container: ViewDB: cleanup error-types
- relates to https://github.com/moby/moby/pull/43624

some changes I had in a local branch while I was reviewing https://github.com/moby/moby/pull/43624 - removes some custom error-types that didn't have to be exported, and fixes some errors to prevent producing 500 "internal server errors".


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container/view.go
package container // import "github.com/docker/docker/container"

import (
	"errors"
	"fmt"
	"strings"
	"time"

	"github.com/docker/docker/api/types"
	"github.com/docker/docker/api/types/network"
	"github.com/docker/go-connections/nat"
	memdb "github.com/hashicorp/go-memdb"
	"github.com/sirupsen/logrus"
)

const (
	memdbContainersTable  = "containers"
	memdbNamesTable       = "names"
	memdbIDIndex          = "id"
	memdbIDIndexPrefix    = "id_prefix"
	memdbContainerIDIndex = "containerid"
)

var (
	// ErrNameReserved is an error which is returned when a name is requested to be reserved that already is reserved
	ErrNameReserved = errors.New("name is reserved")
	// ErrNameNotReserved is an error which is returned when trying to find a name that is not reserved
	ErrNameNotReserved = errors.New("name is not reserved")
)

var (
	// ErrEmptyPrefix is an error returned if the prefix was empty.
	ErrEmptyPrefix = errors.New("Prefix can't be empty")

	// ErrNotExist is returned when ID or its prefix not found in index.
	ErrNotExist = errors.New("ID does not exist")
)

// ErrAmbiguousPrefix is returned if the prefix was ambiguous
// (multiple ids for the prefix).
type ErrAmbiguousPrefix struct {
	prefix string
}

func (e ErrAmbiguousPrefix) Error() string {
	return fmt.Sprintf("Multiple IDs found with provided prefix: %s", e.prefix)
}

// Snapshot is a read only view for Containers. It holds all information necessary to serve container queries in a
// versioned ACID in-memory store.
type Snapshot struct {
	types.Container

	// additional info queries need to filter on
	// preserve nanosec resolution for queries
	CreatedAt    time.Time
	StartedAt    time.Time
	Name         string
	Pid          int
	ExitCode     int
	Running      bool
	Paused       bool
	Managed      bool
	ExposedPorts nat.PortSet
	PortBindings nat.PortSet
	Health       string
	HostConfig   struct {
		Isolation string
	}
}

// nameAssociation associates a container id with a name.
type nameAssociation struct {
	// name is the name to associate. Note that name is the primary key
	// ("id" in memdb).
	name        string
	containerID string
}

var schema = &memdb.DBSchema{
	Tables: map[string]*memdb.TableSchema{
		memdbContainersTable: {
			Name: memdbContainersTable,
			Indexes: map[string]*memdb.IndexSchema{
				memdbIDIndex: {
					Name:    memdbIDIndex,
					Unique:  true,
					Indexer: &containerByIDIndexer{},
				},
			},
		},
		memdbNamesTable: {
			Name: memdbNamesTable,
			Indexes: map[string]*memdb.IndexSchema{
				// Used for names, because "id" is the primary key in memdb.
				memdbIDIndex: {
					Name:    memdbIDIndex,
					Unique:  true,
					Indexer: &namesByNameIndexer{},
				},
				memdbContainerIDIndex: {
					Name:    memdbContainerIDIndex,
					Indexer: &namesByContainerIDIndexer{},
				},
			},
		},
	},
}

// ViewDB provides an in-memory transactional (ACID) container store.
type ViewDB struct {
	store *memdb.MemDB
}

// NoSuchContainerError indicates that the container wasn't found in the
// database.
type NoSuchContainerError struct {
	id string
}

// Error satisfies the error interface.
func (e NoSuchContainerError) Error() string {
	return "no such container " + e.id
}

// NewViewDB provides the default implementation, with the default schema
func NewViewDB() (*ViewDB, error) {
	store, err := memdb.NewMemDB(schema)
	if err != nil {
		return nil, err
	}
	return &ViewDB{store: store}, nil
}

