prometheus_flask_exporter
prometheus_flask_exporter copied to clipboard
Published
20 hours ago •
rycus86
rycus86
🐞 TypeError: The view function for 'main' did not return a valid response.
Did it like described in https://github.com/rycus86/prometheus_flask_exporter#usage but with app.run(debug=True) at the end? 🤔
> curl localhost:5000
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<head>
<title>TypeError: The view function for 'main' did not return a valid response. The function either returned None or ended without a return statement.
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<script>
var CONSOLE_MODE = false,
EVALEX = true,
EVALEX_TRUSTED = false,
SECRET = "Vdo3qNNRy8n4S2jNd334";
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<body style="background-color: #fff">
<div class="debugger">
<h1>TypeError</h1>
<div class="detail">
<p class="errormsg">TypeError: The view function for 'main' did not return a valid response. The function either returned None or ended without a return statement.
</p>
</div>
<h2 class="traceback">Traceback <em>(most recent call last)</em></h2>
<div class="traceback">
<h3></h3>
<ul><li><div class="frame" id="frame-4369751440">
<h4>File <cite class="filename">"/Users/tgotwig/.asdf/installs/python/3.10.5/lib/python3.10/site-packages/flask/app.py"</cite>,
line <em class="line">2095</em>,
in <code class="function">__call__</code></h4>
<div class="source "><pre class="line before"><span class="ws"> </span>def __call__(self, environ: dict, start_response: t.Callable) -> t.Any:</pre>
<pre class="line before"><span class="ws"> </span>"""The WSGI server calls the Flask application object as the</pre>
<pre class="line before"><span class="ws"> </span>WSGI application. This calls :meth:`wsgi_app`, which can be</pre>
<pre class="line before"><span class="ws"> </span>wrapped to apply middleware.</pre>
<pre class="line before"><span class="ws"> </span>"""</pre>
<pre class="line current"><span class="ws"> </span>return self.wsgi_app(environ, start_response)</pre></div>
</div>
<li><div class="frame" id="frame-4369752336">
<h4>File <cite class="filename">"/Users/tgotwig/.asdf/installs/python/3.10.5/lib/python3.10/site-packages/flask/app.py"</cite>,
line <em class="line">2080</em>,
in <code class="function">wsgi_app</code></h4>
<div class="source "><pre class="line before"><span class="ws"> </span>try:</pre>
<pre class="line before"><span class="ws"> </span>ctx.push()</pre>
<pre class="line before"><span class="ws"> </span>response = self.full_dispatch_request()</pre>
<pre class="line before"><span class="ws"> </span>except Exception as e:</pre>
<pre class="line before"><span class="ws"> </span>error = e</pre>
<pre class="line current"><span class="ws"> </span>response = self.handle_exception(e)</pre>
<pre class="line after"><span class="ws"> </span>except: # noqa: B001</pre>
<pre class="line after"><span class="ws"> </span>error = sys.exc_info()[1]</pre>
<pre class="line after"><span class="ws"> </span>raise</pre>
<pre class="line after"><span class="ws"> </span>return response(environ, start_response)</pre>
<pre class="line after"><span class="ws"> </span>finally:</pre></div>
</div>
<li><div class="frame" id="frame-4369752560">
<h4>File <cite class="filename">"/Users/tgotwig/.asdf/installs/python/3.10.5/lib/python3.10/site-packages/flask/app.py"</cite>,
line <em class="line">2077</em>,
in <code class="function">wsgi_app</code></h4>
<div class="source "><pre class="line before"><span class="ws"> </span>ctx = self.request_context(environ)</pre>
<pre class="line before"><span class="ws"> </span>error: t.Optional[BaseException] = None</pre>
<pre class="line before"><span class="ws"> </span>try:</pre>
<pre class="line before"><span class="ws"> </span>try:</pre>
<pre class="line before"><span class="ws"> </span>ctx.push()</pre>
<pre class="line current"><span class="ws"> </span>response = self.full_dispatch_request()</pre>
<pre class="line after"><span class="ws"> </span>except Exception as e:</pre>
