go-ceph/cephfs/admin/volume.go
John Mulligan c4e1292da1 cephfs admin: add EnumerateVolumes function
The EnumerateVolumes function returns a list of Name & ID pairs,
to identify the file systems in the cluster. The enumeration is based
on `ceph fs dump` like JSON, but for implementation only. The dump
feature itself is not currently exported in a raw form.

Signed-off-by: John Mulligan <jmulligan@redhat.com>
2020-09-24 15:50:51 -04:00

70 lines
2.0 KiB
Go

// +build !luminous,!mimic
package admin
var (
listVolumesCmd = []byte(`{"prefix":"fs volume ls"}`)
dumpVolumesCmd = []byte(`{"prefix":"fs dump","format":"json"}`)
)
// ListVolumes return a list of volumes in this Ceph cluster.
//
// Similar To:
// ceph fs volume ls
func (fsa *FSAdmin) ListVolumes() ([]string, error) {
r, s, err := fsa.rawMgrCommand(listVolumesCmd)
return parseListNames(r, s, err)
}
// VolumeIdent contains a pair of file system identifying values: the volume
// name and the volume ID.
type VolumeIdent struct {
Name string
ID int64
}
type cephFileSystem struct {
ID int64 `json:"id"`
MDSMap struct {
FSName string `json:"fs_name"`
} `json:"mdsmap"`
}
type fsDump struct {
FileSystems []cephFileSystem `json:"filesystems"`
}
const (
dumpOkPrefix = "dumped fsmap epoch"
dumpOkLen = len(dumpOkPrefix)
)
func parseDumpToIdents(r []byte, s string, err error) ([]VolumeIdent, error) {
if len(s) >= dumpOkLen && s[:dumpOkLen] == dumpOkPrefix {
// Unhelpfully, ceph drops a status string on success responses for this
// call. this hacks around that by ignoring its typical prefix
s = ""
}
var dump fsDump
if err := unmarshalResponseJSON(r, s, err, &dump); err != nil {
return nil, err
}
// copy the dump json into the simpler enumeration list
idents := make([]VolumeIdent, len(dump.FileSystems))
for i := range dump.FileSystems {
idents[i].ID = dump.FileSystems[i].ID
idents[i].Name = dump.FileSystems[i].MDSMap.FSName
}
return idents, nil
}
// EnumerateVolumes returns a list of volume-name volume-id pairs.
func (fsa *FSAdmin) EnumerateVolumes() ([]VolumeIdent, error) {
// We base our enumeration on the ceph fs dump json. This may not be the
// only way to do it, but it's the only one I know of currently. Because of
// this and to keep our initial implementation simple, we expose our own
// simplified type only, rather do a partial implementation of dump.
r, s, err := fsa.rawMonCommand(dumpVolumesCmd)
return parseDumpToIdents(r, s, err)
}