// GetByPrefix returns a container with the given ID prefix. It returns an
// error if an empty prefix was given or if multiple containers match the prefix.
func (db *ViewDB) GetByPrefix(s string) (string, error) {
	if s == "" {
		return "", ErrEmptyPrefix
	}
	iter, err := db.store.Txn(false).Get(memdbContainersTable, memdbIDIndexPrefix, s)
	if err != nil {
		return "", err
	}

	var id string
	for {
		item := iter.Next()
		if item == nil {
			break
		}
		if id != "" {
			return "", ErrAmbiguousPrefix{prefix: s}
		}
		id = item.(*Container).ID
	}

	if id != "" {
		return id, nil
	}

	return "", ErrNotExist
}

// Snapshot provides a consistent read-only view of the database.
func (db *ViewDB) Snapshot() *View {
	return &View{
		txn: db.store.Txn(false),
	}
}

func (db *ViewDB) withTxn(cb func(*memdb.Txn) error) error {
	txn := db.store.Txn(true)
	err := cb(txn)
	if err != nil {
		txn.Abort()
		return err
	}
	txn.Commit()
	return nil
}

// Save atomically updates the in-memory store state for a Container.
// Only read only (deep) copies of containers may be passed in.
func (db *ViewDB) Save(c *Container) error {
	return db.withTxn(func(txn *memdb.Txn) error {
		return txn.Insert(memdbContainersTable, c)
	})
}

// Delete removes an item by ID
func (db *ViewDB) Delete(c *Container) error {
	return db.withTxn(func(txn *memdb.Txn) error {
		view := &View{txn: txn}
		names := view.getNames(c.ID)

		for _, name := range names {
			txn.Delete(memdbNamesTable, nameAssociation{name: name})
		}

		// Ignore error - the container may not actually exist in the
		// db, but we still need to clean up associated names.
		txn.Delete(memdbContainersTable, NewBaseContainer(c.ID, c.Root))
		return nil
	})
}

// ReserveName registers a container ID to a name
// ReserveName is idempotent
// Attempting to reserve a container ID to a name that already exists results in an `ErrNameReserved`
// A name reservation is globally unique
func (db *ViewDB) ReserveName(name, containerID string) error {
	return db.withTxn(func(txn *memdb.Txn) error {
		s, err := txn.First(memdbNamesTable, memdbIDIndex, name)
		if err != nil {
			return err
		}
		if s != nil {
			if s.(nameAssociation).containerID != containerID {
				return ErrNameReserved
			}
			return nil
		}
		return txn.Insert(memdbNamesTable, nameAssociation{name: name, containerID: containerID})
	})
}

// ReleaseName releases the reserved name
// Once released, a name can be reserved again
func (db *ViewDB) ReleaseName(name string) error {
	return db.withTxn(func(txn *memdb.Txn) error {
		return txn.Delete(memdbNamesTable, nameAssociation{name: name})
	})
}

// View provides a consistent read-only view of the database.
type View struct {
	txn *memdb.Txn
}

// All returns a all items in this snapshot. Returned objects must never be modified.
func (v *View) All() ([]Snapshot, error) {
	var all []Snapshot
	iter, err := v.txn.Get(memdbContainersTable, memdbIDIndex)
	if err != nil {
		return nil, err
	}
	for {
		item := iter.Next()
		if item == nil {
			break
		}
		snapshot := v.transform(item.(*Container))
		all = append(all, *snapshot)
	}
	return all, nil
}

// Get returns an item by id. Returned objects must never be modified.
func (v *View) Get(id string) (*Snapshot, error) {
	s, err := v.txn.First(memdbContainersTable, memdbIDIndex, id)
	if err != nil {
		return nil, err
	}
	if s == nil {
		return nil, NoSuchContainerError{id: id}
	}
	return v.transform(s.(*Container)), nil
}

