[libvirt] [PATCH 14/7] snapshot: virsh shorthand for operating on current snap
Eric Blake
eblake at redhat.com
Thu Oct 6 23:41:11 UTC 2011
Rather than having to do:
$ virsh snapshot-revert dom $(virsh snapshot-current dom --name)
I thought it would be nice to do:
$ virsh snaphot-revert dom --current
I intentionally made it so that omitting both --current and a name
is an error (having the absence of a name imply --current seems
just a bit too magic, so --current must be explicit).
I didn't add 'virsh snapshot-dumpxml --current' since we already
have 'virsh snapshot-current' for the same task. All other
snapshot-* options that take a snapshotname now take --current in
its place; while keeping snapshot-edit backwards-compatible.
* tools/virsh.c (vshLookupSnapshot): New helper function.
(cmdSnapshotEdit, cmdSnapshotList, cmdSnapshotParent)
(cmdSnapshotDelete, cmdDomainSnapshotRevert): Use it, adding an
option where needed.
* tools/virsh.pod (snapshot-delete, snapshot-edit)
(snapshot-list, snapshot-parent, snapshot-revert): Document
use of --current.
(snapshot-dumpxml): Mention alternative.
---
Does not strictly depend on virDomainSnapshotNumChildren, other
than the fact that I'm touching 'virsh snapshot-list dom --from name'
to add 'virsh snapshot-list dom --current'; I could split that
change out from the rest of the patch if desired to get the ease-of-use
in the other snapshot-* commands before the new API is approved.
tools/virsh.c | 109 ++++++++++++++++++++++++++++++++++++-------------------
tools/virsh.pod | 31 ++++++++++------
2 files changed, 90 insertions(+), 50 deletions(-)
diff --git a/tools/virsh.c b/tools/virsh.c
index 86b230d..ea7b56b 100644
--- a/tools/virsh.c
+++ b/tools/virsh.c
@@ -12816,6 +12816,48 @@ cleanup:
return ret;
}
+/* Helper for resolving {--current | --ARG name} into a snapshot
+ * belonging to DOM. If EXCLUSIVE, fail if both --current and arg are
+ * present. On success, populate *SNAP, and if NAME is not NULL,
+ * *NAME, before returning 0. On failure, return -1 after issuing an
+ * error message. */
+static int
+vshLookupSnapshot(vshControl *ctl, const vshCmd *cmd,
+ const char *arg, bool exclusive, virDomainPtr dom,
+ virDomainSnapshotPtr *snap, const char **name)
+{
+ bool current = vshCommandOptBool(cmd, "current");
+ const char *snapname = NULL;
+
+ if (vshCommandOptString(cmd, arg, &snapname) < 0) {
+ vshError(ctl, _("invalid argument for --%s"), arg);
+ return -1;
+ }
+
+ if (exclusive && current && snapname) {
+ vshError(ctl, _("--%s and --current are mutually exclusive"), arg);
+ return -1;
+ }
+
+ if (snapname) {
+ *snap = virDomainSnapshotLookupByName(dom, snapname, 0);
+ } else if (current) {
+ *snap = virDomainSnapshotCurrent(dom, 0);
+ } else {
+ vshError(ctl, _("--%s or --current is required"), arg);
+ return -1;
+ }
+ if (!*snap) {
+ virshReportError(ctl);
+ return -1;
+ }
+
+ if (name && *snap)
+ *name = vshStrdup(ctl, virDomainSnapshotGetName(*snap));
+
+ return 0;
+}
+
/*
* "snapshot-edit" command
*/
@@ -12827,7 +12869,7 @@ static const vshCmdInfo info_snapshot_edit[] = {
