Struct LineStreamHandler 

pub struct LineStreamHandler { /* private fields */ }

Streaming per-line output handler: prints each completed output line as soon as it arrives instead of buffering everything until command exit.

Ports the upstream line-buffering fix (ClusterShell commits 65e5433 / GH#528/GH#597): in Python, Display reconfigures sys.stdout / sys.stderr with line_buffering=True so that piped consumers observe lines in real time. Rust’s io::Stdout is already a LineWriter, and this handler additionally flushes after every completed line, giving the same observable behavior: lines arrive as they are produced, not in one block at process exit.

Partial lines are buffered per node and flushed on on_close, so no output is lost even when a node’s final line lacks a trailing newline. Lines print to stdout with the usual node: label unless disabled.

Note: the core ExecWorker currently reports raw pipe fds in on_read (never normalized to 1/2), so stderr chunks cannot be told apart from stdout here — consistent with TaskGatheringHandler, which also folds them into the stdout buffers. Once the core normalizes fds, a fd == 2 branch can route stderr lines to stderr like Python’s print_line_error.

An optional inner handler (e.g. ProgressHandler) is chained after every callback.

Implementations

impl LineStreamHandler

pub fn new(label: bool) -> Self

Create a handler; label controls the node: prefix on lines.

pub fn with_inner(self, inner: Box<dyn EventHandler>) -> Self

Chain another handler (called after this one on every event).

Trait Implementations

impl EventHandler for LineStreamHandler

fn on_start(&mut self, worker: &dyn Worker)

Called when the worker starts.

fn on_read(&mut self, node: &str, fd: RawFd, msg: &[u8])

Called when data is available for reading from a node.

fn on_close(&mut self, node: &str, rc: i32)

Called when a connection to a node is closed.

fn on_timeout(&mut self, node: &str)

Called when a node operation times out.

fn on_error(&mut self, node: &str, error: &WorkerError)

Called when an error occurs for a node.

fn take_buffers( &mut self, ) -> (HashMap<String, Vec<Vec<u8>>>, HashMap<String, Vec<Vec<u8>>>, HashSet<String>)

Extract buffered stdout/stderr data from this handler. Returns (stdout, stderr, timeouts) where stdout/stderr are node -> Vec<chunks>. Default returns empty maps. Used by Task to collect results after execution.