first

course/13-channels/exercises/3-channels_send/code.go

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+package main
+
+import (
+	"fmt"
+	"time"
+)
+
+func waitForDbs(numDBs int, dbChan chan struct{}) {
+	// ?
+}
+
+// don't touch below this line
+
+func test(numDBs int) {
+	dbChan := getDatabasesChannel(numDBs)
+	fmt.Printf("Waiting for %v databases...\n", numDBs)
+	waitForDbs(numDBs, dbChan)
+	time.Sleep(time.Millisecond * 10) // ensure the last print statement happens
+	fmt.Println("All databases are online!")
+	fmt.Println("=====================================")
+}
+
+func main() {
+	test(3)
+	test(4)
+	test(5)
+}
+
+func getDatabasesChannel(numDBs int) chan struct{} {
+	ch := make(chan struct{})
+	go func() {
+		for i := 0; i < numDBs; i++ {
+			ch <- struct{}{}
+			fmt.Printf("Database %v is online\n", i+1)
+		}
+	}()
+	return ch
+}