Merge bootstack-ops:bypass-question-mark into bootstack-ops:master

[Joe Guo]

juju_bundle_export.py: bypass question mark for empty key

In bindings section, option with empty key is allowed:

    bindings:
        "": internal-space

However, after read bundle with pyyaml, it will be dumped to:

    bindings:
        ? ''
        : internal-space

`?` and space is used by yaml spec to indicate complex mapping keys:

    https://yaml.org/spec/1.2/spec.html#id2760695

For some reason, empty str is also considered as complex key here, and there is no way to turn that off in pyyaml.

It's still valid yaml syntax, but may confuse people.

This patch replace empty key to a placeholder, and replace it back after
dump, to bypass this issue.

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

This merge proposal is being monitored by mergebot. Change the status to Approved to merge.

[Joe Guo (guoqiao)]

I've reported a issue to github/pyyaml: https://github.com/yaml/pyyaml/issues/401
Not sure that can be fixed or not though.

[Xav Paice (xavpaice)]

We should potentially start to look at either converting the script to use 'juju export-bundle' rather than 'juju dump-model', but that'll have the same trouble.

The actual fix LGTM, and produces a workable bundle, unlike the version without this fix. LGTM.

review: Approve

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

Failed to merge change (unable to merge source repository due to conflicts), setting status to needs review.

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

Change successfully merged at revision 4210b3d570fbd74905b004105343d22f3ddccecd

diff --git a/bootstack-ops/juju_bundle_export.py b/bootstack-ops/juju_bundle_export.py
index 7e28440..3cefe35 100755
--- a/bootstack-ops/juju_bundle_export.py
+++ b/bootstack-ops/juju_bundle_export.py
@@ -33,6 +33,7 @@ LOG_FORMAT = '%(asctime)s - %(levelname)-9s - %(module)s - %(message)s'
 logging.basicConfig(format=LOG_FORMAT)
 log = logging.getLogger(__name__)
 
+EMPTY_KEY_PLACE_HOLDER = '__EMPTY_KEY_PLACE_HOLDER__'
 
 MASK_KEYS = ('(.*(ssl-public-key|ssl[_-](ca|cert|key|chain)|secret|password|'
              'pagerduty_key|license-file|registration-key|token|accesskey|'
@@ -76,6 +77,16 @@ class Bundle(object):
                         else:
                             app_data['options'][option] = option_value
                 else:
+                    if param == 'bindings':
+                        # in bindings, option with empty key like `"": internal-space` is allowed.
+                        # however, yaml will consider empty key as complex mapping key
+                        # and dump it to `? ''\n: internal-space`
+                        # here we replace the empty key to a placeholder to bypass this issue
+                        # it will be replaced back after dumped
+                        # ref: https://yaml.org/spec/1.2/spec.html#id2760695
+                        if '' in param_value:
+                            param_value[EMPTY_KEY_PLACE_HOLDER] = param_value['']
+                            del param_value['']
                     app_data[param] = param_value
                 self.common_bundle['applications'][app] = app_data
                 if len(secret_data.keys()) > 0:
@@ -311,8 +322,8 @@ def main():
             'common': entire_bundle.get_common_bundle,
             'secrets': entire_bundle.get_secrets_bundle,
             }
-    print(yaml.dump(grab_out[args.output_type](), default_flow_style=False),
-          file=args.outfile)
+    output = yaml.dump(grab_out[args.output_type](), default_flow_style=False)
+    print(output.replace(EMPTY_KEY_PLACE_HOLDER, '""'), file=args.outfile)
 
 
 if __name__ == "__main__":