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.
75 lines
2.0 KiB
Go
75 lines
2.0 KiB
Go
package spaserver
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import (
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"context"
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"fmt"
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"net"
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"net/http"
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"time"
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"code.nochebuena.dev/einherjar/contracts/logging"
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"code.nochebuena.dev/einherjar/spa-server/health"
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"code.nochebuena.dev/einherjar/spa-server/spa"
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)
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const shutdownTimeout = 10 * time.Second
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// Server is a lifecycle-managed HTTP server that serves a single-page application.
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// Register with [launcher.New] via Append — it implements [lifecycle.Component].
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type Server struct {
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logger logging.Logger
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cfg Config
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srv *http.Server
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}
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// NewServer returns a Server configured by cfg.
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func NewServer(logger logging.Logger, cfg Config) *Server {
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return &Server{logger: logger, cfg: cfg}
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}
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// OnInit builds the HTTP mux and configures the underlying http.Server.
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func (s *Server) OnInit() error {
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mux := http.NewServeMux()
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mux.Handle("GET /health", health.NewHandler(s.logger))
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mux.Handle("/", spa.NewHandler(s.logger, s.cfg.StaticDir))
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s.srv = &http.Server{
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Addr: fmt.Sprintf(":%d", s.cfg.Port),
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Handler: mux,
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}
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return nil
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}
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// OnStart begins serving HTTP requests in a background goroutine.
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// The TCP listener binds synchronously so a port conflict surfaces immediately.
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func (s *Server) OnStart() error {
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ln, err := newListener(s.srv.Addr)
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if err != nil {
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return err
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}
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s.logger.Info("spa-server: listening", "addr", s.srv.Addr, "static_dir", s.cfg.StaticDir)
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go func() {
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if err := s.srv.Serve(ln); err != nil && err != http.ErrServerClosed {
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s.logger.Error("spa-server: serve error", err)
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}
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}()
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return nil
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}
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func newListener(addr string) (net.Listener, error) {
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ln, err := net.Listen("tcp", addr)
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if err != nil {
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return nil, fmt.Errorf("spa-server: bind %s: %w", addr, err)
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}
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return ln, nil
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}
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// OnStop performs a graceful shutdown, waiting up to 10 seconds for in-flight
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// requests to complete before forcefully closing connections.
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func (s *Server) OnStop() error {
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s.logger.Info("spa-server: shutting down")
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ctx, cancel := context.WithTimeout(context.Background(), shutdownTimeout)
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defer cancel()
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return s.srv.Shutdown(ctx)
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}
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