<pre class="line after"><span class="ws"> </span>error = e</pre>
<pre class="line after"><span class="ws"> </span>response = self.handle_exception(e)</pre>
<pre class="line after"><span class="ws"> </span>except: # noqa: B001</pre>
<pre class="line after"><span class="ws"> </span>error = sys.exc_info()[1]</pre></div>
</div>
<li><div class="frame" id="frame-4369752224">
<h4>File <cite class="filename">"/Users/tgotwig/.asdf/installs/python/3.10.5/lib/python3.10/site-packages/flask/app.py"</cite>,
line <em class="line">1526</em>,
in <code class="function">full_dispatch_request</code></h4>
<div class="source "><pre class="line before"><span class="ws"> </span>rv = self.preprocess_request()</pre>
<pre class="line before"><span class="ws"> </span>if rv is None:</pre>
<pre class="line before"><span class="ws"> </span>rv = self.dispatch_request()</pre>
<pre class="line before"><span class="ws"> </span>except Exception as e:</pre>
<pre class="line before"><span class="ws"> </span>rv = self.handle_user_exception(e)</pre>
<pre class="line current"><span class="ws"> </span>return self.finalize_request(rv)</pre>
<pre class="line after"><span class="ws"></span> </pre>
<pre class="line after"><span class="ws"> </span>def finalize_request(</pre>
<pre class="line after"><span class="ws"> </span>self,</pre>
<pre class="line after"><span class="ws"> </span>rv: t.Union[ResponseReturnValue, HTTPException],</pre>
<pre class="line after"><span class="ws"> </span>from_error_handler: bool = False,</pre></div>
</div>
<li><div class="frame" id="frame-4369751328">
<h4>File <cite class="filename">"/Users/tgotwig/.asdf/installs/python/3.10.5/lib/python3.10/site-packages/flask/app.py"</cite>,
line <em class="line">1545</em>,
in <code class="function">finalize_request</code></h4>
<div class="source "><pre class="line before"><span class="ws"> </span>with the `from_error_handler` flag. If enabled, failures in</pre>
<pre class="line before"><span class="ws"> </span>response processing will be logged and otherwise ignored.</pre>
<pre class="line before"><span class="ws"></span> </pre>
<pre class="line before"><span class="ws"> </span>:internal:</pre>
<pre class="line before"><span class="ws"> </span>"""</pre>
<pre class="line current"><span class="ws"> </span>response = self.make_response(rv)</pre>
<pre class="line after"><span class="ws"> </span>try:</pre>
<pre class="line after"><span class="ws"> </span>response = self.process_response(response)</pre>
<pre class="line after"><span class="ws"> </span>request_finished.send(self, response=response)</pre>
<pre class="line after"><span class="ws"> </span>except Exception:</pre>
<pre class="line after"><span class="ws"> </span>if not from_error_handler:</pre></div>
</div>
<li><div class="frame" id="frame-4369752448">
<h4>File <cite class="filename">"/Users/tgotwig/.asdf/installs/python/3.10.5/lib/python3.10/site-packages/flask/app.py"</cite>,
line <em class="line">1701</em>,
in <code class="function">make_response</code></h4>
<div class="source "><pre class="line before"><span class="ws"> </span>" (body, status), or (body, headers)."</pre>
<pre class="line before"><span class="ws"> </span>)</pre>
<pre class="line before"><span class="ws"></span> </pre>
<pre class="line before"><span class="ws"> </span># the body must not be None</pre>
<pre class="line before"><span class="ws"> </span>if rv is None:</pre>
<pre class="line current"><span class="ws"> </span>raise TypeError(</pre>
<pre class="line after"><span class="ws"> </span>f"The view function for {request.endpoint!r} did not"</pre>
<pre class="line after"><span class="ws"> </span>" return a valid response. The function either returned"</pre>
<pre class="line after"><span class="ws"> </span>" None or ended without a return statement."</pre>
<pre class="line after"><span class="ws"> </span>)</pre>
<pre class="line after"><span class="ws"></span> </pre></div>
</div>
</ul>
<blockquote>TypeError: The view function for 'main' did not return a valid response. The function either returned None or ended without a return statement.
