eventcore-postgres 2.1.0

PostgreSQL event store adapter for EventCore event sourcing library
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

//! Contract coverage for durable command-state snapshots in PostgreSQL.

mod common;

use std::collections::HashMap;

use eventcore_types::{
    CommandStateReplayCheckpoint, CommandStateSnapshot, CommandStateSnapshotId, Event, EventStore,
    StreamId, StreamVersion, StreamWrites, collect_events,
};
use serde::{Deserialize, Serialize};
use serde_json::json;

#[derive(Clone, Debug, Deserialize, PartialEq, Eq, Serialize)]
struct SnapshotTestEvent {
    stream_id: StreamId,
    sequence: usize,
}

impl Event for SnapshotTestEvent {
    fn stream_id(&self) -> &StreamId {
        &self.stream_id
    }

    fn event_type_name() -> &'static str {
        "SnapshotTestEvent"
    }
}

fn snapshot_id() -> CommandStateSnapshotId {
    CommandStateSnapshotId::try_new(format!("snapshot::{}", uuid::Uuid::now_v7()))
        .expect("generated snapshot id is valid")
}

fn stream_id() -> StreamId {
    StreamId::try_new(format!("snapshot-stream::{}", uuid::Uuid::now_v7()))
        .expect("generated stream id is valid")
}

#[tokio::test]
async fn command_state_snapshots_round_trip_and_never_regress_their_version_vector() {
    // Given: a durable snapshot that includes two reconstructed streams.
    let store = common::create_test_store().await;
    let snapshot_id = snapshot_id();
    let primary_stream = stream_id();
    let related_stream = stream_id();
    let newer = CommandStateSnapshot::new(
        json!({ "balance": 200 }),
        HashMap::from([
            (primary_stream.clone(), StreamVersion::new(10)),
            (related_stream.clone(), StreamVersion::new(4)),
        ]),
    )
    .with_replay_checkpoints(vec![CommandStateReplayCheckpoint {
        stream_id: primary_stream.clone(),
        state: json!({ "balance": 160 }),
        stream_versions: HashMap::from([(primary_stream.clone(), StreamVersion::new(10))]),
    }]);
    store
        .save_command_state_snapshot(snapshot_id.clone(), newer)
        .await
        .expect("new snapshot should persist");

    // When: a concurrent attempt finishes with a stale projection that omits
    // a stream and trails the primary stream version.
    let stale = CommandStateSnapshot::new(
        json!({ "balance": 100 }),
        HashMap::from([(primary_stream.clone(), StreamVersion::new(9))]),
    );
    store
        .save_command_state_snapshot(snapshot_id.clone(), stale)
        .await
        .expect("stale write should be safely ignored");

    // Then: the durable projection still contains the newer complete vector.
    let stored = store
        .load_command_state_snapshot(snapshot_id)
        .await
        .expect("snapshot read should succeed")
        .expect("snapshot should exist");
    assert_eq!(stored.state, json!({ "balance": 200 }));
    assert_eq!(
        stored.stream_versions.get(&primary_stream),
        Some(&StreamVersion::new(10))
    );
    assert_eq!(
        stored.stream_versions.get(&related_stream),
        Some(&StreamVersion::new(4))
    );
    assert_eq!(stored.replay_checkpoints.len(), 1);
    assert_eq!(
        stored.replay_checkpoints[0].state,
        json!({ "balance": 160 })
    );
}

#[tokio::test]
async fn read_stream_after_seeks_past_the_reconstructed_version() {
    // Given: a stream with a complete history and a snapshot that covers its
    // first two events.
    let store = common::create_test_store().await;
    let stream_id = stream_id();
    let writes = (0..4).try_fold(
        StreamWrites::new()
            .register_stream(stream_id.clone(), StreamVersion::new(0))
            .expect("stream registration should succeed"),
        |writes, sequence| {
            writes.append(SnapshotTestEvent {
                stream_id: stream_id.clone(),
                sequence,
            })
        },
    );
    let _ = store
        .append_events(writes.expect("events should build"))
        .await
        .expect("events should append");

    // When: reconstruction asks for only events after version two.
    let events = collect_events(
        store
            .read_stream_after::<SnapshotTestEvent>(stream_id, StreamVersion::new(2))
            .await
            .expect("stream tail should open"),
    )
    .await
    .expect("stream tail should decode");

    // Then: PostgreSQL returns exactly the remaining suffix.
    assert_eq!(
        events
            .into_iter()
            .map(|event| event.sequence)
            .collect::<Vec<_>>(),
        vec![2, 3]
    );
}