start

cmd/root.go

@@ -0,0 +1,73 @@
+package main
+
+import (
+	"log/slog"
+	"math/rand/v2"
+	"os"
+	"time"
+
+	"github.com/fsnotify/fsnotify"
+	"gopkg.in/yaml.v3"
+)
+
+type InputDb map[int]string
+
+func newInputDbFromFile(path string, db *InputDb) {
+	file, err := os.ReadFile(path)
+	if err != nil {
+		slog.Error("Could not open file", "path", path)
+		os.Exit(1)
+	}
+	err = yaml.Unmarshal(file, &db)
+	if err != nil {
+		slog.Error("Error unmarshaling", "path", path, "error", err)
+	} else {
+		slog.Info("Reloaded Input", "path", path)
+	}
+}
+
+func (db InputDb) Lookup(key int) string {
+	value, ok := db[key]
+	if !ok {
+		return "X"
+	}
+	return value
+}
+
+func main() {
+	var db InputDb
+	done := make(chan struct{}, 1)
+	ticker := time.NewTicker(10 * time.Millisecond)
+
+	watcher, err := fsnotify.NewWatcher()
+	if err != nil {
+		slog.Error("Could not create Watcher", "error", err)
+	}
+	defer watcher.Close()
+	newInputDbFromFile("input/input.yml", &db)
+	slog.Info("Loaded DB", "db", db)
+
+	err = watcher.Add("input/input.yml")
+	if err != nil {
+		slog.Error("Could not watch path", "path", "input/input.yml")
+	}
+
+	go func() {
+		for {
+			select {
+			case t := <-ticker.C:
+				key := rand.IntN(9) + 1
+				value := db.Lookup(key)
+				slog.Info("Got Rand", "key", key, "value", value, "ticker", t)
+			case event, ok := <-watcher.Events:
+				if !ok {
+					slog.Error("Could not log Event", "event.name", event.Name, "event.op", event.Op)
+				}
+				slog.Info("Got Event", "event.name", event.Name, "event.op", event.Op)
+				newInputDbFromFile("input/input.yml", &db)
+			}
+		}
+	}()
+
+	<-done
+}

go.mod

@@ -0,0 +1,10 @@
+module git.bitkraken.net/go/pointerreplacer
+
+go 1.22.4
+
+require (
+	github.com/fsnotify/fsnotify v1.7.0
+	gopkg.in/yaml.v3 v3.0.1
+)
+
+require golang.org/x/sys v0.4.0 // indirect

go.sum

@@ -0,0 +1,8 @@
+github.com/fsnotify/fsnotify v1.7.0 h1:8JEhPFa5W2WU7YfeZzPNqzMP6Lwt7L2715Ggo0nosvA=
+github.com/fsnotify/fsnotify v1.7.0/go.mod h1:40Bi/Hjc2AVfZrqy+aj+yEI+/bRxZnMJyTJwOpGvigM=
+golang.org/x/sys v0.4.0 h1:Zr2JFtRQNX3BCZ8YtxRE9hNJYC8J6I1MVbMg6owUp18=
+golang.org/x/sys v0.4.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

input/input.yml

@@ -0,0 +1,7 @@
+---
+1: A
+2: B
+3: C
+4: D
+5: E
+6: F