</blockquote>
</div>
<div class="plain">
<p>
This is the Copy/Paste friendly version of the traceback.
</p>
<textarea cols="50" rows="10" name="code" readonly>Traceback (most recent call last):
File "/Users/tgotwig/.asdf/installs/python/3.10.5/lib/python3.10/site-packages/flask/app.py", line 2095, in __call__
return self.wsgi_app(environ, start_response)
File "/Users/tgotwig/.asdf/installs/python/3.10.5/lib/python3.10/site-packages/flask/app.py", line 2080, in wsgi_app
response = self.handle_exception(e)
File "/Users/tgotwig/.asdf/installs/python/3.10.5/lib/python3.10/site-packages/flask/app.py", line 2077, in wsgi_app
response = self.full_dispatch_request()
File "/Users/tgotwig/.asdf/installs/python/3.10.5/lib/python3.10/site-packages/flask/app.py", line 1526, in full_dispatch_request
return self.finalize_request(rv)
File "/Users/tgotwig/.asdf/installs/python/3.10.5/lib/python3.10/site-packages/flask/app.py", line 1545, in finalize_request
response = self.make_response(rv)
File "/Users/tgotwig/.asdf/installs/python/3.10.5/lib/python3.10/site-packages/flask/app.py", line 1701, in make_response
raise TypeError(
TypeError: The view function for 'main' did not return a valid response. The function either returned None or ended without a return statement.
</textarea>
</div>
<div class="explanation">
The debugger caught an exception in your WSGI application. You can now
look at the traceback which led to the error. <span class="nojavascript">
If you enable JavaScript you can also use additional features such as code
execution (if the evalex feature is enabled), automatic pasting of the
exceptions and much more.</span>
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Brought to you by <strong class="arthur">DON'T PANIC</strong>, your
friendly Werkzeug powered traceback interpreter.
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<h3>Console Locked</h3>
<p>
The console is locked and needs to be unlocked by entering the PIN.
You can find the PIN printed out on the standard output of your
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<!--
Traceback (most recent call last):
File "/Users/tgotwig/.asdf/installs/python/3.10.5/lib/python3.10/site-packages/flask/app.py", line 2095, in __call__
return self.wsgi_app(environ, start_response)
File "/Users/tgotwig/.asdf/installs/python/3.10.5/lib/python3.10/site-packages/flask/app.py", line 2080, in wsgi_app
response = self.handle_exception(e)
File "/Users/tgotwig/.asdf/installs/python/3.10.5/lib/python3.10/site-packages/flask/app.py", line 2077, in wsgi_app
response = self.full_dispatch_request()
File "/Users/tgotwig/.asdf/installs/python/3.10.5/lib/python3.10/site-packages/flask/app.py", line 1526, in full_dispatch_request
return self.finalize_request(rv)
File "/Users/tgotwig/.asdf/installs/python/3.10.5/lib/python3.10/site-packages/flask/app.py", line 1545, in finalize_request
response = self.make_response(rv)
File "/Users/tgotwig/.asdf/installs/python/3.10.5/lib/python3.10/site-packages/flask/app.py", line 1701, in make_response
raise TypeError(
TypeError: The view function for 'main' did not return a valid response. The function either returned None or ended without a return statement.
-->
I should probably update those examples to return something valid, sorry. 🤦 As the error message explains:
The function either returned None or ended without a return statement.
If you change the pass to something like return 'OK' then it should work.
