`tedge-mapper-c8y` service restart is required after a change of supported operation file contents

[rina23q]

Describe the bug If you update a supported operation file in runtime of tedge-mapper-c8y, the mapper doesn't use the new content. The mapper needs to be restarted. For example,

1. Update the command field of an operation file to new path (from /path/a to /path/b).
2. tedge-mapper-c8y still looks up at /path/a.
3. After restart of tedge-mapper-c8y, it starts looking at /path/b finally.

To Reproduce Prerequisites:

• tedge and tedge-mapper are installed and already connected to c8y.
• /etc/tedge/operations/c8y/c8y_Command doesn't exist yet.

Steps:

1. Create a file /etc/tedge/operations/command0.sh then make it executable.

   echo -e '#!/bin/bash\necho "file: $0"\nexit 0' |  sudo tee /etc/tedge/operations/command0.sh
   sudo chmod +x /etc/tedge/operations/command0.sh

2. Create a file /etc/tedge/operations/c8y/c8y_Command.

   sudo -u tedge touch /etc/tedge/operations/c8y/c8y_Command

3. Add the following content to the file /etc/tedge/operations/c8y/c8y_Command.

   [exec]
   topic = "c8y/s/ds"
   on_message = "511"
   command = "/etc/tedge/operations/command0.sh"

4. Send a random text (e.g. "abc") with the "Shell" tab of c8y.
5. The operation stays pending. (It is because the mapper doesn't look up the updated content in /etc/tedge/operations/c8y/c8y_Command. Should have been marked "successful" without this bug)

Workaround

The current workaround to get the mapper to re-read the custom operation mapping files, you will need to restart the tedge-mapper-c8y service, see below for an example:

sudo systemctl restart tedge-mapper-c8y.service

The pending operation should start processing the tedge-mapper-c8y service restarts. However if there are multiple operations of the same type (e.g. shell operations), then the status/result of the operation might be out of order (due to the id-less handling of operations in Cumulocity).

Expected behavior The tedge-mapper-c8y should catch the contents update of supported operation files immediately. Restart should not be required.

Screenshots

Environment (please complete the following information):

• OS [Ubuntu 20.04]
• Hardware [incl. revision]
• System-Architecture [amd64]
• thin-edge.io version [0.9.0]

Additional context

[didier-wenzek]

Once validated the fix for that issue, one has to close this PR https://github.com/thin-edge/thin-edge.io/pull/1927 documenting a workaround.

[gligorisaev]

Before I validate the bug the one who raised it, in this case @rina23q should first confirm that the bug is fixed (and correct the text in "how to reproduce")

[reubenmiller]

@rina23q After talking with @gligorisaev I made a few improvements to the formatting and description of some of the steps in the initial ticket description.

[gligorisaev]

Bug still exists

[PradeepKiruvale]

Let me try again to reproduce.

[reubenmiller]

It works for me.

We'll debug the issue further to see what is going on here, it might just be a configuration or integration issue.

[reubenmiller]

@gligorisaev It can be retested. The version is already available from cloudsmith.io, 0.10.0-264-gb245979f

[gligorisaev]

Tested and not reproducable,