// getNames lists all the reserved names for the given container ID.
func (v *View) getNames(containerID string) []string {
	iter, err := v.txn.Get(memdbNamesTable, memdbContainerIDIndex, containerID)
	if err != nil {
		return nil
	}

	var names []string
	for {
		item := iter.Next()
		if item == nil {
			break
		}
		names = append(names, item.(nameAssociation).name)
	}

	return names
}

// GetID returns the container ID that the passed in name is reserved to.
func (v *View) GetID(name string) (string, error) {
	s, err := v.txn.First(memdbNamesTable, memdbIDIndex, name)
	if err != nil {
		return "", err
	}
	if s == nil {
		return "", ErrNameNotReserved
	}
	return s.(nameAssociation).containerID, nil
}

// GetAllNames returns all registered names.
func (v *View) GetAllNames() map[string][]string {
	iter, err := v.txn.Get(memdbNamesTable, memdbContainerIDIndex)
	if err != nil {
		return nil
	}

	out := make(map[string][]string)
	for {
		item := iter.Next()
		if item == nil {
			break
		}
		assoc := item.(nameAssociation)
		out[assoc.containerID] = append(out[assoc.containerID], assoc.name)
	}

	return out
}

// transform maps a (deep) copied Container object to what queries need.
// A lock on the Container is not held because these are immutable deep copies.
func (v *View) transform(container *Container) *Snapshot {
	health := types.NoHealthcheck
	if container.Health != nil {
		health = container.Health.Status()
	}
	snapshot := &Snapshot{
		Container: types.Container{
			ID:      container.ID,
			Names:   v.getNames(container.ID),
			ImageID: container.ImageID.String(),
			Ports:   []types.Port{},
			Mounts:  container.GetMountPoints(),
			State:   container.State.StateString(),
			Status:  container.State.String(),
			Created: container.Created.Unix(),
		},
		CreatedAt:    container.Created,
		StartedAt:    container.StartedAt,
		Name:         container.Name,
		Pid:          container.Pid,
		Managed:      container.Managed,
		ExposedPorts: make(nat.PortSet),
		PortBindings: make(nat.PortSet),
		Health:       health,
		Running:      container.Running,
		Paused:       container.Paused,
		ExitCode:     container.ExitCode(),
	}

	if snapshot.Names == nil {
		// Dead containers will often have no name, so make sure the response isn't null
		snapshot.Names = []string{}
	}

	if container.HostConfig != nil {
		snapshot.Container.HostConfig.NetworkMode = string(container.HostConfig.NetworkMode)
		snapshot.HostConfig.Isolation = string(container.HostConfig.Isolation)
		for binding := range container.HostConfig.PortBindings {
			snapshot.PortBindings[binding] = struct{}{}
		}
	}

	if container.Config != nil {
		snapshot.Image = container.Config.Image
		snapshot.Labels = container.Config.Labels
		for exposed := range container.Config.ExposedPorts {
			snapshot.ExposedPorts[exposed] = struct{}{}
		}
	}

	if len(container.Args) > 0 {
		var args []string
		for _, arg := range container.Args {
			if strings.Contains(arg, " ") {
				args = append(args, fmt.Sprintf("'%s'", arg))
			} else {
				args = append(args, arg)
			}
		}
		argsAsString := strings.Join(args, " ")
		snapshot.Command = fmt.Sprintf("%s %s", container.Path, argsAsString)
	} else {
		snapshot.Command = container.Path
	}

