fix: Add default config based on target object (#76)

Only apply "enable.auto.commit", "enable.auto.offset.store",
"enable.partition.eof" and "allow.auto.create.topics" configurations if
the target object is a consumer.

That change fixes #73

c_src/erlkaf_config.cc

@@ -54,19 +54,21 @@ template <typename T> ERL_NIF_TERM parse_config(ErlNifEnv* env, ERL_NIF_TERM lis
     return ATOMS.atomOk;
 }
 
-bool appy_kafka_default_config(rd_kafka_conf_t* config)
+bool appy_kafka_default_config(rd_kafka_conf_t* config, TargetObject target)
 {
-    if(rd_kafka_conf_set(config, "enable.auto.commit", "true", NULL, 0) != RD_KAFKA_CONF_OK)
-        return false;
+    if(target == TargetObject::Consumer) {
+        if(rd_kafka_conf_set(config, "enable.auto.commit", "true", NULL, 0) != RD_KAFKA_CONF_OK)
+            return false;
 
-    if(rd_kafka_conf_set(config, "enable.auto.offset.store", "false", NULL, 0) != RD_KAFKA_CONF_OK)
-        return false;
+        if(rd_kafka_conf_set(config, "enable.auto.offset.store", "false", NULL, 0) != RD_KAFKA_CONF_OK)
+            return false;
 
-    if(rd_kafka_conf_set(config, "enable.partition.eof", "false", NULL, 0) != RD_KAFKA_CONF_OK)
-        return false;
+        if(rd_kafka_conf_set(config, "enable.partition.eof", "false", NULL, 0) != RD_KAFKA_CONF_OK)
+            return false;
 
-    if(rd_kafka_conf_set(config, "allow.auto.create.topics", "true", NULL, 0) != RD_KAFKA_CONF_OK)
-        return false;
+        if(rd_kafka_conf_set(config, "allow.auto.create.topics", "true", NULL, 0) != RD_KAFKA_CONF_OK)
+            return false;
+    }
 
 #ifdef SIGIO
     // quick termination
@@ -99,9 +101,9 @@ ERL_NIF_TERM parse_topic_config(ErlNifEnv* env, ERL_NIF_TERM list, rd_kafka_topi
     return parse_config(env, list, conf, kTopicConfFuns);
 }
 
-ERL_NIF_TERM parse_kafka_config(ErlNifEnv* env, ERL_NIF_TERM list, rd_kafka_conf_t* conf)
+ERL_NIF_TERM parse_kafka_config(ErlNifEnv* env, ERL_NIF_TERM list, rd_kafka_conf_t* conf, TargetObject target)
 {
-    if(!appy_kafka_default_config(conf))
+    if(!appy_kafka_default_config(conf, target))
         return make_error(env, "failed to apply default kafka config");
 
     return parse_config(env, list, conf, kKafkaConfFuns);

c_src/erlkaf_config.h

@@ -6,8 +6,13 @@
 typedef struct rd_kafka_conf_s rd_kafka_conf_t;
 typedef struct rd_kafka_topic_conf_s rd_kafka_topic_conf_t;
 
+enum TargetObject {
+    Producer = 0,
+    Consumer,
+};
+
 ERL_NIF_TERM parse_topic_config(ErlNifEnv* env, ERL_NIF_TERM list, rd_kafka_topic_conf_t* conf);
-ERL_NIF_TERM parse_kafka_config(ErlNifEnv* env, ERL_NIF_TERM list, rd_kafka_conf_t* conf);
+ERL_NIF_TERM parse_kafka_config(ErlNifEnv* env, ERL_NIF_TERM list, rd_kafka_conf_t* conf, TargetObject target);
 
 #endif  // C_SRC_ERLKAF_CONFIG_H_
 

c_src/erlkaf_consumer.cc

@@ -264,7 +264,7 @@ ERL_NIF_TERM enif_consumer_new(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv
     scoped_ptr(client_conf, rd_kafka_conf_t, rd_kafka_conf_new(), rd_kafka_conf_destroy);
     scoped_ptr(topic_conf, rd_kafka_topic_conf_t, rd_kafka_topic_conf_new(), rd_kafka_topic_conf_destroy);
 
-    ERL_NIF_TERM parse_result = parse_kafka_config(env, argv[2], client_conf.get());
+    ERL_NIF_TERM parse_result = parse_kafka_config(env, argv[2], client_conf.get(), TargetObject::Consumer);
 
     if(parse_result != ATOMS.atomOk)
         return parse_result;

c_src/erlkaf_producer.cc

@@ -178,7 +178,7 @@ ERL_NIF_TERM enif_producer_new(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv
 
     scoped_ptr(config, rd_kafka_conf_t, rd_kafka_conf_new(), rd_kafka_conf_destroy);
 
-    ERL_NIF_TERM parse_result = parse_kafka_config(env, argv[1], config.get());
+    ERL_NIF_TERM parse_result = parse_kafka_config(env, argv[1], config.get(), TargetObject::Producer);
 
     if(parse_result != ATOMS.atomOk)
         return parse_result;