dendrites | Scala library for Reactive streaming Microservices | Pub Sub library

dendrites is a Scala library typically used in Messaging, Pub Sub, Docker, Kafka applications. dendrites has no bugs, it has no vulnerabilities and it has low support. However dendrites has a Non-SPDX License. You can download it from GitHub.

Streaming components in Scala for building Microservices, Event Sourcing, Event Logging, CQRS, and Reactive systems. Functions and pre-built stream stages for Akka Streams, HTTP, Actors, Kafka, Cassandra, Algebird, and Avro. The ACK in a SMACK stack. It's meant to be used as. This Readme covers download, setup and configuration, unit and integration testing and adding it to your project. Documentation is on the website, Scaladocs have examples and lower level descriptions. Add dependency in build.sbt. Add dependency in pom.xml. Requires Java 8 download jdk8 and Scala 2.12 download scala. Clone or download dendrites from Github, see cloning-a-repository. sbt version, download, documentation. In a terminal window cd to the dendrites directory. $ sbt launch sbt, returns > prompt. > help list available help. > update Resolves and optionally retrieves dependencies. > clean Deletes files produced by the build under target directory. > compile Compiles sources under src/main/scala. > test:compile Compiles unit test sources under src/test/scala. > it:compile Compiles integration test sources under src/it/scala. > test Executes unit tests. > testOnly Executes specific unit tests. > testQuick Re-executes failed unit tests. > package Produces the jar. > doc Generates Scaladocs in /dendrites/target/scala-2.12/api. > scalastyle Run scalastyle on source code under src/main/scala. > test:scalastyle Run scalastyle on source code under src/test/scala. > dependencyTree Prints an ascii tree of all the dependencies to the console. > exit quit sbt. In a terminal window cd to the dendrites directory. $ mvn dependency:resolve Resolves and optionally retrieves dependencies. $ mvn clean Deletes files produced by the build under target directory. $ mvn compile Compiles sources under src/main/scala. $ mvn scala:testCompile Compiles unit test sources under src/test/scala. $ mvn test Executes unit tests. $ mvn install Install the package in local repository, for use as in other projects locally. $ mvn source:jar Bundle the main sources of the project into a jar archive. $ mvn scala:doc-jar Generate Scaladocs in a jar. Minimal install and configure for running dendrites integration tests. Kafka's documentation, download Kafka. Extract server files tar -xvf kafka_2.12-1.0.*.*.tar. Optionally, create or replace symbolic link ln -nsf kafka_2.12-1.0.*.* kafka. Edit configuration in install directory /config/server.properties. To advertise the broker in a local install. In Socket Server Settings add listeners=PLAINTEXT://localhost:9092. In production, log retention hours are 168 (1 week). For development you can shorten them to 1. In Log Retention Policy. Add dependencies to driver jars. sbt and Maven dependency settings. See kafka-clients Maven repository page. Put a Consumer Config properties file on your classpath. See Kafka's New Consumer Configs documentation and a dendrites example. KafkaSource requires enable.auto.commit=false for stream backpressure to control commit. To pass this configuration to KafkaSource, create a subclass of ConsumerConfig. example. Put a Producer Config properties file on your classpath. See Kafka's Producer Configs documentation example To pass this configuration to KafkaSink, create a subclass of ProducerConfig example. In a Terminal window cd to kafka install directory. Zookeeper will run in the foreground. In a 2nd Terminal window in the same directory. Kafka server will run in the foreground. In a 3rd Terminal window in the same directory. This takes a few seconds. Kafka server must be running and have an account-topic. In dendrites directory terminal window with sbt running. Note: KafkaStreamSpec, ShoppingCartCmdSpec creates KafkaConsumer in KafkaSource. KafkaConsumer calls must all be from the same thread. KafkaSource doesn't close KafkaConsumer until the stream it's in completes. To re-run one of these tests, exit and restart sbt. Delete topic, this may not happen right away. The topic _consumerOffsets can't be deleted from the command line. Kafka Tool is a GUI tool and free for personal use. After topic deleted, stop Kafka server. Give Zookeeper a few seconds. Then stop it too. Minimal install and configure for running dendrites integration tests, Cassandra's documentation, download Cassandra. Extract files tar -xvf apache-cassandra-3.11.*-bin.tar. Optionally, create or replace symbolic link ln -nsf apache-cassandra-3.11.* cassandra. For development, default configuration can be used. Add dependencies to cassandra-driver-core, cassandra-driver-mapping, cassandra-driver-extras. Driver jars with sbt and Maven dependency settings. See Datastax Cassandra Maven repository page. dendrites has an example Cassandra configuration in resource.conf under dendrites/cassandra. You can override these in your application.conf file. CassandraConfig is a trait you can extend. PlayListSongConfig is an example. In a Terminal window cd to cassandra install directory. It will run in the foreground. In a dendrites directory terminal window with sbt running. These tests teardown their keyspaces, tables, and connections, run them one at a time so ScalaTest doesn't mix them up and report false errors. Exit sbt to close its connection to Cassandra. If you kill Cassandra while sbt is still it will keep trying to reconnect to Cassandra. Then, Ctrl-C in the terminal running Cassandra. Balances Server is an example server that handles requests from integration tests under src/it/scala. These integration tests need Balances Server running to handle HTTP requests. > bgRun Runs Balances Server an Http server in the background. In the dendrites directory terminal with sbt running. Sometimes, some of these tests fail because Balances Server has a default limit of 4 concurrent requests and tests are running in parallel and may not get time on the server. If this happens, re-run the failed tests one at a time. Ctrl-C in the terminal window running Balances Server.