d-engine-core 0.2.3

Pure Raft consensus algorithm - for building custom Raft-based systems
Documentation
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
use std::path::Path;
use std::sync::Arc;

use bytes::Bytes;
use d_engine_proto::common::LogId;
use d_engine_proto::server::cluster::ClusterMembership;
use tokio::sync::mpsc;
use tokio::sync::watch;
use tracing::trace;

use crate::ElectionConfig;
use crate::MockElectionCore;
use crate::MockMembership;
use crate::MockPurgeExecutor;
use crate::MockRaftLog;
use crate::MockReplicationCore;
use crate::MockStateMachine;
use crate::MockStateMachineHandler;
use crate::MockTransport;
use crate::MockTypeConfig;
use crate::Raft;
use crate::RaftConfig;
use crate::RaftContext;
use crate::RaftCoreHandlers;
use crate::RaftEvent;
use crate::RaftLog;
use crate::RaftNodeConfig;
use crate::RaftRole;
use crate::RaftStorageHandles;
use crate::RoleEvent;
use crate::SignalParams;
use crate::StateMachine;
use crate::follower_state::FollowerState;

pub struct MockBuilder {
    pub id: Option<u32>,
    pub role: Option<RaftRole<MockTypeConfig>>,
    pub raft_log: Option<MockRaftLog>,
    pub state_machine: Option<Arc<MockStateMachine>>,
    pub transport: Option<MockTransport<MockTypeConfig>>,
    pub membership: Option<Arc<MockMembership<MockTypeConfig>>>,
    pub purge_executor: Option<MockPurgeExecutor>,
    pub election_handler: Option<MockElectionCore<MockTypeConfig>>,
    pub replication_handler: Option<MockReplicationCore<MockTypeConfig>>,
    pub state_machine_handler: Option<Arc<MockStateMachineHandler<MockTypeConfig>>>,
    pub node_config: Option<RaftNodeConfig>,
    pub turn_on_election: Option<bool>,
    shutdown_signal: watch::Receiver<()>,

    pub(crate) event_tx: Option<mpsc::Sender<RaftEvent>>,
    pub(crate) event_rx: Option<mpsc::Receiver<RaftEvent>>,

    pub(crate) role_tx: Option<mpsc::UnboundedSender<RoleEvent>>,
    pub(crate) role_rx: Option<mpsc::UnboundedReceiver<RoleEvent>>,
}

impl MockBuilder {
    pub fn new(shutdown_signal: watch::Receiver<()>) -> Self {
        Self {
            id: None,
            role: None,
            raft_log: None,
            state_machine: None,
            transport: None,
            membership: None,
            purge_executor: None,
            election_handler: None,
            replication_handler: None,
            state_machine_handler: None,
            node_config: None,
            turn_on_election: None,
            shutdown_signal,

            role_tx: None,
            role_rx: None,
            event_tx: None,
            event_rx: None,
        }
    }

    pub fn build_context(self) -> RaftContext<MockTypeConfig> {
        let (
            raft_log,
            state_machine,
            transport,
            election_handler,
            replication_handler,
            state_machine_handler,
            membership,
            purge_executor,
            node_config,
        ) = (
            Arc::new(self.raft_log.unwrap_or_else(mock_raft_log)),
            self.state_machine.unwrap_or_else(|| Arc::new(mock_state_machine())),
            Arc::new(self.transport.unwrap_or_else(mock_transport)),
            self.election_handler.unwrap_or_else(mock_election_core),
            self.replication_handler.unwrap_or_else(mock_replication_handler),
            self.state_machine_handler
                .unwrap_or_else(|| Arc::new(mock_state_machine_handler())),
            self.membership.unwrap_or_else(|| Arc::new(mock_membership())),
            self.purge_executor.unwrap_or_else(mock_purge_exewcutor),
            self.node_config.unwrap_or_else(|| {
                RaftNodeConfig::new()
                    .expect("Should succeed to init RaftNodeConfig")
                    .validate()
                    .expect("Should succeed to validate RaftNodeConfig")
            }),
        );

        let storage = RaftStorageHandles {
            raft_log,
            state_machine,
        };
        let handlers = RaftCoreHandlers {
            election_handler,
            replication_handler,
            state_machine_handler,
            purge_executor: Arc::new(purge_executor),
        };
        mock_raft_context_internal(1, storage, transport, membership, handlers, node_config)
    }

