feat: add visual builder + workspace mode to Burr UI by andreahlert · Pull Request #687 · apache/burr

andreahlert · 2026-03-23T05:13:05Z

Building on #667 (Graph Builder by @skrawcz), this adds a workspace mode and significantly enhanced builder that turns Burr's UI into a development environment.

What's new

Visual Builder (enhanced)

9 node types: Action, Input, Result, LLM Call, API Call, Code, Streaming, Loop, Router
Each type has specialized property editors (LLM: provider/model, API: url/method, Code: inline editor, Router: branch conditions)
Inline + button on edges (Activepieces-style) with searchable type picker
Recursive layout algorithm (replaces dagre) supporting loop arcs and router fan-out/fan-in
Node type picker with search bar and categories (I/O, Logic, Integrations)

Monaco Editor (split view)

Builder canvas on the left, VS Code-style editor on the right
Multi-file code generation: actions.py, app.py, run.py, requirements.txt
File explorer sidebar with tabs (open/close files)
Bidirectional sync: edit code and the graph updates, edit graph and the code updates
Full Ctrl+C/V/Z support in both canvas and editor

Project save/load

File menu (New, Save, Open, Download .py)
Projects persisted server-side in ~/.burr/builder_projects/
Ctrl+S to save

Workspace integration

Backend workspace router with file browsing, code viewing, and script execution (SSE streaming)
Link workspace directories to projects
Path traversal protection with workspace validation

Other improvements

Undo/redo with 50-state history
Keyboard shortcuts (Delete to remove nodes, Ctrl+C/V to copy/paste nodes)
Code generation includes proper imports, sanitized identifiers, and with_tracker()

Screenshots

Builder with nodes and generated code

Node editor with LLM Call configuration

Searchable node type picker

Technical details

Backend (Python)

burr/tracking/server/workspace.py: new APIRouter with endpoints for file tree, file content, script execution (SSE), process management, workspace links, and builder project persistence
Modified run.py to mount workspace router, schema.py to add supports_workspace

Frontend (~6,700 new lines)

utils/: builderTypes, codeGenerator (9 node types + multi-file), codeParser (bidirectional sync), flowLayout (recursive layout), treeUtils (immutable tree ops), stateFlow
hooks/useBuilderState.ts: tree-based state with undo/redo, keyboard shortcuts, save/load
builder/: BuilderView (split layout), BuilderGraph (ReactFlow with custom node/edge types), NodeEditor, NodeTypePicker (portal-based), 4 node components, 5 edge components with inline + buttons
workspace/: FileExplorer, CodeViewer, RunTerminal, WorkspaceSelector
project/: ProjectWorkspaceView, ActivityBar, SidePanel, TabBar, TrackingSidePanel

Dependencies added

@monaco-editor/react (MIT)
@tanstack/react-query (MIT)
@xyflow/react (MIT)
react-joyride (MIT)

All MIT license, ASF Category A compatible.

How I tested

npx tsc --noEmit zero errors
Backend endpoints tested with curl
Manual E2E: create flow, add nodes via toolbar and inline +, edit properties, see code update, save/load projects

Checklist

PR has an informative and human-readable title
Changes are limited to a single goal
Code passed the pre-commit check
New functions are documented
Placeholder code is flagged / future TODOs are captured in comments

burr/tracking/server/workspace.py

skrawcz · 2026-03-28T06:17:16Z

@andreahlert I can't get this to run locally -- did you commit everything? otherwise see the CI failures.

skrawcz · 2026-03-28T06:21:37Z

Also need some example to load to help someone get started.

andreahlert · 2026-03-28T12:33:22Z

Thanks for reviewing. Didn't have the time to check it properly, I'll do it as soon as possible. Target: 03-30-2026

andreahlert · 2026-03-28T20:12:09Z

Thanks for trying it out. Two things:

Missing pieces: This PR is meant to be applied on top of feat: add visual Graph Builder tool to Burr UI #667 (your graph builder). On main alone, the builder route works but some of the other UI improvements (HomeView, SearchView, etc.) won't be there. The builder itself at /builder should load fine since all its deps are self-contained. I'll add a note about this in the PR description.
Example graphs: Good call. I'll add a few pre-loaded examples (chatbot flow, data pipeline, agent with tools) that load from the File > Open menu so someone can see the builder in action without building from scratch.

Working on both now.

JiwaniZakir

In run.py, the shutdown sequence in lifespan calls await workspace.cleanup_processes() directly before await backend.lifespan(app).__anext__(), but there's no try/finally wrapping these calls. If cleanup_processes() raises an exception, the backend's own cleanup will be silently skipped, potentially leaking database connections or other resources. The backend shutdown should be guarded with a try/finally block regardless of what happens in workspace cleanup.

Additionally, supports_workspace=True is hardcoded unconditionally in _get_app_spec() — this means the UI will always advertise workspace support even if the feature is disabled or broken at runtime. This should be derived from a config flag or at least check that the workspace module initialized successfully, similar to how is_snapshotting_backend and is_annotations_backend are computed from the actual backend capabilities.