	snapshot.Ports = []types.Port{}
	networks := make(map[string]*network.EndpointSettings)
	if container.NetworkSettings != nil {
		for name, netw := range container.NetworkSettings.Networks {
			if netw == nil || netw.EndpointSettings == nil {
				continue
			}
			networks[name] = &network.EndpointSettings{
				EndpointID:          netw.EndpointID,
				Gateway:             netw.Gateway,
				IPAddress:           netw.IPAddress,
				IPPrefixLen:         netw.IPPrefixLen,
				IPv6Gateway:         netw.IPv6Gateway,
				GlobalIPv6Address:   netw.GlobalIPv6Address,
				GlobalIPv6PrefixLen: netw.GlobalIPv6PrefixLen,
				MacAddress:          netw.MacAddress,
				NetworkID:           netw.NetworkID,
			}
			if netw.IPAMConfig != nil {
				networks[name].IPAMConfig = &network.EndpointIPAMConfig{
					IPv4Address: netw.IPAMConfig.IPv4Address,
					IPv6Address: netw.IPAMConfig.IPv6Address,
				}
			}
		}
		for port, bindings := range container.NetworkSettings.Ports {
			p, err := nat.ParsePort(port.Port())
			if err != nil {
				logrus.Warnf("invalid port map %+v", err)
				continue
			}
			if len(bindings) == 0 {
				snapshot.Ports = append(snapshot.Ports, types.Port{
					PrivatePort: uint16(p),
					Type:        port.Proto(),
				})
				continue
			}
			for _, binding := range bindings {
				h, err := nat.ParsePort(binding.HostPort)
				if err != nil {
					logrus.Warnf("invalid host port map %+v", err)
					continue
				}
				snapshot.Ports = append(snapshot.Ports, types.Port{
					PrivatePort: uint16(p),
					PublicPort:  uint16(h),
					Type:        port.Proto(),
					IP:          binding.HostIP,
				})
			}
		}
	}
	snapshot.NetworkSettings = &types.SummaryNetworkSettings{Networks: networks}

	return snapshot
}

// containerByIDIndexer is used to extract the ID field from Container types.
// memdb.StringFieldIndex can not be used since ID is a field from an embedded struct.
type containerByIDIndexer struct{}

// FromObject implements the memdb.SingleIndexer interface for Container objects
func (e *containerByIDIndexer) FromObject(obj interface{}) (bool, []byte, error) {
	c, ok := obj.(*Container)
	if !ok {
		return false, nil, fmt.Errorf("%T is not a Container", obj)
	}
	// Add the null character as a terminator
	v := c.ID + "\x00"
	return true, []byte(v), nil
}

// FromArgs implements the memdb.Indexer interface
func (e *containerByIDIndexer) FromArgs(args ...interface{}) ([]byte, error) {
	if len(args) != 1 {
		return nil, fmt.Errorf("must provide only a single argument")
	}
	arg, ok := args[0].(string)
	if !ok {
		return nil, fmt.Errorf("argument must be a string: %#v", args[0])
	}
	// Add the null character as a terminator
	arg += "\x00"
	return []byte(arg), nil
}

func (e *containerByIDIndexer) PrefixFromArgs(args ...interface{}) ([]byte, error) {
	val, err := e.FromArgs(args...)
	if err != nil {
		return nil, err
	}

	// Strip the null terminator, the rest is a prefix
	n := len(val)
	if n > 0 {
		return val[:n-1], nil
	}
	return val, nil
}

// namesByNameIndexer is used to index container name associations by name.
type namesByNameIndexer struct{}

func (e *namesByNameIndexer) FromObject(obj interface{}) (bool, []byte, error) {
	n, ok := obj.(nameAssociation)
	if !ok {
		return false, nil, fmt.Errorf(`%T does not have type "nameAssociation"`, obj)
	}

	// Add the null character as a terminator
	return true, []byte(n.name + "\x00"), nil
}

func (e *namesByNameIndexer) FromArgs(args ...interface{}) ([]byte, error) {
	if len(args) != 1 {
		return nil, fmt.Errorf("must provide only a single argument")
	}
	arg, ok := args[0].(string)
	if !ok {
		return nil, fmt.Errorf("argument must be a string: %#v", args[0])
	}
	// Add the null character as a terminator
	arg += "\x00"
	return []byte(arg), nil
}

// namesByContainerIDIndexer is used to index container names by container ID.
type namesByContainerIDIndexer struct{}

func (e *namesByContainerIDIndexer) FromObject(obj interface{}) (bool, []byte, error) {
	n, ok := obj.(nameAssociation)
	if !ok {
		return false, nil, fmt.Errorf(`%T does not have type "nameAssociation"`, obj)
	}

	// Add the null character as a terminator
	return true, []byte(n.containerID + "\x00"), nil
}

func (e *namesByContainerIDIndexer) FromArgs(args ...interface{}) ([]byte, error) {
	if len(args) != 1 {
		return nil, fmt.Errorf("must provide only a single argument")
	}
	arg, ok := args[0].(string)
	if !ok {
		return nil, fmt.Errorf("argument must be a string: %#v", args[0])
	}
	// Add the null character as a terminator
	arg += "\x00"
	return []byte(arg), nil
}

package container // import "github.com/docker/docker/container"

import (
	"bytes"
	"errors"
	"fmt"
	"strings"
	"time"

