Pass the configured botname to NotifyMattermost by Ayoubhm07 · Pull Request #23281 · PrefectHQ/prefect

Ayoubhm07 · 2026-10-04T23:49:49Z

closes #23282
MattermostWebhook exposes a botname field, but block_initialization never passes it to NotifyMattermost. The name is accepted by pydantic, persisted on the block document, then dropped at send time no exception, no warning, no log line.

$ grep -rn "botname" src/ --include='*.py'
src/prefect/blocks/notifications.py:709:    botname: Optional[str] = Field(     # Mattermost, declared
src/prefect/blocks/notifications.py:811:    botname: Optional[str] = Field(     # Discord, declared
src/prefect/blocks/notifications.py:863:                botname=self.botname,   # Discord, passed

In webhook mode the default, and the only mode this block can reach since it does not expose mode apprise builds the sender name as payload["username"] = self.user if self.user else self.app_id (apprise/plugins/mattermost.py:646). With self.user unset, every message is signed with the asset name instead of the configured one.

How it regressed

#19780 set user=self.botname on this exact call. block_initialization was later rewritten to add the plugin instance directly instead of going through .url(), because apprise >= 1.9.9 stopped putting channels in the URL and renamed channels to targets. That rewrite kept seven of the eight fields and left user=self.botname behind. The comment above the call (notifications.py:747-749) documents the .url() and targets changes only.

Why `user=` and not `botname=`

NotifyMattermost.__init__ takes no botname keyword. apprise declares it as an alias of user (mattermost.py:225-227) and relays **kwargs to URLBase, which reads user. Passing botname= lands in **kwargs and is ignored the original bug #19780 fixed.

Verification

The added test, plus the existing test_notify_with_multiple_channels as a witness, run against the patched source and against the source with the one line removed:

line removed:  1 failed, 1 passed
               AssertionError: assert None == 'Prefect Bot'
line present:  2 passed

Driving the plugin directly with requests.post patched, no network and no server:

before:  plugin.user = None          payload['username'] = 'Apprise'
after:   plugin.user = 'Deploy Bot'  payload['username'] = 'Deploy Bot'

targets and port are unchanged in both.

The full TestMattermostWebhook class could not be run here: every test in it, including the five that predate this change, errors on RuntimeError: Timed out while attempting to connect to hosted test Prefect API (src/prefect/testing/fixtures.py:135). That is my environment, not this change, which is why the checks above were run outside the session fixture.

Measured with apprise==1.13.1 (the pin is apprise>=1.13.0,<2.0.0).

Noted while reproducing, out of scope

The fallback prints Apprise, not Prefect Notifications. Apprise.add() given an already constructed plugin instance just appends it (apprise/apprise.py:308-310) without applying the asset, so the AppriseAsset built at notifications.py:760-764 never reaches this plugin. Separate branding issue, untouched here happy to open a follow-up.

Checklist

This pull request references any related issue by including "closes <link to issue>"
If this is a complex change, a maintainer has confirmed the proposed approach on the linked issue.
- Not complex: one added line, no new field, option, or dependency.
If this pull request adds or changes functionality, it includes tests or explains why tests are not needed.
If this pull request changes user-facing behavior, it updates documentation or explains why documentation is not needed.
- The existing botname description is what is being restored; it is already accurate.
If this pull request removes docs files, it includes redirect settings in mint.json. N/A
If this pull request adds functions or classes, it includes helpful docstrings. N/A

AI tools were used to find this defect and draft this description. I understand the change, I kept it to one line, and I validated it locally as described above.

MattermostWebhook declares a botname field and surfaces it in the UI block form, but block_initialization stopped passing it when it was rewritten to add the NotifyMattermost instance directly instead of going through .url(). Seven of the eight fields survived that rewrite; user=self.botname did not. With self.user unset, apprise falls back to the asset app_id when building the webhook payload (apprise/plugins/mattermost.py:646), so every message is signed with the asset name regardless of what the user configured. The field is accepted, persisted, and then discarded with no exception, warning, or log. The keyword is user= rather than botname=: NotifyMattermost does not take a botname argument, it declares botname as an alias of user and relays **kwargs to URLBase, which reads user. This restores what PrefectHQ#19780 established before the rewrite. Adds test_botname_is_passed_to_apprise to the existing TestMattermostWebhook class.

devin-ai-integration

Devin Review found 2 potential issues.

devin-ai-integration · 2026-10-04T23:50:44Z

contribution guidance

            token=self.token.get_secret_value(),
            fullpath=self.path,
            host=self.hostname,
+            user=self.botname,


🔍 Bug fix lacks issue discussion

This bug fix has no linked issue, despite the issue-first rule in contribution guidance. The cited earlier PR fixed the original defect, not this regression.

Was this helpful? React with 👍 or 👎 to provide feedback.

codspeed · 2026-10-05T00:04:17Z

Merging this PR will not alter performance

✅ 8 untouched benchmarks
⏩ 1 skipped benchmark¹

_{Comparing Ayoubhm07:fix/mattermost-botname (a4852c8) with main (2338265)}

1 benchmark was skipped, so the baseline result was used instead. If it was deleted from the codebase, click here and archive it to remove it from the performance reports. ↩

The test read plugin.user, an apprise-internal attribute reached through the block's private _apprise_client. The contribution guide asks for tests that assert user-visible behavior rather than private implementation details. It now patches requests.post and asserts on payload["username"], which is the name Mattermost actually displays. Without the fix it fails with assert 'Apprise' == 'Prefect Bot' instead of assert None == 'Prefect Bot'.

Ayoubhm07 · 2026-10-05T00:53:20Z

Both points taken

Issue opened at #23282 and linked above : the contribution guide asks for one beyond a doc or typo fix and I read the PR template's "small fix" wording too narrowly

The test now patches requests.post and asserts on payload["username"] rather than plugin.user : without the fix it fails with assert 'Apprise' == 'Prefect Bot' which is the name Mattermost would actually display

On the red group from the first run : the two failures were in tests/test_assets.py and tests/test_flow_engine.py and neither file is touched here
Both landed on gw2 and both were downstream of RuntimeError: Cannot put items in a stopped service instance repeating through the captured logs until AssertingEventsClient had no events attribute and the task run was never persisted
That is what #23172 is still open against : #22995 #23083 #23172 #23247 and #23249 have all been aimed at it since August
Adding a test shifts the pytest-split boundaries so that group ran a different mix it is green on the current head

desertaxle

LGTM!

Ayoubhm07 requested review from chrisguidry, desertaxle and zzstoatzz as code owners October 4, 2026 23:49

devin-ai-integration Bot reviewed Oct 4, 2026

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Ayoubhm07 mentioned this pull request Oct 5, 2026

MattermostWebhook silently ignores the configured botname #23282

Closed

github-actions Bot added the bug Something isn't working label Oct 5, 2026

desertaxle approved these changes Oct 5, 2026

View reviewed changes

desertaxle merged commit 0477263 into PrefectHQ:main Oct 5, 2026
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Pass the configured botname to NotifyMattermost - #23281

Pass the configured botname to NotifyMattermost#23281
desertaxle merged 2 commits into
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Ayoubhm07:fix/mattermost-botname

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Ayoubhm07 commented Oct 4, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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How it regressed

Why user= and not botname=

Verification

Noted while reproducing, out of scope

Checklist

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codspeed Bot commented Oct 5, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Merging this PR will not alter performance

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Ayoubhm07 commented Oct 4, 2026 •

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Why `user=` and not `botname=`

codspeed Bot commented Oct 5, 2026 •

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