CrawlerFlow

CrawlerFlow is a declarative, YAML-based workflow engine for browser automation and web scraping. Workflows describe what should happen; adapters and steps decide how it happens.

Current foundation

• Versioned YAML workflow loading and validation
• Browser-independent adapter contract and a lazy-starting Pydoll implementation
• Extensible step registry
• Isolated plugin API with typed YAML settings, lifecycle hooks, steps, filters, and subscribers
• Async workflow executor and event bus
• Variable interpolation and a built-in expression engine
• Per-run today and now date variables
• Nested foreach, foreach_date, foreach_select, and declarative if control flow
• Reusable parameterized workflow macros
• Per-step retry and continue/fail error policies
• JSON Lines workflow, step, retry, and request event logging
• Built-in navigation, interaction, cookies, downloads, screenshots, and selective HTML output
• run, validate, list-steps, list-plugins, and doctor CLI commands

Development

python -m pip install -e ".[dev]"
pytest
crawlerflow validate examples/basic.yaml
crawlerflow run examples/basic.yaml

Run multiple workflows sequentially by supplying more paths. Execution stops at the first failed workflow:

crawlerflow run examples/first-site.yaml examples/second-site.yaml

A directory argument discovers its directly contained .yaml and .yml files and runs them in alphabetical order:

crawlerflow run examples

Use asynchronous mode to run every supplied workflow in parallel. All workflows are allowed to finish; the command exits with code 1 if any workflow fails:

crawlerflow run --mode async examples/first-site.yaml examples/second-site.yaml

Directory discovery can also be combined with parallel execution:

crawlerflow run --mode async examples

Add --progress to display a live progress bar based on the total workflow count. The bar advances as each workflow succeeds or fails in both sequential and asynchronous modes:

crawlerflow run --mode async --progress examples

Use --concurrency (or -c) to limit how many workflows run at the same time in asynchronous mode. This avoids starting every HTTP client or browser session simultaneously:

crawlerflow run --mode async --concurrency 8 --progress examples

Omitting the option preserves unlimited parallel execution. --concurrency accepts positive integers and can only be used with --mode async.

Install browser support and select Pydoll in a workflow:

python -m pip install -e ".[browser,dev]"

browser:
  engine: pydoll
  headless: true

Browser-free workflows omit the browser section. Applications can also inject another BrowserAdapter into WorkflowRunner. See docs/http-requests.md for direct HTTP requests and shortened map URL coordinate resolution.

External extensions can register entry points under crawlerflow.plugins; workflows activate only the plugins they list. See docs/plugins.md and the installable examples/plugins/example package for the plugin contract, discovery command, and packaging example.