Merge lp:~rackspace-titan/nova/glance_xen_plugin_preserve_headers into lp:~hudson-openstack/nova/trunk

[Dan Prince]

Updates to the XenServer glance plugin so that it obtains the set of
existing headers and sends them along with the request to PUT a
snapshotted image into glance.

[Rick Harris (rconradharris)]

Looks good, thanks for the fix Dan.

Aside:

It's really too bad we have to do this. We're planning to decouple the API from the Registry so that the API will no longer have to handle metadata.

Perhaps in that effort we can have the Registry use the "PATCH" HTTP method so we don't have to pass back the entire metadata structure; instead, we'd only pass the metadata items that were changing.

review: Approve

[Dan Prince (dan-prince)]

Agreed. We've also talked about a sub-resource to manage the registry metadata. In any case the metadata/properties are currently a bit overloaded in the existing implementation. Using headers to maintain the metadata is nice in that its lightweight but it leaves some things to be desired with regard to maintenance of the metadata/properties of images.

[Brian Waldon (bcwaldon)]

Awesome.

review: Approve

=== modified file 'plugins/xenserver/xenapi/etc/xapi.d/plugins/glance'
--- plugins/xenserver/xenapi/etc/xapi.d/plugins/glance	2011-07-27 18:13:04 +0000
+++ plugins/xenserver/xenapi/etc/xapi.d/plugins/glance	2011-08-04 14:45:51 +0000
@@ -248,6 +248,19 @@
     using chunked-transfer-encoded HTTP.
     """
     conn = httplib.HTTPConnection(glance_host, glance_port)
+
+    # NOTE(dprince): We need to resend any existing Glance meta/property
+    # headers so they are preserved in Glance. We obtain them here with a
+    # HEAD request.
+    conn.request('HEAD', '/v1/images/%s' % image_id)
+    resp = conn.getresponse()
+    if resp.status != httplib.OK:
+        raise Exception("Unexpected response from Glance %i" % resp.status)
+    headers = {}
+    for header, value in resp.getheaders():
+        if header.lower().startswith("x-image-meta-property-"):
+            headers[header.lower()] = value
+
     # NOTE(sirp): httplib under python2.4 won't accept a file-like object
     # to request
     conn.putrequest('PUT', '/v1/images/%s' % image_id)
@@ -260,7 +273,7 @@
     #   2. We're currently uploading a vanilla tarball. In order to be OVF/OVA
     #      compliant, we'll need to embed a minimal OVF manifest as the first
     #      file.
-    headers = {
+    ovf_headers = {
         'content-type': 'application/octet-stream',
         'transfer-encoding': 'chunked',
         'x-image-meta-is-public': 'True',
@@ -271,7 +284,9 @@
 
     # If we have an auth_token, set an x-auth-token header
     if auth_token:
-        headers['x-auth-token'] = auth_token
+        ovf_headers['x-auth-token'] = auth_token
+
+    headers.update(ovf_headers)
 
     for header, value in headers.iteritems():
         conn.putheader(header, value)