kafka producer use async interface to request metadata.

@@ -37,10 +37,18 @@ using namespace std;
 
 #ifdef SRS_AUTO_KAFKA
 
+#define SRS_KAKFA_CYCLE_INTERVAL_MS 3000
+
 SrsKafkaProducer::SrsKafkaProducer()
 {
-    lb = new SrsLbRoundRobin();
+    meatadata_ok = false;
+    metadata_expired = st_cond_new();
+    
+    lock = st_mutex_new();
+    pthread = new SrsReusableThread("kafka", this, SRS_KAKFA_CYCLE_INTERVAL_MS * 1000);
     worker = new SrsAsyncCallWorker();
+    
+    lb = new SrsLbRoundRobin();
     transport = new SrsTcpClient();
     kafka = new SrsKafkaClient(transport);
 }
@@ -48,21 +56,21 @@ SrsKafkaProducer::SrsKafkaProducer()
 SrsKafkaProducer::~SrsKafkaProducer()
 {
     srs_freep(lb);
-    srs_freep(worker);
     srs_freep(kafka);
     srs_freep(transport);
+    
+    srs_freep(worker);
+    srs_freep(pthread);
+    
+    st_mutex_destroy(lock);
+    st_cond_destroy(metadata_expired);
 }
 
 int SrsKafkaProducer::initialize()
 {
     int ret = ERROR_SUCCESS;
     
-    // when kafka enabled, request metadata when startup.
-    if ((ret = request_metadata()) != ERROR_SUCCESS) {
-        srs_error("request kafka metadata failed. ret=%d", ret);
-        return ret;
-    }
-    
+    meatadata_ok = false;
     srs_info("initialize kafka producer ok.");
     
     return ret;
@@ -73,20 +81,78 @@ int SrsKafkaProducer::start()
     int ret = ERROR_SUCCESS;
     
     if ((ret = worker->start()) != ERROR_SUCCESS) {
-        srs_error("start kafka failed. ret=%d", ret);
+        srs_error("start kafka worker failed. ret=%d", ret);
         return ret;
     }
     
-    srs_info("kafka worker ok");
+    if ((ret = pthread->start()) != ERROR_SUCCESS) {
+        srs_error("start kafka thread failed. ret=%d", ret);
+    }
+    
+    meatadata_ok = false;
+    st_cond_signal(metadata_expired);
+    srs_trace("kafka work in background");
     
     return ret;
 }
 
 void SrsKafkaProducer::stop()
 {
+    pthread->stop();
     worker->stop();
 }
 
+int SrsKafkaProducer::cycle()
+{
+    int ret = ERROR_SUCCESS;
+    
+    if ((ret = do_cycle()) != ERROR_SUCCESS) {
+        srs_warn("ignore kafka error. ret=%d", ret);
+    }
+    
+    return ret;
+}
+
+int SrsKafkaProducer::on_before_cycle()
+{
+    // wait for the metadata expired.
+    // when metadata is ok, wait for it expired.
+    if (meatadata_ok) {
+        st_cond_wait(metadata_expired);
+    }
+    
+    // request to lock to acquire the socket.
+    st_mutex_lock(lock);
+    
+    return ERROR_SUCCESS;
+}
+
+int SrsKafkaProducer::on_end_cycle()
+{
+    st_mutex_unlock(lock);
+ 
+    return ERROR_SUCCESS;
+}
+
+int SrsKafkaProducer::do_cycle()
+{
+    int ret = ERROR_SUCCESS;
+    
+    // ignore when disabled.
+    bool enabled = _srs_config->get_kafka_enabled();
+    if (!enabled) {
+        return ret;
+    }
+    
+    // when kafka enabled, request metadata when startup.
+    if ((ret = request_metadata()) != ERROR_SUCCESS) {
+        srs_error("request kafka metadata failed. ret=%d", ret);
+        return ret;
+    }
+    
+    return ret;
+}
+
 int SrsKafkaProducer::request_metadata()
 {
     int ret = ERROR_SUCCESS;
@@ -130,9 +196,11 @@ int SrsKafkaProducer::request_metadata()
         std::string senabled = srs_bool2switch(enabled);
         std::string sbrokers = srs_join_vector_string(brokers->args, ",");
         srs_trace("kafka ok, enabled:%s, brokers:%s, current:[%d]%s:%d, topic:%s",
-            senabled.c_str(), sbrokers.c_str(), lb->current(), server.c_str(), port, topic.c_str());
+                  senabled.c_str(), sbrokers.c_str(), lb->current(), server.c_str(), port, topic.c_str());
     }
     
+    meatadata_ok = true;
+    
     return ret;
 }
 

@@ -34,14 +34,22 @@ class SrsAsyncCallWorker;
 class SrsTcpClient;
 class SrsKafkaClient;
 
+#include <srs_app_thread.hpp>
+
 #ifdef SRS_AUTO_KAFKA
 
 /**
  * the kafka producer used to save log to kafka cluster.
  */
-class SrsKafkaProducer
+class SrsKafkaProducer : public ISrsReusableThreadHandler
 {
 private:
+    st_mutex_t lock;
+    SrsReusableThread* pthread;
+private:
+    bool meatadata_ok;
+    st_cond_t metadata_expired;
+private:
     SrsLbRoundRobin* lb;
     SrsAsyncCallWorker* worker;
     SrsTcpClient* transport;
@@ -53,7 +61,13 @@ public:
     virtual int initialize();
     virtual int start();
     virtual void stop();
+// interface ISrsReusableThreadHandler
+public:
+    virtual int cycle();
+    virtual int on_before_cycle();
+    virtual int on_end_cycle();
 private:
+    virtual int do_cycle();
     virtual int request_metadata();
 };