The _validate_workspace allowlist approach in workspace.py is a reasonable security boundary, but _read_links() is called on every file-browsing request with no caching. If the links file is read from disk on each API call under load, this could become a bottleneck — a short-lived in-process cache or memoization with invalidation on write would be worth considering.

skrawcz · 2026-03-29T16:28:18Z

validated things load locally at least.

elijahbenizzy

Played around some -- looking great! Node types should probably have specific implementations but I think this is a good start to put out there.

Adds a low-code visual builder with split-view Monaco editor, workspace file browsing, and project persistence. Builder features: - 9 node types (Action, Input, Result, LLM Call, API Call, Code, Streaming, Loop, Router) with specialized property editors - Inline + buttons on edges for inserting nodes (Activepieces-style) - Recursive layout algorithm supporting loop arcs and router fan-out - Monaco Editor with multi-file code generation (actions.py, app.py, run.py, requirements.txt) - Bidirectional sync between graph and code - Searchable node type picker with categories - File menu with save/load projects, Ctrl+S support - Undo/redo (50-state history), copy/paste, delete shortcuts - Code generation with sanitized identifiers and proper imports Workspace features: - Backend router for file browsing, code viewing, script execution (SSE streaming), process management, and workspace-project linking - Builder project persistence in ~/.burr/builder_projects/ - Path traversal protection with workspace validation New dependencies (all MIT, ASF Category A): - @monaco-editor/react - @tanstack/react-query - @xyflow/react - react-joyride

- Remove unused imports/variables flagged by ESLint - Replace regex literal with RegExp constructor to avoid no-control-regex - Format workspace.py with black and isort

- Replace `as any` with proper types where possible - Add eslint-disable comments for icon type maps (heroicons ForwardRef) - Remove unused `id` from edge component destructures - Remove unused `langMap` variable from BuilderView

@jaeyow

This takes work from @jaeyow and apache#572. Adds a drag-and-drop graph editor for designing Burr application graphs visually and exporting as Python code or JSON. Key changes: - New /graph-builder route with full visual editor (ReactFlow v12) - Migrate existing GraphView from reactflow v11 to @xyflow/react v12 - Remove reactflow and @tisoap/react-flow-smart-edge dependencies - Per-node async/streaming toggles matching Burr's 4 action variants - Python code generation with correct decorators and signatures - 3 pre-built example graphs (MultiModal Chatbot, CRAG, Streaming) - localStorage auto-save/restore of graph state - Empty-state onboarding overlay and structured help sidebar - Fix appcontainer layout for full-height content

Python (workspace.py): - Module-level docstring describing all capabilities - Docstrings on all Pydantic models, endpoints, and helper functions - Documented security functions with Args/Returns/Raises TypeScript: - JSDoc on all exported types in builderTypes, codeGenerator, codeParser - JSDoc on all tree operation functions in treeUtils - JSDoc on layout algorithm functions in flowLayout - JSDoc on useBuilderState hook

Remove the legacy react-query v3 package and standardize on @tanstack/react-query v5 across all components. This fixes the "No QueryClient set" error in BuilderView which was caused by two separate QueryClient providers from different packages.

Wrap workspace.cleanup_processes() in try/finally so backend shutdown always runs even if process cleanup fails. Derive supports_workspace from workspace.is_available() instead of hardcoding True. Add in-process cache to _read_links() to avoid disk reads on every file-browsing request.

andreahlert · 2026-04-09T14:12:30Z

All review feedback addressed. Rebased clean on main, no conflicts.

@JiwaniZakir your three points: cleanup_processes() is wrapped in try/finally now so backend shutdown always runs, supports_workspace is derived from workspace.is_available() instead of hardcoded, and _read_links() has an in-process cache with invalidation on write.

@skrawcz docstrings on every function/class in workspace.py, including the inner ones. Examples were already in from the graph-builder merge.

@elijahbenizzy opened #735 to track the node type implementations as a follow-up. Agreed it's fine for the initial merge.

Ready for re-review whenever you get a chance.

skrawcz reviewed Mar 28, 2026

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skrawcz reviewed Mar 28, 2026

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andreahlert self-assigned this Mar 28, 2026

JiwaniZakir reviewed Mar 29, 2026

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andreahlert added kind/feature Net-new functionality area/ui Burr UI (telemetry frontend) labels Mar 30, 2026

elijahbenizzy reviewed Apr 4, 2026

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andreahlert and others added 11 commits April 9, 2026 10:23

fix: resolve CI lint errors

11dcd5f

- Remove unused imports/variables flagged by ESLint - Replace regex literal with RegExp constructor to avoid no-control-regex - Format workspace.py with black and isort

fix: format workspace.py with black --line-length=100

0d3718a

fix: sort imports in run.py for isort

304b76b

fix: add eslint-disable for ANSI regex control character

4335a70

fix: remove unused useCallback import and console.error

54b8530

andreahlert force-pushed the feat/workspace-builder-lowcode branch from 898f6be to 0fff68f Compare April 9, 2026 13:34

docs: add docstrings to inner functions in stream_output

46d22ff

andreahlert requested review from JiwaniZakir, elijahbenizzy and skrawcz April 9, 2026 14:11

andreahlert mentioned this pull request Apr 9, 2026

Builder: node types with specific implementations #735

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feat: add visual builder + workspace mode to Burr UI#687

feat: add visual builder + workspace mode to Burr UI#687
andreahlert wants to merge 12 commits intoapache:mainfrom
andreahlert:feat/workspace-builder-lowcode

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