Configure dataflows in Azure IoT Operations

Important

This page includes instructions for managing Azure IoT Operations components using Kubernetes deployment manifests, which is in preview. This feature is provided with several limitations, and shouldn't be used for production workloads.

See the Supplemental Terms of Use for Microsoft Azure Previews for legal terms that apply to Azure features that are in beta, preview, or otherwise not yet released into general availability.

A dataflow is the path that data takes from the source to the destination with optional transformations. You can configure the dataflow by creating a Dataflow custom resource or using the Azure IoT Operations Studio portal. A dataflow is made up of three parts: the source, the transformation, and the destination.

To define the source and destination, you need to configure the dataflow endpoints. The transformation is optional and can include operations like enriching the data, filtering the data, and mapping the data to another field.

Important

Each dataflow must have the Azure IoT Operations local MQTT broker default endpoint as either the source or destination.

You can use the operations experience in Azure IoT Operations to create a dataflow. The operations experience provides a visual interface to configure the dataflow. You can also use Bicep to create a dataflow using a Bicep template file, or use Kubernetes to create a dataflow using a YAML file.

Continue reading to learn how to configure the source, transformation, and destination.

Prerequisites

You can deploy dataflows as soon as you have an instance of Azure IoT Operations using the default dataflow profile and endpoint. However, you might want to configure dataflow profiles and endpoints to customize the dataflow.

Dataflow profile

If you don't need different scaling settings for your dataflows, use the default dataflow profile provided by Azure IoT Operations. To learn how to configure a dataflow profile, see Configure dataflow profiles.

Dataflow endpoints

Dataflow endpoints are required to configure the source and destination for the dataflow. To get started quickly, you can use the default dataflow endpoint for the local MQTT broker. You can also create other types of dataflow endpoints like Kafka, Event Hubs, or Azure Data Lake Storage. To learn how to configure each type of dataflow endpoint, see Configure dataflow endpoints.

Get started

Once you have the prerequisites, you can start to create a dataflow.

Portal

To create a dataflow in operations experience, select Dataflow > Create dataflow. Then, you see the page where you can configure the source, transformation, and destination for the dataflow.

Bicep

Create a Bicep .bicep file to start creating a dataflow. This example shows the structure of the dataflow containing the source, transformation, and destination configurations.

param aioInstanceName string = '<AIO_INSTANCE_NAME>'
param customLocationName string = '<CUSTOM_LOCATION_NAME>'
param dataflowName string = '<DATAFLOW_NAME>'

resource aioInstance 'Microsoft.IoTOperations/instances@2024-11-01' existing = {
  name: aioInstanceName
}

resource customLocation 'Microsoft.ExtendedLocation/customLocations@2021-08-31-preview' existing = {
  name: customLocationName
}

resource defaultDataflowEndpoint 'Microsoft.IoTOperations/instances/dataflowEndpoints@2024-11-01' existing = {
  parent: aioInstance
  name: 'default'
}

// Pointer to the default dataflow profile
resource defaultDataflowProfile 'Microsoft.IoTOperations/instances/dataflowProfiles@2024-11-01' existing = {
  parent: aioInstance
  name: 'default'
}

resource dataflow 'Microsoft.IoTOperations/instances/dataflowProfiles/dataflows@2024-11-01' = {
  // Reference to the parent dataflow profile, the default profile in this case
  // Same usage as profileRef in Kubernetes YAML
  parent: defaultDataflowProfile
  name: dataflowName
  extendedLocation: {
    name: customLocation.id
    type: 'CustomLocation'
  }
  properties: {
    mode: 'Enabled'
    operations: [
      {
        operationType: 'Source'
        sourceSettings: {
          // See source configuration section
        }
      }
      // Transformation optional
      {
        operationType: 'BuiltInTransformation'
        builtInTransformationSettings: {
          // See transformation configuration section
        }
      }
      {
        operationType: 'Destination'
        destinationSettings: {
          // See destination configuration section
        }
      }
    ]
  }
}

Kubernetes (preview)

Create a Kubernetes manifest .yaml file to start creating a dataflow. This example shows the structure of the dataflow containing the source, transformation, and destination configurations.

apiVersion: connectivity.iotoperations.azure.com/v1
kind: Dataflow
metadata:
  name: <DATAFLOW_NAME>
  namespace: azure-iot-operations
spec:
  # Reference to the default dataflow profile
  # This field is required when configuring via Kubernetes YAML
  # The syntax is different when using Bicep
  profileRef: default 
  mode: Enabled
  operations:
    - operationType: Source
      sourceSettings:
        # See source configuration section
      # Transformation optional
    - operationType: BuiltInTransformation
      builtInTransformationSettings:
        # See transformation configuration section
    - operationType: Destination
      destinationSettings:
        # See destination configuration section

Review the following sections to learn how to configure the operation types of the dataflow.

