docker/swarmkit

package store

import (
    "strings"

    memdb "github.com/hashicorp/go-memdb"
    "github.com/moby/swarmkit/v2/api"
    "github.com/pkg/errors"
)

const tableResource = "resource"

var (
    // ErrNoKind is returned by resource create operations if the provided Kind
    // of the resource does not exist
    ErrNoKind = errors.New("object kind is unregistered")
)

func init() {
    register(ObjectStoreConfig{
        Table: &memdb.TableSchema{
            Name: tableResource,
            Indexes: map[string]*memdb.IndexSchema{
                indexID: {
                    Name:    indexID,
                    Unique:  true,
                    Indexer: resourceIndexerByID{},
                },
                indexName: {
                    Name:    indexName,
                    Unique:  true,
                    Indexer: resourceIndexerByName{},
                },
                indexKind: {
                    Name:    indexKind,
                    Indexer: resourceIndexerByKind{},
                },
                indexCustom: {
                    Name:         indexCustom,
                    Indexer:      resourceCustomIndexer{},
                    AllowMissing: true,
                },
            },
        },
        Save: func(tx ReadTx, snapshot *api.StoreSnapshot) error {
            var err error
            snapshot.Resources, err = FindResources(tx, All)
            return err
        },
        Restore: func(tx Tx, snapshot *api.StoreSnapshot) error {
            toStoreObj := make([]api.StoreObject, len(snapshot.Resources))
            for i, x := range snapshot.Resources {
                toStoreObj[i] = resourceEntry{x}
            }
            return RestoreTable(tx, tableResource, toStoreObj)
        },
        ApplyStoreAction: func(tx Tx, sa api.StoreAction) error {
            switch v := sa.Target.(type) {
            case *api.StoreAction_Resource:
                obj := v.Resource
                switch sa.Action {
                case api.StoreActionKindCreate:
                    return CreateResource(tx, obj)
                case api.StoreActionKindUpdate:
                    return UpdateResource(tx, obj)
                case api.StoreActionKindRemove:
                    return DeleteResource(tx, obj.ID)
                }
            }
            return errUnknownStoreAction
        },
    })
}

type resourceEntry struct {
    *api.Resource
}

func (r resourceEntry) CopyStoreObject() api.StoreObject {
    return resourceEntry{Resource: r.Resource.Copy()}
}

// ensure that when update events are emitted, we unwrap resourceEntry
func (r resourceEntry) EventUpdate(oldObject api.StoreObject) api.Event {
    if oldObject != nil {
        return api.EventUpdateResource{Resource: r.Resource, OldResource: oldObject.(resourceEntry).Resource}
    }
    return api.EventUpdateResource{Resource: r.Resource}
}

func confirmExtension(tx Tx, r *api.Resource) error {
    // There must be an extension corresponding to the Kind field.
    extensions, err := FindExtensions(tx, ByName(r.Kind))
    if err != nil {
        return errors.Wrap(err, "failed to query extensions")
    }
    if len(extensions) == 0 {
        return ErrNoKind
    }
    return nil
}

// CreateResource adds a new resource object to the store.
// Returns ErrExist if the ID is already taken.
// Returns ErrNameConflict if a Resource with this Name already exists
// Returns ErrNoKind if the specified Kind does not exist
func CreateResource(tx Tx, r *api.Resource) error {
    if err := confirmExtension(tx, r); err != nil {
        return err
    }
    // TODO(dperny): currently the "name" index is unique, which means only one
    // Resource of _any_ Kind can exist with that name. This isn't a problem
    // right now, but the ideal case would be for names to be namespaced to the
    // kind.
    if tx.lookup(tableResource, indexName, strings.ToLower(r.Annotations.Name)) != nil {
        return ErrNameConflict
    }
    return tx.create(tableResource, resourceEntry{r})
}

// UpdateResource updates an existing resource object in the store.
// Returns ErrNotExist if the object doesn't exist.
func UpdateResource(tx Tx, r *api.Resource) error {
    if err := confirmExtension(tx, r); err != nil {
        return err
    }
    return tx.update(tableResource, resourceEntry{r})
}

// DeleteResource removes a resource object from the store.
// Returns ErrNotExist if the object doesn't exist.
func DeleteResource(tx Tx, id string) error {
    return tx.delete(tableResource, id)
}

// GetResource looks up a resource object by ID.
// Returns nil if the object doesn't exist.
func GetResource(tx ReadTx, id string) *api.Resource {
    r := tx.get(tableResource, id)
    if r == nil {
        return nil
    }
    return r.(resourceEntry).Resource
}

// FindResources selects a set of resource objects and returns them.
func FindResources(tx ReadTx, by By) ([]*api.Resource, error) {
    checkType := func(by By) error {
        switch by.(type) {
        case byIDPrefix, byName, byNamePrefix, byKind, byCustom, byCustomPrefix:
            return nil
        default:
            return ErrInvalidFindBy
        }
    }

    resourceList := []*api.Resource{}
    appendResult := func(o api.StoreObject) {
        resourceList = append(resourceList, o.(resourceEntry).Resource)
    }

    err := tx.find(tableResource, by, checkType, appendResult)
    return resourceList, err
}

type resourceIndexerByKind struct{}

func (ri resourceIndexerByKind) FromArgs(args ...interface{}) ([]byte, error) {
    return fromArgs(args...)
}

func (ri resourceIndexerByKind) FromObject(obj interface{}) (bool, []byte, error) {
    r := obj.(resourceEntry)

    // Add the null character as a terminator
    val := r.Resource.Kind + "\x00"
    return true, []byte(val), nil
}

type resourceIndexerByID struct{}

func (indexer resourceIndexerByID) FromArgs(args ...interface{}) ([]byte, error) {
    return api.ResourceIndexerByID{}.FromArgs(args...)
}
func (indexer resourceIndexerByID) PrefixFromArgs(args ...interface{}) ([]byte, error) {
    return api.ResourceIndexerByID{}.PrefixFromArgs(args...)
}
func (indexer resourceIndexerByID) FromObject(obj interface{}) (bool, []byte, error) {
    return api.ResourceIndexerByID{}.FromObject(obj.(resourceEntry).Resource)
}

type resourceIndexerByName struct{}

func (indexer resourceIndexerByName) FromArgs(args ...interface{}) ([]byte, error) {
    return api.ResourceIndexerByName{}.FromArgs(args...)
}
func (indexer resourceIndexerByName) PrefixFromArgs(args ...interface{}) ([]byte, error) {
    return api.ResourceIndexerByName{}.PrefixFromArgs(args...)
}
func (indexer resourceIndexerByName) FromObject(obj interface{}) (bool, []byte, error) {
    return api.ResourceIndexerByName{}.FromObject(obj.(resourceEntry).Resource)
}

type resourceCustomIndexer struct{}

func (indexer resourceCustomIndexer) FromArgs(args ...interface{}) ([]byte, error) {
    return api.ResourceCustomIndexer{}.FromArgs(args...)
}
func (indexer resourceCustomIndexer) PrefixFromArgs(args ...interface{}) ([]byte, error) {
    return api.ResourceCustomIndexer{}.PrefixFromArgs(args...)
}
func (indexer resourceCustomIndexer) FromObject(obj interface{}) (bool, [][]byte, error) {
    return api.ResourceCustomIndexer{}.FromObject(obj.(resourceEntry).Resource)
}