	"github.com/docker/docker/api/types"
	"github.com/docker/docker/api/types/network"
	"github.com/docker/docker/errdefs"
	"github.com/docker/go-connections/nat"
	memdb "github.com/hashicorp/go-memdb"
	"github.com/sirupsen/logrus"
)

const (
	memdbContainersTable  = "containers"
	memdbNamesTable       = "names"
	memdbIDIndex          = "id"
	memdbIDIndexPrefix    = "id_prefix"
	memdbContainerIDIndex = "containerid"
)

var (
	// ErrNameReserved is an error which is returned when a name is requested to be reserved that already is reserved
	ErrNameReserved = errors.New("name is reserved")
	// ErrNameNotReserved is an error which is returned when trying to find a name that is not reserved
	ErrNameNotReserved = errors.New("name is not reserved")
)

// Snapshot is a read only view for Containers. It holds all information necessary to serve container queries in a
// versioned ACID in-memory store.
type Snapshot struct {
	types.Container

	// additional info queries need to filter on
	// preserve nanosec resolution for queries
	CreatedAt    time.Time
	StartedAt    time.Time
	Name         string
	Pid          int
	ExitCode     int
	Running      bool
	Paused       bool
	Managed      bool
	ExposedPorts nat.PortSet
	PortBindings nat.PortSet
	Health       string
	HostConfig   struct {
		Isolation string
	}
}

// nameAssociation associates a container id with a name.
type nameAssociation struct {
	// name is the name to associate. Note that name is the primary key
	// ("id" in memdb).
	name        string
	containerID string
}

var schema = &memdb.DBSchema{
	Tables: map[string]*memdb.TableSchema{
		memdbContainersTable: {
			Name: memdbContainersTable,
			Indexes: map[string]*memdb.IndexSchema{
				memdbIDIndex: {
					Name:    memdbIDIndex,
					Unique:  true,
					Indexer: &containerByIDIndexer{},
				},
			},
		},
		memdbNamesTable: {
			Name: memdbNamesTable,
			Indexes: map[string]*memdb.IndexSchema{
				// Used for names, because "id" is the primary key in memdb.
				memdbIDIndex: {
					Name:    memdbIDIndex,
					Unique:  true,
					Indexer: &namesByNameIndexer{},
				},
				memdbContainerIDIndex: {
					Name:    memdbContainerIDIndex,
					Indexer: &namesByContainerIDIndexer{},
				},
			},
		},
	},
}

// ViewDB provides an in-memory transactional (ACID) container store.
type ViewDB struct {
	store *memdb.MemDB
}

// NewViewDB provides the default implementation, with the default schema
func NewViewDB() (*ViewDB, error) {
	store, err := memdb.NewMemDB(schema)
	if err != nil {
		return nil, errdefs.System(err)
	}
	return &ViewDB{store: store}, nil
}

// GetByPrefix returns a container with the given ID prefix. It returns an
// error if an empty prefix was given or if multiple containers match the prefix.
func (db *ViewDB) GetByPrefix(s string) (string, error) {
	if s == "" {
		return "", errdefs.InvalidParameter(errors.New("prefix can't be empty"))
	}
	iter, err := db.store.Txn(false).Get(memdbContainersTable, memdbIDIndexPrefix, s)
	if err != nil {
		return "", errdefs.System(err)
	}

	var id string
	for {
		item := iter.Next()
		if item == nil {
			break
		}
		if id != "" {
			return "", errdefs.InvalidParameter(errors.New("multiple IDs found with provided prefix: " + s))
		}
		id = item.(*Container).ID
	}

	if id != "" {
		return id, nil
	}

	return "", errdefs.NotFound(errors.New("No such container: " + s))
}

// Snapshot provides a consistent read-only view of the database.
func (db *ViewDB) Snapshot() *View {
	return &View{
		txn: db.store.Txn(false),
	}
}

func (db *ViewDB) withTxn(cb func(*memdb.Txn) error) error {
	txn := db.store.Txn(true)
	err := cb(txn)
	if err != nil {
		txn.Abort()
		return errdefs.System(err)
	}
	txn.Commit()
	return nil
}