Source

To configure a source for the dataflow, specify the endpoint reference and a list of data sources for the endpoint. Choose one of the following options as the source for the dataflow.

If the default endpoint isn't used as the source, it must be used as the destination. To learn more about, see Dataflows must use local MQTT broker endpoint.

Option 1: Use default MQTT endpoint as source

Portal

1. Under Source details, select MQTT.

   

2. Enter the following settings for the MQTT source:

   Setting	Description
   MQTT topic	The MQTT topic filter to subscribe to for incoming messages. See Configure MQTT or Kafka topics.
   Message schema	The schema to use to deserialize the incoming messages. See Specify schema to deserialize data.

3. Select Apply.

Bicep

The MQTT endpoint is configured in the Bicep template file. For example, the following endpoint is a source for the dataflow.

sourceSettings: {
  endpointRef: 'default'
  dataSources: [
    'thermostats/+/telemetry/temperature/#'
    'humidifiers/+/telemetry/humidity/#'
  ]
}

Here, dataSources allow you to specify multiple MQTT or Kafka topics without needing to modify the endpoint configuration. This flexibility means the same endpoint can be reused across multiple dataflows, even if the topics vary. To learn more, see Configure data sources.

Kubernetes (preview)

For example, to configure a source using an MQTT endpoint and two MQTT topic filters, use the following configuration:

sourceSettings:
  endpointRef: default
  dataSources:
    - thermostats/+/telemetry/temperature/#
    - humidifiers/+/telemetry/humidity/#

Because dataSources allows you to specify MQTT or Kafka topics without modifying the endpoint configuration, you can reuse the endpoint for multiple dataflows even if the topics are different. To learn more, see Configure data sources.

Option 2: Use asset as source

Portal

You can use an asset as the source for the dataflow. Using an asset as a source is only available in the operations experience.

1. Under Source details, select Asset.

2. Select the asset you want to use as the source endpoint.

3. Select Proceed.

   A list of datapoints for the selected asset is displayed.

   

4. Select Apply to use the asset as the source endpoint.

Bicep

Configuring an asset as a source is only available in the operations experience.

Kubernetes (preview)

Configuring an asset as a source is only available in the operations experience.

When using an asset as the source, the asset definition is used to infer the schema for the dataflow. The asset definition includes the schema for the asset's datapoints. To learn more, see Manage asset configurations remotely.

Once configured, the data from the asset reached the dataflow via the local MQTT broker. So, when using an asset as the source, the dataflow uses the local MQTT broker default endpoint as the source in actuality.

Option 3: Use custom MQTT or Kafka dataflow endpoint as source

If you created a custom MQTT or Kafka dataflow endpoint (for example, to use with Event Grid or Event Hubs), you can use it as the source for the dataflow. Remember that storage type endpoints, like Data Lake or Fabric OneLake, can't be used as source.

To configure, use Kubernetes YAML or Bicep. Replace placeholder values with your custom endpoint name and topics.

Portal

Using a custom MQTT or Kafka endpoint as a source is currently not supported in the operations experience.

Bicep

sourceSettings: {
  endpointRef: '<CUSTOM_ENDPOINT_NAME>'
  dataSources: [
    '<TOPIC_1>'
    '<TOPIC_2>'
    // See section on configuring MQTT or Kafka topics for more information
  ]
}

Kubernetes (preview)

sourceSettings:
  endpointRef: <CUSTOM_ENDPOINT_NAME>
  dataSources:
  - <TOPIC_1>
  - <TOPIC_2>
  # See section on configuring MQTT or Kafka topics for more information

Configure data sources (MQTT or Kafka topics)

You can specify multiple MQTT or Kafka topics in a source without needing to modify the dataflow endpoint configuration. This flexibility means the same endpoint can be reused across multiple dataflows, even if the topics vary. For more information, see Reuse dataflow endpoints.

