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Avgustin Marinov edited this page Nov 6, 2024 · 1 revision

The DMF API provides Java classes which allows that the message body can be deserialized at runtime into a Java object. Also Java classes can be used to serialize Java objects into JSON bodies to send a message to hawkBit. Currently, bodies of messages are based on JSON.

Basics

There are three basic concepts of AMQP:

  • Exchanges - what you publish to.
  • Queues - what you consume from.
  • Bindings - configuration that maps an exchange to a queue.

Queues are just a place for receiving messages.
Bindings determine how messages get put in this place Queues can also be bound to multiple exchanges.

Exchanges are just publish messages. The user decides who can produce on an exchange and who can create bindings on that exchange for delivery to a specific queue.

hawkBit will create all necessary queues, exchanges and bindings for the user, making it easy to get started. The exchange name for outgoing messages is dmf.exchange.

The user has to set a reply_to header (see chapter below), in order to specify the exchange to which hawkBit should reply to.

The following chapter describes the message body, header and properties.

Note: the DMF protocol was intended to be compatible to other use cases by design. As a result, DMF uses the term * thing* and not target but they are actually synonyms in this case.

Messages sent to hawkBit (Client -> hawkBit)

THING_CREATED

Message to register and update a provisioning target.

Header Description Type Mandatory
type Type of the message Fixed string "THING_CREATED" true
thingId The ID of the registered provisioning target String true
tenant The tenant this provisioning target belongs to String true
sender Name of the message sender String false
Message Properties Description Type Mandatory
content_type The content type of the payload String true
reply_to Exchange to reply to String true

Example headers and payload:

Header MessageProperties
type=THING_CREATED
tenant=default
thingId=abc
sender=myClient		 content_type=application/json
reply_to=myExchangeToReplyTo

Payload Template (optional):

{
    "name": "String",
    "type": "String",
    "attributeUpdate": {
        "attributes": {
            "exampleKey1" : "exampleValue1",
            "exampleKey2" : "exampleValue2"
        },
        "mode": "String"
    }
}

The "name" property specifies the name of the thing, which by default is the thing ID. This property is optional.

The "type" property specifies name of a target type which should be assigned to the created/updated target. The target type with the specified name should be created in advance, otherwise it can't be assigned to the target, resulting in:

  • error is logged
  • if the target does not exist then it is created without any target type assigned
  • if it exists already then no changes to its target type assignment are made.

If the "type" property is set to a blank string while updating an existing target then any eventual target type assignment is removed from the target. This property is optional and if omitted then no changes to the target type assignment are made.

The "attributeUpdate" property provides the attributes of the thing, for details see UPDATE_ATTRIBUTES message. This property is optional.

THING_REMOVED

Message to request the deletion of a provisioning target.

Header Description Type Mandatory
type Type of the message Fixed string "THING_REMOVED" true
thingId The ID of the registered provisioning target String true
tenant The tenant this provisioning target belongs to String false
Message Properties Description Type Mandatory
content_type The content type of the payload String true

Example headers

Header MessageProperties
type=THING_REMOVED
tenant=default
thingId=abc		 content_type=application/json

UPDATE_ATTRIBUTES

Message to update target attributes. This message can be send in response to a REQUEST_ATTRIBUTES_UPDATE event, sent by hawkBit.

Header Description Type Mandatory
type Type of the message Fixed string "EVENT" true
topic Topic name identifying the event Fixed string "UPDATE_ATTRIBUTES" true
thingId The ID of the registered thing String true
tenant The tenant this thing belongs to String false
Message Properties Description Type Mandatory
content_type The content type of the payload String true

Example header and payload:

Header MessageProperties
type=EVENT
tenant=default
thingId=abc
topic=UPDATE_ATTRIBUTES		 content_type=application/json

Payload Template:

{
    "attributes": {
        "exampleKey1" : "exampleValue1",
        "exampleKey2" : "exampleValue2"
    },
    "mode": "String"
}

The "mode" property specifies the update mode that should be applied. This property is optional. Possible mode values:

Value Description
MERGE The target attributes specified in the payload are merged into the existing attributes. This is the default mode that is applied if no "mode" property is specified in the payload.
REPLACE The existing attributes are replaced with the target attributes specified in the payload.
REMOVE The target attributes specified in the payload are removed from the existing attributes.

UPDATE_ACTION_STATUS

Message to send an action status event to hawkBit.

