Module feed 

The server-side half of the live feed: a FeedHub that watches every published blockfile event in-process (a broker observer, so no WebSocket route is involved) and hands each open feed the changes of the one file it follows: an agent’s transcript (output), or a terminal’s output (term, for the terminal feed in super::terminal); plus the pure pieces of the feed’s wire (cursor, frame truncation, SSE framing) the route assembles.

Nothing is buffered without bound for a slow device: a subscription counts the bytes queued for it, and once more than MAX_BEHIND_BYTES wait it stops queueing and receives one HubEvent::Behind, on which the feed sends reset and closes (the device reconnects and gets a snapshot).

Structs

Cursor

Where a feed stands in its stream: the generation it is reading and the next line it has not sent.

FeedHub

Every open feed’s subscription, by the block and file it follows.

FeedSubscription

One feed’s subscription; unsubscribes when dropped.

Subscriber 🔒

Enums

AppendStep

What to do with one published append.

HubEvent

What a subscription receives.

Constants

MAX_BEHIND_BYTES

A stream more than this far behind is reset and closed.

MAX_FRAME_BYTES

A frame longer than this is replaced by an amx_truncated frame.

TERM_FILE

A terminal block’s output file: raw PTY bytes.

TRUNCATED_HEAD_CHARS

How much of a truncated frame is kept, in characters.

Functions

apply_append

Apply one published append to cursor.

device_frame

A frame as the device gets it: as written, or, over MAX_FRAME_BYTES, an amx_truncated frame with its size and head.

device_frames

device_frame over a batch.

parse_event_id

Last-Event-ID read back: (gen, next line).

queued_size 🔒

What records of filename cost a subscriber: a transcript’s lines as the device gets them (wire_size); a terminal’s bytes as they are.

split_records

The lines in published records, split the way blockfile:read_range splits the file, so the counts agree.

sse_event

One SSE event. data is serde output on one line, so no raw newline can end the data: field early.

status_step

Whether a feed sends a status event now, given the state it last sent (shown, updated here) and the state now: Some(Some(_)) sends a state, Some(None) sends state: null so the device drops a chip it shows, None sends nothing. Right after a snapshot (after_snapshot) a known state is always sent; otherwise only a change of state or since_ms is. An agent that has never had a state gets no event at all.

wire_size

About how many bytes records cost on the wire: each line as the device gets it, so at most MAX_FRAME_BYTES however large it is written. One 5 MB tool result is 64 KB behind, not 5 MB.