es-entity 0.12.10

Event Sourcing Entity Framework
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

#![allow(dead_code)]

use derive_builder::Builder;
use serde::{Deserialize, Serialize};

use es_entity::*;

es_entity::entity_id! { CustomerId }

#[derive(EsEvent, Debug, Serialize, Deserialize)]
#[serde(tag = "type", rename_all = "snake_case")]
#[es_event(id = "CustomerId")]
pub enum CustomerEvent {
    Initialized {
        id: CustomerId,
        name: Forgettable<String>,
        email: String,
    },
    NameUpdated {
        name: Forgettable<String>,
    },
    EmailUpdated {
        email: String,
    },
    /// Client-declared erasure event (convention): staged before `forget()`
    /// so the erasure consumes a sequence number (fencing stale writers) and
    /// is recorded in the event stream.
    Forgot {},
}

#[derive(EsEntity, Builder)]
#[builder(pattern = "owned", build_fn(error = "EntityHydrationError"))]
pub struct Customer {
    pub id: CustomerId,
    pub name: String,
    pub email: String,

    events: EntityEvents<CustomerEvent>,
}

impl Customer {
    pub fn update_name(&mut self, new_name: impl Into<String>) -> Idempotent<()> {
        let new_name = new_name.into();
        self.name = new_name.clone();
        self.events.push(CustomerEvent::NameUpdated {
            name: Forgettable::new(new_name),
        });
        Idempotent::Executed(())
    }

    pub fn update_email(&mut self, new_email: impl Into<String>) -> Idempotent<()> {
        let new_email = new_email.into();
        self.email = new_email.clone();
        self.events
            .push(CustomerEvent::EmailUpdated { email: new_email });
        Idempotent::Executed(())
    }

    /// Stages the domain erasure event. Call before `forget()` so the
    /// erasure consumes a sequence number and lands in the event stream.
    pub fn record_erasure(&mut self) {
        self.events.push(CustomerEvent::Forgot {});
    }
}

impl TryFromEvents<CustomerEvent> for Customer {
    fn try_from_events(events: EntityEvents<CustomerEvent>) -> Result<Self, EntityHydrationError> {
        let mut builder = CustomerBuilder::default();
        for event in events.iter_all() {
            match event {
                CustomerEvent::Initialized { id, name, email } => {
                    builder = builder
                        .id(*id)
                        .name(
                            name.value()
                                .map(|r| r.clone())
                                .unwrap_or_else(|| "[forgotten]".into()),
                        )
                        .email(email.clone());
                }
                CustomerEvent::NameUpdated { name } => {
                    if let Some(n) = name.value() {
                        builder = builder.name(n.clone());
                    }
                }
                CustomerEvent::EmailUpdated { email } => {
                    builder = builder.email(email.clone());
                }
                // Erasure event (client convention): payloads were deleted
                // at this point in the stream. No state to apply.
                CustomerEvent::Forgot { .. } => {}
            }
        }
        builder.events(events).build()
    }
}

#[derive(Debug, Builder)]
pub struct NewCustomer {
    #[builder(setter(into))]
    pub id: CustomerId,
    #[builder(setter(into))]
    pub name: String,
    #[builder(setter(into))]
    pub email: String,
}

impl NewCustomer {
    pub fn builder() -> NewCustomerBuilder {
        NewCustomerBuilder::default()
    }
}

impl IntoEvents<CustomerEvent> for NewCustomer {
    fn into_events(self) -> EntityEvents<CustomerEvent> {
        EntityEvents::init(
            self.id,
            [CustomerEvent::Initialized {
                id: self.id,
                name: Forgettable::new(self.name),
                email: self.email,
            }],
        )
    }
}