cmd: cloud-init query fails for juju units with UnicodeDecodeError

[Chad Smith]

sudo cloud-init query --all fails on juju deployed units with the following trace:
Traceback (most recent call last):
  File "/usr/bin/cloud-init", line 11, in <module>
    load_entry_point('cloud-init==20.2', 'console_scripts', 'cloud-init')()
  File "/usr/lib/python3/dist-packages/cloudinit/cmd/main.py", line 893, in main
    get_uptime=True, func=functor, args=(name, args))
  File "/usr/lib/python3/dist-packages/cloudinit/util.py", line 2620, in log_time
    ret = func(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/cloudinit/cmd/query.py", line 123, in handle_args
    instance_data['userdata'] = util.load_file(user_data_fn)
  File "/usr/lib/python3/dist-packages/cloudinit/util.py", line 1432, in load_file
    return decode_binary(contents)
  File "/usr/lib/python3/dist-packages/cloudinit/util.py", line 132, in decode_binary
    return blob.decode(encoding)
UnicodeDecodeError: 'utf-8' codec can't decode byte 0x8b in position 1: invalid start byte

On some platforms (juju deployed instances and various openstack platforms), user-data is compressed when provided to the instance.

When deploying juju units in ec2 regions, user-data provided to the instance is gzip compressed.

The cloud-init query command attempts to load, decode and read raw userdata content from /var/lib/cloud/instance/user-data.txt. In cases where the user-data is gzip compressed, decoding fails.

[Chad Smith (chad.smith)]

Upstream commitish merged related to this bug https://github.com/canonical/cloud-init/commit/747723a42c98fa13080ea31127e289e7b826046f

[James Falcon (falcojr)]

This bug is believed to be fixed in cloud-init in version 20.3. If this is still a problem for you, please make a comment and set the state back to New

Thank you.

[James Falcon (falcojr)]

Tracked in Github Issues as https://github.com/canonical/cloud-init/issues/3768