MQTT topics

When the source is an MQTT (Event Grid included) endpoint, you can use the MQTT topic filter to subscribe to incoming messages. The topic filter can include wildcards to subscribe to multiple topics. For example, thermostats/+/telemetry/temperature/# subscribes to all temperature telemetry messages from thermostats. To configure the MQTT topic filters:

Portal

In the operations experience dataflow Source details, select MQTT, then use the MQTT topic field to specify the MQTT topic filter to subscribe to for incoming messages.

Note

Only one MQTT topic filter can be specified in the operations experience. To use multiple MQTT topic filters, use Bicep or Kubernetes.

Bicep

sourceSettings: {
  endpointRef: '<MQTT_ENDPOINT_NAME>'
  dataSources: [
    '<MQTT_TOPIC_FILTER_1>'
    '<MQTT_TOPIC_FILTER_2>'
    // Add more MQTT topic filters as needed
  ]
}

Example with multiple MQTT topic filters with wildcards:

sourceSettings: {
  endpointRef: 'default'
  dataSources: [
    'thermostats/+/telemetry/temperature/#'
    'humidifiers/+/telemetry/humidity/#'
  ]
}

Here, the wildcard + is used to select all devices under the thermostats and humidifiers topics. The # wildcard is used to select all telemetry messages under all subtopics of the temperature and humidity topics.

Kubernetes (preview)

sourceSettings:
  endpointRef: <MQTT_ENDPOINT_NAME>
  dataSources:
    - <MQTT_TOPIC_FILTER_1>
    - <MQTT_TOPIC_FILTER_2>
    # Add more MQTT topic filters as needed

Example with multiple MQTT topic filters with wildcards:

sourceSettings:
  endpointRef: default
  dataSources:
    - thermostats/+/telemetry/temperature/#
    - humidifiers/+/telemetry/humidity/#

Here, the wildcard + is used to select all devices under the thermostats and humidifiers topics. The # wildcard is used to select all telemetry messages under all subtopics of the temperature and humidity topics.

Shared subscriptions

To use shared subscriptions with MQTT sources, you can specify the shared subscription topic in the form of $shared/<GROUP_NAME>/<TOPIC_FILTER>.

Portal

In operations experience dataflow Source details, select MQTT and use the MQTT topic field to specify the shared subscription group and topic.

Bicep

sourceSettings: {
  dataSources: [
    '$shared/<GROUP_NAME>/<TOPIC_FILTER>'
  ]
}

Kubernetes (preview)

sourceSettings:
  dataSources:
    - $shared/<GROUP_NAME>/<TOPIC_FILTER>

If the instance count in the dataflow profile is greater than one, shared subscription is automatically enabled for all dataflows that use MQTT source. In this case, the $shared prefix is added and the shared subscription group name automatically generated. For example, if you have a dataflow profile with an instance count of 3, and your dataflow uses an MQTT endpoint as source configured with topics topic1 and topic2, they are automatically converted to shared subscriptions as $shared/<GENERATED_GROUP_NAME>/topic1 and $shared/<GENERATED_GROUP_NAME>/topic2.

You can explicitly create a topic named $shared/mygroup/topic in your configuration. However, adding the $shared topic explicitly isn't recommended since the $shared prefix is automatically added when needed. Dataflows can make optimizations with the group name if it isn't set. For example, $share isn't set and dataflows only has to operate over the topic name.

Important

Dataflows requiring shared subscription when instance count is greater than one is important when using Event Grid MQTT broker as a source since it doesn't support shared subscriptions. To avoid missing messages, set the dataflow profile instance count to one when using Event Grid MQTT broker as the source. That is when the dataflow is the subscriber and receiving messages from the cloud.

Kafka topics

When the source is a Kafka (Event Hubs included) endpoint, specify the individual Kafka topics to subscribe to for incoming messages. Wildcards are not supported, so you must specify each topic statically.

Note

When using Event Hubs via the Kafka endpoint, each individual event hub within the namespace is the Kafka topic. For example, if you have an Event Hubs namespace with two event hubs, thermostats and humidifiers, you can specify each event hub as a Kafka topic.

To configure the Kafka topics:

Portal

Using a Kafka endpoint as a source is currently not supported in the operations experience.

