mirror of
https://github.com/priyanshujain/sanderling.git
synced 2026-10-02 19:17:10 +00:00
81 lines
3.5 KiB
Markdown
81 lines
3.5 KiB
Markdown
---
|
|
title: Architecture
|
|
---
|
|
|
|
# Architecture
|
|
|
|
```mermaid
|
|
flowchart TB
|
|
subgraph go["sanderling (Go)"]
|
|
direction LR
|
|
B["Bundler / esbuild"] --> V["Verifier / goja + LTL"]
|
|
V <--> R["Runner"]
|
|
R --> D["DeviceDriver"]
|
|
R --> T["Trace writer\nJSONL + PNG"]
|
|
end
|
|
|
|
SC["Maestro sidecar (JVM)"]
|
|
SDK["in-app SDK\n(Device / Emulator)"]
|
|
CH["Chrome (CDP)"]
|
|
RD[("runs/")]
|
|
IN["sanderling inspect\nHTTP + SSE"]
|
|
UI["Web UI (React)"]
|
|
|
|
D -->|gRPC| SC
|
|
SC -->|UIAutomator / XCTest| SDK
|
|
R -->|"Unix socket<br/>(pause / state / logs)"| SDK
|
|
D -->|CDP| CH
|
|
|
|
T --> RD --> IN --> UI
|
|
```
|
|
|
|
## Processes
|
|
|
|
**sanderling (Go).** The top-level binary. Bundles the spec with esbuild, evaluates it in goja, runs the main loop, dispatches actions through the `DeviceDriver` interface, writes the trace.
|
|
|
|
**Maestro sidecar (JVM).** A Kotlin process that wraps `maestro-client` and exposes a gRPC surface matching the `DeviceDriver` interface. Handles UI input, screenshots, the system accessibility tree, and OS-level alerts. Native platforms only.
|
|
|
|
**In-app SDK.** A Kotlin (or Swift for iOS) library linked into the app under test. Exposes a Unix socket to the runner. Provides pause and resume, view-hierarchy dumps, coverage reads, log capture, and user-registered state extractors. Native platforms only.
|
|
|
|
**Chrome (CDP).** For web targets, the Go binary drives Chrome directly over the Chrome DevTools Protocol. No sidecar or in-app SDK is involved.
|
|
|
|
## Transports
|
|
|
|
| Channel | Platform | Transport | Purpose |
|
|
|---|---|---|---|
|
|
| Go to Maestro sidecar | Native | gRPC (localhost TCP) | UI input, screenshots, system alerts |
|
|
| Go to in-app SDK | Native | Unix domain socket | Pause / resume, hierarchy, coverage, logs, extractors |
|
|
| Go to Chrome | Web | Chrome DevTools Protocol | UI input, screenshots, DOM hierarchy, console logs |
|
|
|
|
On native, the transport split exists because only real UI events need to cross process and OS-API boundaries. Introspection is cheap, frequent, and lives on a fast local socket directly to the app. On web, CDP handles both.
|
|
|
|
## Inspect UI
|
|
|
|
`sanderling inspect` is a separate mode of the same Go binary. It serves an embedded React bundle and reads `runs/` from disk, streaming file-watcher events over SSE so the UI updates as new steps land. It has no connection to any driver; it only consumes the trace artifacts.
|
|
|
|
## Per-step cycle
|
|
|
|
The heart of the system is:
|
|
|
|
```
|
|
pause ─► capture state ─► evaluate properties ─► pick action ─► resume ─► dispatch
|
|
```
|
|
|
|
**Native (Android / iOS):**
|
|
|
|
1. The runner asks the driver to wait until the UI is idle.
|
|
2. The runner sends `PAUSE` to the SDK over the Unix socket. The SDK freezes the main runloop at a safe point.
|
|
3. The SDK sends back a `STATE` message: view hierarchy, coverage delta, logs since last step, exception list, snapshot values.
|
|
4. The runner feeds state into goja. Extractors re-read; properties re-evaluate; the action generator returns a weighted tree.
|
|
5. The runner writes the trace entry for this step.
|
|
6. The runner picks an action by weight.
|
|
7. The runner sends `RESUME` to the SDK, then dispatches the action through the driver (gRPC to sidecar → Maestro → UIAutomator or XCTest).
|
|
8. Loop.
|
|
|
|
**Web (Chrome):**
|
|
|
|
Steps 2-3 use CDP to capture the DOM hierarchy and console logs directly; there is no SDK pause/resume. The rest of the cycle is identical.
|
|
|
|
The cycle runs hundreds of times per minute. Every step produces one row in `trace.jsonl` and one screenshot.
|
|
|