Configuring the Bridge

Overview

Each JSON object that is processed in a configuration file is considered to be a modification from the previous instance of the same object. During the initial configuration, when there is no existing object, the whole object is specified. When a dynamic update is made, only the changed fields are modified. Items such as strings, numbers, boolean, or arrays of strings are replaced.

To delete an object, you can either use the REST DELETE method or you can specify the object type and name in the configuration file and give the value as null. Removing an object from the configuration file might not delete the object. For example, if the configuration defines a durable MQTT session with a SessionExpiry > 0, the session continues to exist on the MQTT server after it is removed from a configuration file. If the configuration object is explicitly deleted, the object is removed from the MQTT server.

Connecting to an MQTT server

The following table shows the properties that are defined by a connection object, which are required to connect to an MQTT server:

The following section shows an example connection object:

{
    "Connection": { 
        "MyServer": 
            "MQTTServerList”: [ mymqtt1.ibm.com:16104, mymqtt2.ibm.com:16104 ]
            "ClientID": "MQTTBridge-",
            “SessionExpiry”: 0,
            "Version": "5.0",
            "TLS": "TLSv1.2",
            "Username": "msgUser2",
            "Password": "!Fqun1VseY4Pmruz/Z5KjkmK/FhyZudVZVSdHYeXzx"
        }
    }
}

For an Event Streams destination, the MQTTServerList is replaced with EventStreamsBrokerList.

For Event Streams connections, the properties ClientID, SessionExpiry and Version are not used. For MQTT connections the MaxBatchTimeMS property is not used.

Most items in Connection can be set back to the default by setting the value to null. This does not work for some values, which are required for the connection to work.

Forwarder

The following table shows the rules that are defined by the forwarder object. The rules are used to forward messages from a source MQTT server to a destination:

The following section shows an example forwarder:

{ 
    "Forwarder": {
        "m2w": {
            "Topic": ["wiotp/event/+/+/MyEvent/#"],
            "Enabled": true,
            "Source": "MyServer",
            "Destination": "WIoTP",
            "TopicMap": "iot-2/type/${Topic2}/id/${Topic3}/evt/${Topic4}/fmt/json'"
        }
    }
}

The following table shows the name, type and description of the fields that are added for forwarders with an Event Streams destination:

Most items in Forwarder can be set back to the default by setting the value to null. This does not work for some values, which are required for the forwarder to work.

Endpoint

An Endpoint object defines the properties needed to define an administrative REST interface for the Bridge. The following table shows the name, type and description of the properties that are used to define an administrative REST interface for the Bridge:

{
    "Endpoint": { 
        "admin": { 
            "Port": 9961,
            "Enabled": true,
            "Secure": true,
            "Ciphers": "Fast", 
            "Method": "TLSv1.2",
            "Certificate": "mycert.pem",
            "Key": "mykey.pem",
            “KeyPassword”: “!HCuwKKpW2sUeQEUJIYkWpJp5HX/nBGDpMYQMhjRhE”
        }
    }
}

User

A User object defines a user who can connect on the administrative endpoint.

{
    "User": { 
        "user": { "Password": "=0hRDkZDpoF+e0sLJrgMpv7c2xeyApDR/6DWWzD8JfWI=" },
        "fred": { "Password": "very_secret" }
    }    
}