Fernsicht (Python)

Remote progress tracking over WebRTC. Wrap your loop, get a shareable URL, watch from anywhere.

Install

pip install fernsicht

Quick Start

from fernsicht import blick

# Wrap any iterable
for item in blick(range(10000), desc="Training"):
    process(item)

# Allow up to 4 concurrent viewers
for item in blick(range(10000), desc="Training", max_viewers=4):
    process(item)

# Manual updates
from fernsicht import manual

bar = manual(total=100, desc="Uploading")
for chunk in stream:
    upload(chunk)
    bar.update(len(chunk))
bar.close()

# Context manager
with blick(total=500, desc="Epochs") as bar:
    for batch in data_loader:
        train(batch)
        bar.update(len(batch))

A URL like https://.../#room=<id>&role=viewer is printed when the bar starts. Open it on your phone or another machine to watch live progress including elapsed time, ETA, rate, and item count.

Configuration

No configuration is required for the default hosted node — the SDK points at https://signal.fernsicht.space out of the box.

Self-hosting

To use your own signaling server:

export FERNSICHT_SERVER_URL="https://your-signal-domain"

Authenticated session endpoint

If your server requires an API key on POST /session:

export FERNSICHT_SESSION_API_KEY="your-api-key"

Viewer limits

• Default is max_viewers=8 (matches the R SDK and CLI defaults).
• Pass max_viewers=1 for a single-viewer-only room, or any value up to the server's MAX_VIEWERS_PER_ROOM cap.
• The server enforces an upper bound via MAX_VIEWERS_PER_ROOM.

How it works

1. blick() calls POST /session on the signaling server, which creates a new room and returns a sender_secret.
2. A background thread polls GET /poll/{room}?secret=… every ~25 seconds to check for viewer connections.
3. When a viewer opens the link, it posts a WebRTC offer; the sender thread picks it up, creates an answer, and completes the handshake.
4. Progress data flows directly over the WebRTC DataChannel — the server is never in the data path.

No persistent connection is held by the SDK. Between polls, the background thread is idle.

Other ways to use Fernsicht

Don't want to add a blick() import? Two alternatives:

• CLI — fernsicht run -- python train.py wraps any command and auto-detects tqdm/[N/M]/percent-style progress with no code change. See cli/README.md.
• R — remotes::install_github("MuteJester/Fernsicht", subdir="publishers/r") for the R sibling SDK.

All three speak the same wire protocol; rooms / viewer URLs / hosted defaults are identical.