Bicep

sourceSettings: {
  endpointRef: '<KAFKA_ENDPOINT_NAME>'
  dataSources: [
    '<KAFKA_TOPIC_1>'
    '<KAFKA_TOPIC_2>'
    // Add more Kafka topics as needed
  ]
}

Kubernetes (preview)

sourceSettings:
  endpointRef: <KAFKA_ENDPOINT_NAME>
  dataSources:
    - <KAFKA_TOPIC_1>
    - <KAFKA_TOPIC_2>
    # Add more Kafka topics as needed

Specify source schema

When using MQTT or Kafka as the source, you can specify a schema to display the list of data points in the operations experience portal. Note that using a schema to deserialize and validate incoming messages isn't currently supported.

If the source is an asset, the schema is automatically inferred from the asset definition.

Tip

To generate the schema from a sample data file, use the Schema Gen Helper.

To configure the schema used to deserialize the incoming messages from a source:

Portal

In operations experience dataflow Source details, select MQTT and use the Message schema field to specify the schema. You can use the Upload button to upload a schema file first. To learn more, see Understand message schemas.

Bicep

Once you have used the schema registry to store the schema, you can reference it in the dataflow configuration.

sourceSettings: {
  serializationFormat: 'Json'
  schemaRef: 'aio-sr://<SCHEMA_NAMESPACE>/<SCHEMA_NAME>:<VERSION>'
}

Kubernetes (preview)

Once you have used the schema registry to store the schema, you can reference it in the dataflow configuration.

sourceSettings:
  serializationFormat: Json
  schemaRef: 'aio-sr://<SCHEMA_NAMESPACE>/<SCHEMA_NAME>:<VERSION>'

To learn more, see Understand message schemas.

Transformation

The transformation operation is where you can transform the data from the source before you send it to the destination. Transformations are optional. If you don't need to make changes to the data, don't include the transformation operation in the dataflow configuration. Multiple transformations are chained together in stages regardless of the order in which they're specified in the configuration. The order of the stages is always:

1. Enrich: Add additional data to the source data given a dataset and condition to match.
2. Filter: Filter the data based on a condition.
3. Map, Compute, Rename, or add a New property: Move data from one field to another with an optional conversion.

This section is an introduction to dataflow transforms. For more detailed information, see Map data by using dataflows, Convert data by using dataflow conversions, and Enrich data by using dataflows.

Portal

In the operations experience, select Dataflow > Add transform (optional).

Bicep

builtInTransformationSettings: {
  datasets: [
    // See section on enriching data
  ]
  filter: [
    // See section on filtering data
  ]
  map: [
    // See section on mapping data
  ]
}

Kubernetes (preview)

builtInTransformationSettings:
  datasets:
    # See section on enriching data
  filter:
    # See section on filtering data
  map:
    # See section on mapping data

Enrich: Add reference data

To enrich the data, first add reference dataset in the Azure IoT Operations state store. The dataset is used to add extra data to the source data based on a condition. The condition is specified as a field in the source data that matches a field in the dataset.

You can load sample data into the state store by using the state store CLI. Key names in the state store correspond to a dataset in the dataflow configuration.

Portal

Currently, the Enrich stage isn't supported in the operations experience.

Bicep

This example shows how you could use the deviceId field in the source data to match the asset field in the dataset:

builtInTransformationSettings: {
  datasets: [
    {
      key: 'assetDataset'
      inputs: [
        '$source.deviceId' // ---------------- $1
        '$context(assetDataset).asset' // ---- $2
      ]
      expression: '$1 == $2'
    }
  ]
}

Kubernetes (preview)

For example, you could use the deviceId field in the source data to match the asset field in the dataset:

builtInTransformationSettings:
  datasets:
  - key: assetDataset
    inputs:
      - $source.deviceId # ------------- $1
      - $context(assetDataset).asset # - $2
    expression: $1 == $2

If the dataset has a record with the asset field, similar to:

{
  "asset": "thermostat1",
  "location": "room1",
  "manufacturer": "Contoso"
}

The data from the source with the deviceId field matching thermostat1 has the location and manufacturer fields available in filter and map stages.

For more information about condition syntax, see Enrich data by using dataflows and Convert data using dataflows.

