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MQTT Engine provides a configuration section to the Ignition Gateway.  These can be seen in the Configure section of the Ignition Gateway web UI in the left panel.

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Once in the configuration section there are three tabs: Servers, Advanced, and Namespaces.  Each of these tabs is described in detail in the following sections.

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• Block Node Commands
  • Whether or not to block outgoing commands from MQTT Engine to Edge Nodes. This is true by default and provides a security mechanism for preventing accidental outgoing commands from MQTT Engine.
• Block Device Commands
  
  • Whether or not to block outgoing commands from MQTT Engine to Devices. This is true by default and provides a security mechanism for preventing accidental outgoing commands from MQTT Engine.
• File Policy
  
  • The policy for handling Files contained within a Sparkplug payload.
    • Ignore: The default policy. The file will be ignored.
    • Store: The file will be stored to the local file system in the directory specified by the File Location field.  A Tag will be created with a String value representing the file URI.
• File Location
  
  • The directory to store the files when using the Store policy described above.
• Store Historical Events
  • Whether or not to write historical change events directly to the Historian (if history is enabled on a Tag) instead of updating the live Tag value.

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Servers

The second tab is a list of MQTT Servers that MQTT Engine should connect to.  By default, MQTT Engine is configured to connect to the local MQTT Distributor based MQTT Server.  It is set up to connect to localhost, port 1883, using the default username/password pair of admin/changeme.  Out of the box MQTT Engine will work with MQTT Distributor and its default configuration.  The connection status of each server can be seen in the 'Status' column.  

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Additional or alternative MQTT Servers can be configured in MQTT Engine.  Often times more than one will be configured to handle fail-over in redundant or geographically distributed systems.  The configuration options for servers are listed below.

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Clicking on the 'Create new MQTT Server...' link will bring up the following form to add a new Server.

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Namespaces

The third tab is used for configuring namespaces.  Each namespace configuration represents a family of devices and/or data that MQTT Engine will support.  A namespace defines the topics that each MQTT Engine client will subscribe on as well as indicates how the payload will be handled.  There are two types of namespaces: Default and Custom.  

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If a namespace is enabled, MQTT Engine will subscribe to the topics necessary to provide support for devices and data associated with that namespace.  If a namespace is disabled, MQTT Engine will unsubscribe from those topics and no longer support the devices and data associated with that namespace.

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Image RemovedCustom Namespaces

Custom namespaces are used to provide support for generic MQTT messages with string based payloads.  If a custom namespace is configured MQTT Engine will convert all messages received to tags.  The topic of each message will directly translate into the tag's path.  The payload of the message will be that tag's value.   

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Each custom namespace has the following properties:

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Clicking on the 'Create new Custom Namespace...' link will bring up the following form to add a new Custom Namespace.

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Custom Namespace Example  

Let say we have a publish received on the topic "test/data/point" with value "12345".  If no Tag Value is configured, and a message is received, MQTT Engine will create a two folders "test" and "data" and a tag "point" with the value of "12345".

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Alternatively if a Tag Name is configured, lets call it "payload", then MQTT Engine will convert each token in the topic to a folder and create a tag called "payload" with the value "12345"

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