demo

Pacto dashboard — WebAssembly demo

A static, browser-only build of pacto dashboard. The Pacto engine and a curated set of demo contracts are compiled to WebAssembly and baked in, so the whole dashboard — fleet, dependency graph, version history, version diff, readiness — runs client-side with no backend and no live registry.

Live site: https://trianalab.github.io/pacto/demo/

How it works

index.html ─► assets/*          the dashboard's Svelte UI, rebuilt with base=/pacto/demo/
   ├─ wasm_exec.js              Go's wasm runtime glue
   └─ boot.js                   loads app.wasm; routes /api,/health,/metrics into wasm
                                     │
   app fetch('/api/services') ──────┘  (a fetch shim intercepts only those paths)
                                     ▼
                                app.wasm: httptest → Pacto's Huma handlers
                                     │
                                EmbedSource  (dashboard.DataSource over //go:embed bundles)

• source_embed.go — indexes the embedded bundles and implements dashboard.DataSource.
• main_wasm.go — builds the dashboard's Huma API in memory and exposes __pactoServe.
• boot.js — loads the wasm engine and shims fetch for /api, /health, /metrics.

The graph, dependents and cross-reference views derive from each contract's declared dependencies (every referenced service is embedded), so no OCI resolver is needed.

Build

Requirements: Go 1.26+, Node 22+, make.

make build                 # builds dist/ at base /pacto/demo/
make build BASE=/          # build at site root for local preview
make smoke                 # exercise the built wasm engine in Node
make serve                 # preview at http://localhost:8088/pacto/demo/

make build rebuilds the dashboard UI from ../../pkg/dashboard/frontend into a scratch dir and copies it into dist/; it never modifies the committed pkg/dashboard/ui (which the real pacto dashboard server uses).

Explore the contracts on the CLI (offline)

These work on the local bundles with no registry. Build the CLI first with make build at the repo root.

# A breaking change: payments-service v1.2.0 -> v2.0.0 (drops /charges).
make breaking-change

# A non-breaking evolution: v1.0.0 -> v1.1.0.
make evolution

# Inspect any contract.
make explain REF=bundles/payments-service/v2.1.0

Full contract validation (pacto validate) and live graph resolution (pacto graph) resolve refs over the network and require the contracts to be published to a registry; this demo publishes nothing, so use the live dashboard above for the dependency graph.

Size

app.wasm is ≈52 MB raw / ~9.6 MB gzipped: it links Kubernetes and OCI client init code that the demo never calls, which dead-code elimination can't drop. Acceptable for a cached static asset.

Don't use sudo

This build never needs root. A single sudo make leaves root-owned artifacts that wedge later non-sudo builds; the Makefile's preflight detects this and prints a one-time fix.