fix(ipc): retry unix socket comms if none available

[LeoBorai]

Instead of sleeping to give time to processes, we now use IPC to check for them

[Copilot]

Pull request overview

This PR aims to make IPC over Unix sockets more resilient during component startup by retrying sends when the target socket isn’t immediately available, and by switching the hub startup flow from a fixed sleep to explicit component readiness checks.

Changes:

• Add a short retry loop waiting for the target Unix socket file to appear before connecting/sending.
• Add tracing dependency to the mate_ipc crate to support new debug logging.
• Replace a fixed startup delay in the hub with wait_for_components() readiness checks (plus minor import cleanup in CLI).

Reviewed changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/ipc/src/transport/unix_socket.rs	Adds socket-availability polling + debug logging before connect/send.
src/ipc/Cargo.toml	Adds tracing as a dependency for IPC crate.
src/cli/src/transport.rs	Import formatting cleanup only.
src/cli/src/process/hub.rs	Replaces fixed sleep with wait_for_components() during process spawn.
Cargo.lock	Locks tracing dependency addition.

Comments suppressed due to low confidence (2)

src/ipc/src/transport/unix_socket.rs:200

• The new socket-availability wait only sleeps 10ms * 3 plus connect retries (10ms + 20ms), so send_message_internal will fail after ~60ms if the target component is still starting. Previously the CLI waited 1s before pinging components, so this change can reintroduce flaky startup failures on slower machines/CI. Consider retrying up to a time-based deadline (e.g., a few seconds) with exponential backoff, or make the retry count/delay configurable.

        let target_socket = Self::socket_path_for_process(&self.base_path, &msg.to);
        let mut tries = 0;

        if !target_socket.exists() {
            loop {
                if target_socket.exists() {
                    break;
                }

                if tries >= UNIX_SOCKET_CONNECTION_RETRIES {
                    return Err(anyhow!(
                        "Target process {:?} socket does not exist at {:?}",
                        msg.to,
                        target_socket
                    ));
                }

                sleep(Duration::from_millis(10)).await;

                tries += 1;

                debug!(
                    "Waiting for target process {:?} socket to be available at {:?} (attempt {}/{})",
                    msg.to, target_socket, tries, UNIX_SOCKET_CONNECTION_RETRIES
                );
            }
        }

        let mut stream =
            Self::connect_with_retry(&target_socket, UNIX_SOCKET_CONNECTION_RETRIES).await?;
        let serialized = serde_json::to_vec(msg)?;
        let len = (serialized.len() as u32).to_le_bytes();

src/ipc/src/transport/unix_socket.rs:200

• There are now two layers of retry logic: a manual target_socket.exists() polling loop and then connect_with_retry(...) which already retries on connect errors (including ENOENT). This duplication increases complexity and extends the overall wait in a hard-to-reason-about way; it would be simpler to consolidate into a single retry/backoff path (and optionally improve the error message when the last error is ENOENT).

        if !target_socket.exists() {
            loop {
                if target_socket.exists() {
                    break;
                }

                if tries >= UNIX_SOCKET_CONNECTION_RETRIES {
                    return Err(anyhow!(
                        "Target process {:?} socket does not exist at {:?}",
                        msg.to,
                        target_socket
                    ));
                }

                sleep(Duration::from_millis(10)).await;

                tries += 1;

                debug!(
                    "Waiting for target process {:?} socket to be available at {:?} (attempt {}/{})",
                    msg.to, target_socket, tries, UNIX_SOCKET_CONNECTION_RETRIES
                );
            }
        }

        let mut stream =
            Self::connect_with_retry(&target_socket, UNIX_SOCKET_CONNECTION_RETRIES).await?;
        let serialized = serde_json::to_vec(msg)?;
        let len = (serialized.len() as u32).to_le_bytes();

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