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Azure Device Update for IoT Hub update manifest

  • Članak

This article describes the update manifest data that Azure Device Update for IoT Hub sends to devices during update deployment. The update manifest is a serialized JSON string object containing metadata about the update to install.

Device Update uses IoT Plug and Play to send the update manifest, and cryptographically signs it so that the Device Update agent can verify its authenticity. For more information about how the update manifest is used to securely install content, see Device Update security.

Import manifest vs update manifest

The update manifest is different from the Device Update import manifest.

  • The import manifest is a JSON file that describes the update to import into Device Update. Whoever creates the update for Device Update creates the corresponding import manifest file.
  • The update manifest is a JSON string object that communicates information to the Device Update agent during an update. The Device Update service automatically generates the update manifest by including some of the same properties defined in the import manifest.

Each manifest type has its own schema and schema version. For more information about the import manifest schema, see Device Update import manifest schema.

Update manifest schema

The update manifest JSON schema version 4 is hosted at SchemaStore.org.

Example update manifest

{
  "manifestVersion": "4",
  "updateId": {
    "provider": "Contoso",
    "name": "Toaster",
    "version": "1.0"
  },
  "compatibility": [
    {
      "manufacturer": "Contoso",
      "model": "Toaster"
    }
  ],
  "instructions": {
    "steps": [
      {
        "handler": "microsoft/swupdate:1",
        "handlerProperties": {
          "installedCriteria": "1.0"
        },
        "files": [
          "fileId0"
        ]
      }
    ]
  },
  "files": {
    "fileId0": {
      "filename": "contoso.toaster.1.0.swu",
      "sizeInBytes": 718,
      "hashes": {
        "sha256": "mcB5SexMU4JOOzqmlJqKbue9qMskWY3EI/iVjJxCtAs="
      }
    }
  },
  "createdDateTime": "2021-09-28T18:32:01.8404544Z"
}

Full vs mini update manifest

If an update manifest is too large to be communicated efficiently, Device Update sends it to the device in detached format, also called a mini update manifest. A mini manifest contains metadata about the update manifest that the Device Update agent can use to download the full update manifest and verify its authenticity.

The following example shows a mini update manifest:

{
  "manifestVersion": "4",
  "updateId": {
    "provider": "Contoso",
    "name": "Toaster",
    "version": "1.0"
  },
  "detachedManifestFileId": "fileId1",
  "files": {
    "fileId1": {
      "filename": "contoso.toaster.1.0.updatemanifest.json",
      "sizeInBytes": 2048,
      "hashes": {
        "sha256": "789s9PDfX4uA9wFUubyC30BWkLFbgmpkpmz1fEdqo2U="
      }
    }
  }
}

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