Rene Nochebuena
e978d60851
Introduces code.nochebuena.dev/einherjar/spa-server — a container-first HTTP
server for single-page applications and progressive web apps. Produces a Docker
base image; downstream SPA Dockerfiles require only a single COPY instruction.
Interfaces and types (CT-6: one TypeSpec per file):
- Config — Port (EINHERJAR_SPA_PORT, default 8080) and StaticDir
(EINHERJAR_SPA_STATIC_DIR, default /srv/www); parsed via os.Getenv
- Server — implements lifecycle.Component; registered with launcher.New
Implementation:
- NewServer(logger, cfg) *Server — returns a lifecycle-managed HTTP server
- OnInit: builds http.NewServeMux with GET /health and /* routes
- OnStart: binds TCP listener synchronously via net.Listen (port conflicts
surface immediately), then serves in a background goroutine
- OnStop: graceful shutdown via http.Server.Shutdown with 10s timeout
spa.NewHandler(logger, staticDir) http.Handler:
- Uses http.Dir.Open for path sanitisation (prevents directory traversal)
- File exists and is not a directory → served by http.FileServer
- File missing or is a directory → serves index.html (SPA router owns all routes)
- Directory listing is disabled
health.NewHandler(logger) http.Handler:
- Always responds 200 {"status":"UP","components":{}}
- Wire format matches web/health.Response without importing the web module
- No external checks — process reachability is the only meaningful health signal
Config (EINHERJAR_SPA_* env vars):
Port(8080), StaticDir(/srv/www)
Docker:
- Multi-stage: golang:1.26-alpine builder → alpine:3.21 runtime
- Image published as:
code.nochebuena.dev/einherjar/spa-server:v1.0.0
code.nochebuena.dev/einherjar/spa-server:latest
- VOLUME ["/srv/www"] declared; consumer overrides via COPY or volume mount
No external dependencies beyond contracts, core, and the Go standard library.
87 lines
2.6 KiB
Markdown
87 lines
2.6 KiB
Markdown
# einherjar/spa-server
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[](https://code.nochebuena.dev/einherjar/spa-server)
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[](LICENSE)
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[](https://go.dev)
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> A shield wall holds because every warrior knows their position. The SPA asks only for the wall — not for every soldier's name.
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`code.nochebuena.dev/einherjar/spa-server` is a container-first HTTP server for single-page applications and progressive web apps. It serves static assets directly and falls back to `index.html` for any path that does not resolve to a file on disk — the standard SPA routing contract.
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The module ships as a ready-to-use Docker base image. Deploying a SPA to a container requires a single `COPY` instruction. No nginx, no custom configuration, no index.html redirect logic to maintain.
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---
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## Container usage
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```dockerfile
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FROM code.nochebuena.dev/einherjar/spa-server:v1.0.0
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COPY dist/ /srv/www/
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```
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That is the complete Dockerfile for a production SPA container.
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---
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## Environment variables
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| Variable | Default | Description |
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| `EINHERJAR_SPA_PORT` | `8080` | TCP port the server listens on |
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| `EINHERJAR_SPA_STATIC_DIR` | `/srv/www` | Path to the directory containing `index.html` and assets |
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| `EINHERJAR_LOG_LEVEL` | `INFO` | Log level: `DEBUG`, `INFO`, `WARN`, `ERROR` |
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---
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## Health endpoint
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`GET /health` returns `200 OK` with a JSON body consistent with all Einherjar health responses:
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```json
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{"status":"UP","components":{}}
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```
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`503 Service Unavailable` is never returned — if the process is alive, it is healthy. Wire `/health` directly to your container liveness and readiness probes.
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---
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## Routing behaviour
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| Request | Result |
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|---|---|
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| `/app.js` — file exists | Served directly with correct `Content-Type` |
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| `/assets/logo.png` — file exists | Served directly |
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| `/dashboard` — no matching file | `index.html` served (SPA router handles it) |
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| `/` — directory | `index.html` served (directory listing is disabled) |
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---
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## Dependency graph
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```
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contracts (zero dependencies)
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↑
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core
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↑
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spa-server (contracts, core, stdlib only)
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```
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No external dependencies beyond the Go standard library.
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---
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## Verification
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```bash
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cd spa-server/
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go build ./...
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go vet ./...
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go test ./...
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gofmt -l .
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```
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---
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> *A shield wall holds because every warrior knows their position.*
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> *The SPA asks only for the wall — not for every soldier's name.*
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