Filter: Filter data based on a condition

To filter the data on a condition, you can use the filter stage. The condition is specified as a field in the source data that matches a value.

Portal

1. Under Transform (optional), select Filter > Add.

   

2. Enter the required settings.

   Setting	Description
   Filter condition	The condition to filter the data based on a field in the source data.
   Description	Provide a description for the filter condition.

   In the filter condition field, type @ or select Ctrl + Space to select datapoints from a dropdown.

   You can access MQTT metadata properties using the format @$metadata.user_properties.<property> or @$metadata.topic. You can also enter $metadata headers using the format @$metadata.<header>. For more information, see field references.

   The condition can use the fields in the source data. For example, you could use a filter condition like @temperature > 20 to filter data less than or equal to 20 based on the temperature field.

3. Select Apply.

Bicep

For example, you could use the temperature field in the source data to filter the data:

builtInTransformationSettings: {
  filter: [
    {
      inputs: [
        'temperature ? $last'
      ]
      expression: '$1 > 20'
    }
  ]
}

If the temperature field is greater than 20, the data is passed to the next stage. If the temperature field is less than or equal to 20, the data is filtered.

Kubernetes (preview)

For example, you could use the temperature field in the source data to filter the data:

builtInTransformationSettings:
  filter:
    - inputs:
      - temperature ? $last # - $1
      expression: "$1 > 20"

If the temperature field is greater than 20, the data is passed to the next stage. If the temperature field is less than or equal to 20, the data is filtered.

Map: Move data from one field to another

To map the data to another field with optional conversion, you can use the map operation. The conversion is specified as a formula that uses the fields in the source data.

Portal

In the operations experience, mapping is currently supported using Compute, Rename, and New property transforms.

Compute

You can use the Compute transform to apply a formula to the source data. This operation is used to apply a formula to the source data and store the result field.

1. Under Transform (optional), select Compute > Add.

   

2. Enter the required settings.

   Setting	Description
   Select formula	Choose an existing formula from the dropdown or select Custom to enter a formula manually.
   Output	Specify the output display name for the result.
   Formula	Enter the formula to be applied to the source data.
   Description	Provide a description for the transformation.
   Last known value	Optionally, use the last known value if the current value isn't available.

   You can enter or edit a formula in the Formula field. The formula can use the fields in the source data. Type @ or select Ctrl + Space to select datapoints from a dropdown.

   You can access MQTT metadata properties using the format @$metadata.user_properties.<property> or @$metadata.topic. You can also enter $metadata headers using the format @$metadata.<header>. For more information, see field references.

   The formula can use the fields in the source data. For example, you could use the temperature field in the source data to convert the temperature to Celsius and store it in the temperatureCelsius output field.

3. Select Apply.

Rename

You can rename a datapoint using the Rename transform. This operation is used to rename a datapoint in the source data to a new name. The new name can be used in the subsequent stages of the dataflow.

1. Under Transform (optional), select Rename > Add.

   

2. Enter the required settings.

   Setting	Description
   Datapoint	Select a datapoint from the dropdown or enter a $metadata header using the format $metadata.<header>.
   New datapoint name	Enter the new name for the datapoint.
   Description	Provide a description for the transformation.

   You can access MQTT metadata properties using the format @$metadata.user_properties.<property> or @$metadata.topic. You can also enter $metadata headers using the format @$metadata.<header>. For more information, see field references.

3. Select Apply.

New property

You can add a new property to the source data using the New property transform. This operation is used to add a new property to the source data. The new property can be used in the subsequent stages of the dataflow.

1. Under Transform (optional), select New property > Add.

   

2. Enter the required settings.

   Setting	Description
   Property key	Enter the key for the new property.
   Property value	Enter the value for the new property.
   Description	Provide a description for the new property.

3. Select Apply.

Bicep

You can access MQTT metadata properties using the format $metadata.user_properties.<property> or $metadata.topic. You can also enter $metadata headers using the format $metadata.<header>. For more information, see field references.

For example, you could use the temperature field in the source data to convert the temperature to Celsius and store it in the temperatureCelsius field. You could also enrich the source data with the location field from the contextualization dataset:

builtInTransformationSettings: {
  map: [
    {
      inputs: [
        'temperature'
      ]
      output: 'temperatureCelsius'
      expression: '($1 - 32) * 5/9'
    }
    {
      inputs: [
        '$context(assetDataset).location'
      ]
      output: 'location'
    }
  ]
}

Kubernetes (preview)

You can access MQTT metadata properties using the format $metadata.user_properties.<property> or $metadata.topic. You can also enter $metadata headers using the format $metadata.<header>. For more information, see field references.