static const vshCmdOptDef opts_snapshot_edit[] = {
{"domain", VSH_OT_DATA, VSH_OFLAG_REQ, N_("domain name, id or uuid")},
- {"snapshotname", VSH_OT_DATA, VSH_OFLAG_REQ, N_("snapshot name")},
+ {"snapshotname", VSH_OT_DATA, 0, N_("snapshot name")},
{"current", VSH_OT_BOOL, 0, N_("also set edited snapshot as current")},
{NULL, 0, 0, NULL}
};
@@ -12845,21 +12887,19 @@ cmdSnapshotEdit(vshControl *ctl, const vshCmd *cmd)
unsigned int getxml_flags = VIR_DOMAIN_XML_SECURE;
unsigned int define_flags = VIR_DOMAIN_SNAPSHOT_CREATE_REDEFINE;
- if (vshCommandOptBool(cmd, "current"))
+ if (vshCommandOptBool(cmd, "current") &&
+ vshCommandOptBool(cmd, "snapshotname"))
define_flags |= VIR_DOMAIN_SNAPSHOT_CREATE_CURRENT;
if (!vshConnectionUsability(ctl, ctl->conn))
return false;
- if (vshCommandOptString(cmd, "snapshotname", &name) <= 0)
- goto cleanup;
-
dom = vshCommandOptDomain(ctl, cmd, NULL);
if (dom == NULL)
goto cleanup;
- snapshot = virDomainSnapshotLookupByName(dom, name, 0);
- if (snapshot == NULL)
+ if (vshLookupSnapshot(ctl, cmd, "snapshotname", false, dom,
+ &snapshot, &name) < 0)
goto cleanup;
/* Get the XML configuration of the snapshot. */
@@ -13109,6 +13149,8 @@ static const vshCmdOptDef opts_snapshot_list[] = {
N_("list only snapshots that have metadata that would prevent undefine")},
{"tree", VSH_OT_BOOL, 0, N_("list snapshots in a tree")},
{"from", VSH_OT_DATA, 0, N_("limit list to children of given snapshot")},
+ {"current", VSH_OT_BOOL, 0,
+ N_("limit list to children of current snapshot")},
{"descendants", VSH_OT_BOOL, 0, N_("with --from, list all descendants")},
{NULL, 0, 0, NULL}
};
@@ -13142,10 +13184,17 @@ cmdSnapshotList(vshControl *ctl, const vshCmd *cmd)
int start_index = -1;
bool descendants = false;
- if (vshCommandOptString(cmd, "from", &from) < 0) {
- vshError(ctl, _("invalid from argument '%s'"), from);
+ if (!vshConnectionUsability(ctl, ctl->conn))
+ goto cleanup;
+
+ dom = vshCommandOptDomain(ctl, cmd, NULL);
+ if (dom == NULL)
+ goto cleanup;
+
+ if ((vshCommandOptBool(cmd, "from") ||
+ vshCommandOptBool(cmd, "current")) &&
+ vshLookupSnapshot(ctl, cmd, "from", true, dom, &start, &from) < 0)
goto cleanup;
- }
if (vshCommandOptBool(cmd, "parent")) {
if (vshCommandOptBool(cmd, "roots")) {
@@ -13176,18 +13225,8 @@ cmdSnapshotList(vshControl *ctl, const vshCmd *cmd)
flags |= VIR_DOMAIN_SNAPSHOT_LIST_METADATA;
}
- if (!vshConnectionUsability(ctl, ctl->conn))
- goto cleanup;
-
- dom = vshCommandOptDomain(ctl, cmd, NULL);
- if (dom == NULL)
- goto cleanup;
-
if (from) {
descendants = vshCommandOptBool(cmd, "descendants");
- start = virDomainSnapshotLookupByName(dom, from, 0);
- if (!start)
- goto cleanup;
if (descendants || tree) {
flags |= VIR_DOMAIN_SNAPSHOT_LIST_DESCENDANTS;
}
@@ -13519,7 +13558,8 @@ static const vshCmdInfo info_snapshot_parent[] = {
static const vshCmdOptDef opts_snapshot_parent[] = {
{"domain", VSH_OT_DATA, VSH_OFLAG_REQ, N_("domain name, id or uuid")},
- {"snapshotname", VSH_OT_DATA, VSH_OFLAG_REQ, N_("snapshot name")},
+ {"snapshotname", VSH_OT_DATA, 0, N_("find parent of snapshot name")},