Header Description Type Mandatory
type Type of the message Fixed string "EVENT" true
topic Topic name identifying the event Fixed string "UPDATE_ACTION_STATUS" true
tenant The tenant this thing belongs to String false
Message Properties Description Type Mandatory
content_type The content type of the payload String true

Payload Template (the Java representation is ActionUpdateStatus):

{
  "actionId": long,
  "softwareModuleId": long,
  "actionStatus":"String",
  "message":["String"]
}

Possible actionStatus values:

Value Description
DOWNLOAD Device is downloading
DOWNLOADED Device completed download
RETRIEVED Device has retrieved the artifact
RUNNING Update is running
FINISHED Update process finished successful
ERROR Error during update process
WARNING Warning during update process
CANCELED Cancel update process successful
CANCEL_REJECTED Cancel update process has been rejected

Example header and payload:

Header MessageProperties
type=EVENT
tenant=default
topic=UPDATE_ACTION_STATUS		 content_type=application/json 
{
  "actionId":137,
  "softwareModuleId":17,
  "actionStatus":"DOWNLOAD",
  "message":["The download has started"]
}

PING

hawkBit allows DMF clients to check the availability of the DMF service. For this scenario DMF specifies a PING message that can be sent by the client:

Header Description Type Mandatory
type Type of the message Fixed string "PING" true
tenant The tenant the PING belongs to String false
Message Properties Description Type Mandatory
correlationId CorrelationId that allows the client to map a PING request to PING_RESPONSE String true

Messages sent by hawkBit (hawkBit -> Client)

CANCEL_DOWNLOAD

Message to cancel an update task.

Header Description Type Mandatory
type Type of the message Fixed string "Event" true
thingId The ID of the registered provisioning target String true
topic Topic name identifying the event Fixed string "CANCEL_DOWNLOAD" true
tenant The tenant this provisioning target belongs to String false
Message Properties Description Type Mandatory
content_type The content type of the payload String true

Payload template:

{
    "actionId": long
}

Example Headers and Payload:

Header MessageProperties
type=EVENT
tenant=default
thingId=abc
topic=CANCEL_DOWNLOAD		 content_type=application/json 
{
"actionId":137
}

After sending this message, an action status event with either actionStatus=CANCELED or actionStatus=CANCEL_REJECTED has to be returned.

Example header and payload when cancellation is successful:

Header MessageProperties
type=EVENT
tenant=default
topic=UPDATE_ACTION_STATUS		 content_type=application/json 
{
  "actionId":137,
  "softwareModuleId":17,
  "actionStatus":"CANCELED",
  "message":["The update was canceled."]
}

Example header and payload when cancellation is rejected:

Header MessageProperties
type=EVENT
tenant=default
topic=UPDATE_ACTION_STATUS		 content_type=application/json 
{
  "actionId":137,
  "softwareModuleId":17,
  "actionStatus":"CANCEL_REJECTED",
  "message":["The cancellation was not possible since the target sent an unexpected response."]
}

DOWNLOAD_AND_INSTALL or DOWNLOAD

Message sent by hawkBit to initialize an update or download task. Note: in case of a maintenance window configured but not yet active the message will have the topic DOWNLOAD instead of DOWNLOAD_AND_INSTALL.

Header Description Type Mandatory
type Type of the message Fixed string "EVENT" true
thingId The ID of the registered provisioning target String true
topic Topic name identifying the event Fixed string "DOWNLOAD_AND_INSTALL" or "DOWNLOAD" true
tenant The tenant this provisioning target belongs to String false
Message Properties Description Type Mandatory
content_type The content type of the payload String true

Payload Template (the Java representation is DmfDownloadAndUpdateRequest):

{
"actionId": long,
"targetSecurityToken": "String",
"softwareModules":[
    {
    "moduleId": long,
    "moduleType":"String",
    "moduleVersion":"String",
    "artifacts":[
        {
        "filename":"String",
        "urls":{
            "HTTP":"String",
            "HTTPS":"String"
            },
        "hashes":{
            "md5":"String",
            "sha1":"String"
            },
        "size":long
        }],
    "metadata":[
        {
            "key":"String",
            "value":"String"
        }
    ]
    }]
}

Example header and payload:

Header MessageProperties
type=EVENT
tenant=default
thingId=abc
topic=DOWNLOAD_AND_INSTALL		 content_type=application/json 
{
"actionId":137,
"targetSecurityToken":"bH7XXAprK1ChnLfKSdtlsp7NOlPnZAYY",
"softwareModules":[
    {
    "moduleId":7,
    "moduleType":"firmware",
    "moduleVersion":"7.7.7",
    "artifacts":[
        {
        "filename":"artifact.zip",
        "urls":{
            "HTTP":"http://download-from-url.com",
            "HTTPS":"https://download-from-url.com"
            },
        "hashes":{
            "md5":"md5hash",
            "sha1":"sha1hash"
            },
        "size":512
        }],
    "metadata":[
        {
            "key":"installationType",
            "value":"5784K#"
        }
    ]
    }]
}

MULTI_ACTION

If multi.assignments.enabled is enabled, this message is sent instead of DOWNLOAD_AND_INSTALL, DOWNLOAD, or CANCEL_DOWNLOAD by hawkBit to initialize update, download, or cancel task(s).

With weight, one can set the priority to the action. The higher the weight, the higher is the priority of an action.