    pub fn build_raft(self) -> Raft<MockTypeConfig> {
        let (role_tx, role_rx) = mpsc::unbounded_channel();
        let (event_tx, event_rx) = mpsc::channel(10);
        let (cmd_tx, cmd_rx) = mpsc::unbounded_channel();
        let (
            id,
            raft_log,
            state_machine,
            transport,
            election_handler,
            replication_handler,
            state_machine_handler,
            membership,
            purge_executor,
            node_config,
            role_tx,
            role_rx,
            event_tx,
            event_rx,
        ) = (
            self.id.unwrap_or(1),
            self.raft_log.unwrap_or_else(mock_raft_log),
            self.state_machine.unwrap_or_else(|| Arc::new(mock_state_machine())),
            self.transport.unwrap_or_else(mock_transport),
            self.election_handler.unwrap_or_else(mock_election_core),
            self.replication_handler.unwrap_or_else(mock_replication_handler),
            self.state_machine_handler
                .unwrap_or_else(|| Arc::new(mock_state_machine_handler())),
            self.membership.unwrap_or_else(|| Arc::new(mock_membership())),
            self.purge_executor.unwrap_or_else(mock_purge_exewcutor),
            self.node_config.unwrap_or_else(|| {
                RaftNodeConfig::new()
                    .expect("Should succeed to init RaftNodeConfig")
                    .validate()
                    .expect("Should succeed to validate RaftNodeConfig")
            }),
            self.role_tx.unwrap_or(role_tx),
            self.role_rx.unwrap_or(role_rx),
            self.event_tx.unwrap_or(event_tx),
            self.event_rx.unwrap_or(event_rx),
        );
        trace!(node_config.raft.election.election_timeout_min, "build_raft");

        let election_config = {
            if self.turn_on_election.unwrap_or(true) {
                ElectionConfig {
                    election_timeout_min: 1,
                    election_timeout_max: 2,
                    ..node_config.raft.election
                }
            } else {
                node_config.raft.election
            }
        };
        let arc_node_config = Arc::new(RaftNodeConfig {
            raft: RaftConfig {
                election: election_config,
                ..node_config.raft
            },
            ..node_config
        });

        let role = self.role.unwrap_or(RaftRole::Follower(Box::new(FollowerState::new(
            id,
            arc_node_config.clone(),
            raft_log.load_hard_state().expect("Failed to load hard state"),
            Some(state_machine.last_applied().index),
        ))));

        Raft::new(
            id,
            role,
            RaftStorageHandles::<MockTypeConfig> {
                raft_log: Arc::new(raft_log),
                state_machine,
            },
            transport,
            RaftCoreHandlers::<MockTypeConfig> {
                election_handler,
                replication_handler,
                state_machine_handler,
                purge_executor: Arc::new(purge_executor),
            },
            membership,
            SignalParams {
                role_tx,
                role_rx,
                event_tx,
                event_rx,
                cmd_tx,
                cmd_rx,
                shutdown_signal: self.shutdown_signal,
            },
            arc_node_config.clone(),
        )
    }

    pub fn id(
        mut self,
        id: u32,
    ) -> Self {
        self.id = Some(id);
        self
    }
    pub fn with_role(
        mut self,
        role: RaftRole<MockTypeConfig>,
    ) -> Self {
        self.role = Some(role);
        self
    }
    pub fn with_raft_log(
        mut self,
        raft_log: MockRaftLog,
    ) -> Self {
        self.raft_log = Some(raft_log);
        self
    }
    pub fn with_state_machine(
        mut self,
        sm: MockStateMachine,
    ) -> Self {
        self.state_machine = Some(Arc::new(sm));
        self
    }

    pub fn with_transport(
        mut self,
        transport: MockTransport<MockTypeConfig>,
    ) -> Self {
        self.transport = Some(transport);
        self
    }

    pub fn with_membership(
        mut self,
        membership: MockMembership<MockTypeConfig>,
    ) -> Self {
        self.membership = Some(Arc::new(membership));
        self
    }

    pub fn with_election_handler(
        mut self,
        election_handler: MockElectionCore<MockTypeConfig>,
    ) -> Self {
        self.election_handler = Some(election_handler);
        self
    }

    pub fn with_replication_handler(
        mut self,
        replication_handler: MockReplicationCore<MockTypeConfig>,
    ) -> Self {
        self.replication_handler = Some(replication_handler);
        self
    }

    pub fn with_state_machine_handler(
        mut self,
        state_machine_handler: MockStateMachineHandler<MockTypeConfig>,
    ) -> Self {
        self.state_machine_handler = Some(Arc::new(state_machine_handler));
        self
    }

    pub fn with_node_config(
        mut self,
        node_config: RaftNodeConfig,
    ) -> Self {
        self.node_config = Some(node_config);
        self
    }

    pub fn with_db_path(
        mut self,
        db_root_dir: impl AsRef<Path>,
    ) -> Self {
        let mut node_config = RaftNodeConfig::new().expect("Should succeed to init RaftNodeConfig");
        node_config.cluster.db_root_dir = db_root_dir.as_ref().to_path_buf();
        let node_config =
            node_config.validate().expect("Should succeed to validate RaftNodeConfig");
        self.node_config = Some(node_config);
        self
    }

