Sentry raising BadRequest in Flask 2.1.2

[antonpirker]

How do you use Sentry?

Sentry Saas (sentry.io)

Version

1.5.12

Steps to Reproduce

See also internal ticket here: https://getsentry.atlassian.net/jira/software/c/projects/WEBBACKEND/boards/150?modal=detail&selectedIssue=ISSUE-1506&quickFilter=260

Create a sample application with Flask 2.1.2 like this:

from flask import Flask
import sentry_sdk

from sentry_sdk.integrations.flask import FlaskIntegration

sentry_sdk.init(
    dsn="https://d767560f70c3498ba64a91a16d987514@o447951.ingest.sentry.io/6483053",
    integrations=[FlaskIntegration()],
    debug=True,

    # Set traces_sample_rate to 1.0 to capture 100%
    # of transactions for performance monitoring.
    # We recommend adjusting this value in production.
#    traces_sample_rate=1.0
)


app = Flask(__name__)

@app.route("/")
def hello_world():
    return "<p>Hello, World!</p>"

@app.route('/debug-sentry')
def trigger_error():
    division_by_zero = 1 / 0
    return "<p>bla</p>"

put this in hello.py and start with FLASK_APP=hello flask run.

Expected Result

The errors should be caught and sent to Sentry.

Actual Result

There is a BadRequest Error during processing of the Error. (But the error is still sent to Sentry, but this BadRequest should not be there):

 [sentry] ERROR: Internal error in sentry_sdk
Traceback (most recent call last):
  File "/Users/antonpirker/tmp/flask/.venv/lib/python3.9/site-packages/flask/wrappers.py", line 128, in on_json_loading_failed
    return super().on_json_loading_failed(e)
  File "/Users/antonpirker/tmp/flask/.venv/lib/python3.9/site-packages/werkzeug/wrappers/request.py", line 611, in on_json_loading_failed
    raise BadRequest(
werkzeug.exceptions.BadRequest: 400 Bad Request: Did not attempt to load JSON data because the request Content-Type was not 'application/json'.

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/Users/antonpirker/tmp/flask/.venv/lib/python3.9/site-packages/sentry_sdk/integrations/flask.py", line 192, in inner
    FlaskRequestExtractor(request).extract_into_event(event)
  File "/Users/antonpirker/tmp/flask/.venv/lib/python3.9/site-packages/sentry_sdk/integrations/_wsgi_common.py", line 72, in extract_into_event
    parsed_body = self.parsed_body()
  File "/Users/antonpirker/tmp/flask/.venv/lib/python3.9/site-packages/sentry_sdk/integrations/_wsgi_common.py", line 121, in parsed_body
    return self.json()
  File "/Users/antonpirker/tmp/flask/.venv/lib/python3.9/site-packages/sentry_sdk/integrations/flask.py", line 172, in json
    return self.request.get_json()
  File "/Users/antonpirker/tmp/flask/.venv/lib/python3.9/site-packages/werkzeug/wrappers/request.py", line 571, in get_json
    return self.on_json_loading_failed(None)
  File "/Users/antonpirker/tmp/flask/.venv/lib/python3.9/site-packages/flask/wrappers.py", line 133, in on_json_loading_failed
    raise BadRequest() from e
werkzeug.exceptions.BadRequest: 400 Bad Request: The browser (or proxy) sent a request that this server could not understand.
 [sentry] INFO: Discarded session update because of missing release

When you downgrade some of the requirements of Flask, it works:

Flask              2.1.2
itsdangerous       2.1.2
Jinja2             3.1.2
MarkupSafe         2.1.1
Werkzeug           2.0.3

[hitvoice]

I had the same issue without using sentry. It worked after downgrading werkzeug. I think it's a bug from there.

[azzamsa]

@hitvoice what werkzeug version works for you?

Related:

• Did not attempt to load JSON data because the request Content-Type was not 'application/json'. flask-restful/flask-restful#953
• pallets/werkzeug@bf4ede2

[azzamsa]

I managed to solve the issue. I put the full explanation in my StackOverflow answer

[antonpirker]

As this is no Sentry bug, I am closing this.