gce_metadata_server.py 文件源码

def __call__(self, environ, start_response):
    req = Request(environ, shallow=True)  
    host = req.headers.get('Host')
    if host not in ('metadata.google.internal', '169.254.169.254' , 'metadata'):
      status = '403 Forbidden'
      response_headers = [('Content-Type','text/html; charset=UTF-8')]
      start_response(status, response_headers)
      return ['Host Header nust be one of (metadata.google.internal, metadata, 169.254.169.254)']
    req_path = environ.get('PATH_INFO')
    metadata_flavor = req.headers.get('Metadata-Flavor')
    if (metadata_flavor is None and req_path != '/'):
      status = '403 Forbidden'
      response_headers = [('Content-Type','text/html; charset=UTF-8')]
      start_response(status, response_headers)
      logging.error("Metadata-Flavor: Google header not sent for: " + environ.get('PATH_INFO'))
      t = Template('''<p>Your client does not have permission to get URL 
      <code>{{ err_path }}</code> from this server. Missing Metadata-Flavor:Google header. ''')
      return [str(t.render(err_path= environ.get('PATH_INFO')))]
    return self.app(environ, start_response)


# Make sure every response has these headers (which is what gce does)