<p dir="auto"><strong>Apache Airflow version</strong>:<br>
2.0.0</p>
<p dir="auto"><strong>Kubernetes version (if you are using kubernetes)</strong> (use <code class="notranslate">kubectl version</code>):<br>
N/A</p>
<p dir="auto"><strong>Environment</strong>:<br>
virtualenv</p>
<ul dir="auto">
<li><strong>Cloud provider or hardware configuration</strong>: N/A - Localhost:8080</li>
<li><strong>OS</strong> (e.g. from /etc/os-release): MacOS Cataline 10.15.7</li>
<li><strong>Kernel</strong> (e.g. <code class="notranslate">uname -a</code>): Kernel Version 19.6.0</li>
<li><strong>Install tools</strong>: pip</li>
<li><strong>Others</strong>:</li>
</ul>
<p dir="auto"><strong>What happened</strong>:<br>
Could not fire up 'airflow webserver.'  Error Message as follows:</p>

<h2 dir="auto">Python version: 3.8.3<br>
Airflow version: 2.0.0<br>
Node: CHAAZML-T3CAMD6</h2>
<p dir="auto">Traceback (most recent call last):<br>
File "/Users/Me/projects/git_stuff/pols_analytics_general/airflow/lib/python3.8/site-packages/flask/app.py", line 2447, in wsgi_app<br>
response = self.full_dispatch_request()<br>
File "/Users/Me/projects/git_stuff/pols_analytics_general/airflow/lib/python3.8/site-packages/flask/app.py", line 1953, in full_dispatch_request<br>
return self.finalize_request(rv)<br>
File "/Users/Me/projects/git_stuff/pols_analytics_general/airflow/lib/python3.8/site-packages/flask/app.py", line 1970, in finalize_request<br>
response = self.process_response(response)<br>
File "/Users/Me/projects/git_stuff/pols_analytics_general/airflow/lib/python3.8/site-packages/flask/app.py", line 2269, in process_response<br>
self.session_interface.save_session(self, ctx.session, response)<br>
File "/Users/Me/projects/git_stuff/pols_analytics_general/airflow/lib/python3.8/site-packages/flask/sessions.py", line 379, in save_session<br>
response.set_cookie(<br>
File "/Users/Me/projects/git_stuff/pols_analytics_general/airflow/lib/python3.8/site-packages/werkzeug/wrappers/base_response.py", line 468, in set_cookie<br>
dump_cookie(<br>
File "/Users/Me/projects/git_stuff/pols_analytics_general/airflow/lib/python3.8/site-packages/werkzeug/http.py", line 1217, in dump_cookie<br>
raise ValueError("SameSite must be 'Strict', 'Lax', or 'None'.")<br>
ValueError: SameSite must be 'Strict', 'Lax', or 'None'.</p>
<p dir="auto"><strong>What you expected to happen</strong>:<br>
Webserver start.</p>

