Merge pull request #85 from thaJeztah/18.09_backport_deprecated_storagedrivers

[18.09 backport] deprecate legacy "overlay", and "devicemapper" storage drivers 
Upstream-commit: 7a566c0e4a98ec9960b5312e806ab546203dff15
Component: engine

components/engine/daemon/graphdriver/driver.go

@@ -195,6 +195,7 @@ type Options struct {
 func New(name string, pg plugingetter.PluginGetter, config Options) (Driver, error) {
 	if name != "" {
 		logrus.Debugf("[graphdriver] trying provided driver: %s", name) // so the logs show specified driver
+		logDeprecatedWarning(name)
 		return GetDriver(name, pg, config)
 	}
 
@@ -232,6 +233,7 @@ func New(name string, pg plugingetter.PluginGetter, config Options) (Driver, err
 			}
 
 			logrus.Infof("[graphdriver] using prior storage driver: %s", name)
+			logDeprecatedWarning(name)
 			return driver, nil
 		}
 	}
@@ -245,6 +247,7 @@ func New(name string, pg plugingetter.PluginGetter, config Options) (Driver, err
 			}
 			return nil, err
 		}
+		logDeprecatedWarning(name)
 		return driver, nil
 	}
 
@@ -257,6 +260,7 @@ func New(name string, pg plugingetter.PluginGetter, config Options) (Driver, err
 			}
 			return nil, err
 		}
+		logDeprecatedWarning(name)
 		return driver, nil
 	}
 	return nil, fmt.Errorf("No supported storage backend found")
@@ -305,3 +309,20 @@ func isEmptyDir(name string) bool {
 	}
 	return false
 }
+
+// isDeprecated checks if a storage-driver is marked "deprecated"
+func isDeprecated(name string) bool {
+	switch name {
+	// NOTE: when deprecating a driver, update daemon.fillDriverInfo() accordingly
+	case "devicemapper", "overlay":
+		return true
+	}
+	return false
+}
+
+// logDeprecatedWarning logs a warning if the given storage-driver is marked "deprecated"
+func logDeprecatedWarning(name string) {
+	if isDeprecated(name) {
+		logrus.Warnf("[graphdriver] WARNING: the %s storage-driver is deprecated, and will be removed in a future release", name)
+	}
+}

components/engine/daemon/info.go

@@ -131,6 +131,10 @@ func (daemon *Daemon) fillDriverInfo(v *types.Info) {
 		if len(daemon.graphDrivers) > 1 {
 			drivers += fmt.Sprintf(" (%s) ", os)
 		}
+		switch gd {
+		case "devicemapper", "overlay":
+			v.Warnings = append(v.Warnings, fmt.Sprintf("WARNING: the %s storage-driver is deprecated, and will be removed in a future release.", gd))
+		}
 	}
 	drivers = strings.TrimSpace(drivers)