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Bflow

Workflow Execution

🌊 Workflow Execution

Section titled “🌊 Workflow Execution”

Workflows in Bflow are declarative, version-controllable JSON files. You can execute them headless in CI/CD pipelines or headed on your local desktop.

🚀 Running a Workflow

Section titled “🚀 Running a Workflow”

Headless Execution (Default / CI Mode)

Section titled “Headless Execution (Default / CI Mode)”

Headless mode runs Chrome invisibly in the background. It is blazing fast and ideal for automated testing, cron jobs, and CI/CD pipelines:

Terminal window
bun flow workflows/hn-top-stories.json

Headed Execution (Visible Chrome Window)

Section titled “Headed Execution (Visible Chrome Window)”

Headed mode launches a visible Chrome window so you can watch each step execute live in real time:

Terminal window
bun flow workflows/hn-top-stories.json --headed

🔄 Dynamic Variable Overrides

Section titled “🔄 Dynamic Variable Overrides”

You can pass dynamic variables into any workflow via CLI arguments. This allows you to write reusable templates:

Terminal window
bun flow workflows/search-workflow.json --query="Bun runtime" --limit=10

Inside your workflow JSON, use {{variableName}} syntax:

{
  "name": "Search Workflow",
  "startUrl": "https://duckduckgo.com",
  "variables": {
    "query": "Default Query",
    "limit": 5
  },
  "steps": [
    { "action": "goto", "url": "https://duckduckgo.com" },
    { "action": "type", "selector": "input[name='q']", "text": "{{query}}" },
    { "action": "click", "selector": "button[type='submit']" }
  ]
}

Nested paths and transformation pipelines are also supported:

{
  "action": "type",
  "selector": "#email",
  "text": "{{row.contact.email | trim | lowercase}}"
}

Use {{env.SECRET_NAME}} for secrets. Missing environment references fail instead of being typed literally. Variable precedence from highest to lowest is system values, CLI overrides, workflow variables, row values, and step-local variables.

🧾 Running Once Per External Row

Section titled “🧾 Running Once Per External Row”

Use the data-aware command when every provider row should receive an isolated browser run:

Terminal window
bun workflow run workflows/signup.json \
  --data='google-sheets://SPREADSHEET_ID/Users?range=A:E' \
  --dry-run

After reviewing the dry-run summary, remove --dry-run. Data runs can filter rows, use bounded parallel workers, retry transient failures, resume checkpoints, and write status/results back without changing source cells. See External Data for the full workflow structure.

📄 Example Workflow: Hacker News Scraper

Section titled “📄 Example Workflow: Hacker News Scraper”

Here is a complete workflow example (workflows/hn-top-stories.json):

{
  "name": "Hacker News Top Stories",
  "startUrl": "https://news.ycombinator.com",
  "variables": {
    "targetSite": "news.ycombinator.com"
  },
  "steps": [
    {
      "action": "goto",
      "url": "https://news.ycombinator.com",
      "waitUntil": "domcontentloaded"
    },
    {
      "action": "assert",
      "text": "Hacker News",
      "contains": "Hacker News"
    },
    {
      "action": "extractMultiple",
      "containerSelector": ".athing",
      "as": "topStories",
      "limit": 10,
      "fields": {
        "title": ".titleline > a",
        "url": ".titleline > a@href"
      }
    },
    {
      "action": "screenshot",
      "path": "output/hn-top.png",
      "fullPage": true
    },
    {
      "action": "save",
      "path": "output/hn-stories.json",
      "format": "json"
    }
  ]
}

📊 Workflow Execution Output

Section titled “📊 Workflow Execution Output”

When a workflow runs, the CLI logs a step-by-step progress report with execution times:

🌊 Starting flow: Hacker News Top Stories (5 steps)
  [1/5] 🌐 goto https://news.ycombinator.com ... ✓ (284ms)
  [2/5] 🔎 assert "Hacker News" ... ✓ (12ms)
  [3/5] 📊 extractMultiple (.athing) -> topStories (10 items) ... ✓ (45ms)
  [4/5] 📷 screenshot -> output/hn-top.png ... ✓ (120ms)
  [5/5] 💾 save -> output/hn-stories.json ... ✓ (4ms)


✨ Flow completed successfully in 465ms!

Normal workflow results, screenshots, PDFs, and saved extracts are written beneath output/ relative to the current working directory. Data-driven runs suppress per-row result files and write one workflow-<run-id>-summary.json plus a resumable workflow state file.