<p dir="auto">Uknown</p>
<p dir="auto"><strong>How to reproduce it</strong>:</p>

<p dir="auto"><strong>Anything else we need to know</strong>:</p>
<p dir="auto">Log in Terminal says:</p>
<p dir="auto">/Users/me/projects/git_stuff/pols_analytics_general/airflow/lib/python3.8/site-packages/airflow/configuration.py:324 DeprecationWarning: The statsd_on option in [scheduler] has been moved to the statsd_on option in [metrics] - the old setting has been used, but please update your config.<br>
/Users/me/projects/git_stuff/pols_analytics_general/airflow/lib/python3.8/site-packages/airflow/configuration.py:324 DeprecationWarning: The logging_config_class option in [core] has been moved to the logging_config_class option in [logging] - the old setting has been used, but please update your config.<br>
/Users/me/projects/git_stuff/pols_analytics_general/airflow/lib/python3.8/site-packages/airflow/configuration.py:324 DeprecationWarning: The task_log_reader option in [core] has been moved to the task_log_reader option in [logging] - the old setting has been used, but please update your config.</p>
<h3 dir="auto">Apache Airflow version</h3>
<p dir="auto">2.3.3 (latest released)</p>
<h3 dir="auto">What happened</h3>
<p dir="auto">In 2.3.3</p>
<p dir="auto">If I use <a href="https://airflow.apache.org/docs/apache-airflow/stable/plugins.html#plugins-as-python-packages" rel="nofollow">https://airflow.apache.org/docs/apache-airflow/stable/plugins.html#plugins-as-python-packages</a> feature, then I see these Error:</p>
<p dir="auto">short:<br>
<code class="notranslate">ValueError: The name 'airs' is already registered for this blueprint. Use 'name=' to provide a unique name.</code></p>
<p dir="auto">long:</p>
<blockquote>
<p dir="auto">i'm trying to reproduce it...</p>
</blockquote>
<p dir="auto">If I don't use it(workarounding by AIRFLOW__CORE__PLUGINS_FOLDER), errors doesn't occur.</p>
<p dir="auto">It didn't happend in 2.3.2 and earlier</p>
<h3 dir="auto">What you think should happen instead</h3>
<p dir="auto">Looks like plugins are import multiple times if it is plugins-as-python-packages.</p>
<p dir="auto">Perhaps flask's major version change  is the main cause.<br>
Presumably, in flask 1.0, duplicate registration of blueprint was quietly filtered out, but in 2.0 it seems to have been changed to generate an error. (I am trying to find out if this hypothesis is correct)</p>
<p dir="auto">Anyway, use the latest version of FAB is important. we will have to adapt to this change, so plugins will have to be imported once regardless how it defined.</p>
<h3 dir="auto">How to reproduce</h3>
<blockquote>
<p dir="auto">It was reproduced in the environment used at work, but it is difficult to disclose or explain it.<br>
I'm working to reproduce it with the breeze command, and I open the issue first with the belief that it's not just me.</p>
</blockquote>
<h3 dir="auto">Operating System</h3>
<p dir="auto">CentOS Linux release 7.9.2009 (Core)</p>
<h3 dir="auto">Versions of Apache Airflow Providers</h3>
<div class="highlight highlight-source-shell notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="$ SHIV_INTERPRETER=1 airsflow -m pip freeze | grep apache-
apache-airflow==2.3.3
apache-airflow-providers-apache-hive==3.1.0
apache-airflow-providers-apache-spark==2.1.0
apache-airflow-providers-celery==3.0.0
apache-airflow-providers-common-sql==1.0.0
apache-airflow-providers-ftp==3.1.0
apache-airflow-providers-http==3.0.0
apache-airflow-providers-imap==3.0.0
apache-airflow-providers-postgres==5.1.0
apache-airflow-providers-redis==3.0.0
apache-airflow-providers-sqlite==3.1.0"><pre class="notranslate">$ SHIV_INTERPRETER=1 airsflow -m pip freeze <span class="pl-k">|</span> grep apache-
apache-airflow==2.3.3
apache-airflow-providers-apache-hive==3.1.0
apache-airflow-providers-apache-spark==2.1.0
apache-airflow-providers-celery==3.0.0
apache-airflow-providers-common-sql==1.0.0
apache-airflow-providers-ftp==3.1.0
apache-airflow-providers-http==3.0.0
apache-airflow-providers-imap==3.0.0
apache-airflow-providers-postgres==5.1.0
apache-airflow-providers-redis==3.0.0
apache-airflow-providers-sqlite==3.1.0</pre></div>
<p dir="auto">but I think these are irrelevant.</p>
<h3 dir="auto">Deployment</h3>
<p dir="auto">Other 3rd-party Helm chart</p>
<h3 dir="auto">Deployment details</h3>
<p dir="auto">docker image based on centos7, python 3.9.10 interpreter, self-written helm2 chart ....</p>
<p dir="auto">... but I think these are irrelevant.</p>
<h3 dir="auto">Anything else</h3>
<p dir="auto"><em>No response</em></p>
<h3 dir="auto">Are you willing to submit PR?</h3>
<ul class="contains-task-list">
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> Yes I am willing to submit a PR!</li>
</ul>
<h3 dir="auto">Code of Conduct</h3>
<ul class="contains-task-list">
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> I agree to follow this project's <a href="https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md">Code of Conduct</a></li>
</ul>