/*
Copyright 2016 The Rook Authors. All rights reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

	http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package osd

import (
	"fmt"
	"os"
	"os/signal"
	"path/filepath"
	"regexp"
	"strings"
	"syscall"

	"github.com/coreos/pkg/capnslog"
	"github.com/pkg/errors"
	"github.com/rook/rook/pkg/clusterd"
	"github.com/rook/rook/pkg/daemon/ceph/client"
	oposd "github.com/rook/rook/pkg/operator/ceph/cluster/osd"
	"github.com/rook/rook/pkg/util/sys"
)

const (
	pvcDataTypeDevice     = "data"
	pvcMetadataTypeDevice = "metadata"
	pvcWalTypeDevice      = "wal"
	lvmCommandToCheck     = "lvm"
)

var (
	logger = capnslog.NewPackageLogger("github.com/rook/rook", "cephosd")
)

// StartOSD starts an OSD on a device that was provisioned by ceph-volume
func StartOSD(context *clusterd.Context, osdType, osdID, osdUUID, lvPath string, pvcBackedOSD, lvBackedPV bool, cephArgs []string) error {

	// ensure the config mount point exists
	configDir := fmt.Sprintf("/var/lib/ceph/osd/ceph-%s", osdID)
	err := os.Mkdir(configDir, 0750)
	if err != nil {
		logger.Errorf("failed to create config dir %q. %v", configDir, err)
	}

	// Update LVM config at runtime
	if err := UpdateLVMConfig(context, pvcBackedOSD, lvBackedPV); err != nil {
		return errors.Wrap(err, "failed to update lvm configuration file") // fail return here as validation provided by ceph-volume
	}

	var volumeGroupName string
	if pvcBackedOSD && !lvBackedPV {
		volumeGroupName := getVolumeGroupName(lvPath)
		if volumeGroupName == "" {
			return errors.Wrapf(err, "error fetching volume group name for OSD %q", osdID)
		}

		go handleTerminate(context, lvPath, volumeGroupName)

		// It's fine to continue if deactivate fails since we will return error if activate fails
		if op, err := context.Executor.ExecuteCommandWithCombinedOutput("vgchange", "-an", "-vv", volumeGroupName); err != nil {
			logger.Errorf("failed to deactivate volume group for lv %q. output: %s. %v", lvPath, op, err)
			return nil
		}

		if op, err := context.Executor.ExecuteCommandWithCombinedOutput("vgchange", "-ay", "-vv", volumeGroupName); err != nil {
			return errors.Wrapf(err, "failed to activate volume group for lv %q. output: %s", lvPath, op)
		}
	}

	// activate the osd with ceph-volume
	storeFlag := "--" + osdType
	if err := context.Executor.ExecuteCommand("stdbuf", "-oL", "ceph-volume", "lvm", "activate", "--no-systemd", storeFlag, osdID, osdUUID); err != nil {
		return errors.Wrap(err, "failed to activate osd")
	}

	// run the ceph-osd daemon
	if err := context.Executor.ExecuteCommand("ceph-osd", cephArgs...); err != nil {
		// Instead of returning, we want to allow the lvm release to happen below, so we just log the err
		logger.Errorf("failed to start osd or shutting down. %v", err)
	}

	if pvcBackedOSD && !lvBackedPV {
		if err := releaseLVMDevice(context, volumeGroupName); err != nil {
			// Let's just report the error and not fail as a best-effort since some drivers will force detach anyway
			// Failing to release the device does not means the detach will fail so let's proceed
			logger.Errorf("failed to release device from lvm. %v", err)
			return nil
		}
	}

	return nil
}

func handleTerminate(context *clusterd.Context, lvPath, volumeGroupName string) {
	sigc := make(chan os.Signal, 1)
	signal.Notify(sigc, syscall.SIGTERM)

