blobstore

type Blob struct {
	Type    string
	Key     string
	Value   []byte
	Version uint64
}

type BlobStorageFactory interface {
	InitializeFactory() error
	// StartTransaction opens a transaction for all following blob storage
	// operations, and returns a TransactionalBlobStorage instance tied to the
	// opened transaction.
	StartTransaction(opts *storage.TxOptions) (TransactionalBlobStorage, error)
}

type LoadCriteria struct {
	// LoadValue specifies whether to load the value of a blob.
	// Set to false to only load blob metadata.
	LoadValue bool
}

type SearchFilter struct {
	// Optional network ID to search within
	NetworkID *string

	// Limit search to an OR matching any of the specified types
	Types map[string]bool
	// Limit search to an OR matching any of the specified keys
	// If the KeyPrefix of the search filter is specified, this argument will
	// be ignored by the blobstore.
	Keys map[string]bool
	// Prefix to match keys against. If this is specified (non-nil and non-
	// empty), the values of Keys will be ignored.
	KeyPrefix *string
}

type TransactionalBlobStorage interface {
	// Commit commits the existing transaction.
	// If an error is returned from the backing storage while committing,
	// the transaction will be rolled back.
	Commit() error

	// Rollback rolls back the existing transaction.
	// If the targeted transaction has already been committed,
	// rolling back has no effect and returns an error.
	Rollback() error

	// ListKeys returns all the blob keys stored for the network and type.
	ListKeys(networkID string, typeVal string) ([]string, error)

	// Get loads a specific blob from storage.
	// If there is no blob matching the given ID, ErrNotFound from
	// "github.com/go-magma/magma/lib/go/errors will be returned.
	Get(networkID string, id storage.TypeAndKey) (Blob, error)

	// GetMany loads and returns a collection of blobs matching the
	// specifiedIDs.
	// If there is no blob corresponding to a TypeAndKey, the returned list
	// will not have a corresponding Blob.
	GetMany(networkID string, ids []storage.TypeAndKey) ([]Blob, error)

	// Search returns a filtered collection of blobs keyed by the network ID
	// to which they belong.
	// Blobs are filtered according to the search filter. Empty filter returns
	// all blobs. Blobs contents are loaded according to the load criteria.
	// Empty criteria loads all fields.
	Search(filter SearchFilter, criteria LoadCriteria) (map[string][]Blob, error)

	// CreateOrUpdate writes blobs to the storage.
	// Blobs are either updated in-place or created. The Version field of
	// blobs passed here will be used if it is not set to 0, otherwise version
	// incrementation will be handled internally inside the storage
	// implementation.
	CreateOrUpdate(networkID string, blobs []Blob) error

	// GetExistingKeys takes in a list of keys and returns a list of keys that
	// exist from the input.
	// The filter specifies whether to look at the entire storage or just in
	// a network.
	GetExistingKeys(keys []string, filter SearchFilter) ([]string, error)

	// Delete deletes specified blobs from storage.
	Delete(networkID string, ids []storage.TypeAndKey) error

	// IncrementVersion is an atomic upsert (INSERT DO ON CONFLICT) that
	// increments the version column or inserts 1 if it does not exist.
	IncrementVersion(networkID string, id storage.TypeAndKey) error
}