[DPE-8863] Custom username and prefixes for v1 by dragomirp · Pull Request #258 · canonical/data-platform-libs

dragomirp · 2026-02-11T14:48:39Z

Port of #239 and #245 for DPLv1

Add custom username support
Add prefix resources support

dragomirp · 2026-03-14T15:44:55Z

+                try:
+                    secret = repository.get_secret(
+                        secret_group, secret_uri=secret_uri, short_uuid=short_uuid
+                    )
+                except SecretNotFoundError:
+                    # v0 deletes the requested entity secret
+                    if secret_group == "requested-entity":
+                        logger.debug("Missing requested entity secret")
+                        continue
+                    raise


v0 will delete the helper secret once the relation was established.

dragomirp · 2026-03-14T15:45:34Z

    mtls_cert: MtlsSecretStr = Field(default=None)
+    secret_requested_entity: SecretString | None = Field(
+        default=None,
+        validation_alias=AliasChoices("requested-entity-secret", "secret-requested-entity"),


Should match both the old and new secret field.

dragomirp · 2026-03-14T15:48:32Z

    entity_name: EntitySecretStr = Field(default=None)
    entity_password: EntitySecretStr = Field(default=None)
    version: str | None = Field(default=None)
+    prefix_resources: str | None = Field(default=None)


I wanted to use PlainSerializer to sort the CSV list, but it seems that the field_info.annotation in OptionalSecrets traps other annotations as well. Leaving it be for now.

Interesting.
Maybe we can add just a field serializer for this one in this class ? Or that prevents it?

What I tried to do was:

data-platform-libs/lib/charms/data_platform_libs/v1/data_interfaces.py

Line 1070 in 4a7774a

prefix_resources: Annotated[str | None, PlainSerializer(csv_list_sorter)] = Field(default=None)

With the serialiser being:

data-platform-libs/lib/charms/data_platform_libs/v1/data_interfaces.py

Lines 1032 to 1036 in 4a7774a

def csv_list_sorter(el: str | None) -> str | None:

"""Serialization sorter for comma separated lists."""

if el:

return ",".join(sorted(el.split(",")))

return None

But then the field got turned into a secret. I guess that the OptionalSecretStr alias traps this, since they are both str | None, but didn't dig further, since autosorting is nice to have, but not strictly necessary.

dragomirp · 2026-03-14T15:49:44Z

                    "startup": "enabled",
                    "environment": {
-                        "PGDATA": "/var/lib/postgresql/data/pgdata",
+                        "PGDATA": "/var/lib/postgresql/data/pgdata/data",


For Canonical k8s compatibility (non-empty volume is provided).

dragomirp · 2026-03-15T14:19:26Z

+            if response.prefix_resources:
+                self.interface.repository(relation_id).write_field(
+                    "prefix-databases", response.prefix_resources
+                )


Is there a better way to inject this field?

Oh, this is because the field is renamed ?
Then probably we can do like we do for the other resources: here

I think the original_field is still written in the provider response with write_field here:

data-platform-libs/lib/charms/data_platform_libs/v1/data_interfaces.py

Lines 2588 to 2596 in ba0faad

old_name = request_model.original_field

request_model.request_id = None # For safety, let's ensure that we don't have a model.

self._handle_event(event, repository, request_model)

logger.info(

f"Patching databag for v0 compatibility: replacing 'resource' by '{old_name}'"

)

self.interface.repository(

event.relation.id,

).write_field(old_name, request_model.resource)

Gu1nness

All seems good.
Let's investigate on the CSV ordering.
For the prefix-database vs prefix-resource let's try like we do for the resource field.
Same pattern, a dedicated field that we don't serialize just to store the original field name.

Gu1nness · 2026-03-19T09:15:52Z

    entity_name: EntitySecretStr = Field(default=None)
    entity_password: EntitySecretStr = Field(default=None)
    version: str | None = Field(default=None)
+    prefix_resources: str | None = Field(default=None)


Interesting.
Maybe we can add just a field serializer for this one in this class ? Or that prevents it?