	<-sigc
	logger.Infof("shutdown signal received, exiting...")
	err := killCephOSDProcess(context, lvPath)
	if err != nil {
		logger.Errorf("failed to kill ceph-osd process. %v", err)
	}
}

func killCephOSDProcess(context *clusterd.Context, lvPath string) error {

	pid, err := context.Executor.ExecuteCommandWithOutput("fuser", "-a", lvPath)
	if err != nil {
		return errors.Wrapf(err, "failed to retrieve process ID for %q", lvPath)
	}

	logger.Infof("process ID for ceph-osd: %s", pid)

	// shut down the osd-ceph process so that lvm release does not show device in use error.
	if pid != "" {
		if err := context.Executor.ExecuteCommand("kill", pid); err != nil {
			return errors.Wrap(err, "failed to kill ceph-osd process")
		}
	}

	return nil
}

func configRawDevice(name string, context *clusterd.Context) (*sys.LocalDisk, error) {
	rawDevice, err := clusterd.PopulateDeviceInfo(name, context.Executor)
	if err != nil {
		return nil, errors.Wrapf(err, "failed to get device info for %q", name)
	}

	// set the device type: data, block_db(metadata) or wal.
	if strings.HasPrefix(name, "/mnt") {
		rawDevice, err = clusterd.PopulateDeviceUdevInfo(rawDevice.KernelName, context.Executor, rawDevice)
		if err != nil {
			logger.Warningf("failed to get udev info for device %q. %v", name, err)
		}
		rawDevice.Type = pvcDataTypeDevice
	} else if strings.HasPrefix(name, "/srv") {
		rawDevice.Type = pvcMetadataTypeDevice
	} else if strings.HasPrefix(name, "/wal") {
		rawDevice.Type = pvcWalTypeDevice
	}

	return rawDevice, nil
}

// Provision provisions an OSD
func Provision(context *clusterd.Context, agent *OsdAgent, crushLocation, topologyAffinity string) error {
	if agent.pvcBacked {
		// Init KMS store, retrieve the KEK and store it as an env var for ceph-volume
		err := setKEKinEnv(context, agent.clusterInfo)
		if err != nil {
			return errors.Wrap(err, "failed to set kek as an environment variable")
		}
	}

	// Print dmsetup version
	err := dmsetupVersion(context)
	if err != nil {
		return errors.Wrap(err, "failed to print device mapper version")
	}

	// set the initial orchestration status
	status := oposd.OrchestrationStatus{Status: oposd.OrchestrationStatusOrchestrating}
	oposd.UpdateNodeOrPVCStatus(agent.kv, agent.nodeName, status)

	if err := client.WriteCephConfig(context, agent.clusterInfo); err != nil {
		return errors.Wrap(err, "failed to generate ceph config")
	}

	logger.Infof("discovering hardware")

	var rawDevices []*sys.LocalDisk
	if agent.pvcBacked {
		for i := range agent.devices {
			rawDevice, err := configRawDevice(agent.devices[i].Name, context)
			if err != nil {
				return err
			}

			rawDevices = append(rawDevices, rawDevice)
		}
	} else {
		// We still need to use 'lsblk' as the underlying way to discover devices
		// Ideally, we would use the "ceph-volume inventory" command instead
		// However, it suffers from some limitation such as exposing available partitions and LVs
		// See: https://tracker.ceph.com/issues/43579
		rawDevices, err = clusterd.DiscoverDevices(context.Executor)
		if err != nil {
			return errors.Wrap(err, "failed initial hardware discovery")
		}
	}

	context.Devices = rawDevices

	logger.Info("creating and starting the osds")

	// determine the set of devices that can/should be used for OSDs.
	devices, err := getAvailableDevices(context, agent)
	if err != nil {
		return errors.Wrap(err, "failed to get available devices")
	}

	// orchestration is about to start, update the status
	status = oposd.OrchestrationStatus{Status: oposd.OrchestrationStatusOrchestrating, PvcBackedOSD: agent.pvcBacked}
	oposd.UpdateNodeOrPVCStatus(agent.kv, agent.nodeName, status)

