Event Hub Publisher Block Config

The Event Hub Publisher block can be instantiated by using the block type eventhub.

See The Blocks Section for an explanation of what a block is in the Cloud Gateway.

Note: The Event Hub block's configuration has changed significantly from its earlier iterations.

The configuration fields (in the config portion of the block configuration) for the eventhub block are as follows:

Table 1. Configuration Fields
Field	Type	Required	Default
log_name	String	no	<block name>
log_level	String	no	'off'
mqtt/transport_addr	String	yes
mqtt/qos	Integer	no	0
mqtt/client_id	String	no
mqtt/topics	Array of Strings	yes
store_forward	Object	yes
store_forward/max_store_percent	Integer	no	10
store_forward/max_batch_interval	Integer	no	1000
eventhub/transport_addr	String	yes
eventhub/predix_zone_id	String	yes
eventhub/token_file	String	yes
eventhub/topic_map	Array of Objects	yes

The following is a sample block config for the eventhub block. This should be placed in the blocks section of the overall configuration file.

The block below is configured to subscribe to the MQTT topic input_data on the Predix Edge Broker and publish all data received from that topic to the Event Hub topic output_data on a Predix Time Series instance with the Predix Zone ID xxx-xxx at the URL event-hub-aws-usw02.data-services.predix.io:443.

The block's name in this example is event_hub_sender, but it can be any string you wish to use.

"event_hub_sender": {
    "type": "eventhub",
    "config": {
        "log_name": "eventhub_block",
        "log_level": "debug",
        "mqtt": {
            "transport_addr": "mqtt-tcp://predix-edge-broker",
            "qos": 1,
            "client_id": "event_hub_mqtt_client0",
            "topics": [
                "input_data"
            ]
        },
        "store_forward": {
            "max_store_percent": 30,
            "max_batch_interval": 2000
        },
        "eventhub": {
            "transport_addr": "event-hub-aws-usw02.data-services.predix.io:443",
            "predix_zone_id": "xxx-xxx",
            "token_file": "/edge-agent/access_token",
            "topic_map": [
                {
                    "eventhub_topic": "output_data",
                    "mqtt_topics": [
                        "input_data"
                    ]
                }
            ]
        }
    }
}

log_level and log_name

For details on the log_level and log_name fields of the Event Hub Publisher block's config section, see Common Block Config Fields.

mqtt

For details on fields within the mqtt portion of the Event Hub Publisher block's config section, see Common Block Config Fields.

store_forward/max_store_percent and store_forward/max_batch_interval

For details on the store_forward/max_store_percent and store_forward/max_batch_interval fields of the Event Hub Publisher block's config section, see Common Block Config Fields.

eventhub/transport_addr

The transport_addr field within the eventhub section should be set to the URI of whatever Predix Event Hub instance you wish to publish data to.

eventhub/predix_zone_id

The predix_zone_id field within the eventhub section should be set to the Predix Zone ID of whatever Predix Event Hub instance you wish to publish data to.

eventhub/token_file

The token_file field within the eventhub section should be set to the path to the file on your Predix Edge device that holds your UAA token for authentication with your Predix Event Hub instance.

eventhub/topic_map

The proxy_url field within the eventhub section specifies how data will be forwarded from input MQTT topics to output Event Hub topics. This section is an array of objects with the following fields:


Field	Type	Required
eventhub_topic	String	yes
mqtt_topics	Array of Strings	yes

Data received from subscriptions to the topics in the mqtt_topics field of one object will be published to the Event Hub topic in the eventhub_topic field of that same object.

Note: If an MQTT topic is not specified anywhere in the topic map, it will NOT be subscribed to even if it is in the topics list in the mqtt section of the block's config section.

Note: The Event Hub block does not currently support forwarding data from one MQTT topic to multiple Predix Event Hub topics.