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

src/dynamic/framework/adapters/kafka_python.rs

@@ -0,0 +1,136 @@
+//! Phase 20 (Track M.2) — Python Kafka consumer adapter.
+//!
+//! Fires when the surrounding source imports the canonical Python
+//! Kafka clients (`kafka-python` or `confluent-kafka`) and the function
+//! body invokes a consumer-shaped callee.  The binding's
+//! [`EntryKind::MessageHandler`] is stamped with a best-effort `queue`
+//! extracted from the source (a `KafkaConsumer('topic', ...)` /
+//! `Consumer({"group.id": ..., "topics": ["t"]}).subscribe([...])`
+//! literal); a missing topic falls back to the empty string.
+
+use crate::dynamic::framework::{FrameworkAdapter, FrameworkBinding};
+use crate::evidence::EntryKind;
+use crate::summary::FuncSummary;
+use crate::symbol::Lang;
+
+pub struct KafkaPythonAdapter;
+
+const ADAPTER_NAME: &str = "kafka-python";
+
+fn callee_is_kafka_consumer(name: &str) -> bool {
+    let last = name.rsplit_once('.').map(|(_, s)| s).unwrap_or(name);
+    matches!(
+        last,
+        "KafkaConsumer" | "Consumer" | "subscribe" | "poll" | "consume" | "process_message"
+    )
+}
+
+fn source_imports_kafka(file_bytes: &[u8]) -> bool {
+    const NEEDLES: &[&[u8]] = &[
+        b"from kafka",
+        b"import kafka",
+        b"from confluent_kafka",
+        b"import confluent_kafka",
+    ];
+    NEEDLES
+        .iter()
+        .any(|n| file_bytes.windows(n.len()).any(|w| w == *n))
+}
+
+fn extract_topic_literal(file_bytes: &[u8]) -> String {
+    let text = std::str::from_utf8(file_bytes).unwrap_or("");
+    for needle in ["KafkaConsumer(", ".subscribe(", "topic="] {
+        if let Some(idx) = text.find(needle) {
+            let after = &text[idx + needle.len()..];
+            for (open, close) in [('"', '"'), ('\'', '\'')] {
+                if let Some(o) = after.find(open) {
+                    let rest = &after[o + 1..];
+                    if let Some(c) = rest.find(close) {
+                        return rest[..c].to_owned();
+                    }
+                }
+            }
+        }
+    }
+    String::new()
+}
+
+impl FrameworkAdapter for KafkaPythonAdapter {
+    fn name(&self) -> &'static str {
+        ADAPTER_NAME
+    }
+
+    fn lang(&self) -> Lang {
+        Lang::Python
+    }
+
+    fn detect(
+        &self,
+        summary: &FuncSummary,
+        _ast: tree_sitter::Node<'_>,
+        file_bytes: &[u8],
+    ) -> Option<FrameworkBinding> {
+        let matches_call = super::any_callee_matches(summary, callee_is_kafka_consumer);
+        let matches_source = source_imports_kafka(file_bytes);
+        if matches_call || matches_source {
+            Some(FrameworkBinding {
+                adapter: ADAPTER_NAME.to_owned(),
+                kind: EntryKind::MessageHandler {
+                    queue: extract_topic_literal(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_python(src: &[u8]) -> tree_sitter::Tree {
+        let mut parser = tree_sitter::Parser::new();
+        let lang = tree_sitter::Language::from(tree_sitter_python::LANGUAGE);
+        parser.set_language(&lang).unwrap();
+        parser.parse(src, None).unwrap()
+    }
+
+    #[test]
+    fn fires_on_kafka_python_consumer() {
+        let src: &[u8] = b"from kafka import KafkaConsumer\n\n\
+            def handler(msg):\n    print(msg)\n\n\
+            consumer = KafkaConsumer('orders', bootstrap_servers='broker:9092')\n";
+        let tree = parse_python(src);
+        let summary = FuncSummary {
+            name: "handler".into(),
+            ..Default::default()
+        };
+        let binding = KafkaPythonAdapter
+            .detect(&summary, tree.root_node(), src)
+            .expect("kafka import binds");
+        assert_eq!(binding.adapter, "kafka-python");
+        assert!(matches!(binding.kind, EntryKind::MessageHandler { .. }));
+        if let EntryKind::MessageHandler { queue, .. } = binding.kind {
+            assert_eq!(queue, "orders");
+        }
+    }
+
+    #[test]
+    fn skips_plain_function() {
+        let src: &[u8] = b"def add(a, b):\n    return a + b\n";
+        let tree = parse_python(src);
+        let summary = FuncSummary {
+            name: "add".into(),
+            ..Default::default()
+        };
+        assert!(KafkaPythonAdapter
+            .detect(&summary, tree.root_node(), src)
+            .is_none());
+    }
+}