[microTVM] Arduino retry on flash failure

[guberti]

Previously, the flash function would sometimes lock up indefinitely without failing, stalling for hours or more. This pull request changes it to have a 60-second timeout (more than enough time to upload a sketch), and adds the ability to retry the command if it fails.

This pull request also adds a unit test for this functionality, and also makes a few changes to microtvm_api_server.py to better comply with pylint.

cc @alanmacd @gromero @mehrdadh

[gromero]

@guberti Thanks for the enhancement, I remember facing this issue sometimes in my setup in the past. The changes LGTM (although already merged by @areusch -- he merged right when I was about to finish the review lol, but no worries since you tagged me 4 days ago so fair enough! heh). The only thing I think that needs to get fixed on a follow-on PR are these two f-strings here:

diff --git a/apps/microtvm/arduino/template_project/microtvm_api_server.py b/apps/microtvm/arduino/template_project/microtvm_api_server.py
index 053acefa3..047164eff 100644
--- a/apps/microtvm/arduino/template_project/microtvm_api_server.py
+++ b/apps/microtvm/arduino/template_project/microtvm_api_server.py
@@ -495,12 +495,12 @@ class Handler(server.ProjectAPIHandler):
             # be caught.
             except subprocess.TimeoutExpired:
                 _LOG.warning(
-                    "Upload attempt to port {port} timed out after {self.FLASH_TIMEOUT_SEC} seconds"
+                    f"Upload attempt to port {port} timed out after {self.FLASH_TIMEOUT_SEC} seconds"
                 )
 
         else:
             raise RuntimeError(
-                "Unable to flash Arduino board after {self.FLASH_MAX_RETRIES} attempts"
+                f"Unable to flash Arduino board after {self.FLASH_MAX_RETRIES} attempts"
             )
 
     def open_transport(self, options):

Cheers.

[guberti]

Oops - nice catch @gromero! I'll send a follow up to fix that.

[gromero]

Oops - nice catch @gromero! I'll send a follow up to fix that.

@guberti ok! tag me on the PR and this time I promise I'll be quicker on reviewing it :)

[gromero]

@guberti FYI I've just created #12175 fixing the f-strings since I'm using it for some tests regarding the tvm-bot on merge.

[guberti]

Oops, this totally slipped my mind. Thanks for the change @gromero !