docs/libmachine/host/migrate.go

128 lines
3.8 KiB
Go

package host
import (
"encoding/json"
"errors"
"fmt"
"path/filepath"
"github.com/docker/machine/drivers/none"
"github.com/docker/machine/libmachine/log"
"github.com/docker/machine/libmachine/version"
)
type RawDataDriver struct {
*none.Driver
data []byte // passed directly back when invoking json.Marshal on this type
}
func (r *RawDataDriver) MarshalJSON() ([]byte, error) {
// now marshal it back up
return r.data, nil
}
func getMigratedHostMetadata(data []byte) (*HostMetadata, error) {
// HostMetadata is for a "first pass" so we can then load the driver
var (
hostMetadata *HostMetadataV0
)
if err := json.Unmarshal(data, &hostMetadata); err != nil {
return &HostMetadata{}, err
}
migratedHostMetadata := MigrateHostMetadataV0ToHostMetadataV1(hostMetadata)
return migratedHostMetadata, nil
}
func MigrateHost(h *Host, data []byte) (*Host, bool, error) {
var (
migrationNeeded = false
migrationPerformed = false
hostV1 *HostV1
hostV2 *HostV2
)
migratedHostMetadata, err := getMigratedHostMetadata(data)
if err != nil {
return nil, false, err
}
globalStorePath := filepath.Dir(filepath.Dir(migratedHostMetadata.HostOptions.AuthOptions.StorePath))
driver := none.NewDriver(h.Name, globalStorePath)
if migratedHostMetadata.ConfigVersion > version.ConfigVersion {
return nil, false, errors.New("Config version is from the future, please upgrade your Docker Machine client.")
}
if migratedHostMetadata.ConfigVersion == version.ConfigVersion {
h.Driver = driver
if err := json.Unmarshal(data, &h); err != nil {
return nil, migrationPerformed, fmt.Errorf("Error unmarshalling most recent host version: %s", err)
}
// We are config version 3, so we definitely should have a
// RawDriver field. However, it's possible some might use
// older clients after already migrating, so check if it exists
// and create one if not. The following code is an (admittedly
// fragile) attempt to account for the fact that the above code
// to forbid loading from future clients was not introduced
// sooner.
if h.RawDriver == nil {
log.Warn("It looks like you have used an older Docker Machine binary to interact with hosts after using a 0.5.0 binary.")
log.Warn("Please be advised that doing so can result in erratic behavior due to migrated configuration settings.")
log.Warn("Machine will attempt to re-migrate the configuration settings, but safety is not guaranteed.")
migrationNeeded = true
// Treat the data as config version 1, even though it
// says "latest".
migratedHostMetadata.ConfigVersion = 1
}
} else {
migrationNeeded = true
}
if migrationNeeded {
migrationPerformed = true
for h.ConfigVersion = migratedHostMetadata.ConfigVersion; h.ConfigVersion < version.ConfigVersion; h.ConfigVersion++ {
log.Debugf("Migrating to config v%d", h.ConfigVersion)
switch h.ConfigVersion {
case 0:
hostV0 := &HostV0{
Driver: driver,
}
if err := json.Unmarshal(data, &hostV0); err != nil {
return nil, migrationPerformed, fmt.Errorf("Error unmarshalling host config version 0: %s", err)
}
hostV1 = MigrateHostV0ToHostV1(hostV0)
case 1:
if hostV1 == nil {
hostV1 = &HostV1{
Driver: driver,
}
if err := json.Unmarshal(data, &hostV1); err != nil {
return nil, migrationPerformed, fmt.Errorf("Error unmarshalling host config version 1: %s", err)
}
}
hostV2 = MigrateHostV1ToHostV2(hostV1)
case 2:
if hostV2 == nil {
hostV2 = &HostV2{
Driver: driver,
}
if err := json.Unmarshal(data, &hostV2); err != nil {
return nil, migrationPerformed, fmt.Errorf("Error unmarshalling host config version 2: %s", err)
}
}
h = MigrateHostV2ToHostV3(hostV2, data, globalStorePath)
h.Driver = RawDataDriver{driver, nil}
case 3:
}
}
}
return h, migrationPerformed, nil
}