	// start the desired OSDs on devices
	logger.Infof("configuring osd devices: %+v", devices)

	deviceOSDs, err := agent.configureCVDevices(context, devices)
	if err != nil {
		return errors.Wrap(err, "failed to configure devices")
	}

	// Let's fail if no OSDs were configured
	// This likely means the filter for available devices passed (in PVC case)
	// but the resulting device was already configured for another cluster (disk not wiped and leftover)
	// So we need to make sure the list is filled up, otherwise fail
	if len(deviceOSDs) == 0 {
		logger.Warningf("skipping OSD configuration as no devices matched the storage settings for this node %q", agent.nodeName)
		status = oposd.OrchestrationStatus{OSDs: deviceOSDs, Status: oposd.OrchestrationStatusCompleted, PvcBackedOSD: agent.pvcBacked}
		oposd.UpdateNodeOrPVCStatus(agent.kv, agent.nodeName, status)
		return nil
	}

	// Populate CRUSH location for each OSD on the host
	for i := range deviceOSDs {
		deviceOSDs[i].Location = crushLocation
		deviceOSDs[i].TopologyAffinity = topologyAffinity
	}

	logger.Infof("devices = %+v", deviceOSDs)

	// Since we are done configuring the PVC we need to release it from LVM
	// If we don't do this, the device will remain hold by LVM and we won't be able to detach it
	// When running on PVC, the device is:
	//  * attached on the prepare pod
	//  * osd is mkfs
	//  * detached from the prepare pod
	//  * attached to the activate pod
	//  * then the OSD runs
	if agent.pvcBacked && !deviceOSDs[0].SkipLVRelease && !deviceOSDs[0].LVBackedPV {
		// Try to discover the VG of that LV
		volumeGroupName := getVolumeGroupName(deviceOSDs[0].BlockPath)

		// If empty the osd is using the ceph-volume raw mode
		// so it's consumming a raw block device and LVM is not used
		// so there is nothing to de-activate
		if volumeGroupName != "" {
			if err := releaseLVMDevice(context, volumeGroupName); err != nil {
				return errors.Wrap(err, "failed to release device from lvm")
			}
		} else {
			// TODO
			// don't assume this and run a bluestore check on the device to be sure?
			logger.Infof("ceph-volume raw mode used by block %q, no VG to de-activate", deviceOSDs[0].BlockPath)
		}
	}

	// orchestration is completed, update the status
	status = oposd.OrchestrationStatus{OSDs: deviceOSDs, Status: oposd.OrchestrationStatusCompleted, PvcBackedOSD: agent.pvcBacked}
	oposd.UpdateNodeOrPVCStatus(agent.kv, agent.nodeName, status)

	return nil
}

func getAvailableDevices(context *clusterd.Context, agent *OsdAgent) (*DeviceOsdMapping, error) {
	desiredDevices := agent.devices
	logger.Debugf("desiredDevices are %+v", desiredDevices)

	logger.Debug("context.Devices are:")
	for _, disk := range context.Devices {
		logger.Debugf("%+v", disk)
	}

	available := &DeviceOsdMapping{Entries: map[string]*DeviceOsdIDEntry{}}
	for _, device := range context.Devices {
		// Ignore 'dm' device since they are not handled by c-v properly
		// see: https://tracker.ceph.com/issues/43209
		if strings.HasPrefix(device.Name, sys.DeviceMapperPrefix) && device.Type == sys.LVMType {
			logger.Infof("skipping 'dm' device %q", device.Name)
			continue
		}

		// Ignore device with filesystem signature since c-v inventory
		// cannot detect that correctly
		// see: https://tracker.ceph.com/issues/43585
		if device.Filesystem != "" {
			// Allow further inspection of that device before skipping it
			if device.Filesystem == "crypto_LUKS" && agent.pvcBacked {
				if isCephEncryptedBlock(context, agent.clusterInfo.FSID, device.Name) {
					logger.Infof("encrypted disk %q is an OSD part of this cluster, considering it", device.Name)
				}
			} else {
				logger.Infof("skipping device %q because it contains a filesystem %q", device.Name, device.Filesystem)
				continue
			}
		}

		if device.Type == sys.PartType {
			device, err := clusterd.PopulateDeviceUdevInfo(device.Name, context.Executor, device)
			if err != nil {
				logger.Errorf("failed to get udev info of partition %q. %v", device.Name, err)
				continue
			}
		}