For example, you could use the temperature field in the source data to convert the temperature to Celsius and store it in the temperatureCelsius field. You could also enrich the source data with the location field from the contextualization dataset:

builtInTransformationSettings:
  map:
    - inputs:
      - temperature # - $1
      expression: "($1 - 32) * 5/9"
      output: temperatureCelsius
    - inputs:
      - $context(assetDataset).location  
      output: location

To learn more, see Map data by using dataflows and Convert data by using dataflows.

Serialize data according to a schema

If you want to serialize the data before sending it to the destination, you need to specify a schema and serialization format. Otherwise, the data is serialized in JSON with the types inferred. Storage endpoints like Microsoft Fabric or Azure Data Lake require a schema to ensure data consistency. Supported serialization formats are Parquet and Delta.

Tip

To generate the schema from a sample data file, use the Schema Gen Helper.

Portal

For operations experience, you specify the schema and serialization format in the dataflow endpoint details. The endpoints that support serialization formats are Microsoft Fabric OneLake, Azure Data Lake Storage Gen 2, and Azure Data Explorer. For example, to serialize the data in Delta format, you need to upload a schema to the schema registry and reference it in the dataflow destination endpoint configuration.

Bicep

Once you upload a schema to the schema registry, you can reference it in the dataflow configuration.

builtInTransformationSettings: {
  serializationFormat: 'Delta'
  schemaRef: 'aio-sr://<SCHEMA_NAMESPACE>/<SCHEMA>:<VERSION>'
}

Kubernetes (preview)

Once you upload a schema to the schema registry, you can reference it in the dataflow configuration.

builtInTransformationSettings:
  serializationFormat: Delta
  schemaRef: 'aio-sr://<SCHEMA_NAMESPACE>/<SCHEMA>:<VERSION>'

For more information about schema registry, see Understand message schemas.

Destination

To configure a destination for the dataflow, specify the endpoint reference and data destination. You can specify a list of data destinations for the endpoint.

To send data to a destination other than the local MQTT broker, create a dataflow endpoint. To learn how, see Configure dataflow endpoints. If the destination isn't the local MQTT broker, it must be used as a source. To learn more about, see Dataflows must use local MQTT broker endpoint.

Important

Storage endpoints require a schema for serialization. To use dataflow with Microsoft Fabric OneLake, Azure Data Lake Storage, Azure Data Explorer, or Local Storage, you must specify a schema reference.

Portal

1. Select the dataflow endpoint to use as the destination.

   

   Storage endpoints require a schema for serialization. If you choose a Microsoft Fabric OneLake, Azure Data Lake Storage, Azure Data Explorer, or Local Storage destination endpoint, you must specify a schema reference. For example, to serialize the data to a Microsoft Fabric endpoint in Delta format, you need to upload a schema to the schema registry and reference it in the dataflow destination endpoint configuration.

   

2. Select Proceed to configure the destination.

3. Enter the required settings for the destination, including the topic or table to send the data to. See Configure data destination (topic, container, or table) for more information.

Bicep

destinationSettings: {
  endpointRef: '<CUSTOM_ENDPOINT_NAME>'
  dataDestination: '<TOPIC_OR_TABLE>' // See section on configuring data destination
}

Kubernetes (preview)

destinationSettings:
  endpointRef: <CUSTOM_ENDPOINT_NAME>
  dataDestination: <TOPIC_OR_TABLE> # See section on configuring data destination

Configure data destination (topic, container, or table)

Similar to data sources, data destination is a concept that is used to keep the dataflow endpoints reusable across multiple dataflows. Essentially, it represents the subdirectory in the dataflow endpoint configuration. For example, if the dataflow endpoint is a storage endpoint, the data destination is the table in the storage account. If the dataflow endpoint is a Kafka endpoint, the data destination is the Kafka topic.

