mq(kafka): scaffold Kafka gateway command and minimal TCP server with basic Start/Stop test; register command

weed/command/command.go

@@ -35,6 +35,7 @@ var Commands = []*Command{
 	cmdMount,
 	cmdMqAgent,
 	cmdMqBroker,
+	cmdMqKafkaGateway,
 	cmdDB,
 	cmdS3,
 	cmdScaffold,

weed/command/mq_kafka_gateway.go

@@ -0,0 +1,48 @@
+package command
+
+import (
+    "github.com/seaweedfs/seaweedfs/weed/glog"
+    "github.com/seaweedfs/seaweedfs/weed/mq/kafka/gateway"
+)
+
+var (
+    mqKafkaGatewayOptions mqKafkaGatewayOpts
+)
+
+type mqKafkaGatewayOpts struct {
+    listen *string
+}
+
+func init() {
+    cmdMqKafkaGateway.Run = runMqKafkaGateway
+    mqKafkaGatewayOptions.listen = cmdMqKafkaGateway.Flag.String("listen", ":9092", "Kafka gateway listen address")
+}
+
+var cmdMqKafkaGateway = &Command{
+    UsageLine: "mq.kafka.gateway [-listen=:9092]",
+    Short:     "start a Kafka wire-protocol gateway for SeaweedMQ",
+    Long: `Start a Kafka wire-protocol gateway translating Kafka client requests to SeaweedMQ.
+
+This is experimental and currently supports a minimal subset for development.
+`,
+}
+
+func runMqKafkaGateway(cmd *Command, args []string) bool {
+    srv := gateway.NewServer(gateway.Options{
+        Listen: *mqKafkaGatewayOptions.listen,
+    })
+
+    glog.V(0).Infof("Starting MQ Kafka Gateway on %s", *mqKafkaGatewayOptions.listen)
+    if err := srv.Start(); err != nil {
+        glog.Fatalf("mq kafka gateway start: %v", err)
+        return false
+    }
+    // Serve blocks until closed
+    if err := srv.Wait(); err != nil {
+        glog.Errorf("mq kafka gateway wait: %v", err)
+        return false
+    }
+    return true
+}
+
+