fix(pdb): Enable running cloud-init under pdb

[holmanb]

Proposed Commit Message

fix(pdb): Enable running cloud-init under pdb

Cloud-init closes stdin on startup, which breaks interactively running cloud-init under pdb.

Leave stdin open if it is connected to a tty, which fixes pdb use.


File "/usr/lib/python3.12/bdb.py", line 90, in trace_dispatch
  return self.dispatch_line(frame)
         ^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/lib/python3.12/bdb.py", line 115, in dispatch_line
    if self.quitting: raise BdbQuit
                      ^^^^^^^^^^^^^
bdb.BdbQuit
------------------------------------------------------------
The program exited via sys.exit(). Exit status: 1

Merge type

• [x] Squash merge using "Proposed Commit Message"
• [ ] Rebase and merge unique commits. Requires commit messages per-commit each referencing the pull request number (#<PR_NUM>)

[CalvoM]

Thanks for this. I ran into this issue when trying to debug some issues.

[holmanb]

@TheRealFalcon @CalvoM Thanks for the reviews! I think I've addressed all of the comments, requesting re-review.