Endpoint type	Data destination meaning	Description
MQTT (or Event Grid)	Topic	The MQTT topic where the data is sent. Only static topics are supported, no wildcards.
Kafka (or Event Hubs)	Topic	The Kafka topic where the data is sent. Only static topics are supported, no wildcards. If the endpoint is an Event Hubs namespace, the data destination is the individual event hub within the namespace.
Azure Data Lake Storage	Container	The container in the storage account. Not the table.
Microsoft Fabric OneLake	Table or Folder	Corresponds to the configured path type for the endpoint.
Azure Data Explorer	Table	The table in the Azure Data Explorer database.
Local Storage	Folder	The folder or directory name in the local storage persistent volume mount. When using Azure Container Storage enabled by Azure Arc Cloud Ingest Edge Volumes, this must match the spec.path parameter for the subvolume you created.

To configure the data destination:

Portal

When using the operations experience, the data destination field is automatically interpreted based on the endpoint type. For example, if the dataflow endpoint is a storage endpoint, the destination details page prompts you to enter the container name. If the dataflow endpoint is an MQTT endpoint, the destination details page prompts you to enter the topic, and so on.

Bicep

The syntax is the same for all dataflow endpoints:

destinationSettings: {
  endpointRef: "<CUSTOM_ENDPOINT_NAME>"
  dataDestination: '<TOPIC_OR_TABLE>'
}

For example, to send data back to the local MQTT broker a static MQTT topic, use the following configuration:

destinationSettings: {
  endpointRef: 'default'
  dataDestination: 'example-topic'
}

Or, if you have custom event hub endpoint, the configuration would look like:

destinationSettings: {
  endpointRef: 'my-eh-endpoint'
  dataDestination: 'individual-event-hub'
}

Another example using a storage endpoint as the destination:

destinationSettings: {
  endpointRef: 'my-adls-endpoint'
  dataDestination: 'my-container'
}

Kubernetes (preview)

The syntax is the same for all dataflow endpoints:

destinationSettings:
  endpointRef: <CUSTOM_ENDPOINT_NAME>
  dataDestination: <TOPIC_OR_TABLE>

For example, to send data back to the local MQTT broker a static MQTT topic, use the following configuration:

destinationSettings:
  endpointRef: default
  dataDestination: example-topic

Or, if you have custom event hub endpoint, the configuration would look like:

destinationSettings:
  endpointRef: my-eh-endpoint
  dataDestination: individual-event-hub

Another example using a storage endpoint as the destination:

destinationSettings:
  endpointRef: my-adls-endpoint
  dataDestination: my-container

Example

The following example is a dataflow configuration that uses the MQTT endpoint for the source and destination. The source filters the data from the MQTT topic azure-iot-operations/data/thermostat. The transformation converts the temperature to Fahrenheit and filters the data where the temperature multiplied by the humidity is less than 100000. The destination sends the data to the MQTT topic factory.

Portal

See Bicep or Kubernetes tabs for the configuration example.

Bicep

param aioInstanceName string = '<AIO_INSTANCE_NAME>'
param customLocationName string = '<CUSTOM_LOCATION_NAME>'
param dataflowName string = '<DATAFLOW_NAME>'

resource aioInstance 'Microsoft.IoTOperations/instances@2024-11-01' existing = {
  name: aioInstanceName
}

resource customLocation 'Microsoft.ExtendedLocation/customLocations@2021-08-31-preview' existing = {
  name: customLocationName
}

// Pointer to the default dataflow endpoint
resource defaultDataflowEndpoint 'Microsoft.IoTOperations/instances/dataflowEndpoints@2024-11-01' existing = {
  parent: aioInstance
  name: 'default'
}

// Pointer to the default dataflow profile
resource defaultDataflowProfile 'Microsoft.IoTOperations/instances/dataflowProfiles@2024-11-01' existing = {
  parent: aioInstance
  name: 'default'
}

