App Engine deployment fails with "Client Error (400) The request is invalid for an unspecified reason."

Question

my python27 app deployment is failing for some reasons:

2012-03-09 16:46:25 Running command: "['C:\\Python27\\pythonw.exe', '-u', 'C:\\Program Files (x86)\\Google\\google_appengine\\appcfg.py', '--no_cookies', u'[email protected]', '--passin', 'update', 'C:\\Users\\XXXXXXXXXXXXXX\\GoogleAppEngine\\XXXXXXXXXXXXXX']"
Application: XXXXXXXXXXXXXX; version: 1
Host: appengine.google.com

Starting update of app: XXXXXXXXXXXXXXX, version: 1
Getting current resource limits.
Password for [email protected]: Scanning files on local disk.
Scanned 500 files.
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Cloning 2973 static files.
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Cloning 3 application files.

Uploading 4 files and blobs.
Uploaded 4 files and blobs
Compilation starting.
Compilation completed.
Starting deployment.
Rolling back the update.
Error 400: --- begin server output ---

Client Error (400)
The request is invalid for an unspecified reason.
--- end server output ---
2012-03-09 16:47:14 (Process exited with code 1)

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How can I debug that? Thanks, Carl

Answer 1

This is a fall-back error message that is triggered when your deployment sends very unexpected data to App Engine during deployment.

In other words, there's no quick fix here, but there are a couple things you can check:

• Check your apps metadata in app.yaml for Python and appengine-web.xml for Java. Double check each field. If the application name is very wrong, it may trigger this error.
• Make sure that your deployment credentials are valid. If you're authenticating with OAuth 2.0, try using password based authentication.

Answer 2

Just recording my experience in this related question.

I got a 'Client Error 400/unspecified reason' because my app.yaml error handlers were pointing to files in a static directory.

I moved the error files to a separate directory and updated app.yaml paths.

Update worked properly.

Answer 3

i know this is an old question, but i thought i would provide the solution that worked for me. Select Control from the GAE Launcher, then Clear Deployment Credential. Deploy again. The deployment script will open a web page where GAE is requesting access to use your Google account to authenticate. the answer from Jen Tong helped me get to my solution.