+ {"current", VSH_OT_BOOL, 0, N_("find parent of current snapshot")},
{NULL, 0, 0, NULL}
};
@@ -13539,11 +13579,8 @@ cmdSnapshotParent(vshControl *ctl, const vshCmd *cmd)
if (dom == NULL)
goto cleanup;
- if (vshCommandOptString(cmd, "snapshotname", &name) <= 0)
- goto cleanup;
-
- snapshot = virDomainSnapshotLookupByName(dom, name, 0);
- if (snapshot == NULL)
+ if (vshLookupSnapshot(ctl, cmd, "snapshotname", true, dom,
+ &snapshot, &name) < 0)
goto cleanup;
if (vshGetSnapshotParent(ctl, snapshot, &parent) < 0)
@@ -13578,7 +13615,8 @@ static const vshCmdInfo info_snapshot_revert[] = {
static const vshCmdOptDef opts_snapshot_revert[] = {
{"domain", VSH_OT_DATA, VSH_OFLAG_REQ, N_("domain name, id or uuid")},
- {"snapshotname", VSH_OT_DATA, VSH_OFLAG_REQ, N_("snapshot name")},
+ {"snapshotname", VSH_OT_DATA, 0, N_("snapshot name")},
+ {"current", VSH_OT_BOOL, 0, N_("revert to current snapshot")},
{"running", VSH_OT_BOOL, 0, N_("after reverting, change state to running")},
{"paused", VSH_OT_BOOL, 0, N_("after reverting, change state to paused")},
{"force", VSH_OT_BOOL, 0, N_("try harder on risky reverts")},
@@ -13614,11 +13652,8 @@ cmdDomainSnapshotRevert(vshControl *ctl, const vshCmd *cmd)
if (dom == NULL)
goto cleanup;
- if (vshCommandOptString(cmd, "snapshotname", &name) <= 0)
- goto cleanup;
-
- snapshot = virDomainSnapshotLookupByName(dom, name, 0);
- if (snapshot == NULL)
+ if (vshLookupSnapshot(ctl, cmd, "snapshotname", true, dom,
+ &snapshot, &name) < 0)
goto cleanup;
result = virDomainRevertToSnapshot(snapshot, flags);
@@ -13654,7 +13689,8 @@ static const vshCmdInfo info_snapshot_delete[] = {
static const vshCmdOptDef opts_snapshot_delete[] = {
{"domain", VSH_OT_DATA, VSH_OFLAG_REQ, N_("domain name, id or uuid")},
- {"snapshotname", VSH_OT_DATA, VSH_OFLAG_REQ, N_("snapshot name")},
+ {"snapshotname", VSH_OT_DATA, 0, N_("snapshot name")},
+ {"current", VSH_OT_BOOL, 0, N_("delete current snapshot")},
{"children", VSH_OT_BOOL, 0, N_("delete snapshot and all children")},
{"children-only", VSH_OT_BOOL, 0, N_("delete children but not snapshot")},
{"metadata", VSH_OT_BOOL, 0,
@@ -13678,7 +13714,8 @@ cmdSnapshotDelete(vshControl *ctl, const vshCmd *cmd)
if (dom == NULL)
goto cleanup;
- if (vshCommandOptString(cmd, "snapshotname", &name) <= 0)
+ if (vshLookupSnapshot(ctl, cmd, "snapshotname", true, dom,
+ &snapshot, &name) < 0)
goto cleanup;
if (vshCommandOptBool(cmd, "children"))
@@ -13688,10 +13725,6 @@ cmdSnapshotDelete(vshControl *ctl, const vshCmd *cmd)
if (vshCommandOptBool(cmd, "metadata"))
flags |= VIR_DOMAIN_SNAPSHOT_DELETE_METADATA_ONLY;
- snapshot = virDomainSnapshotLookupByName(dom, name, 0);
- if (snapshot == NULL)
- goto cleanup;
-
/* XXX If we wanted, we could emulate DELETE_CHILDREN_ONLY even on
* older servers that reject the flag, by manually computing the
* list of descendants. But that's a lot of code to maintain. */
diff --git a/tools/virsh.pod b/tools/virsh.pod
index dd60a64..e1a9b86 100644
--- a/tools/virsh.pod
+++ b/tools/virsh.pod
@@ -1951,11 +1951,13 @@ the XML.
