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https://github.com/pacphi/reactive-cassy

Sample Spring Boot + Spring Data Cassandra project
https://github.com/pacphi/reactive-cassy

Last synced: 13 days ago
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Sample Spring Boot + Spring Data Cassandra project

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# Reactive Cassandra Example



[![Build Status](https://travis-ci.org/pacphi/reactive-cassy.svg)](https://travis-ci.org/pacphi/reactive-cassy) [![Known Vulnerabilities](https://snyk.io/test/github/pacphi/reactive-cassy/badge.svg)](https://snyk.io/test/github/pacphi/reactive-cassy)



This project explores the [Reactive Cassandra Support](https://docs.spring.io/spring-data/cassandra/docs/2.1.0.RELEASE/reference/html/#cassandra.reactive) in [Spring Data Cassandra](https://spring.io/projects/spring-data-cassandra), specifically: how to implement a [reactive repository](https://docs.spring.io/spring-data/cassandra/docs/2.1.0.RELEASE/reference/html/#cassandra.reactive.repositories), author integration tests, configuring the app to run locally against a [Docker image](https://hub.docker.com/r/bitnami/cassandra/) of Cassandra, and deploying the app to [Pivotal Application Service](https://pivotal.io/platform/pivotal-application-service) interacting with an Azure CosmosDB instance via the [Cassandra API](https://docs.microsoft.com/en-us/azure/cosmos-db/cassandra-introduction).



## Prerequisites



* An account with [Space Developer role](https://docs.cloudfoundry.org/concepts/roles.html#roles) access on a Cloud Foundry foundation, e.g., [Pivotal Web Services](https://run.pivotal.io)

* An [account](https://azure.microsoft.com/free/) on Microsoft [Azure](https://azure.microsoft.com/)

* [Azure CLI](https://docs.microsoft.com/en-us/cli/azure/install-azure-cli?view=azure-cli-latest) 2.0.46 or better

* [CF CLI](https://github.com/cloudfoundry/cli#downloads) 6.40.0 or better if you want to push the application to a Cloud Foundry (CF) instance

* [httpie](https://httpie.org/#installation) 1.0.2 or better to simplify interaction with API endpoints

* [jq](https://stedolan.github.io/jq/) 1.6 or better

* Java [JDK](https://openjdk.java.net/install/) 1.8u192 or better to compile and run the code

* [Gradle](https://gradle.org/releases/) 4.10.3 or better to build and package source code

* Docker for [Mac](https://store.docker.com/editions/community/docker-ce-desktop-mac) or [Windows](https://store.docker.com/editions/community/docker-ce-desktop-windows) for spinning up a local instance of Cassandra and [cassandra-web](https://hub.docker.com/r/metavige/cassandra-web/) (an administration interface)

* [cqlsh](http://cassandra.apache.org/doc/4.0/tools/cqlsh.html) the CQL shell 

	* on a Mac it's easy to install w/ [Homebrew](https://brew.sh) using `brew install cassandra`



## Clone



```

git clone https://github.com/pacphi/reactive-cassy.git

```



## Build



Build this project with Gradle



```

gradle clean build

```



If you're on a Mac you will want to execute the following (once) 



```bash

./install.sigar.macos.sh

```



and then



```

gradle clean build -Djava.library.path=$JAVA_LIBRARY_PATH:~/Library/Java/Extensions:/Library/Java/Extensions:/Network/Library/Java/Extensions:/System/Library/Java/Extensions:/usr/lib/java:. -Ddebug

```



## Prepare



To run the project, need to run below `cql` commands on Cassandra.



### Connect to a Cassandra instance



We'll explore two options



#### Docker hosted



Start the server



```

docker run -d --name cassandra-server \

    --network app-tier \

    bitnami/cassandra:latest

```



Connect via cqlsh



```

docker run -it --rm \

    --network app-tier \

    bitnami/cassandra:latest cqlsh --username cassandra --password cassandra cassandra-server

```



If you want to access the server from the host machine where you have `cqlsh` already installed, you could start it with 



```

docker run -d -p 9042:9042 -e CASSANDRA_HOST=127.0.0.1 \

    --name cassandra-server \

    --network app-tier \

    bitnami/cassandra:latest

```



then



```

cqlsh -u cassandra -p cassandra

```



#### Azure hosted CosmosDB



Fire up a browser and [login](http://portal.azure.com) to the Azure portal



Also launch a [Terminal](https://macpaw.com/how-to/use-terminal-on-mac) session, set your subscription account and create a new resource group, e.g.,



```

az login

az account set --subscription 90c2a5c6-0aef-963d-b153-f44d21402d98

az group create --name spring-data-experiments --location westus

```



> Replace values for `--subscription`, `--name`, and `--location` above with your own.



Visit the Azure portal in your browser, navigate to `Azure Cosmos DB`, and add a new instance



![Image from Azure portal illustrating how to create a new Cosmos DB instance](docs/new-cosmos-db-cassandra-instance.png)



Visit your new instance's `Settings > Connection String` and make a note of the: `contact point`, `port`, `username` and `primary password`.



