Handle create/update of images with unknown size

It may not be possible to know in advance the total
size of image data which is to be uploaded, for example
if the data is being piped to stdin.

To handle this we use HTTP Transfer-Encoding: chunked
and do not set any image size headers.

Various subtly different cases needed to be handled for
both image-create and image-update, including:

 * input from named pipe
 * piped input of zero size
 * regular file of zero length

Fix for bug 1056220.

Change-Id: I0c7f0a64d883e058993b954a1c465c5b057f2bcf

glanceclient/common/http.py

@@ -146,7 +146,19 @@ class HTTPClient(object):
 
         try:
             conn_url = os.path.normpath('%s/%s' % (self.endpoint_path, url))
-            conn.request(method, conn_url, **kwargs)
+            if kwargs['headers'].get('Transfer-Encoding') == 'chunked':
+                conn.putrequest(method, conn_url)
+                for header, value in kwargs['headers'].items():
+                    conn.putheader(header, value)
+                conn.endheaders()
+                chunk = kwargs['body'].read(CHUNKSIZE)
+                # Chunk it, baby...
+                while chunk:
+                    conn.send('%x\r\n%s\r\n' % (len(chunk), chunk))
+                    chunk = kwargs['body'].read(CHUNKSIZE)
+                conn.send('0\r\n\r\n')
+            else:
+                conn.request(method, conn_url, **kwargs)
             resp = conn.getresponse()
         except socket.gaierror as e:
             message = "Error finding address for %(url)s: %(e)s" % locals()
@@ -201,6 +213,12 @@ class HTTPClient(object):
         kwargs.setdefault('headers', {})
         kwargs['headers'].setdefault('Content-Type',
                                      'application/octet-stream')
+        if 'body' in kwargs:
+            if (hasattr(kwargs['body'], 'read')
+                and method.lower() in ('post', 'put')):
+                # We use 'Transfer-Encoding: chunked' because
+                # body size may not always be known in advance.
+                kwargs['headers']['Transfer-Encoding'] = 'chunked'
         return self._http_request(url, method, **kwargs)
 
 

glanceclient/v1/images.py

@@ -177,10 +177,15 @@ class ImageManager(base.Manager):
                     # Illegal seek. This means the user is trying
                     # to pipe image data to the client, e.g.
                     # echo testdata | bin/glance add blah..., or
-                    # that stdin is empty
-                    return 0
+                    # that stdin is empty, or that a file-like
+                    # object which doesn't support 'seek/tell' has
+                    # been supplied.
+                    return None
                 else:
                     raise
+        else:
+            # Cannot determine size of input image
+            return None
 
     def create(self, **kwargs):
         """Create an image
@@ -190,10 +195,8 @@ class ImageManager(base.Manager):
         image_data = kwargs.pop('data', None)
         if image_data is not None:
             image_size = self._get_file_size(image_data)
-            if image_size != 0:
+            if image_size is not None:
                 kwargs.setdefault('size', image_size)
-            else:
-                image_data = None
 
         fields = {}
         for field in kwargs:
@@ -218,16 +221,13 @@ class ImageManager(base.Manager):
 
         TODO(bcwaldon): document accepted params
         """
-        hdrs = {}
         image_data = kwargs.pop('data', None)
         if image_data is not None:
             image_size = self._get_file_size(image_data)
-            if image_size != 0:
+            if image_size is not None:
                 kwargs.setdefault('size', image_size)
-                hdrs['Content-Length'] = image_size
-            else:
-                image_data = None
 
+        hdrs = {}
         try:
             purge_props = 'true' if kwargs.pop('purge_props') else 'false'
         except KeyError:

glanceclient/v1/shell.py

@@ -81,9 +81,20 @@ def _set_data_field(fields, args):
         if args.file:
             fields['data'] = open(args.file, 'rb')
         else:
-            if msvcrt:
-                msvcrt.setmode(sys.stdin.fileno(), os.O_BINARY)
-            fields['data'] = sys.stdin
+            # We distinguish between cases where image data is pipelined:
+            # (1) glance ... < /tmp/file or cat /tmp/file | glance ...
+            # and cases where no image data is provided:
+            # (2) glance ...
+            if (sys.stdin.isatty() is not True):
+                # Our input is from stdin, and we are part of
+                # a pipeline, so data may be present. (We are of
+                # type (1) above.)
+                if msvcrt:
+                    msvcrt.setmode(sys.stdin.fileno(), os.O_BINARY)
+                fields['data'] = sys.stdin
+            else:
+                # We are of type (2) above, no image data supplied
+                fields['data'] = None
 
 
 @utils.arg('id', metavar='<IMAGE_ID>', help='ID of image to describe.')

tests/v1/test_images.py

@@ -390,7 +390,7 @@ class ImageManagerTest(unittest.TestCase):
     def test_update_with_data(self):
         image_data = StringIO.StringIO('XXX')
         self.mgr.update('1', data=image_data)
-        expect_headers = {'x-image-meta-size': '3', 'Content-Length': 3}
+        expect_headers = {'x-image-meta-size': '3'}
         expect = [('PUT', '/v1/images/1', expect_headers, image_data)]
         self.assertEqual(self.api.calls, expect)