// Save atomically updates the in-memory store state for a Container.
// Only read only (deep) copies of containers may be passed in.
func (db *ViewDB) Save(c *Container) error {
	return db.withTxn(func(txn *memdb.Txn) error {
		return txn.Insert(memdbContainersTable, c)
	})
}

// Delete removes an item by ID
func (db *ViewDB) Delete(c *Container) error {
	return db.withTxn(func(txn *memdb.Txn) error {
		view := &View{txn: txn}
		names := view.getNames(c.ID)

		for _, name := range names {
			txn.Delete(memdbNamesTable, nameAssociation{name: name})
		}

		// Ignore error - the container may not actually exist in the
		// db, but we still need to clean up associated names.
		txn.Delete(memdbContainersTable, NewBaseContainer(c.ID, c.Root))
		return nil
	})
}

// ReserveName registers a container ID to a name
// ReserveName is idempotent
// Attempting to reserve a container ID to a name that already exists results in an `ErrNameReserved`
// A name reservation is globally unique
func (db *ViewDB) ReserveName(name, containerID string) error {
	return db.withTxn(func(txn *memdb.Txn) error {
		s, err := txn.First(memdbNamesTable, memdbIDIndex, name)
		if err != nil {
			return errdefs.System(err)
		}
		if s != nil {
			if s.(nameAssociation).containerID != containerID {
				return ErrNameReserved
			}
			return nil
		}
		return txn.Insert(memdbNamesTable, nameAssociation{name: name, containerID: containerID})
	})
}

// ReleaseName releases the reserved name
// Once released, a name can be reserved again
func (db *ViewDB) ReleaseName(name string) error {
	return db.withTxn(func(txn *memdb.Txn) error {
		return txn.Delete(memdbNamesTable, nameAssociation{name: name})
	})
}

// View provides a consistent read-only view of the database.
type View struct {
	txn *memdb.Txn
}

// All returns a all items in this snapshot. Returned objects must never be modified.
func (v *View) All() ([]Snapshot, error) {
	var all []Snapshot
	iter, err := v.txn.Get(memdbContainersTable, memdbIDIndex)
	if err != nil {
		return nil, errdefs.System(err)
	}
	for {
		item := iter.Next()
		if item == nil {
			break
		}
		snapshot := v.transform(item.(*Container))
		all = append(all, *snapshot)
	}
	return all, nil
}

// Get returns an item by id. Returned objects must never be modified.
func (v *View) Get(id string) (*Snapshot, error) {
	s, err := v.txn.First(memdbContainersTable, memdbIDIndex, id)
	if err != nil {
		return nil, errdefs.System(err)
	}
	if s == nil {
		return nil, errdefs.NotFound(errors.New("No such container: " + id))
	}
	return v.transform(s.(*Container)), nil
}

// getNames lists all the reserved names for the given container ID.
func (v *View) getNames(containerID string) []string {
	iter, err := v.txn.Get(memdbNamesTable, memdbContainerIDIndex, containerID)
	if err != nil {
		return nil
	}

	var names []string
	for {
		item := iter.Next()
		if item == nil {
			break
		}
		names = append(names, item.(nameAssociation).name)
	}

	return names
}

// GetID returns the container ID that the passed in name is reserved to.
func (v *View) GetID(name string) (string, error) {
	s, err := v.txn.First(memdbNamesTable, memdbIDIndex, name)
	if err != nil {
		return "", errdefs.System(err)
	}
	if s == nil {
		return "", ErrNameNotReserved
	}
	return s.(nameAssociation).containerID, nil
}

