gemini_adk_rs/text/
route.rs

1use std::sync::Arc;
2
3use async_trait::async_trait;
4
5use super::TextAgent;
6use crate::context::AgentEvent;
7use crate::error::AgentError;
8use crate::middleware::MiddlewareChain;
9use crate::state::State;
10
11/// A routing rule: predicate over state → target agent.
12pub struct RouteRule {
13    predicate: Box<dyn Fn(&State) -> bool + Send + Sync>,
14    agent: Arc<dyn TextAgent>,
15}
16
17impl RouteRule {
18    /// Create a new route rule with a predicate and target agent.
19    pub fn new(
20        predicate: impl Fn(&State) -> bool + Send + Sync + 'static,
21        agent: Arc<dyn TextAgent>,
22    ) -> Self {
23        Self {
24            predicate: Box::new(predicate),
25            agent,
26        }
27    }
28}
29
30/// State-driven deterministic branching — evaluates predicates in order,
31/// dispatches to the first matching agent. Falls back to default if none match.
32pub struct RouteTextAgent {
33    name: String,
34    rules: Vec<RouteRule>,
35    default: Arc<dyn TextAgent>,
36    middleware: MiddlewareChain,
37}
38
39impl RouteTextAgent {
40    /// Create a new route agent with rules and a default fallback.
41    pub fn new(
42        name: impl Into<String>,
43        rules: Vec<RouteRule>,
44        default: Arc<dyn TextAgent>,
45    ) -> Self {
46        Self {
47            name: name.into(),
48            rules,
49            default,
50            middleware: MiddlewareChain::new(),
51        }
52    }
53
54    /// Attach a middleware chain. `AgentEvent::RouteSelected` is emitted through
55    /// it with the chosen branch, so `on_event` observers (`M::on_route`) fire.
56    pub fn with_middleware_chain(mut self, chain: MiddlewareChain) -> Self {
57        self.middleware = chain;
58        self
59    }
60}
61
62#[async_trait]
63impl TextAgent for RouteTextAgent {
64    fn name(&self) -> &str {
65        &self.name
66    }
67
68    async fn run(&self, state: &State) -> Result<String, AgentError> {
69        for rule in &self.rules {
70            if (rule.predicate)(state) {
71                let _ = self
72                    .middleware
73                    .run_on_event(&AgentEvent::RouteSelected {
74                        agent_name: rule.agent.name().to_string(),
75                    })
76                    .await;
77                return rule.agent.run(state).await;
78            }
79        }
80        let _ = self
81            .middleware
82            .run_on_event(&AgentEvent::RouteSelected {
83                agent_name: self.default.name().to_string(),
84            })
85            .await;
86        self.default.run(state).await
87    }
88}
gemini_adk_rs/text/route.rs

gemini_adk_rs/text/
route.rs
