a3s-flow 1.1.0

Durable workflow engine and Rust SDK for A3S
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

use super::*;

#[test]
fn retry_policy_serializes_failure_action_only_when_non_default() {
    let default_policy = RetryPolicy::none();
    let encoded = serde_json::to_value(default_policy).unwrap();
    assert_eq!(encoded, json!({ "max_attempts": 1, "delay_ms": 0 }));

    let recoverable = RetryPolicy::none().continue_workflow_on_failure();
    let encoded = serde_json::to_value(recoverable).unwrap();
    assert_eq!(
        encoded,
        json!({
            "max_attempts": 1,
            "delay_ms": 0,
            "on_exhausted": "continue_workflow",
        })
    );

    let decoded: RetryPolicy = serde_json::from_value(json!({
        "max_attempts": 1,
        "delay_ms": 0,
        "on_exhausted": "continue_workflow",
    }))
    .unwrap();
    assert_eq!(decoded.on_exhausted, StepFailureAction::ContinueWorkflow);
}

#[test]
fn retry_policy_preserves_fixed_history_shape_and_serializes_bounded_exponential_backoff() {
    let fixed = serde_json::to_value(RetryPolicy::fixed(3, Duration::from_secs(1))).unwrap();
    assert_eq!(fixed, json!({ "max_attempts": 3, "delay_ms": 1_000 }));

    let exponential = serde_json::to_value(RetryPolicy::exponential(
        8,
        Duration::from_secs(1),
        Duration::from_secs(30),
    ))
    .unwrap();
    assert_eq!(
        exponential,
        json!({
            "max_attempts": 8,
            "delay_ms": 1_000,
            "backoff": "exponential",
            "max_delay_ms": 30_000,
        })
    );

    let legacy: RetryPolicy = serde_json::from_value(json!({
        "max_attempts": 3,
        "delay_ms": 1_000,
    }))
    .unwrap();
    assert_eq!(legacy, RetryPolicy::fixed(3, Duration::from_secs(1)));
}

struct StaticHistoryStore {
    run_id: String,
    events: Vec<FlowEventEnvelope>,
}

impl StaticHistoryStore {
    fn new(run_id: &str, events: Vec<FlowEventEnvelope>) -> Self {
        Self {
            run_id: run_id.to_string(),
            events,
        }
    }
}

#[async_trait]
impl FlowEventStore for StaticHistoryStore {
    async fn append(
        &self,
        _run_id: &str,
        _event: FlowEvent,
    ) -> a3s_flow::Result<FlowEventEnvelope> {
        Err(FlowError::Store(
            "static history store does not append".to_string(),
        ))
    }

    async fn append_if_sequence(
        &self,
        _run_id: &str,
        _expected_sequence: u64,
        _event: FlowEvent,
    ) -> a3s_flow::Result<FlowEventEnvelope> {
        Err(FlowError::Store(
            "static history store does not append".to_string(),
        ))
    }

    async fn list(&self, run_id: &str) -> a3s_flow::Result<Vec<FlowEventEnvelope>> {
        if run_id == self.run_id {
            Ok(self.events.clone())
        } else {
            Err(FlowError::RunNotFound(run_id.to_string()))
        }
    }

    async fn list_run_ids(&self) -> a3s_flow::Result<Vec<String>> {
        Ok(vec![self.run_id.clone()])
    }
}

fn corrupt_engine(events: Vec<FlowEventEnvelope>) -> FlowEngine {
    FlowEngine::new(
        Arc::new(StaticHistoryStore::new("corrupt-run", events)),
        Arc::new(SequentialRuntime),
    )
}

#[tokio::test]
async fn snapshot_rejects_non_contiguous_event_sequence() {
    let engine = corrupt_engine(vec![
        envelope("corrupt-run", 1, run_created_event()),
        envelope("corrupt-run", 3, FlowEvent::RunStarted),
    ]);

    let err = engine.snapshot("corrupt-run").await.unwrap_err();
    assert_invalid_transition(err, "event sequence must be contiguous");
}

#[tokio::test]
async fn snapshot_rejects_duplicate_step_created_history() {
    let engine = corrupt_engine(vec![
        envelope("corrupt-run", 1, run_created_event()),
        envelope("corrupt-run", 2, FlowEvent::RunStarted),
        envelope(
            "corrupt-run",
            3,
            FlowEvent::StepCreated {
                step_id: "load-user".to_string(),
                step_name: "loadUser".to_string(),
                input: json!({ "version": 1 }),
                retry: RetryPolicy::default(),
            },
        ),
        envelope(
            "corrupt-run",
            4,
            FlowEvent::StepCreated {
                step_id: "load-user".to_string(),
                step_name: "loadUser".to_string(),
                input: json!({ "version": 2 }),
                retry: RetryPolicy::default(),
            },
        ),
    ]);

    let err = engine.snapshot("corrupt-run").await.unwrap_err();
    assert_invalid_transition(err, "step_created duplicates step load-user");
}

#[tokio::test]
async fn snapshot_rejects_events_after_terminal_run_state() {
    let engine = corrupt_engine(vec![
        envelope("corrupt-run", 1, run_created_event()),
        envelope("corrupt-run", 2, FlowEvent::RunStarted),
        envelope(
            "corrupt-run",
            3,
            FlowEvent::RunCompleted {
                output: json!({ "ok": true }),
            },
        ),
        envelope("corrupt-run", 4, FlowEvent::RunStarted),
    ]);

    let err = engine.snapshot("corrupt-run").await.unwrap_err();
    assert_invalid_transition(err, "appears after terminal run state");
}