AzureEventHubsConnector

Connects to Azure Event Hubs to send, receive, and checkpoint messages.

Typical Uses

Communicating with Event Hubs to interact with devices, data, and platforms.

How does it work?

The AzureEventHubsConnector uses your Azure account credentials to connect to Azure’s Event Hubs and perform various tasks:

Action	Task
Checkpoint	Manually checkpoint a message or event.
Receive	Receive messages and events.
Send	Send messages and events.

Optional Input Port

This transformer has two modes, depending on whether a connector is attached to the Input port or not:

Input-driven: When input features are connected, the transformer runs once for each feature it receives in the Input port.
Run Once: When no input features are connected, the transformer runs one time.

When the Input port is in use, the Initiator output port is also enabled.

Checkpointing

A checkpoint records the last successfully processed event's offset (position in the partition), enabling a restart without reprocessing old data. Checkpoints are also used for load balancing when receiving from more than one partition.

When Action is Receive, checkpointing is optional. If a valid Checkpoint Store is provided including Container Name and Connection String, checkpointing will be performed.

When Action is Checkpoint, a manual checkpoint is added to a message previously received via Action > Receive.

A valid Checkpoint Store is required. This action can be useful when messages are post-processed in the workspace, postponing the checkpoint until after processing is complete, as in:

AzureEventHubsConnector: Action > Receive, no checkpointing
Message processing in the workspace
AzureEventHubsConnector: Action > Checkpoint

Heartbeat

When Action is Receive and the connection is still alive (Receive Mode is Stream or a batch is not yet complete), heartbeat features are output at a specified interval after a period of non-activity.

Heartbeat features have two attributes:

_heartbeat_id: Integer starting at 0. This is a unique identifier for each heartbeat feature output from this port.
_heartbeat_counter: Integer starting at 0 that resets whenever the connector receives a new message and a new period of inactivity begins. This counter represents the number of consecutive heartbeat features.

Configuration

Input Ports

Output Ports

Output

Features with added attributes, as specified in parameters and according to Action:

Action	Output - Input-Driven	Output - Run Once
Checkpoint	Multiple features, one for each message checkpointed, with information about the checkpointed message.	Multiple features, one for each message checkpointed, with information about the checkpointed message.
Receive	Multiple features, one for each message received, with details about the message.	Multiple features, one for each message received, with details about the message.
Send	Input feature with details about the sent message.	One new feature with details about the sent message.

Parameters

Authentication

Credential Source

Select the type of credentials to use:

Web Connection: (Recommended) Use an Azure Event Hubs Web Connection .
Embedded: Embed an account name and access key as transformer parameters.
Default Azure Credential: Obtain credentials from Microsoft Entra ID, Managed Identity, or Azure CLI.

Account

When Credential Source is Web Connection, select or create a Web Connection connecting to an Azure Event Hubs Web Service.

See Using Web Connections.

Namespace

When Credential Source is Default Azure Credential, provide an Event Hubs namespace, typically a hostname under servicebus.windows.net.

Embedded Credentials

When Credential Source is Embedded:

Event Hub Connection String

Provide a connection string, found in the Azure Portal Event Hubs Namespace under Shared Access Policies.

Action > Checkpoint

Checkpoint Options

Received Message ID

Provide the ID of the message to be checkpointed, typically the _receive_id attribute created by an upstream AzureEventHubsConnector using Action > Receive.

Checkpoint Store (Azure blob)

Container Name	Specify the Azure Blob container name .
Connection String	Provide a connection string to an Azure Storage account. Use only one of Connection String or Blob Storage Account URL.
Blob Storage Account URL	Provide the URL of an Azure Storage account. Use only one of Connection String or Blob Storage Account URL. Blob Storage Account URL can only be used for checkpoint storage if: Credential Source is Default Azure Credential, or A Microsoft Azure Event Hubs Service Principal web connection is used.
Checkpoint Interval	(Optional) Specify a number-of-messages interval at which checkpoints are submitted. There will always be a checkpoint at the end of a message stream.

Output Attributes

Attributes to Add

Select any available attributes to be included on the output features:

_enqueued_time	The timestamp when the message was sent.
_offset	The offset of the message.
_partition_key	The partition of the message.
_payload	The message payload. UTF-8 string if possible to decode, otherwise binary or numeric.
_properties	A key, value pair of message properties.
_sequence_number	The sequence number of the message.
_system_properties	Metadata set by the Event Hubs Service associated with the message.

Action > Receive

Receive Options

Consumer Group	Specify the consumer group to receive from. The default is $Default.
Receive Mode	Select a message receiving method: Stream: The connector continues to receive messages indefinitely. The translation must be terminated to stop receiving. Batch: Only a given number of messages are received before the connection is closed.
Batch Size	When Receive Mode is Batch, specify the number of messages to read per batch.
Partition ID	(Optional) If specified, the client will receive from this partition only. If empty, the client will receive from all partitions. It is recommended that there is only one active receiver on a partition per consumer group.
Prefetch Count	(Optional) Specify the number of messages to prefetch from Azure. Default is 300.
Starting Position	(Optional) Specify an event position to start receiving from if there is no checkpoint data for the partition. Value may be a string, integer or datetime. Checkpoint data will be used if available. Default (empty) is @latest which receives only new events. -1 starts receiving at the beginning of the stream.
Starting Position Mode	Select a starting position option: Exclusive (default) Inclusive

Heartbeat

Interval

Specify the duration of a period of inactivity before a heartbeat feature is emitted, in Time Units.