Header Description Type Mandatory
type Type of the message Fixed string "EVENT" true
thingId The ID of the registered provisioning target String true
topic Topic name identifying the event Fixed string "MULTI_ACTION" true
tenant The tenant this provisioning target belongs to String false
Message Properties Description Type Mandatory
content_type The content type of the payload String true

Payload Template (the Java representation is DmfMultiActionRequest):

[{
"topic": "String",
"weight": long,
"action": {
  "actionId": long,
  "targetSecurityToken": "String",
  "softwareModules":[
      {
      "moduleId": long,
      "moduleType":"String",
      "moduleVersion":"String",
      "artifacts":[
          {
          "filename":"String",
          "urls":{
              "HTTP":"String",
              "HTTPS":"String"
              },
          "hashes":{
              "md5":"String",
              "sha1":"String"
              },
          "size":long
          }],
      "metadata":[
          {
              "key":"String",
              "value":"String"
          }
      ]
      }]
  }
},
{
"topic": "String",
"weight": long,
"action": {
  "actionId": long,
  "targetSecurityToken": "String",
  "softwareModules":[
      {
      "moduleId": long,
      "moduleType":"String",
      "moduleVersion":"String",
      "artifacts":[
          {
          "filename":"String",
          "urls":{
              "HTTP":"String",
              "HTTPS":"String"
              },
          "hashes":{
              "md5":"String",
              "sha1":"String"
              },
          "size":long
          }],
      "metadata":[
          {
              "key":"String",
              "value":"String"
          }
      ]
      }]
  }
}]

Example header and payload:

Header MessageProperties
type=EVENT
tenant=default
thingId=abc
topic=MULTI_ACTION		 content_type=application/json 
[{
"topic": "DOWNLOAD_AND_INSTALL",
"weight": 600,
"action": {
  "actionId":137,
  "targetSecurityToken":"bH7XXAprK1ChnLfKSdtlsp7NOlPnZAYY",
  "softwareModules":[
      {
      "moduleId":7,
      "moduleType":"firmware",
      "moduleVersion":"7.7.7",
      "artifacts":[
          {
          "filename":"artifact.zip",
          "urls":{
              "HTTP":"http://download-from-url.com",
              "HTTPS":"https://download-from-url.com"
              },
          "hashes":{
              "md5":"md5hash",
              "sha1":"sha1hash"
              },
          "size":512
          }],
      "metadata":[
          {
              "key":"installationType",
              "value":"5784K#"
          }
      ]
      }]
  }
},
{
"topic": "DOWNLOAD",
"weight": 500,
"action": {
  "actionId":138,
  "targetSecurityToken":"bH7XXAprK1ChnLfKSdtlsp7NOlPnZAYY",
  "softwareModules":[
      {
      "moduleId":4,
      "moduleType":"firmware",
      "moduleVersion":"7.7.9",
      "artifacts":[
          {
          "filename":"artifact.zip",
          "urls":{
              "HTTP":"http://download-from-url.com",
              "HTTPS":"https://download-from-url.com"
              },
          "hashes":{
              "md5":"md5hash",
              "sha1":"sha1hash"
              },
          "size":512
          }],
      "metadata":[
          {
              "key":"installationType",
              "value":"5784K#"
          }
      ]
      }]
  }
}]

THING_DELETED

Message sent by hawkBit when a target has been deleted.

Header Description Type Mandatory
type Type of the message Fixed string "THING_DELETED" true
thingId The ID of the registered provisioning target String true
tenant The tenant this provisioning target belongs to String true

Example header:

Header MessageProperties
type=THING_DELETED
tenant=default
thingId=abc

REQUEST_ATTRIBUTES_UPDATE

Message sent by Eclipse hawkBit when a re-transmission of target attributes is requested.

Header Description Type Mandatory
type Type of the message Fixed string "EVENT" true
thingId The ID of the registered provisioning target String true
topic Topic name identifying the event Fixed string "REQUEST_ATTRIBUTES_UPDATE" true
tenant The tenant this provisioning target belongs to String true

Example headers:

Header MessageProperties
type=EVENT
tenant=default
thingId=abc
topic=REQUEST_ATTRIBUTES_UPDATE

PING_RESPONSE

hawkBit will respond to the PING message with a PING_RESPONSE type message that has the same correlationId as the original PING message:

Header Description Type Mandatory
type Type of the message Fixed string "PING_RESPONSE" true
tenant The tenant the PING belongs to String false
Message Properties Description Type Mandatory
correlationId CorrelationId of the original PING request String true
content_type The content type of the payload String true

The PING_RESPONSE also contains a timestamp (i.e. the difference, measured in milliseconds, between the current time and midnight, January 1, 1970 UTC) as plain text. It is not guaranteed that this timestamp is completely accurate.

Header MessageProperties
type=PING_RESPONSE
tenant=default		 content_type=text/plain 
1505215891247

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