[pitboss] phase 20: Track M.2 — MessageHandler end-to-end (Kafka / SQS / Pub-Sub / NATS / RabbitMQ)

src/dynamic/framework/adapters/nats_go.rs

@@ -0,0 +1,108 @@
+//! Phase 20 (Track M.2) — Go NATS subscriber adapter (`nats.go`).
+
+use crate::dynamic::framework::{FrameworkAdapter, FrameworkBinding};
+use crate::evidence::EntryKind;
+use crate::summary::FuncSummary;
+use crate::symbol::Lang;
+
+pub struct NatsGoAdapter;
+
+const ADAPTER_NAME: &str = "nats-go";
+
+fn callee_is_nats(name: &str) -> bool {
+    let last = name.rsplit_once('.').map(|(_, s)| s).unwrap_or(name);
+    matches!(
+        last,
+        "Subscribe" | "QueueSubscribe" | "Publish" | "HandleMessage" | "OnMessage"
+    )
+}
+
+fn source_imports_nats(file_bytes: &[u8]) -> bool {
+    const NEEDLES: &[&[u8]] = &[
+        b"github.com/nats-io/nats.go",
+        b"nats.Connect",
+        b"nats.Msg",
+    ];
+    NEEDLES
+        .iter()
+        .any(|n| file_bytes.windows(n.len()).any(|w| w == *n))
+}
+
+fn extract_subject(file_bytes: &[u8]) -> String {
+    let text = std::str::from_utf8(file_bytes).unwrap_or("");
+    for needle in [".Subscribe(\"", ".QueueSubscribe(\""] {
+        if let Some(idx) = text.find(needle) {
+            let after = &text[idx + needle.len()..];
+            if let Some(end) = after.find('"') {
+                return after[..end].to_owned();
+            }
+        }
+    }
+    String::new()
+}
+
+impl FrameworkAdapter for NatsGoAdapter {
+    fn name(&self) -> &'static str {
+        ADAPTER_NAME
+    }
+
+    fn lang(&self) -> Lang {
+        Lang::Go
+    }
+
+    fn detect(
+        &self,
+        summary: &FuncSummary,
+        _ast: tree_sitter::Node<'_>,
+        file_bytes: &[u8],
+    ) -> Option<FrameworkBinding> {
+        let matches_call = super::any_callee_matches(summary, callee_is_nats);
+        let matches_source = source_imports_nats(file_bytes);
+        if matches_call || matches_source {
+            Some(FrameworkBinding {
+                adapter: ADAPTER_NAME.to_owned(),
+                kind: EntryKind::MessageHandler {
+                    queue: extract_subject(file_bytes),
+                    message_schema: None,
+                },
+                route: None,
+                request_params: Vec::new(),
+                response_writer: None,
+                middleware: Vec::new(),
+            })
+        } else {
+            None
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn parse_go(src: &[u8]) -> tree_sitter::Tree {
+        let mut parser = tree_sitter::Parser::new();
+        let lang = tree_sitter::Language::from(tree_sitter_go::LANGUAGE);
+        parser.set_language(&lang).unwrap();
+        parser.parse(src, None).unwrap()
+    }
+
+    #[test]
+    fn fires_on_nats_subscribe() {
+        let src: &[u8] = b"package entry\nimport \"github.com/nats-io/nats.go\"\n\
+            func OnMessage(msg *nats.Msg) {}\n\
+            var nc = nats.Connect()\n\
+            var sub, _ = nc.Subscribe(\"events\", OnMessage)\n";
+        let tree = parse_go(src);
+        let summary = FuncSummary {
+            name: "OnMessage".into(),
+            ..Default::default()
+        };
+        let binding = NatsGoAdapter
+            .detect(&summary, tree.root_node(), src)
+            .expect("nats.Subscribe binds");
+        if let EntryKind::MessageHandler { queue, .. } = binding.kind {
+            assert_eq!(queue, "events");
+        }
+    }
+}