ruststream_lapin/
exchange.rs

1//! The exchange half of a queue binding descriptor.
2
3use lapin::ExchangeKind;
4
5/// Describes the exchange side of a [`RabbitQueue`](crate::RabbitQueue) binding.
6///
7/// Like every descriptor in this crate it only records the EXPECTED topology; nothing is
8/// declared unless the broker was built with
9/// [`declare_topology(true)`](crate::LapinBroker::declare_topology).
10///
11/// # Examples
12///
13/// ```
14/// use ruststream_lapin::RabbitExchange;
15///
16/// let events = RabbitExchange::topic("events").durable(true);
17/// assert_eq!(events.name(), "events");
18/// ```
19#[derive(Debug, Clone, PartialEq, Eq)]
20pub struct RabbitExchange {
21    name: String,
22    kind: ExchangeKind,
23    durable: bool,
24    auto_delete: bool,
25}
26
27impl RabbitExchange {
28    fn new(name: impl Into<String>, kind: ExchangeKind) -> Self {
29        Self {
30            name: name.into(),
31            kind,
32            durable: true,
33            auto_delete: false,
34        }
35    }
36
37    /// A direct exchange: routes on an exact routing-key match.
38    #[must_use]
39    pub fn direct(name: impl Into<String>) -> Self {
40        Self::new(name, ExchangeKind::Direct)
41    }
42
43    /// A topic exchange: routes on dot-separated routing-key patterns (`order.*`).
44    #[must_use]
45    pub fn topic(name: impl Into<String>) -> Self {
46        Self::new(name, ExchangeKind::Topic)
47    }
48
49    /// A fanout exchange: routes every message to every bound queue.
50    #[must_use]
51    pub fn fanout(name: impl Into<String>) -> Self {
52        Self::new(name, ExchangeKind::Fanout)
53    }
54
55    /// A headers exchange: routes on header attributes instead of the routing key.
56    #[must_use]
57    pub fn headers(name: impl Into<String>) -> Self {
58        Self::new(name, ExchangeKind::Headers)
59    }
60
61    /// An exchange of a plugin-provided type, for example `"x-delayed-message"`.
62    #[must_use]
63    pub fn custom(name: impl Into<String>, kind: impl Into<String>) -> Self {
64        Self::new(name, ExchangeKind::Custom(kind.into()))
65    }
66
67    /// A consistent-hash exchange (the `x-consistent-hash` type from the
68    /// [`rabbitmq_consistent_hash_exchange`](https://github.com/rabbitmq/rabbitmq-server/tree/main/deps/rabbitmq_consistent_hash_exchange)
69    /// plugin): distributes messages across the queues bound to it by hashing the routing key,
70    /// so partition-like fan-out is a server-side concern rather than a client one.
71    ///
72    /// Each queue binds with a routing key that is its integer weight (`"1"`, `"2"`, ...); the
73    /// broker splits the hash space proportionally. Requires the plugin to be enabled on the
74    /// broker, so it lives behind the `plugin-consistent-hash` feature.
75    ///
76    /// # Examples
77    ///
78    /// ```
79    /// use ruststream_lapin::{RabbitExchange, RabbitQueue};
80    ///
81    /// let hashed = RabbitExchange::consistent_hash("orders-by-key");
82    /// // Bind a queue with its weight as the routing key:
83    /// let shard = RabbitQueue::new("shard-a").bind(hashed, "1");
84    /// # let _ = shard;
85    /// ```
86    #[cfg(feature = "plugin-consistent-hash")]
87    #[must_use]
88    pub fn consistent_hash(name: impl Into<String>) -> Self {
89        Self::new(name, ExchangeKind::Custom("x-consistent-hash".to_owned()))
90    }
91
92    /// Whether the exchange survives a broker restart. Defaults to `true`.
93    #[must_use]
94    pub fn durable(mut self, durable: bool) -> Self {
95        self.durable = durable;
96        self
97    }
98
99    /// Whether the exchange is deleted when its last binding is removed. Defaults to `false`.
100    #[must_use]
101    pub fn auto_delete(mut self, auto_delete: bool) -> Self {
102        self.auto_delete = auto_delete;
103        self
104    }
105
106    /// The exchange name.
107    #[must_use]
108    pub fn name(&self) -> &str {
109        &self.name
110    }
111
112    pub(crate) fn kind(&self) -> &ExchangeKind {
113        &self.kind
114    }
115
116    pub(crate) fn is_durable(&self) -> bool {
117        self.durable
118    }
119
120    pub(crate) fn is_auto_delete(&self) -> bool {
121        self.auto_delete
122    }
123}
ruststream_lapin/exchange.rs

ruststream_lapin/
exchange.rs
