examples/http: Add HTTP example to demonstrate RunShutdownable

2025-01-30 19:30:07 -05:00 · 2025-01-30 19:30:07 -05:00 · 772e9ca290
commit 772e9ca290
parent 5e38cec135
1 changed files with 90 additions and 0 deletions
--- a/examples/http/main.go
+++ b/examples/http/main.go
@ -0,0 +1,90 @@
+// Example http demonstrates the usage of [camfish.RunShutdowner] to run an http
+// server.
+package main
+
+import "fmt"
+import "log"
+import "iter"
+import "errors"
+import "context"
+import "net/http"
+import "git.tebibyte.media/sashakoshka/camfish"
+import "git.tebibyte.media/sashakoshka/go-util/sync"
+
+func main() {
+	camfish.Run("http",
+		"Example http demonstrates the usage of " +
+		"camfish.RunShutdowner to run an http server",
+		new(httpServer),
+		new(database))
+}
+
+// httpServer serves data over http.
+type httpServer struct {
+	server *http.Server
+	database *database
+}
+var _ camfish.RunShutdownable = new(httpServer)
+var _ camfish.Initializable = new(httpServer)
+func (this *httpServer) Type() string { return "http-server" }
+
+func (this *httpServer) Init(ctx context.Context) error {
+	this.server = &http.Server {
+		Addr: "localhost:8080",
+		Handler: this,
+	}
+	if actor, ok := camfish.Find("database").(*database); ok {
+		this.database = actor
+	} else {
+		return errors.New("could not locate database")
+	}
+	return ctx.Err()
+}
+
+func (this *httpServer) Run() error {
+	log.Printf("[http] listening on %s", this.server.Addr)
+	err := this.server.ListenAndServe()
+	if errors.Is(err, http.ErrServerClosed) { return nil }
+	return err
+}
+
+func (this *httpServer) Shutdown(ctx context.Context) error {
+	return this.server.Shutdown(ctx)
+}
+
+func (this *httpServer) ServeHTTP(res http.ResponseWriter, req *http.Request) {
+	fmt.Fprintf(res, "<!DOCTYPE html><html><head><title>inventory</title></head><body>")
+	fmt.Fprintf(res, "<table><tr><th>Item</th><th>Count</th></tr>")
+	for item, count := range this.database.Inventory() {
+		fmt.Fprintf(res, "<tr><td>%s</td><td>%d</td></tr>", item, count)
+	}
+	fmt.Fprintf(res, "</table>")
+	fmt.Fprintf(res, "</body></html>")
+}
+
+// database provides data that can be served.
+type database struct {
+	inventory usync.RWMonitor[map[string] int]
+}
+func (this *database) Type() string { return "database" }
+
+func (this *database) Init(ctx context.Context) error {
+	this.inventory.Set(map[string] int {
+		"screws": 34,
+		"blood": 90,
+		"paperclips": 5230,
+		"wood": 3,
+		"grains of rice": 238409,
+	})
+	return ctx.Err()
+}
+
+func (this *database) Inventory() iter.Seq2[string, int] {
+	return func(yield func(string, int) bool) {
+		inventory, done := this.inventory.RBorrow()
+		defer done()
+		for item, amount := range inventory {
+			yield(item, amount)
+		}
+	}
+}