Avi Kivity <a...@redhat.com> writes:
> On 06/04/2010 05:16 PM, Markus Armbruster wrote:
>> - "protocol": json-array of json-object
>> Each element object has a member "name"
>> - Possible values: "file", "nbd", ...
>> Additional members depend on the value of "name".
>> For "name" = "file":
>> - "file": file name (json-string)
>> For "name" = "nbd":
>> - "domain": address family (json-string, optional)
>> - Possible values: "inet" (default), "unix"
>> - "file": file name (json-string), only with "domain" = "unix"
>> - "host": host name (json-string), only with "domain" = "inet"
>> - "port": port (json-int), only with "domain" = "inet"
>> ...
>>
>>
>
> This loses the nesting that protocols have. I'd like to see the each
> nested protocol as member of the parent protocol. Besides the lovely
> } } }s in the json representation, this allows us to have more
> complicated protocols, for example a mirror protocol that has two
> child protocol each specifying a different backing store.
Even though we don't have such a protocol yet, not even plans to get it,
your argument tips the balance towards nesting.
Revised sketch: instead of
- "file": the disk image file to use (json-string, optional)
- "format": disk format (json-string, optional)
- Possible values: "raw", "qcow2", ...
have
- "format": image format (json-string, optional)
- Possible values: "raw", "qcow2", [...]
- "protocol": image access protocol (json-object)
- It has a member "name" (json-string), and depending on its value
additional members.
- For "name" = "auto", "file", [...]
- "file": name of image file (json-string)
- For "name" = "nbd":
- "domain": address family (json-string, optional)
- Possible values: "inet" (default), "unix"
- "file": name of socket file (json-string), only with "domain" =
"unix"
- "host": host name (json-string), only with "domain" = "inet"
- "port": port (json-int), only with "domain" = "inet"
- For "name" = "blkdebug":
- "config": name of config file (json-string)
- "protocol": image access protocol (json-object), as above
[...]
Examples:
* Format "qcow2", protocol "auto" with argument filename "foo.img"
"format": "qcow2",
"protocol": { "name": "auto", "file": "foo.qcow2" }
* Format "raw", protocol "nbd" with arguments domain "unix", filename
"/tmp/my_socket"
"format": "raw"
"protocol": { "name": "nbd", "domain": "unix", "file": "/tmp/my_socket" }
* Format not specified (system guesses one), protocol "blkdebug" with
argument filename "/tmp/blkdebug.cfg" stacked onto protocol "fat" with
arguments floppy true, dirname "/tmp/dir"
"protocol": { "name": "blkdebug", "file": "/tmp/blkdebug.cfg",
"protocol": { "name": "fat", "floppy": true, "dir": "/tmp/dir" }
}
This nesting business is easy enough for QMP, but it'll be awkward on
the command line. Ideas on how to do it cleanly with -blockdev?
