Tahu Host Application

Since Camel 4.8

Only consumer is supported

URI format

Host Application endpoints, where hostId is the Sparkplug Host Application ID
tahu-host://hostId?options
Example: Host Application Consumer for Host App 'BasicHostApp' using MQTT Client ID 'HostClient1'
tahu-host:BasicHostApp?clientId=HostClient1

Configuring Options

Camel components are configured on two separate levels:

  • component level

  • endpoint level

Configuring Component Options

At the component level, you set general and shared configurations that are, then, inherited by the endpoints. It is the highest configuration level.

For example, a component may have security settings, credentials for authentication, urls for network connection and so forth.

Some components only have a few options, and others may have many. Because components typically have pre-configured defaults that are commonly used, then you may often only need to configure a few options on a component; or none at all.

You can configure components using:

  • the Component DSL.

  • in a configuration file (application.properties, *.yaml files, etc).

  • directly in the Java code.

Configuring Endpoint Options

You usually spend more time setting up endpoints because they have many options. These options help you customize what you want the endpoint to do. The options are also categorized into whether the endpoint is used as a consumer (from), as a producer (to), or both.

Configuring endpoints is most often done directly in the endpoint URI as path and query parameters. You can also use the Endpoint DSL and DataFormat DSL as a type safe way of configuring endpoints and data formats in Java.

A good practice when configuring options is to use Property Placeholders.

Property placeholders provide a few benefits:

  • They help prevent using hardcoded urls, port numbers, sensitive information, and other settings.

  • They allow externalizing the configuration from the code.

  • They help the code to become more flexible and reusable.

The following two sections list all the options, firstly for the component followed by the endpoint.

Component Options

The Tahu Host Application component supports 12 options, which are listed below.

Name Description Default Type

checkClientIdLength (common)

MQTT client ID length check enabled.

false

boolean

clientId (common)

Required MQTT client ID to use for all server definitions, rather than specifying the same one for each. Note that if neither the 'clientId' parameter nor an 'MqttClientId' are defined for an MQTT Server, a random MQTT Client ID will be generated automatically, prefaced with 'Camel'.

String

keepAliveTimeout (common)

MQTT connection keep alive timeout, in seconds.

30

int

rebirthDebounceDelay (common)

Delay before recurring node rebirth messages will be sent.

5000

long

servers (common)

Required MQTT server definitions, given with the following syntax in a comma-separated list: MqttServerName:(MqttClientId:)(tcp/ssl)://hostname(:port),…​

String

bridgeErrorHandler (consumer)

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions (if possible) occurred while the Camel consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. Important: This is only possible if the 3rd party component allows Camel to be alerted if an exception was thrown. Some components handle this internally only, and therefore bridgeErrorHandler is not possible. In other situations we may improve the Camel component to hook into the 3rd party component and make this possible for future releases. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

boolean

autowiredEnabled (advanced)

Whether autowiring is enabled. This is used for automatic autowiring options (the option must be marked as autowired) by looking up in the registry to find if there is a single instance of matching type, which then gets configured on the component. This can be used for automatic configuring JDBC data sources, JMS connection factories, AWS Clients, etc.

true

boolean

configuration (advanced)

To use a shared Tahu configuration.

TahuConfiguration

password (security)

Password for MQTT server authentication.

String

sslContextParameters (security)

SSL configuration for MQTT server connections.

SSLContextParameters

useGlobalSslContextParameters (security)

Enable/disable global SSL context parameters use.

false

boolean

username (security)

Username for MQTT server authentication.

String

Endpoint Options

The Tahu Host Application endpoint is configured using URI syntax:

tahu-host:hostId

With the following path and query parameters:

Path Parameters (1 parameters)

Name Description Default Type

hostId (consumer)

Required ID for the host application.

String

Query Parameters (11 parameters)

Name Description Default Type

checkClientIdLength (common)

MQTT client ID length check enabled.

false

boolean

clientId (common)

Required MQTT client ID to use for all server definitions, rather than specifying the same one for each. Note that if neither the 'clientId' parameter nor an 'MqttClientId' are defined for an MQTT Server, a random MQTT Client ID will be generated automatically, prefaced with 'Camel'.

String

keepAliveTimeout (common)

MQTT connection keep alive timeout, in seconds.

30

int

rebirthDebounceDelay (common)

Delay before recurring node rebirth messages will be sent.

5000

long

servers (common)

Required MQTT server definitions, given with the following syntax in a comma-separated list: MqttServerName:(MqttClientId:)(tcp/ssl)://hostname(:port),…​

String

bridgeErrorHandler (consumer (advanced))

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions (if possible) occurred while the Camel consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. Important: This is only possible if the 3rd party component allows Camel to be alerted if an exception was thrown. Some components handle this internally only, and therefore bridgeErrorHandler is not possible. In other situations we may improve the Camel component to hook into the 3rd party component and make this possible for future releases. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

boolean

exceptionHandler (consumer (advanced))

To let the consumer use a custom ExceptionHandler. Notice if the option bridgeErrorHandler is enabled then this option is not in use. By default the consumer will deal with exceptions, that will be logged at WARN or ERROR level and ignored.

ExceptionHandler

exchangePattern (consumer (advanced))

Sets the exchange pattern when the consumer creates an exchange.

Enum values:

  • InOnly

  • InOut

ExchangePattern

password (security)

Password for MQTT server authentication.

String

sslContextParameters (security)

SSL configuration for MQTT server connections.

SSLContextParameters

username (security)

Username for MQTT server authentication.

String

Message Headers

The Tahu Host Application component supports 5 message header(s), which is/are listed below:

Name Description Default Type

CamelTahuMessageType (consumer)

Constant: MESSAGE_TYPE

The Sparkplug message type of the message.

Enum values:

  • NBIRTH

  • NDATA

  • NDEATH

  • DBIRTH

  • DDATA

  • DDEATH

String

CamelTahuEdgeNodeDescriptor (consumer)

Constant: EDGE_NODE_DESCRIPTOR

The Sparkplug edge node descriptor string source of a message or metric.

String

CamelTahuMessageTimestamp (consumer)

Constant: MESSAGE_TIMESTAMP

The timestamp of a Sparkplug message.

Long

CamelTahuMessageUUID (consumer)

Constant: MESSAGE_UUID

The UUID of a Sparkplug message.

UUID

CamelTahuMessageSequenceNumber (consumer)

Constant: MESSAGE_SEQUENCE_NUMBER

The sequence number of a Sparkplug message.

Long
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