		// Check if the desired device is available
		//
		// We need to use the /dev path, provided by the NAME property from "lsblk --paths",
		// especially when running on PVC and/or on dm device
		// When running on PVC we use the real device name instead of the Kubernetes mountpoint
		// When running on dm device we use the dm device name like "/dev/mapper/foo" instead of "/dev/dm-1"
		// Otherwise ceph-volume inventory will fail on the udevadm check
		// udevadm does not support device path different than /dev or /sys
		//
		// So earlier lsblk extracted the '/dev' path, hence the device.Name property
		// device.Name can be 'xvdca', later this is formatted to '/dev/xvdca'
		var err error
		var isAvailable bool
		rejectedReason := ""
		if agent.pvcBacked {
			block := fmt.Sprintf("/mnt/%s", agent.nodeName)
			rawOsds, err := GetCephVolumeRawOSDs(context, agent.clusterInfo, agent.clusterInfo.FSID, block, agent.metadataDevice, "", false, true)
			if err != nil {
				isAvailable = false
				rejectedReason = fmt.Sprintf("failed to detect if there is already an osd. %v", err)
			} else if len(rawOsds) > 0 {
				isAvailable = false
				rejectedReason = "already in use by a raw OSD, no need to reconfigure"
			} else {
				isAvailable = true
			}
		} else {
			isAvailable, rejectedReason, err = sys.CheckIfDeviceAvailable(context.Executor, device.RealPath, agent.pvcBacked)
			if err != nil {
				isAvailable = false
				rejectedReason = fmt.Sprintf("failed to check if the device %q is available. %v", device.Name, err)
			}
		}

		if !isAvailable {
			logger.Infof("skipping device %q: %s.", device.Name, rejectedReason)
			continue
		} else {
			logger.Infof("device %q is available.", device.Name)
		}

		var deviceInfo *DeviceOsdIDEntry
		if agent.metadataDevice != "" && agent.metadataDevice == device.Name {
			// current device is desired as the metadata device
			deviceInfo = &DeviceOsdIDEntry{Data: unassignedOSDID, Metadata: []int{}, DeviceInfo: device}
		} else if len(desiredDevices) == 1 && desiredDevices[0].Name == "all" {
			// user has specified all devices, use the current one for data
			deviceInfo = &DeviceOsdIDEntry{Data: unassignedOSDID, DeviceInfo: device}
		} else if len(desiredDevices) > 0 {
			var matched bool
			var matchedDevice DesiredDevice
			for _, desiredDevice := range desiredDevices {
				if desiredDevice.IsFilter {
					// the desired devices is a regular expression
					matched, err = regexp.Match(desiredDevice.Name, []byte(device.Name))
					if err != nil {
						logger.Errorf("regex failed on device %q and filter %q. %v", device.Name, desiredDevice.Name, err)
						continue
					}

					if matched {
						logger.Infof("device %q matches device filter %q", device.Name, desiredDevice.Name)
					}
				} else if desiredDevice.IsDevicePathFilter {
					pathnames := append(strings.Fields(device.DevLinks), filepath.Join("/dev", device.Name))
					for _, pathname := range pathnames {
						matched, err = regexp.Match(desiredDevice.Name, []byte(pathname))
						if err != nil {
							logger.Errorf("regex failed on device %q and filter %q. %v", device.Name, desiredDevice.Name, err)
							continue
						}

						if matched {
							logger.Infof("device %q (aliases: %q) matches device path filter %q", device.Name, device.DevLinks, desiredDevice.Name)
							break
						}
					}
				} else if device.Name == desiredDevice.Name {
					logger.Infof("%q found in the desired devices", device.Name)
					matched = true
				} else if strings.HasPrefix(desiredDevice.Name, "/dev/") {
					devLinks := strings.Split(device.DevLinks, " ")
					for _, link := range devLinks {
						if link == desiredDevice.Name {
							logger.Infof("%q found in the desired devices (matched by link: %q)", device.Name, link)
							matched = true
							break
						}
					}
				}
				matchedDevice = desiredDevice