Default is 1.

Time Unit

Select the Interval unit:

Seconds
Minutes
Hours (default)
Days

Checkpoint Store (Azure Blob) - Optional

See Checkpointing.

Container Name

Specify the Azure Blob container name .

Connection String

Provide a connection string to an Azure Storage account.

Checkpoint Interval

(Optional) Specify a number-of-messages interval at which checkpoints are submitted.

There will always be a checkpoint at the end of a message stream.

Output Attributes

Attributes to Add

Select any available attributes to be included on the output features:

_enqueued_time	The timestamp when the message was sent.
_offset	The offset of the message.
_partition_key	The partition of the message.
_payload	The message payload. UTF-8 string if possible to decode, otherwise binary or numeric.
_properties	A key, value pair of message properties.
_receive_id	An id generated to identify the message used for the Checkpoint action.
_sequence_number	The sequence number of the message.
_system_properties	Metadata set by the Event Hubs Service associated with the message.

Action > Send

Send Options

Payload

Provide the message content.

This is often JSON, but can be any string, binary, integer or floating-point value.

Partition ID

(Optional) Specify a partition ID to send to.

If empty, a message will be assigned to a random partition using round-robin.

Message Properties

(Optional) Specify additional properties to send with each message.

Key	The custom name of the property.
Value	The content of the property.

Output Attributes

Attributes to Add

Select any available attributes to be included on the output features:

_enqueued_time	The timestamp when the message was sent.
_offset	The offset of the message.
_partition_key	The partition of the message.
_payload	The message payload. UTF-8 string if possible to decode, otherwise binary or numeric.
_properties	A key, value pair of message properties.
_sequence_number	The sequence number of the message.
_system_properties	Metadata set by the Event Hubs Service associated with the message.

Editing Transformer Parameters

Transformer parameters can be set by directly entering values, using expressions, or referencing other elements in the workspace such as attribute values or user parameters. Various editors and context menus are available to assist. To see what is available, click beside the applicable parameter.

How to Set Parameter Values

Defining Values

There are several ways to define a value for use in a Transformer. The simplest is to simply type in a value or string, which can include functions of various types such as attribute references, math and string functions, and workspace parameters.

Using the Text Editor

The Text Editor provides a convenient way to construct text strings (including regular expressions) from various data sources, such as attributes, parameters, and constants, where the result is used directly inside a parameter.

Text Editor

Using the Arithmetic Editor

The Arithmetic Editor provides a convenient way to construct math expressions from various data sources, such as attributes, parameters, and feature functions, where the result is used directly inside a parameter.

Arithmetic Editor

Conditional Values

Set values depending on one or more test conditions that either pass or fail.

Parameter Condition Definition Dialog

Content

Expressions and strings can include a number of functions, characters, parameters, and more.

When setting values - whether entered directly in a parameter or constructed using one of the editors - strings and expressions containing String, Math, Date/Time or FME Feature Functions will have those functions evaluated. Therefore, the names of these functions (in the form @<function_name>) should not be used as literal string values.

Content Types

String Functions	These functions manipulate and format strings.
Special Characters	A set of control characters is available in the Text Editor.
Math Functions	Math functions are available in both editors.
Date/Time Functions	Date and time functions are available in the Text Editor.
Math Operators	These operators are available in the Arithmetic Editor.
FME Feature Functions	These return primarily feature-specific values.
FME Parameters	FME and workspace-specific parameters may be used.
Creating and Modifying User Parameters	Create your own editable parameters.

Dialog Options - Tables

Table Tools

Transformers with table-style parameters have additional tools for populating and manipulating values.

Row Reordering

Enabled once you have clicked on a row item. Choices include:

Add a row
Remove a row
Move current row up one
Move current row down one
Move current row to top
Move current row to bottom

Cut, Copy, and Paste

Enabled once you have clicked on a row item. Choices include:

Cut a row - delete and copy to clipboard
Copy a row to the clipboard
Paste a row from the clipboard

Cut, copy, and paste may be used within a transformer, or between transformers.

Filter

Start typing a string, and the matrix will only display rows matching those characters. Searches all columns. This only affects the display of attributes within the transformer - it does not alter which attributes are output.

Import

Import populates the table with a set of new attributes read from a dataset. Specific application varies between transformers.

Reset/Refresh

Generally resets the table to its initial state, and may provide additional options to remove invalid entries. Behavior varies between transformers.

Note: Not all tools are available in all transformers.

For more information, see Transformer Parameter Menu Options.

Reference

Processing Behavior	Feature-Based
Feature Holding	No
Dependencies	Microsoft Azure Account with the Event Hubs Service
Aliases
History

FME Online Resources

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