// GetAllNames returns all registered names.
func (v *View) GetAllNames() map[string][]string {
	iter, err := v.txn.Get(memdbNamesTable, memdbContainerIDIndex)
	if err != nil {
		return nil
	}

	out := make(map[string][]string)
	for {
		item := iter.Next()
		if item == nil {
			break
		}
		assoc := item.(nameAssociation)
		out[assoc.containerID] = append(out[assoc.containerID], assoc.name)
	}

	return out
}

// transform maps a (deep) copied Container object to what queries need.
// A lock on the Container is not held because these are immutable deep copies.
func (v *View) transform(container *Container) *Snapshot {
	health := types.NoHealthcheck
	if container.Health != nil {
		health = container.Health.Status()
	}
	snapshot := &Snapshot{
		Container: types.Container{
			ID:      container.ID,
			Names:   v.getNames(container.ID),
			ImageID: container.ImageID.String(),
			Ports:   []types.Port{},
			Mounts:  container.GetMountPoints(),
			State:   container.State.StateString(),
			Status:  container.State.String(),
			Created: container.Created.Unix(),
		},
		CreatedAt:    container.Created,
		StartedAt:    container.StartedAt,
		Name:         container.Name,
		Pid:          container.Pid,
		Managed:      container.Managed,
		ExposedPorts: make(nat.PortSet),
		PortBindings: make(nat.PortSet),
		Health:       health,
		Running:      container.Running,
		Paused:       container.Paused,
		ExitCode:     container.ExitCode(),
	}

	if snapshot.Names == nil {
		// Dead containers will often have no name, so make sure the response isn't null
		snapshot.Names = []string{}
	}

	if container.HostConfig != nil {
		snapshot.Container.HostConfig.NetworkMode = string(container.HostConfig.NetworkMode)
		snapshot.HostConfig.Isolation = string(container.HostConfig.Isolation)
		for binding := range container.HostConfig.PortBindings {
			snapshot.PortBindings[binding] = struct{}{}
		}
	}

	if container.Config != nil {
		snapshot.Image = container.Config.Image
		snapshot.Labels = container.Config.Labels
		for exposed := range container.Config.ExposedPorts {
			snapshot.ExposedPorts[exposed] = struct{}{}
		}
	}

	if len(container.Args) > 0 {
		var args []string
		for _, arg := range container.Args {
			if strings.Contains(arg, " ") {
				args = append(args, fmt.Sprintf("'%s'", arg))
			} else {
				args = append(args, arg)
			}
		}
		argsAsString := strings.Join(args, " ")
		snapshot.Command = fmt.Sprintf("%s %s", container.Path, argsAsString)
	} else {
		snapshot.Command = container.Path
	}

	snapshot.Ports = []types.Port{}
	networks := make(map[string]*network.EndpointSettings)
	if container.NetworkSettings != nil {
		for name, netw := range container.NetworkSettings.Networks {
			if netw == nil || netw.EndpointSettings == nil {
				continue
			}
			networks[name] = &network.EndpointSettings{
				EndpointID:          netw.EndpointID,
				Gateway:             netw.Gateway,
				IPAddress:           netw.IPAddress,
				IPPrefixLen:         netw.IPPrefixLen,
				IPv6Gateway:         netw.IPv6Gateway,
				GlobalIPv6Address:   netw.GlobalIPv6Address,
				GlobalIPv6PrefixLen: netw.GlobalIPv6PrefixLen,
				MacAddress:          netw.MacAddress,
				NetworkID:           netw.NetworkID,
			}
			if netw.IPAMConfig != nil {
				networks[name].IPAMConfig = &network.EndpointIPAMConfig{
					IPv4Address: netw.IPAMConfig.IPv4Address,
					IPv6Address: netw.IPAMConfig.IPv6Address,
				}
			}
		}
		for port, bindings := range container.NetworkSettings.Ports {
			p, err := nat.ParsePort(port.Port())
			if err != nil {
				logrus.WithError(err).Warn("invalid port map")
				continue
			}
			if len(bindings) == 0 {
				snapshot.Ports = append(snapshot.Ports, types.Port{
					PrivatePort: uint16(p),
					Type:        port.Proto(),
				})
				continue
			}
			for _, binding := range bindings {
				h, err := nat.ParsePort(binding.HostPort)
				if err != nil {
					logrus.WithError(err).Warn("invalid host port map")
					continue
				}
				snapshot.Ports = append(snapshot.Ports, types.Port{
					PrivatePort: uint16(p),
					PublicPort:  uint16(h),
					Type:        port.Proto(),
					IP:          binding.HostIP,
				})
			}
		}
	}
	snapshot.NetworkSettings = &types.SummaryNetworkSettings{Networks: networks}

