This sample demonstrates consuming Eclipse Ditto events and messages with a Spring Boot app and Spring Cloud Stream Kafka integration.
First create a Azure resource group if you have not done so yet.
export resourceGroupName=myresourcegroup
az group create --name $resourceGroupName --location westeurope
Now create your Azure Event Hub’s namespace and hub. The namespace needs to be globally unique as it is used as DNS name as well.
Note: this sample leverages Azure Event Hub’s Kafka support as an option for consuming Ditto thing updates.
export namespace=MY_DITTO_NAMESPACE
export eventHubName=ditto
export consumerGroup=dittocg
az eventhubs namespace create --name $namespace --resource-group $resourceGroupName --enable-kafka
az eventhubs eventhub create --name $eventHubName --resource-group $resourceGroupName --namespace-name $namespace --message-retention 1 --partition-count 2
az eventhubs eventhub consumer-group create --eventhub-name $eventHubName --resource-group $resourceGroupName --namespace-name $namespace --name $consumerGroup
Now we can create users for Ditto with Send permission and for the sample app to Listen.
export ditto_user_sas_key_name=dittouser
export sample_app_user_sas_key_name=samplereader
az eventhubs eventhub authorization-rule create --resource-group $resourceGroupName --namespace-name $namespace --eventhub-name $eventHubName --name $ditto_user_sas_key_name --rights Send
az eventhubs eventhub authorization-rule create --resource-group $resourceGroupName --namespace-name $namespace --eventhub-name $eventHubName --name $sample_app_user_sas_key_name --rights Listen
Now the CLI again to retrieve the key necessary in the REST call to Ditto below:
az eventhubs eventhub authorization-rule keys list --resource-group $resourceGroupName --namespace-name $namespace --eventhub-name $eventHubName --name $ditto_user_sas_key_name --query primaryKey
To register the connection to the Event Hub in your Ditto instance. Follow Ditto’s Manage Connection documentation.
A payload could look like this:
{
"targetActorSelection": "/system/sharding/connection",
"headers": {},
"piggybackCommand": {
"type": "connectivity.commands:createConnection",
"connection": {
"id": "azure-example-connection",
"connectionType": "amqp-10",
"connectionStatus": "open",
"failoverEnabled": false,
"uri": "amqps://YOUR_SAS_KEY_NAME:YOUR_SAS_KEY@YOUR_NAMESPACE_NAME.servicebus.windows.net:5671",
"targets": [
{
"address": "YOUR_HUB_NAME",
"topics": ["_/_/things/twin/events", "_/_/things/live/messages"],
"authorizationContext": ["ditto"]
}
]
}
}
}
Now it is time to compile and run our sample:
mvn clean install
export sample_app_user_sas_key=`az eventhubs eventhub authorization-rule keys list --resource-group $resourceGroupName --namespace-name $namespace --eventhub-name $eventHubName --name $sample_app_user_sas_key_name --query primaryConnectionString --output tsv`
java -jar target/azure-eventhub-consumer-0.0.1-SNAPSHOT.jar --azure.event-hubs.namespace=$namespace --azure.event-hubs.connection-string=$sample_app_user_sas_key --azure.event-hubs.hubname=$eventHubName --azure.event-hubs.consumer-group=$consumerGroup
Now you should see on the console events comming in as you change data in Ditto, e.g. as described in the Ditto hello world.