Initial Store & Forward Implementation (#2917)

This adds store & forward relays into dendrite for p2p.
A few things have changed:
- new relay api serves new http endpoints for s&f federation
- updated outbound federation queueing which will attempt to forward
using s&f if appropriate
- database entries to track s&f relays for other nodes

test/memory_relay_db.go

@@ -0,0 +1,140 @@
+// Copyright 2022 The Matrix.org Foundation C.I.C.
+//
+// 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 test
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"sync"
+
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+type InMemoryRelayDatabase struct {
+	nid          int64
+	nidMutex     sync.Mutex
+	transactions map[int64]json.RawMessage
+	associations map[gomatrixserverlib.ServerName][]int64
+}
+
+func NewInMemoryRelayDatabase() *InMemoryRelayDatabase {
+	return &InMemoryRelayDatabase{
+		nid:          1,
+		nidMutex:     sync.Mutex{},
+		transactions: make(map[int64]json.RawMessage),
+		associations: make(map[gomatrixserverlib.ServerName][]int64),
+	}
+}
+
+func (d *InMemoryRelayDatabase) InsertQueueEntry(
+	ctx context.Context,
+	txn *sql.Tx,
+	transactionID gomatrixserverlib.TransactionID,
+	serverName gomatrixserverlib.ServerName,
+	nid int64,
+) error {
+	if _, ok := d.associations[serverName]; !ok {
+		d.associations[serverName] = []int64{}
+	}
+	d.associations[serverName] = append(d.associations[serverName], nid)
+	return nil
+}
+
+func (d *InMemoryRelayDatabase) DeleteQueueEntries(
+	ctx context.Context,
+	txn *sql.Tx,
+	serverName gomatrixserverlib.ServerName,
+	jsonNIDs []int64,
+) error {
+	for _, nid := range jsonNIDs {
+		for index, associatedNID := range d.associations[serverName] {
+			if associatedNID == nid {
+				d.associations[serverName] = append(d.associations[serverName][:index], d.associations[serverName][index+1:]...)
+			}
+		}
+	}
+
+	return nil
+}
+
+func (d *InMemoryRelayDatabase) SelectQueueEntries(
+	ctx context.Context,
+	txn *sql.Tx, serverName gomatrixserverlib.ServerName,
+	limit int,
+) ([]int64, error) {
+	results := []int64{}
+	resultCount := limit
+	if limit > len(d.associations[serverName]) {
+		resultCount = len(d.associations[serverName])
+	}
+	if resultCount > 0 {
+		for i := 0; i < resultCount; i++ {
+			results = append(results, d.associations[serverName][i])
+		}
+	}
+
+	return results, nil
+}
+
+func (d *InMemoryRelayDatabase) SelectQueueEntryCount(
+	ctx context.Context,
+	txn *sql.Tx,
+	serverName gomatrixserverlib.ServerName,
+) (int64, error) {
+	return int64(len(d.associations[serverName])), nil
+}
+
+func (d *InMemoryRelayDatabase) InsertQueueJSON(
+	ctx context.Context,
+	txn *sql.Tx,
+	json string,
+) (int64, error) {
+	d.nidMutex.Lock()
+	defer d.nidMutex.Unlock()
+
+	nid := d.nid
+	d.transactions[nid] = []byte(json)
+	d.nid++
+
+	return nid, nil
+}
+
+func (d *InMemoryRelayDatabase) DeleteQueueJSON(
+	ctx context.Context,
+	txn *sql.Tx,
+	nids []int64,
+) error {
+	for _, nid := range nids {
+		delete(d.transactions, nid)
+	}
+
+	return nil
+}
+
+func (d *InMemoryRelayDatabase) SelectQueueJSON(
+	ctx context.Context,
+	txn *sql.Tx,
+	jsonNIDs []int64,
+) (map[int64][]byte, error) {
+	result := make(map[int64][]byte)
+	for _, nid := range jsonNIDs {
+		if transaction, ok := d.transactions[nid]; ok {
+			result[nid] = transaction
+		}
+	}
+
+	return result, nil
+}