On Wed, Feb 08, 2023 at 02:17:12PM -0600, Eric Blake wrote: > On Wed, Feb 08, 2023 at 09:35:56AM +0000, Het Gala wrote: > > Existing 'migrate' QAPI design enforces transport mechanism, ip address > > of destination interface and corresponding port number in the form > > of a unified string 'uri' parameter for initiating a migration stream. > > This scheme has a significant flaw in it - double encoding of existing > > URIs to extract migration info. > > > > The current patch maps QAPI uri design onto well defined MigrateChannel > > struct. This modified QAPI helps in preventing multi-level uri > > encodings ('uri' parameter is kept for backward compatibility). > > > > Suggested-by: Daniel P. Berrange <berra...@redhat.com> > > Suggested-by: Manish Mishra <manish.mis...@nutanix.com> > > Suggested-by: Aravind Retnakaran <aravind.retnaka...@nutanix.com> > > Signed-off-by: Het Gala <het.g...@nutanix.com> > > --- > > qapi/migration.json | 131 +++++++++++++++++++++++++++++++++++++++++++- > > 1 file changed, 129 insertions(+), 2 deletions(-) > > > > diff --git a/qapi/migration.json b/qapi/migration.json > > index c84fa10e86..79acfcfe4e 100644 > > --- a/qapi/migration.json > > +++ b/qapi/migration.json > > @@ -1449,12 +1449,108 @@ > > ## > > { 'command': 'migrate-continue', 'data': {'state': 'MigrationStatus'} } > > > > +## > > +# @MigrateTransport: > > +# > > +# The supported communication transport mechanisms for migration > > +# > > +# @socket: Supported communication type between two devices for migration. > > +# Socket is able to cover all of 'tcp', 'unix', 'vsock' and > > +# 'fd' already > > +# > > +# @exec: Supported communication type to redirect migration stream into > > file. > > +# > > +# @rdma: Supported communication type to redirect rdma type migration > > stream. > > +# > > +# Since 8.0 > > +## > > +{ 'enum': 'MigrateTransport', > > + 'data': ['socket', 'exec', 'rdma'] } > > + > > +## > > +# @MigrateSocketAddr: > > +# > > +# To support different type of socket. > > +# > > +# @socket-type: Different type of socket connections. > > +# > > +# Since 8.0 > > +## > > +{ 'struct': 'MigrateSocketAddr', > > + 'data': {'socket-type': 'SocketAddress' } } > > Here, you use 'socket-type',... > > > + > > +## > > +# @MigrateExecAddr: > > + # > > + # Since 8.0 > > + ## > > +{ 'struct': 'MigrateExecAddr', > > + 'data' : {'data': ['str'] } } > > Inconsistent on whether you have a space before :. Most of our qapi > files prefer the layout: > > 'key': 'value' > > that is, no space before, one space after. It doesn't affect > correctness, but a consistent visual style is worth striving for. > > > + > > +## > > +# @MigrateRdmaAddr: > > +# > > +# Since 8.0 > > +## > > +{ 'struct': 'MigrateRdmaAddr', > > + 'data' : {'data': 'InetSocketAddress' } } > > ...while these branches supply everything else under 'data'. Also, > while you documented @socket-type above, you did not document @data in > either of these two types. [1] > > > + > > +## > > +# @MigrateAddress: > > +# > > +# The options available for communication transport mechanisms for > > migration > > +# > > +# Since 8.0 > > +## > > +{ 'union' : 'MigrateAddress', > > + 'base' : { 'transport' : 'MigrateTransport'}, > > + 'discriminator' : 'transport', > > + 'data' : { > > + 'socket' : 'MigrateSocketAddr', > > + 'exec' : 'MigrateExecAddr', > > + 'rdma': 'MigrateRdmaAddr' } } > > Another example of inconsistent spacing around :. > > I'm guessing the reason you didn't go with 'socket': 'SocketAddress' > is that SocketAddress is itself a discriminated union, and Markus does > not yet have the QAPI generator wired up to support one union as a > branch of another larger union? It leads to extra nesting on the wire > [2]
I don't know the backstory on this limitation. Is it something that is very difficult to resolve ? I think it is highly desirable to have 'socket': 'SocketAddress' here. It would be a shame to introduce this better migration API design and then have it complicated by a possibly short term limitation of QAPI. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|