resource dataflow 'Microsoft.IoTOperations/instances/dataflowProfiles/dataflows@2024-11-01' = {
  // Reference to the parent dataflow profile, the default profile in this case
  // Same usage as profileRef in Kubernetes YAML
  parent: defaultDataflowProfile
  name: dataflowName
  extendedLocation: {
    name: customLocation.id
    type: 'CustomLocation'
  }
  properties: {
    mode: 'Enabled'
    operations: [
      {
        operationType: 'Source'
        sourceSettings: {
          // Use the default MQTT endpoint as the source
          endpointRef: defaultDataflowEndpoint.name
          // Filter the data from the MQTT topic azure-iot-operations/data/thermostat
          dataSources: [
            'azure-iot-operations/data/thermostat'
          ]
        }
      }
      // Transformation optional
      {
        operationType: 'BuiltInTransformation'
        builtInTransformationSettings: {
          // Filter the data where temperature * "Tag 10" < 100000
          filter: [
            {
              inputs: [
                'temperature.Value'
                '"Tag 10".Value'
              ]
              expression: '$1 * $2 < 100000'
            }
          ]
          map: [
            // Passthrough all values by default
            {
              inputs: [
                '*'
              ]
              output: '*'
            }
            // Convert temperature to Fahrenheit and output it to TemperatureF
            {
              inputs: [
                'temperature.Value'
              ]
              output: 'TemperatureF'
              expression: 'cToF($1)'
            }
          // Extract the "Tag 10" value and output it to Humidity
            {
              inputs: [
                '"Tag 10".Value'
              ]
              output: 'Humidity'
            }
          ]
        }
      }
      {
        operationType: 'Destination'
        destinationSettings: {
          // Use the default MQTT endpoint as the destination
          endpointRef: defaultDataflowEndpoint.name
          // Send the data to the MQTT topic factory
          dataDestination: 'factory'
        }
      }
    ]
  }
}

Kubernetes (preview)

apiVersion: connectivity.iotoperations.azure.com/v1
kind: Dataflow
metadata:
  name: my-dataflow
  namespace: azure-iot-operations
spec:
  # Reference to the default dataflow profile
  profileRef: default
  mode: Enabled
  operations:
    - operationType: Source
      sourceSettings:
        # Use the default MQTT endpoint as the source
        endpointRef: default
        # Filter the data from the MQTT topic azure-iot-operations/data/thermostat
        dataSources:
          - azure-iot-operations/data/thermostat
    # Transformation optional
    - operationType: builtInTransformation
      builtInTransformationSettings:
        # Filter the data where temperature * "Tag 10" < 100000
        filter:
          - inputs:
              - 'temperature.Value'
              - '"Tag 10".Value'
            expression: '$1 * $2 < 100000'
        map:
          # Passthrough all values by default
          - inputs:
              - '*'
            output: '*'
          # Convert temperature to Fahrenheit and output it to TemperatureF
          - inputs:
              - temperature.Value
            output: TemperatureF
            expression: cToF($1)
          # Extract the "Tag 10" value and output it to Humidity
          - inputs:
              - '"Tag 10".Value'
            output: 'Humidity'
    - operationType: Destination
      destinationSettings:
        # Use the default MQTT endpoint as the destination
        endpointRef: default
        # Send the data to the MQTT topic factory
        dataDestination: factory

To see more examples of dataflow configurations, see Azure REST API - Dataflow and the quickstart Bicep.

Verify a dataflow is working

Follow Tutorial: Bi-directional MQTT bridge to Azure Event Grid to verify the dataflow is working.

Export dataflow configuration

To export the dataflow configuration, you can use the operations experience or by exporting the Dataflow custom resource.

Portal

Select the dataflow you want to export and select Export from the toolbar.

Bicep

Bicep is infrastructure as code and no export is required. Use the Bicep template file to create a dataflow to quickly set up and configure dataflows.

Kubernetes (preview)

kubectl get dataflow my-dataflow -o yaml > my-dataflow.yaml

Proper dataflow configuration

To ensure the dataflow is working as expected, verify the following:

• The default MQTT dataflow endpoint must be used as either the source or destination.
• The dataflow profile exists and is referenced in the dataflow configuration.
• Source is either an MQTT endpoint, Kafka endpoint, or an asset. Storage type endpoints can't be used as a source.
• When using Event Grid as the source, the dataflow profile instance count is set to 1 because Event Grid MQTT broker doesn't support shared subscriptions.
• When using Event Hubs as the source, each event hub in the namespace is a separate Kafka topic and must be specified as the data source.
• Transformation, if used, is configured with proper syntax, including proper escaping of special characters.
• When using storage type endpoints as destination, a schema is specified.

Next steps

• Map data by using dataflows
• Convert data by using dataflows
• Enrich data by using dataflows
• Understand message schemas
• Manage dataflow profiles