Re: [libvirt] [RFC]: Snapshot API v2

Based on discussion, I've modified the snapshot API to the below.  I've incorporated most of the semantic changes we talked about; the renaming of various API calls I've left for later, since it is a minor point. More comments welcome! /* NOTE: struct _virDomainSnapshot is a private structure, ala  * struct _virDomain.  */ typedef struct _virDomainSnapshot virDomainSnapshot; /* Take a snapshot of the current VM state.  Throws an error if  * the VM is not currently running */ virDomainSnapshotPtr virDomainSnapshotCreateXML(virDomainPtr domain,                                                const char *xmlDesc,                                                unsigned int flags); /* Dump the XML of a snapshot */ /* NOTE: see below for proposed XML */ char *virDomainSnapshotGetXMLDesc(virDomainSnapshotPtr snapshot,                                  unsigned int flags); /* Return the number of snapshots for this domain */ int virDomainSnapshotNum(virDomainPtr domain, unsigned int flags); /* Get the names of all snapshots for this domain */ int virDomainListSnapshotNames(virDomainPtr domain, char **names, int nameslen,                               unsigned int flags); /* Get a handle to a named snapshot */ virDomainSnapshotPtr virDomainSnapshotLookupByName(virDomainPtr domain,                                                   const char *name,                                                   unsigned int flags); /* Start the guest "domain" from the snapshot "snapshot" */ int virDomainCreateWithSnapshot(virDomainPtr domain,                                virDomainSnapshotPtr snapshot,                                unsigned int flags); /* Deactivate a snapshot - with no flags, the snapshot is not used anymore,  * but also not removed.  With a MERGE flag, it merges the snapshot into  * the parent snapshot (or the base image, if there is no parent snapshot).  * Note that if other snapshots would be discarded because of this  * MERGE action, this operation will fail.  If that is really what is intended,  * use MERGE_FORCE.  *  * With a DISCARD flag, it deletes the snapshot.  Note that if other snapshots  * would be discarded because of this delete action, this operation will  * fail.  If this is really what is intended, use DISCARD_FORCE.  *  * MERGE, MERGE_FORCE, DISCARD, and DISCARD_FORCE are mutually-exclusive.  *  * Note that this operation can generally only happen when the domain is shut  * down, though this is hypervisor-specific */ typedef enum {    VIR_DOMAIN_SNAPSHOT_DEACTIVATE_MERGE,    VIR_DOMAIN_SNAPSHOT_DEACTIVATE_MERGE_FORCE,    VIR_DOMAIN_SNAPSHOT_DEACTIVATE_DISCARD,    VIR_DOMAIN_SNAPSHOT_DEACTIVATE_DISCARD_FORCE, } virDomainSnapshotDeactivate; int virDomainSnapshotDeactivate(virDomainSnapshotPtr snapshot,                                unsigned int flags); int virDomainSnapshotFree(virDomainSnapshotPtr snapshot); NOTE: During snapshot creation, *none* of the fields are required.  That is, you can call virDomainSnapshotCreateXML() with an XML of "<domainsnapshot/>". In this case, the individual driver will make up a <name> for you, the <creationdate> will be set to the current time+date, <description> will be empty, <state> will be "off", <compression> will be empty, and <parent> will be set to the current snapshot (if any).  If you do want to specify some fields during virDomainSnapshotCreateXML(), note that the only ones that are settable are <name>, <description>, and <compression>; the rest are ignored, and filled in by the driver when the snapshot is actually created. NOTE: <compression> is used to compress snapshots, and may or may not be supported by individual hypervisor implementations.  If <compression> is specified and the underlying hypervisor does not support it, an error will be thrown. <domainsnapshot>   <name>XYZ</name>   <creationdate>...</creationdate>   <description>...</description>   <state>RUNNING</state>   <domain>      <uuid>XXXXX-XXXX-XXXX-XXXX-XXXXXXXXX</uuid>   </domain>   <compression>gzip</compression>   <parent>     <name>ABC</name>   </parent> </domainsnapshot> The virsh commands will be: virsh snapshot-create [--compress] <dom> <xmlfile> virsh snapshot-list <dom> virsh snapshot-dumpxml <dom> <name> virsh create-with-snapshot <dom> <snapshotname>

virsh snapshot-deactivate <dom> <snapshotname> [--merge|--delete|--mergeforce|--mergedelete] -- Chris Lalancette