title: GAE error (Error code 104) while creating a new blob
body: <p>On GAE this line of code:</p>
  
  <p><strong>file_name = files.blobstore.create(mime_type='image/png')</strong></p>
  
  <p>drops <strong>google.appengine.runtime.DeadlineExceededError</strong></p>
  
  <p>Here is the full method code:</p>
  
  <pre><code>class UploadsHandler(JSONRequestHandler):
      def upload_blob(self, content, filename):
          file_name = files.blobstore.create(mime_type='image/png')
  
          file_str_list = split_len(content, 65520)
  
          with files.open(file_name, 'a') as f:
              for line in file_str_list:
                  f.write(line)
  
          files.finalize(file_name)
          return files.blobstore.get_blob_key(file_name)
  </code></pre>
  
  <p>Logging message ends with:</p>
  
  <p><em>A serious problem was encountered with the process that handled this request, causing it to exit. This is likely to cause a new process to be used for the next request to your application. If you see this message frequently, you may be throwing exceptions during the initialization of your application. (<strong>Error code 104</strong>)</em></p>
  
  <p>Full error stack:</p>
  
  <pre><code>&lt;class 'google.appengine.runtime.DeadlineExceededError'&gt;: 
  Traceback (most recent call last):
    File "/base/data/home/apps/s~mockup-cloud/1.352909931378411668/main.py", line 389, in main
      util.run_wsgi_app(application)
    File "/base/python_runtime/python_lib/versions/1/google/appengine/ext/webapp/util.py", line 98, in run_wsgi_app
      run_bare_wsgi_app(add_wsgi_middleware(application))
    File "/base/python_runtime/python_lib/versions/1/google/appengine/ext/webapp/util.py", line 116, in run_bare_wsgi_app
      result = application(env, _start_response)
    File "/base/python_runtime/python_lib/versions/1/google/appengine/ext/webapp/_webapp25.py", line 703, in __call__
      handler.post(*groups)
    File "/base/data/home/apps/s~mockup-cloud/1.352909931378411668/main.py", line 339, in post
      original_key = "%s" % self.upload_blob(src)
    File "/base/data/home/apps/s~mockup-cloud/1.352909931378411668/main.py", line 268, in upload_blob
      file_name = files.blobstore.create(mime_type='image/png')
    File "/base/python_runtime/python_lib/versions/1/google/appengine/api/files/blobstore.py", line 68, in create
      return files._create(_BLOBSTORE_FILESYSTEM, params=params)
    File "/base/python_runtime/python_lib/versions/1/google/appengine/api/files/file.py", line 487, in _create
      _make_call('Create', request, response)
    File "/base/python_runtime/python_lib/versions/1/google/appengine/api/files/file.py", line 228, in _make_call
      rpc.wait()
    File "/base/python_runtime/python_lib/versions/1/google/appengine/api/apiproxy_stub_map.py", line 533, in wait
      self.__rpc.Wait()
    File "/base/python_runtime/python_lib/versions/1/google/appengine/api/apiproxy_rpc.py", line 119, in Wait
      rpc_completed = self._WaitImpl()
    File "/base/python_runtime/python_lib/versions/1/google/appengine/runtime/apiproxy.py", line 131, in _WaitImpl
      rpc_completed = _apphosting_runtime___python__apiproxy.Wait(self)
  </code></pre>
  
  <p>Blob is created while file upload. Other methods of the app work great. It looks like blobstore is not responding for under 30 sec.</p>
  
  <p>Any ideas why this happens?
  Thanks!</p>