Gu1nness · 2026-03-19T09:18:04Z

+            if response.prefix_resources:
+                self.interface.repository(relation_id).write_field(
+                    "prefix-databases", response.prefix_resources
+                )


Oh, this is because the field is renamed ?
Then probably we can do like we do for the other resources: here

dragomirp added 3 commits February 11, 2026 16:43

WIP

c09144b

Merge branch 'main' into dpe-8863-username-prefixes

5509544

Bump version

519be02

dragomirp changed the title ~~[DPE-8863] username prefixes~~ [DPE-8863] username prefixes v1 Feb 11, 2026

dragomirp changed the title ~~[DPE-8863] username prefixes v1~~ [DPE-8863] Custom username and prefixes for v1 Feb 12, 2026

dragomirp force-pushed the dpe-8863-username-prefixes branch from 0bd5433 to 3f798ce Compare February 12, 2026 14:46

Prefix int test

f61dd66

dragomirp force-pushed the dpe-8863-username-prefixes branch from 3f798ce to f61dd66 Compare February 12, 2026 16:02

Bump microk8s version

371fba2

dragomirp force-pushed the dpe-8863-username-prefixes branch from 72c3e5a to 371fba2 Compare February 12, 2026 23:09

dragomirp added 6 commits February 13, 2026 16:04

Regen locks

d0513ac

Bump microk8s version

a1e10e4

Set permissions

d77f03c

Username test

f112bbb

Merge branch 'ci-fixes' into dpe-8863-username-prefixes

32bc391

Secret helper creation

e8b3da7

dragomirp force-pushed the dpe-8863-username-prefixes branch 2 times, most recently from 83c0c4c to 0b29a12 Compare February 14, 2026 17:52

dragomirp changed the base branch from main to ci-fixes February 14, 2026 18:04

dragomirp force-pushed the dpe-8863-username-prefixes branch 11 times, most recently from a94372a to 66af6bc Compare February 15, 2026 02:44

dragomirp added 2 commits March 6, 2026 04:01

Fix tests

dd7386b

Prefixes to csv list

4a7774a

dragomirp force-pushed the dpe-8863-username-prefixes branch 3 times, most recently from bddfdd4 to 4a7774a Compare March 10, 2026 20:47

dragomirp added 2 commits March 10, 2026 22:48

Fix tests

5c172e8

Merge branch 'main' into dpe-8863-username-prefixes

4ae1370

dragomirp force-pushed the dpe-8863-username-prefixes branch 8 times, most recently from 2ee2a5e to 97a4f1a Compare March 13, 2026 23:11

Backwards compatibility

557065c

dragomirp force-pushed the dpe-8863-username-prefixes branch from 97a4f1a to 557065c Compare March 14, 2026 11:51

dragomirp commented Mar 14, 2026

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dragomirp marked this pull request as ready for review March 14, 2026 15:50

dragomirp requested review from Gu1nness and marceloneppel March 14, 2026 15:50

dragomirp commented Mar 15, 2026

View reviewed changes

Gu1nness reviewed Mar 19, 2026

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marceloneppel reviewed Mar 20, 2026

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Comment thread lib/charms/data_platform_libs/v1/data_interfaces.py Outdated

dragomirp added 2 commits March 21, 2026 20:45

Code review changes

9e37b63

Merge branch 'main' into dpe-8863-username-prefixes

5d5a17b

marceloneppel approved these changes Apr 16, 2026

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[DPE-8863] Custom username and prefixes for v1#258

[DPE-8863] Custom username and prefixes for v1#258
dragomirp wants to merge 26 commits intomainfrom
dpe-8863-username-prefixes

dragomirp commented Feb 11, 2026 •

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	def csv_list_sorter(el: str \| None) -> str \| None:
	"""Serialization sorter for comma separated lists."""
	if el:
	return ",".join(sorted(el.split(",")))
	return None

	old_name = request_model.original_field
	request_model.request_id = None # For safety, let's ensure that we don't have a model.
	self._handle_event(event, repository, request_model)
	logger.info(
	f"Patching databag for v0 compatibility: replacing 'resource' by '{old_name}'"
	)
	self.interface.repository(
	event.relation.id,
	).write_field(old_name, request_model.resource)

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dragomirp commented Feb 11, 2026 •

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