tempo/
overrides.rs

1use tempo_node::TempoNode;
2
3/// Function used to modify the [`TempoNode`] before launch.
4pub type TempoNodeMapper = dyn FnOnce(TempoNode) -> TempoNode + Send + 'static;
5
6/// Optional programmatic overrides for [`tempo_main_with`](crate::tempo_main_with).
7///
8/// These hooks are applied during startup after CLI arguments have been parsed.
9/// Empty overrides are a no-op, so embedding binaries can start from
10/// [`TempoOverrides::default`] or [`TempoOverrides::new`] and opt into only the
11/// hooks they need.
12///
13/// The initial one-shot hook surface maps the [`TempoNode`] produced from CLI arguments
14/// before it is passed to Reth's node launcher. This is useful for settings that
15/// are intentionally not exposed as CLI flags, such as additional transaction
16/// pool validation.
17///
18/// # Example
19///
20/// This rejects externally sourced transactions whose encoded size exceeds a
21/// local policy limit while preserving the rest of the CLI-derived node
22/// configuration.
23///
24/// ```no_run
25/// use tempo::{
26///     InvalidPoolTransactionError, PoolTransaction, TempoOverrides, tempo_main_with,
27/// };
28///
29/// fn main() -> eyre::Result<()> {
30///     const MAX_EXTERNAL_TX_ENCODED_LEN: usize = 128 * 1024;
31///
32///     let overrides = TempoOverrides::new().map_tempo_node(|node| {
33///         node.map_pool_builder(|pool| {
34///             pool.with_additional_stateless_validation(|origin, tx| {
35///                 let size = tx.encoded_length();
36///                 if origin.is_external() && size > MAX_EXTERNAL_TX_ENCODED_LEN {
37///                     return Err(InvalidPoolTransactionError::OversizedData {
38///                         size,
39///                         limit: MAX_EXTERNAL_TX_ENCODED_LEN,
40///                     });
41///                 }
42///
43///                 Ok(())
44///             })
45///         })
46///     });
47///
48///     tempo_main_with(overrides)
49/// }
50/// ```
51#[derive(Default)]
52pub struct TempoOverrides {
53    pub(crate) tempo_node_mapper: Option<Box<TempoNodeMapper>>,
54}
55
56impl TempoOverrides {
57    /// Creates empty overrides.
58    pub fn new() -> Self {
59        Self::default()
60    }
61
62    /// Adds a mapper for the [`TempoNode`] built from CLI arguments.
63    ///
64    /// Multiple mappers are applied in the order they were added.
65    pub fn map_tempo_node<F>(mut self, mapper: F) -> Self
66    where
67        F: FnOnce(TempoNode) -> TempoNode + Send + 'static,
68    {
69        self.tempo_node_mapper = Some(match self.tempo_node_mapper.take() {
70            Some(previous) => Box::new(move |node| mapper(previous(node))),
71            None => Box::new(mapper),
72        });
73        self
74    }
75
76    pub(crate) fn apply_tempo_node(&mut self, node: TempoNode) -> TempoNode {
77        match self.tempo_node_mapper.take() {
78            Some(mapper) => mapper(node),
79            None => node,
80        }
81    }
82}
83
84#[cfg(test)]
85mod tests {
86    use std::sync::{
87        Arc, Mutex,
88        atomic::{AtomicBool, Ordering},
89    };
90
91    use super::TempoOverrides;
92    use tempo_node::TempoNode;
93
94    #[test]
95    fn maps_tempo_node() {
96        let called = Arc::new(AtomicBool::new(false));
97        let called_clone = called.clone();
98
99        let mut overrides = TempoOverrides::new().map_tempo_node(move |node| {
100            called_clone.store(true, Ordering::Relaxed);
101            node
102        });
103
104        let _ = overrides.apply_tempo_node(TempoNode::default());
105
106        assert!(called.load(Ordering::Relaxed));
107    }
108
109    #[test]
110    fn applies_tempo_node_mappers_in_order() {
111        let calls = Arc::new(Mutex::new(Vec::new()));
112        let first = calls.clone();
113        let second = calls.clone();
114
115        let mut overrides = TempoOverrides::new()
116            .map_tempo_node(move |node| {
117                first.lock().unwrap().push(1);
118                node
119            })
120            .map_tempo_node(move |node| {
121                second.lock().unwrap().push(2);
122                node
123            });
124
125        let _ = overrides.apply_tempo_node(TempoNode::default());
126
127        assert_eq!(*calls.lock().unwrap(), vec![1, 2]);
128    }
129}
tempo/overrides.rs

tempo/
overrides.rs