    pub fn turn_on_election(
        mut self,
        is_on: bool,
    ) -> Self {
        self.turn_on_election = Some(is_on);
        self
    }
}

pub fn mock_raft_log() -> MockRaftLog {
    let mut raft_log = MockRaftLog::new();
    raft_log.expect_last_entry_id().returning(|| 0);
    raft_log.expect_last_log_id().returning(|| None);
    raft_log.expect_flush().returning(|| Ok(()));
    raft_log.expect_load_hard_state().returning(|| Ok(None));
    raft_log.expect_save_hard_state().returning(|_| Ok(()));
    raft_log.expect_calculate_majority_matched_index().returning(|_, _, _| None);
    raft_log
}

pub fn mock_transport() -> MockTransport<MockTypeConfig> {
    MockTransport::new()
}

pub fn mock_election_core() -> MockElectionCore<MockTypeConfig> {
    let mut election_handler = MockElectionCore::new();
    election_handler
        .expect_broadcast_vote_requests()
        .returning(|_, _, _, _, _| Ok(()));
    election_handler
}

pub fn mock_replication_handler() -> MockReplicationCore<MockTypeConfig> {
    MockReplicationCore::new()
}

pub fn mock_state_machine() -> MockStateMachine {
    let mut mock = MockStateMachine::new();

    mock.expect_start().returning(|| Ok(()));
    mock.expect_stop().returning(|| Ok(()));
    mock.expect_is_running().returning(|| true);

    mock.expect_get().returning(|_| Ok(None));
    mock.expect_entry_term().returning(|_| None);
    mock.expect_apply_chunk().returning(|_| Ok(vec![]));
    mock.expect_len().returning(|| 0);

    mock.expect_update_last_applied().returning(|_| ());
    mock.expect_last_applied().return_const(LogId::default());
    mock.expect_persist_last_applied().returning(|_| Ok(()));

    mock.expect_update_last_snapshot_metadata().returning(|_| Ok(()));
    mock.expect_snapshot_metadata().returning(|| None);
    mock.expect_persist_last_snapshot_metadata().returning(|_| Ok(()));

    mock.expect_apply_snapshot_from_file().returning(|_, _| Ok(()));
    mock.expect_generate_snapshot_data()
        .returning(|_, _| Ok(Bytes::copy_from_slice(&[0u8; 32])));

    mock.expect_save_hard_state().returning(|| Ok(()));
    mock.expect_flush().returning(|| Ok(()));

    mock
}

pub fn mock_state_machine_handler() -> MockStateMachineHandler<MockTypeConfig> {
    let mut state_machine_handler = MockStateMachineHandler::new();
    state_machine_handler.expect_update_pending().returning(|_| {});
    state_machine_handler.expect_read_from_state_machine().returning(|_| None);
    state_machine_handler.expect_should_snapshot().returning(|_| false);
    state_machine_handler
}

pub fn mock_purge_exewcutor() -> MockPurgeExecutor {
    let mut purge_exewcutor = MockPurgeExecutor::new();
    purge_exewcutor.expect_execute_purge().returning(|_| Ok(()));
    purge_exewcutor
}
pub fn mock_membership() -> MockMembership<MockTypeConfig> {
    let mut membership = MockMembership::new();
    membership.expect_can_rejoin().returning(|_, _| Ok(()));
    membership.expect_pre_warm_connections().returning(|| Ok(()));
    membership.expect_voters().returning(Vec::new);
    membership.expect_replication_peers().returning(Vec::new);
    membership.expect_members().returning(Vec::new);

    membership.expect_check_cluster_is_ready().returning(|| Ok(()));
    membership
        .expect_retrieve_cluster_membership_config()
        .returning(|_current_leader_id| ClusterMembership {
            version: 1,
            nodes: vec![],
            current_leader_id: None,
        });
    membership.expect_get_zombie_candidates().returning(Vec::new);
    membership.expect_get_peers_id_with_condition().returning(|_| vec![]);

    // Mock single-node cluster detection (default to multi-node with no peers)
    membership.expect_is_single_node_cluster().returning(|| false);
    membership.expect_initial_cluster_size().returning(|| 3);
    membership
}

fn mock_raft_context_internal(
    id: u32,
    storage: RaftStorageHandles<MockTypeConfig>,
    transport: Arc<MockTransport<MockTypeConfig>>,
    membership: Arc<MockMembership<MockTypeConfig>>,
    handlers: RaftCoreHandlers<MockTypeConfig>,
    node_config: RaftNodeConfig,
) -> RaftContext<MockTypeConfig> {
    RaftContext {
        node_id: id,
        storage,

        transport,
        membership,

        handlers,

        node_config: Arc::new(node_config),
    }
}