nuts-foundation/nuts-node

/*
 * Copyright (C) 2021 Nuts community
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 */

package network

import (
    "context"
    "github.com/nuts-foundation/go-did/did"
    "github.com/nuts-foundation/nuts-node/crypto/hash"
    "github.com/nuts-foundation/nuts-node/network/dag"
    "github.com/nuts-foundation/nuts-node/network/transport"
)

// MaxReprocessBufferSize is the maximum number of events for Nats resulting from a Reprocess
const MaxReprocessBufferSize = 1000000

// Transactions is the interface that defines the API for creating, reading and subscribing to Nuts Network transactions.
type Transactions interface {
    // Subscribe registers a receiver for the specified transaction type.
    // A filter can be passed as option with the WithSelectionFilter function.
    // The events for the receiver can be made persistent by passing the network.WithPersistency() option.
    Subscribe(name string, receiver dag.ReceiverFn, filters ...SubscriberOption) error
    // Subscribers returns the list of notifiers on the DAG that emit events to subscribers.
    Subscribers() []dag.Notifier
    // CleanupSubscriberEvents removes events. Example use is cleaning up events that errored but should be removed due to a bugfix.
    CleanupSubscriberEvents(subcriberName, errorPrefix string) error
    // GetTransactionPayload retrieves the transaction Payload for the given transaction.
    // If the transaction or Payload is not found, dag.ErrPayloadNotFound is returned.
    GetTransactionPayload(transactionRef hash.SHA256Hash) ([]byte, error)
    // GetTransaction retrieves the transaction for the given reference.
    // If the transaction is not found, a dag.ErrTransactionNotFound is returned.
    GetTransaction(transactionRef hash.SHA256Hash) (dag.Transaction, error)
    // CreateTransaction creates a new transaction according to the given spec.
    CreateTransaction(ctx context.Context, spec Template) (dag.Transaction, error)
    // ListTransactionsInRange returns all transactions known to this Network instance with lamport clock value between startInclusive and endExclusive.
    // endExclusive must be larger than startInclusive.
    ListTransactionsInRange(startInclusive uint32, endExclusive uint32) ([]dag.Transaction, error)
    // PeerDiagnostics returns a map containing diagnostic information of the node's peers. The key contains the remote peer's ID.
    PeerDiagnostics() map[transport.PeerID]transport.Diagnostics
    // Reprocess walks the DAG and publishes all transactions matching the contentType via Nats
    Reprocess(ctx context.Context, contentType string) (*ReprocessReport, error)
    // WithPersistency returns a SubscriberOption for persistency. It allows the DAG KVStore to be used as persistent store for notifications.
    // The notifications will then have ACID properties
    WithPersistency() SubscriberOption
    // DiscoverServices should be called by the VDR to let the network know it has processed and verified a document (update) for the DID.
    DiscoverServices(updatedDID did.DID)
    // AddressBook returns the list of contacts in the address book.
    AddressBook() []transport.Contact
}

// EventType defines a type for specifying the kind of events that can be published/subscribed on the Network.
type EventType string

// AnyPayloadType is a wildcard that matches with any payload type.
const AnyPayloadType = "*"

// Receiver defines a callback function for processing transactions/payloads received by the DAG.
type Receiver func(transaction dag.Transaction, payload []byte) error

// SubscriberOption creates a dag.NotifierOption
type SubscriberOption func() dag.NotifierOption