				if matchedDevice.DeviceClass == "" {
					classNotSet := true
					if agent.pvcBacked {
						crushDeviceClass := os.Getenv(oposd.CrushDeviceClassVarName)
						if crushDeviceClass != "" {
							matchedDevice.DeviceClass = crushDeviceClass
							classNotSet = false
						}
					}
					if classNotSet {
						matchedDevice.DeviceClass = sys.GetDiskDeviceClass(device)
					}
				}

				if matched {
					break
				}
			}

			if err == nil && matched {
				// the current device matches the user specifies filter/list, use it for data
				logger.Infof("device %q is selected by the device filter/name %q", device.Name, matchedDevice.Name)
				deviceInfo = &DeviceOsdIDEntry{Data: unassignedOSDID, Config: matchedDevice, PersistentDevicePaths: strings.Fields(device.DevLinks), DeviceInfo: device}

				// set that this is not an OSD but a metadata device
				if device.Type == pvcMetadataTypeDevice {
					logger.Infof("metadata device %q is selected by the device filter/name %q", device.Name, matchedDevice.Name)
					deviceInfo = &DeviceOsdIDEntry{Config: matchedDevice, PersistentDevicePaths: strings.Fields(device.DevLinks), Metadata: []int{1}, DeviceInfo: device}
				}

				// set that this is not an OSD but a wal device
				if device.Type == pvcWalTypeDevice {
					logger.Infof("wal device %q is selected by the device filter/name %q", device.Name, matchedDevice.Name)
					deviceInfo = &DeviceOsdIDEntry{Config: matchedDevice, PersistentDevicePaths: strings.Fields(device.DevLinks), Metadata: []int{2}, DeviceInfo: device}
				}
			} else {
				logger.Infof("skipping device %q that does not match the device filter/list (%v). %v", device.Name, desiredDevices, err)
			}
		} else {
			logger.Infof("skipping device %q until the admin specifies it can be used by an osd", device.Name)
		}

		if deviceInfo != nil {
			// When running on PVC, we typically have a single device only
			// So it's fine to name the first entry of the map "data" instead of the PVC name
			// It is particularly useful when a metadata PVC is used because we need to identify it in the map
			// So the entry must be named "metadata" so it can accessed later
			if agent.pvcBacked {
				if device.Type == pvcDataTypeDevice {
					available.Entries[pvcDataTypeDevice] = deviceInfo
				} else if device.Type == pvcMetadataTypeDevice {
					available.Entries[pvcMetadataTypeDevice] = deviceInfo
				} else if device.Type == pvcWalTypeDevice {
					available.Entries[pvcWalTypeDevice] = deviceInfo
				}
			} else {
				available.Entries[device.Name] = deviceInfo
			}
		}
	}

	return available, nil
}

// releaseLVMDevice deactivates the LV to release the device.
func releaseLVMDevice(context *clusterd.Context, volumeGroupName string) error {
	if op, err := context.Executor.ExecuteCommandWithCombinedOutput("lvchange", "-an", "-vv", volumeGroupName); err != nil {
		return errors.Wrapf(err, "failed to deactivate LVM %s. output: %s", volumeGroupName, op)
	}
	logger.Info("successfully released device from lvm")
	return nil
}

// getVolumeGroupName returns the Volume group name from the given Logical Volume Path
func getVolumeGroupName(lvPath string) string {
	vgSlice := strings.Split(lvPath, "/")
	// Assert that lvpath is in correct format `/dev/<vg name>/<lv name>` before extracting the vg name
	if len(vgSlice) != 4 || vgSlice[2] == "" {
		logger.Warningf("invalid LV Path: %q", lvPath)
		return ""
	}

	return vgSlice[2]
}