// TODO(vmarmol): Deprecate over time as old Dockers are phased out.
func ReadConfig(dockerRoot, dockerRun, containerID string) (*configs.Config, error) {
// Try using the new config if it is available.
configPath := configPath(dockerRun, containerID)
if utils.FileExists(configPath) {
out, err := ioutil.ReadFile(configPath)
if err != nil {
return nil, err
}
var state libcontainer.State
err = json.Unmarshal(out, &state)
if err != nil {
glog.Errorf("Unmarshal failure for: \n\n%v\n", string(out))
return nil, err
}
return &state.Config, nil
}
// Fallback to reading the old config which is comprised of the state and config files.
oldConfigPath := oldConfigPath(dockerRoot, containerID)
out, err := ioutil.ReadFile(oldConfigPath)
if err != nil {
glog.Errorf("Unmarshal failure for: \n\n%v\n", string(out))
return nil, err
}
// Try reading the preAPIConfig.
var config preAPIConfig
err = json.Unmarshal(out, &config)
if err != nil {
// Try to parse the old pre-API config. The main difference is that namespaces used to be a map, now it is a slice of structs.
// The JSON marshaler will use the non-nested field before the nested one.
type oldLibcontainerConfig struct {
preAPIConfig
OldNamespaces map[string]bool `json:"namespaces,omitempty"`
}
var oldConfig oldLibcontainerConfig
err2 := json.Unmarshal(out, &oldConfig)
if err2 != nil {
// Use original error.
return nil, err
}
// Translate the old pre-API config into the new config.
config = oldConfig.preAPIConfig
for ns := range oldConfig.OldNamespaces {
config.Namespaces = append(config.Namespaces, configs.Namespace{
Type: configs.NamespaceType(ns),
})
}
}
// Read the old state file as well.
state, err := readState(dockerRoot, containerID)
if err != nil {
return nil, err
}
// Convert preAPIConfig + old state file to Config.
// This only converts some of the fields, the ones we use.
// You may need to add fields if the one you're interested in is not available.
var result configs.Config
result.Cgroups = new(configs.Cgroup)
result.Rootfs = config.RootFs
result.Hostname = config.Hostname
result.Namespaces = config.Namespaces
result.Capabilities = config.Capabilities
for _, net := range config.Networks {
n := &configs.Network{
Name: state.NetworkState.VethChild,
Bridge: net.Bridge,
MacAddress: net.MacAddress,
Address: net.Address,
Gateway: net.Gateway,
IPv6Address: net.IPv6Address,
IPv6Gateway: net.IPv6Gateway,
HostInterfaceName: state.NetworkState.VethHost,
}
result.Networks = append(result.Networks, n)
}
result.Routes = config.Routes
if config.Cgroups != nil {
result.Cgroups = config.Cgroups
}
return &result, nil
}