	return snapshot
}

// containerByIDIndexer is used to extract the ID field from Container types.
// memdb.StringFieldIndex can not be used since ID is a field from an embedded struct.
type containerByIDIndexer struct{}

// terminator is the null character, used as a terminator.
const terminator = "\x00"

// FromObject implements the memdb.SingleIndexer interface for Container objects
func (e *containerByIDIndexer) FromObject(obj interface{}) (bool, []byte, error) {
	c, ok := obj.(*Container)
	if !ok {
		return false, nil, fmt.Errorf("%T is not a Container", obj)
	}
	// Add the null character as a terminator
	return true, []byte(c.ID + terminator), nil
}

// FromArgs implements the memdb.Indexer interface
func (e *containerByIDIndexer) FromArgs(args ...interface{}) ([]byte, error) {
	if len(args) != 1 {
		return nil, fmt.Errorf("must provide only a single argument")
	}
	arg, ok := args[0].(string)
	if !ok {
		return nil, fmt.Errorf("argument must be a string: %#v", args[0])
	}
	// Add the null character as a terminator
	return []byte(arg + terminator), nil
}

func (e *containerByIDIndexer) PrefixFromArgs(args ...interface{}) ([]byte, error) {
	val, err := e.FromArgs(args...)
	if err != nil {
		return nil, err
	}

	// Strip the null terminator, the rest is a prefix
	return bytes.TrimSuffix(val, []byte(terminator)), nil
}

// namesByNameIndexer is used to index container name associations by name.
type namesByNameIndexer struct{}

func (e *namesByNameIndexer) FromObject(obj interface{}) (bool, []byte, error) {
	n, ok := obj.(nameAssociation)
	if !ok {
		return false, nil, fmt.Errorf(`%T does not have type "nameAssociation"`, obj)
	}

	// Add the null character as a terminator
	return true, []byte(n.name + terminator), nil
}

func (e *namesByNameIndexer) FromArgs(args ...interface{}) ([]byte, error) {
	if len(args) != 1 {
		return nil, fmt.Errorf("must provide only a single argument")
	}
	arg, ok := args[0].(string)
	if !ok {
		return nil, fmt.Errorf("argument must be a string: %#v", args[0])
	}
	// Add the null character as a terminator
	return []byte(arg + terminator), nil
}

// namesByContainerIDIndexer is used to index container names by container ID.
type namesByContainerIDIndexer struct{}

func (e *namesByContainerIDIndexer) FromObject(obj interface{}) (bool, []byte, error) {
	n, ok := obj.(nameAssociation)
	if !ok {
		return false, nil, fmt.Errorf(`%T does not have type "nameAssociation"`, obj)
	}

	// Add the null character as a terminator
	return true, []byte(n.containerID + terminator), nil
}

func (e *namesByContainerIDIndexer) FromArgs(args ...interface{}) ([]byte, error) {
	if len(args) != 1 {
		return nil, fmt.Errorf("must provide only a single argument")
	}
	arg, ok := args[0].(string)
	if !ok {
		return nil, fmt.Errorf("argument must be a string: %#v", args[0])
	}
	// Add the null character as a terminator
	return []byte(arg + terminator), nil
}

I removed the last commit; need to look more in-depth;

While these errors are "invalid parameter", the cause of the invalid parameter (wrong type) is not due to what the user did.

I'll revisit this one, and have a closer look;

- Either: keep InvalidParameter, but make sure it's wrapped to "system" after that
- Or (this commit); consider it "system" errors from the start


It's slightly difficult to follow where these are called, as it's implementing an interface, and that interface is called from the vendored memdb code, so need to look closer