feat: manage multiple ssh machines from one client (#3670)

1 files changed, 63 insertions, 0 deletions

diff --git a/src/client/endpoint/control.rs b/src/client/endpoint/control.rs
new file mode 100644
index 00000000..7cf1159f
--- /dev/null
+++ b/src/client/endpoint/control.rs
@@ -0,0 +1,63 @@
+use super::ClientEndpointId;
+
+pub(crate) enum EndpointControlMessage {
+    HealthPong,
+    Snapshot(Box<crate::protocol::ClientShellSnapshot>),
+    Ignored,
+}
+
+pub(crate) fn decode_endpoint_control(
+    kind: &str,
+    data: &str,
+) -> Result<EndpointControlMessage, String> {
+    if kind == crate::protocol::endpoint::HEALTH_PONG_KIND {
+        return Ok(EndpointControlMessage::HealthPong);
+    }
+    if kind == crate::protocol::endpoint::ENDPOINT_SNAPSHOT_KIND {
+        let snapshot = serde_json::from_str(data)
+            .map_err(|error| format!("invalid endpoint snapshot: {error}"))?;
+        return Ok(EndpointControlMessage::Snapshot(Box::new(snapshot)));
+    }
+    if kind.starts_with("shell.snapshot.") {
+        return Err(format!(
+            "unsupported mandatory endpoint snapshot codec {kind:?}"
+        ));
+    }
+    Ok(EndpointControlMessage::Ignored)
+}
+
+pub(crate) fn protocol_failure_is_fatal(endpoint_id: &ClientEndpointId) -> bool {
+    endpoint_id.is_local()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::client::endpoint::ProfileId;
+
+    #[test]
+    fn unknown_optional_controls_are_ignored() {
+        assert!(matches!(
+            decode_endpoint_control("future.optional", "not json").unwrap(),
+            EndpointControlMessage::Ignored
+        ));
+    }
+
+    #[test]
+    fn unknown_snapshot_codecs_are_rejected() {
+        assert_eq!(
+            decode_endpoint_control("shell.snapshot.v2", "{}")
+                .err()
+                .as_deref(),
+            Some("unsupported mandatory endpoint snapshot codec \"shell.snapshot.v2\"")
+        );
+    }
+
+    #[test]
+    fn only_local_protocol_failures_end_the_client() {
+        let remote =
+            ClientEndpointId::Ssh(ProfileId::parse("0123456789abcdef0123456789abcdef").unwrap());
+        assert!(protocol_failure_is_fatal(&ClientEndpointId::Local));
+        assert!(!protocol_failure_is_fatal(&remote));
+    }
+}