With I<snapshotname>, this is a request to make the existing named
snapshot become the current snapshot, without reverting the domain.
-=item B<snapshot-edit> I<domain> I<snapshotname> [I<--current>]
+=item B<snapshot-edit> I<domain> [I<snapshotname>] [I<--current>]
Edit the XML configuration file for I<snapshotname> of a domain. If
-I<--current> is specified, also force the edited snapshot to become
-the current snapshot.
+both I<snapshotname> and I<--current> are specified, also force the
+edited snapshot to become the current snapshot. If I<snapshotname>
+is omitted, then I<--current> must be supplied, to edit the current
+snapshot.
This is equivalent to:
@@ -1969,7 +1971,7 @@ The editor used can be supplied by the C<$VISUAL> or C<$EDITOR> environment
variables, and defaults to C<vi>.
=item B<snapshot-list> I<domain> [{I<--parent> | I<--roots> | I<--tree>}]
-[I<--metadata>] [[I<--from>] B<snapshot> [I<--descendants>]]
+[I<--metadata>] [{[I<--from>] B<snapshot> | I<--current>} [I<--descendants>]]
List all of the available snapshots for the given domain, defaulting
to show columns for the snapshot name, creation time, and domain state.
@@ -1981,7 +1983,8 @@ If I<--tree> is specified, the output will be in a tree format, listing
just snapshot names. These three options are mutually exclusive.
If I<--from> is provided, filter the list to snapshots which are
-children of the given B<snapshot>. When used in isolation or with
+children of the given B<snapshot>; or if I<--current> is provided,
+start at the current snapshot. When used in isolation or with
I<--parent>, the list is limited to direct children unless
I<--descendants> is also present. When used with I<--tree>, the
use of I<--descendants> is implied. This option is not compatible
@@ -1996,15 +1999,18 @@ a transient domain.
Output the snapshot XML for the domain's snapshot named I<snapshot>.
Using I<--security-info> will also include security sensitive information.
+Use B<snapshot-current> to easily access the XML of the current snapshot.
-=item B<snapshot-parent> I<domain> I<snapshot>
+=item B<snapshot-parent> I<domain> {I<snapshot> | I<--current>}
-Output the name of the parent snapshot for the given I<snapshot>, if any.
+Output the name of the parent snapshot, if any, for the given
+I<snapshot>, or for the current snapshot with I<--current>.
-=item B<snapshot-revert> I<domain> I<snapshot> [{I<--running> | I<--paused>}]
-[I<--force>]
+=item B<snapshot-revert> I<domain> {I<snapshot> | I<--current>}
+[{I<--running> | I<--paused>}] [I<--force>]
-Revert the given domain to the snapshot specified by I<snapshot>. Be aware
+Revert the given domain to the snapshot specified by I<snapshot>, or to
+the current snapshot with I<--current>. Be aware
that this is a destructive action; any changes in the domain since the last
snapshot was taken will be lost. Also note that the state of the domain after
snapshot-revert is complete will be the state of the domain at the time
@@ -2034,10 +2040,11 @@ snapshot that uses a provably incompatible configuration, as well as
with an inactive snapshot that is combined with the I<--start> or
I<--pause> flag.
-=item B<snapshot-delete> I<domain> I<snapshot> [I<--metadata>]
+=item B<snapshot-delete> I<domain> {I<snapshot> | I<--current>} [I<--metadata>]
[{I<--children> | I<--children-only>}]
-Delete the snapshot for the domain named I<snapshot>. If this snapshot
+Delete the snapshot for the domain named I<snapshot>, or the current
+snapshot with I<--current>. If this snapshot
has child snapshots, changes from this snapshot will be merged into the
children. If I<--children> is passed, then delete this snapshot and any
children of this snapshot. If I<--children-only> is passed, then delete
--
1.7.4.4
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