Then connect (on a Mac) with, e.g.,



```

export SSL_VERSION=TLSv1_2 

export SSL_VALIDATE=false 

cqlsh cassy.cassandra.cosmosdb.azure.com 10350 -u cassy -p XJuTjJZLHaAVcAqrVYH4aVu6lhfDk9vOMJ9ePHosv3p4Tpa19N0ZBydmpDtBwpnaaMQeGLzBvKCD7ObEjGXgTU== --ssl

```



> Replace the last line above with your own instance's connection details, like `cqlsh {contact point} {port} -u {username} -p {primary password} --ssl`



### Keyspace Creation



Once connected we need to create a keyspace



```bash

CREATE KEYSPACE IF NOT EXISTS customers WITH replication = {'class': 'SimpleStrategy', 'replication_factor': '3' };

```



### Table Creation



Let's create a table and indexes



```

USE customers;

CREATE TABLE customer (id TimeUUID PRIMARY KEY, firstname text, lastname text);

CREATE INDEX customerfirstnameindex ON customer (firstname);

CREATE INDEX customerlastnameindex ON customer (lastname);

```



> As of 2018-10-13 Azure Cosmos DB does not yet support `CREATE INDEX`; therefore, skip executing the last two lines above when connected to a Cosmos DB instance



## Run 



To startup the application, execute



### Simple case 



We'll fire up a local Docker instance of Cassandra, execute the [Keyspace](#keyspace-creation) and [Table](#table-creation) creation steps above, then start the application 



```bash

docker run -d -p 9042:9042 -e CASSANDRA_HOST=127.0.0.1 \

    --name cassandra-server \

    --network app-tier \

    bitnami/cassandra:latest

gradle bootRun -Dspring.profiles.active=docker

```



### with Docker Compose



// TODO



### with Kubernetes



// TODO



## How to deploy to Pivotal Application Service



These instructions assume that a Cassandra instance is available and was pre-provisioned "off-platform" (e.g., on PKS or Azure Cosmos DB).



### Authenticating



Authenticate to a foundation using the API endpoint. 

> E.g., login to [Pivotal Web Services](https://run.pivotal.io)



```

cf login -a https:// api.run.pivotal.io

```



### Managing secrets



Place secrets in `config/secrets.json`, e.g.,



```

{

	"CONTACT_POINT" : "xxxxx",

	"PORT" : xxxxx,

	"USERNAME" : "xxxxx",

	"PASSWORD" : "xxxxx"

}

```



We'll use this file later as input configuration for the creation of either a [credhub](https://docs.pivotal.io/credhub-service-broker/using.html) or [user-provided](https://docs.cloudfoundry.org/devguide/services/user-provided.html#credentials) service instance.



> Replace occurrences of `xxxxx` above with appropriate values



### Deploy and shutdown



Deploy the app (w/ a user-provided service instance vending secrets)



```

./deploy.sh

```



Deploy the app (w/ a Credhub service instance vending secrets)



```

./deploy.sh --with-credhub

```



Shutdown and destroy the app and service instances



```

./destroy.sh

```



## Endpoints



Current implementation supports



### POST /customers



```

http POST {host}:{port}/customers firstName=Nick lastName=Fury

```



### PUT /customers/{id}



```

http PUT {host}:{port}/customers/f91116f0-cf20-11e8-b999-7fb395277057 firstName=Nick lastName=Gone

```



### GET /customers/{id}



```

http {host}:{port}/customers/f91116f0-cf20-11e8-b999-7fb395277057

```



### GET /customers?lastName={lastName}&firstName={firstName}



```

http {host}:{port}/customers?lastName=Gone

http {host}:{port}/customers?firstName=Nick

http {host}:{port}/customers?lastName=Gone&firstName=Nick

```



### GET /stream/customers



```

http {host}:{port}/stream/customers

```



### DELETE /customers/{id}



```

http DELETE {host}:{port}/customers/f91116f0-cf20-11e8-b999-7fb395277057

```



## Credits and further reading



To those who've blazed trails...



* [Building REST services with Spring](https://spring.io/guides/tutorials/rest/)

* [Spring Data for Cassandra - Reference Documentation](https://docs.spring.io/spring-data/cassandra/docs/2.0.5.RELEASE/reference/html/)

* [Cassandra with Java](https://www.baeldung.com/cassandra-with-java)

* [Cannot execute this query as it might involve data filtering](https://medium.com/@sameira/spring-data-cassandra-cannot-execute-this-query-as-it-might-involve-data-filtering-377cb5afda68)

* [Reactive Streams with Spring Data Cassandra](https://dzone.com/articles/reactive-streams-with-spring-data-cassandra)

* [Spring Data Cassandra 2.0 - Reactive examples](https://github.com/spring-projects/spring-data-examples/tree/master/cassandra/reactive)

* [Spring HATEOAS - API Evolution Example](https://github.com/spring-projects/spring-hateoas-examples/tree/master/api-evolution)

* [Introduction to the Azure Cosmos DB Cassandra API](https://docs.microsoft.com/en-us/azure/cosmos-db/cassandra-introduction)