusterEnvironment.builder
      // You should uncomment this if running in a production environment.
      // .securityConfig(
      //   SecurityConfig()
      //     .enableTls(true)
      //     .trustCertificate(Path.of("/path/to/cluster-root-certificate.pem"))
      // )
      .timeoutConfig(
        TimeoutConfig()
          .kvTimeout(10.seconds)
      )
      .build
      .get
    
    val cluster = Cluster
      .connect(
        "couchbase://localhost",
        ClusterOptions
          .create(username, password)
          .environment(env)
      )
      .get

    Couchbase uses Role Based Access Control (RBAC) to control access to resources. For the purposes of this example, we are connecting to Couchbase using the Full Admin role created during the installation of our Couchbase Server.

    Couchbase RBAC is fully described in the Manage Users, Groups, and Roles page.

    Cluster.connect returns a Try[Cluster], as the Scala client uses functional error handling and does not throw exceptions. You’ll see examples later of how to better handle a Try, but for simplicity here we’ll assume the operation succeeded and get the result as a Cluster using .get.

    Following successful authentication, the bucket can be opened:

    val bucket = cluster.bucket(bucketName)
    bucket.waitUntilReady(30.seconds).get
    We are working with the travel-sample data bucket. If you are not, update the bucketName variable used in the example with your own.

    waitUntilReady is an optional call. Opening resources such as buckets is asynchronous — that is, the cluster.bucket call returns immediately and proceeds in the background. waitUntilReady ensures that the bucket resource is fully loaded before proceeding. If not present, then the first Key Value (KV) operation on the bucket will wait for it to be ready. As with Cluster.connect, we use .get on the result here for simplicity.

    The Scala SDK supports full integration with the Collections feature introduced in Couchbase Server 7.0. Collections allow documents to be grouped by purpose or theme, according to a specified Scope. Here we will use the users collection within the tenant_agent_00 scope from travel-sample bucket as an example.

    // get a reference to the default collection, required for Couchbase server 6.5 or earlier
    // val collection = bucket.defaultCollection
    
    val collection = bucket.scope("inventory").collection("airport")

    If you do not refer to a named collection, you can access the 'default collection', which includes all documents in a bucket, and is forwards and backwards compatible with all supported versions of Couchbase Server.

    JSON

    Now we can do some simple Key Value operations. First, let’s create some JSON.

    The Scala SDK directly supports several popular JSON libraries, including uPickle/uJson, Circe, Play Json, Jawn, and Json4s (if you’d like to see your favorite supported, please let us know). In addition you can supply JSON encoded into a String or Array[Byte], opening the door to any JSON library; Jsoniter and Jackson have been tested this way, but any should work.

    You can also directly encode and decode Scala case classes to and from the SDK.

    To make things easy and to help get you started, the Scala SDK also bundles a home-grown small JSON library, which you are free to use instead of or alongside any of the other supported JSON libraries. The philosophy behind this library is to provide a very easy-to-use API and the fastest JSON implementation possible.

    These options are described in detail here, but to get us started let’s created some simple JSON using the built-in JsonObject library:

    val json = JsonObject("status" -> "awesome")

    Key-Value Operations

    And now let’s upsert it into Couchbase (upsert is an operation that will insert the document if it does not exist, or replace it if it does). We need to provide a unique ID for the JSON, and we’ll use a UUID here:

    val docId = UUID.randomUUID().toString
    collection.upsert(docId, json) match {
      case Success(result)    =>
      case Failure(exception) => println("Error: " + exception)
    }

    As mentioned above, the Scala SDK will not throw exceptions. Instead, methods that can error - such as the upsert above - will return a Scala Try result, which can either be a Success containing the result, or a Failure containing a Throwable exception. The easiest way to handle a single operation is with pattern matching, as shown above.

    Now let’s get the data back (this example will look a little messy due the the nested handling of multiple Try results, but we’ll see how to clean it up shortly):

    // Get a document
    collection.get(docId) match {
      case Success(result) =>
        // Convert the content to a JsonObjectSafe
        result.contentAs[JsonObjectSafe] match {
          case Success(json) =>
            // Pull out the JSON's status field, if it exists
            json.str("status") match {
              case Success(hello) => println(s"Couchbase is $hello")
              case _              => println("Field 'status' did not exist")
            }
          case Failure(err) => println("Error decoding result: " + err)
        }
      case Failure(err) => println("Error getting document: " + err)
    }

    Here we’re fetching the value for the key docId, converting that value to a JsonObjectSafe (a simple wrapper around JsonObject that returns Try results - see here for details), and then accessing the value of the status key as a String.

    Better Error Handling

    All three of these operations could fail, so there’s quite a lot of error handling code here to do something quite simple. One way to improve on this is by using flatMap, like this:

    val result: Try[String] = collection
      .get(docId)
      .flatMap(_.contentAs[JsonObjectSafe])
      .flatMap(_.str("status"))
    
    result match {
      case Success(status) => println(s"Couchbase is $status")
      case Failure(err)    => println("Error: " + err)
    }

    Alternatively, you can use a for-comprehension, like so:

    val result: Try[String] = for {
      result <- collection.get(docId)
      json <- result.contentAs[JsonObjectSafe]
      status <- json.str("status")
    } yield status
    
    result match {
      case Success(status) => println(s"Couchbase is $status")
      case Failure(err)    => println("Error: " + err)
    }

    Either of these methods will stop on the first failed operation. So the final returned Try contains either a) Success and the result of the final operation, indicating that everything was successful, or b) Failure with the error returned by the first failing operation.

    Overloads

    You’ll notice that most operations in the Scala SDK have two overloads. One will take an Options builder, which provides all possible options that operation takes. For instance:

    collection.replace(
      docId,
      json,
      ReplaceOptions()
        .expiry(10.seconds)
        .durability(Durability.Majority)
    ) match {
      case Success(status) =>
      case Failure(err)    => println("Error: " + err)
    }

    These options blocks are implemented as Scala case classes, e.g. they are immutable data objects that return a copy of themselves on each change.

    The other overload is provided purely for convenience. It takes named arguments instead of an Options object, and provides only the most commonly used options:

    collection.replace(docId, json, durability = Durability.Majority) match {
      case Success(status) =>
      case Failure(err)    => println("Error: " + err)
    }

    Next Steps

    Now you’re up and running, try one of the following:

    Additional Resources

    The Scala SDK includes three APIs. The examples above show the simple blocking API, for simplicity, but you can also perform all operations in an async style using Scala Future, and a reactive style using Project Reactor SMono and SFlux. Please see Choosing an API for more details.

    The API reference is generated for each release and the latest can be found here.

    Couchbase welcomes community contributions to the Scala SDK. The SDK source code is available on GitHub.

    Troubleshooting