screencastgen

Pipeline Events

Structured progress reporting for pipelines.

Source: screencastgen/pipelines/events.py

Overview

PipelineReporter bridges human-readable console output and machine-parseable structured events. Pipelines call reporter methods at each phase; consumers (CLI stdout, web progress bridge) receive the output.

Dataclass

`PipelineEvent`

Field	Type	Description
`status`	`str`	Current status (e.g., `"running"`, `"completed"`)
`phase`	`str`	Current phase name
`current`	`int`	Progress numerator
`total`	`int`	Progress denominator
`message`	`str`	Human-readable description
`data`	`dict \\| None`	Optional structured payload for richer UI updates, such as lip-sync page timing

Class: `PipelineReporter`

Constructor

PipelineReporter(stream=sys.stdout, on_event=None, should_cancel=None)

on_event is a callback (PipelineEvent) -> None for structured event consumers. should_cancel is an optional callback used by long-running hosts such as the web worker.

Methods

Method	Description
`cancelled()`	Returns whether the host requested early cancellation
`line(message)`	Write a human-readable line to the stream
`emit(phase, current, total, message, status="running", data=None)`	Publish a structured event and update internal state
`phase_start(phase, message)`	Announce a phase transition

Event Flow

Pipeline Runner
    │
    ├── reporter.phase_start("extraction", "Extracting text...")
    ├── reporter.emit("synthesis", 1, 10, "Chunk 1/10")
    ├── reporter.emit("synthesis", 2, 10, "Chunk 2/10")
    │   ...
    └── reporter.emit("complete", 10, 10, "Done", status="completed")
         │
         ▼
    ┌────────────────┐     ┌──────────────────────┐
    │  CLI stdout    │     │ Progress Reporter   │
    │  (human text)  │     │  (DB + Redis pubsub)  │
    └────────────────┘     └──────────────────────┘

Dependencies

Pipeline Events
└──▶ consumed by Audio Pipeline
     ├──▶ Highlight Pipeline
     ├──▶ Lipsync Pipeline
     ├──▶ Pipeline Common
     └──▶ Progress Reporter (web app)