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Uploading Files

thin-edge.io provides the tedge upload c8y command to upload a file from the device to the cloud.

tedge upload c8y --file /path/to/some/file
  • creates a new event on the device tenant
  • uploads the file to Cumulocity, attaching this file to the event
  • and returns the event ID for further processing by the invoking script.
Output: the Cumulocity ID of the new event
151205

The tedge upload c8y determines the MIME type of the file content using the file extension. If no rules applies, then application/octet-stream is taken as a default. When these rules are not appropriate, the MIME type of the file content can be explicitly set.

--mime-type <MIME_TYPE>
    MIME type of the file content
    
    If not provided, the mime type is determined from the file extension
    If no rules apply, application/octet-stream is taken as a default

Setting the event properties​

The properties of the event created by the tedge upload c8y command can be set on the command line:

--type <EVENT_TYPE>
  Type of the event
  
  [default: tedge_UploadedFile]

--text <TEXT>
  Text description of the event. Defaults to "Uploaded file: <FILE>"

--json <JSON>
  JSON fragment attached to the event
  
  [default: {}]

Uploading a file from a child device​

The tedge upload c8y can also be used from a child device or on behalf of a service.

For that to work, one has to provide the child device / service identifier as registered on Cumulocity

--device-id <DEVICE_ID>
  Cumulocity external id of the device/service on which the file has to be attached.
  
  If not given, the file is attached to the main device.

Prerequisites​

Under the hood the tedge upload c8y use the local HTTP proxy between the device and its Cumulocity tenant, notably delegating to this proxy authentication and JWT token handling.

This implies that:

  • The device must be connected to its tenant, i.e tedge connect c8y --test must be successful.
  • The c8y mapper must be running on the main device, enabling the local HTTP proxy to Cumulocity.
  • To upload a file from a child device the proxy must be accessible from the child device.
    • The default for the proxy is to listen only on the loopback address (127.0.0.1), meaning that the default settings have to be changed for a child device to use the proxy.
    • On the main device, both the bind address of the proxy (c8y.proxy.bind.address) and the client address c8y.proxy.client.host have to be set to the IP address of the main device.
    • On the child devices, the client address c8y.proxy.client.host has to be set accordingly.
    • proxy listens to the IP address and port configured by c8y.proxy.bind.address and c8y.proxy.bind.port.
    • Run tedge config list --doc proxy for the full list of options.