基于NNG的六种通信模式

NNG是一个消息传递框架，用来解决常见的消息传递问题。NNG是nanomsg的继任版本，纯c语言开发，工作模式分为一下几种：

Pipeline单向管道

此模式可用于解决生产者/消费者问题，包括负载均衡。
消息从推侧流向拉侧。
如果多个同级节点连接在一起，则模式会尝试公平分配。

pipeline.cpp

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
// #include <unistd.h> sleep(1);
#include <Windows.h>  // Windows系统下用Sleep#include <nng/nng.h>
#include <nng/protocol/pipeline0/pull.h>
#include <nng/protocol/pipeline0/push.h>#define NODE0 "node0"
#define NODE1 "node1"void
fatal(const char* func, int rv)
{fprintf(stderr, "%s: %s\n", func, nng_strerror(rv));exit(1);
}int
node0(const char* url)
{nng_socket sock;int rv;if ((rv = nng_pull0_open(&sock)) != 0) {fatal("nng_pull0_open", rv);}if ((rv = nng_listen(sock, url, NULL, 0)) != 0) {fatal("nng_listen", rv);}for (;;) {char* buf = NULL;size_t sz;if ((rv = nng_recv(sock, &buf, &sz, NNG_FLAG_ALLOC)) != 0) {fatal("nng_recv", rv);}printf("NODE0: RECEIVED \"%s\"\n", buf);nng_free(buf, sz);}
}int
node1(const char* url, char* msg)
{int sz_msg = strlen(msg) + 1; // '\0' toonng_socket sock;int rv;int bytes;if ((rv = nng_push0_open(&sock)) != 0) {fatal("nng_push0_open", rv);}if ((rv = nng_dial(sock, url, NULL, 0)) != 0) {fatal("nng_dial", rv);}printf("NODE1: SENDING \"%s\"\n", msg);if ((rv = nng_send(sock, msg, strlen(msg) + 1, 0)) != 0) {fatal("nng_send", rv);}Sleep(1); // wait for messages to flush before shutting downnng_close(sock);return (0);
}int
main(int argc, char** argv)
{if ((argc > 1) && (strcmp(NODE0, argv[1]) == 0))return (node0(argv[2]));if ((argc > 2) && (strcmp(NODE1, argv[1]) == 0))return (node1(argv[2], argv[3]));fprintf(stderr, "Usage: pipeline %s|%s <URL> <ARG> ...'\n",NODE0, NODE1);return (1);
}

执行

./pipeline node0 ipc:///tmp/pipeline.ipc & node0=$! && sleep 1
./pipeline node1 ipc:///tmp/pipeline.ipc "Hello, World!"
./pipeline node1 ipc:///tmp/pipeline.ipc "Goodbye."

输出：

NODE1: SENDING "Hello, World!"
NODE0: RECEIVED "Hello, World!"
NODE1: SENDING "Goodbye."
NODE0: RECEIVED "Goodbye."

Request/Reply (我问，你答)

请求/应答用于同步通信，其中每个问题都有一个答案，例如远程过程调用（RPC）。
与Pipeline一样，它也可以执行负载平衡。
这是套件中唯一可靠的消息传递模式，因为如果请求与响应不匹配，它会自动重试。

reqprep.cpp

#define  _CRT_SECURE_NO_WARNINGS true#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <time.h>#include <nng/nng.h>
#include <nng/protocol/reqrep0/rep.h>
#include <nng/protocol/reqrep0/req.h>#define NODE0 "node0"
#define NODE1 "node1"
char DATE[] = "DATE";void
fatal(const char* func, int rv)
{fprintf(stderr, "%s: %s\n", func, nng_strerror(rv));exit(1);
}char*
date(void)
{time_t now = time(&now);struct tm* info = localtime(&now);char* text = asctime(info);text[strlen(text) - 1] = '\0'; // remove '\n'return (text);
}int
node0(const char* url)
{nng_socket sock;int rv;if ((rv = nng_rep0_open(&sock)) != 0) {fatal("nng_rep0_open", rv);}if ((rv = nng_listen(sock, url, NULL, 0)) != 0) {fatal("nng_listen", rv);}for (;;) {char* buf = NULL;size_t sz;if ((rv = nng_recv(sock, &buf, &sz, NNG_FLAG_ALLOC)) != 0) {fatal("nng_recv", rv);}if ((sz == (strlen(DATE) + 1)) && (strcmp(DATE, buf) == 0)) {printf("NODE0: RECEIVED DATE REQUEST\n");char* d = date();printf("NODE0: SENDING DATE %s\n", d);if ((rv = nng_send(sock, d, strlen(d) + 1, 0)) != 0) {fatal("nng_send", rv);}}nng_free(buf, sz);}
}int
node1(const char* url)
{nng_socket sock;int rv;size_t sz;char* buf = NULL;if ((rv = nng_req0_open(&sock)) != 0) {fatal("nng_socket", rv);}if ((rv = nng_dial(sock, url, NULL, 0)) != 0) {fatal("nng_dial", rv);}printf("NODE1: SENDING DATE REQUEST %s\n", DATE);if ((rv = nng_send(sock, DATE, strlen(DATE) + 1, 0)) != 0) {fatal("nng_send", rv);}if ((rv = nng_recv(sock, &buf, &sz, NNG_FLAG_ALLOC)) != 0) {fatal("nng_recv", rv);}printf("NODE1: RECEIVED DATE %s\n", buf);nng_free(buf, sz);nng_close(sock);return (0);
}int
main(const int argc, const char** argv)
{if ((argc > 1) && (strcmp(NODE0, argv[1]) == 0))return (node0(argv[2]));if ((argc > 1) && (strcmp(NODE1, argv[1]) == 0))return (node1(argv[2]));fprintf(stderr, "Usage: reqrep %s|%s <URL> ...\n", NODE0, NODE1);return (1);
}

执行

reqrep node0 ipc:///tmp/reqrep.ipc & node0=$! && sleep 1
reqrep node1 ipc:///tmp/reqrep.ipc

输出结果

NODE1: SENDING DATE REQUEST DATE
NODE1: RECEIVED DATE Tue Aug 27 14:10:23 2024
NODE0: RECEIVED DATE REQUEST
NODE0: SENDING DATE Tue Aug 27 09:47:29 2024

Pair (Two Way Radio)

一对一双向通信，类似对讲机。
当存在一对一的对等关系时，使用配对模式。一次只能有一个对等体连接到另一个对等方，但两个对等体都可以自由发言。

pair.cpp

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
// #include <unistd.h>
#include <Windows.h>#include <nng/nng.h>
#include <nng/protocol/pair0/pair.h>char NODE0[] = "node0";
char NODE1[] = "node1";void
fatal(const char* func, int rv)
{fprintf(stderr, "%s: %s\n", func, nng_strerror(rv));exit(1);
}int
send_name(nng_socket sock, char* name)
{int rv;printf("%s: SENDING \"%s\"\n", name, name);if ((rv = nng_send(sock, name, strlen(name) + 1, 0)) != 0) {fatal("nng_send", rv);}return (rv);
}int
recv_name(nng_socket sock, char* name)
{char* buf = NULL;int rv;size_t sz;if ((rv = nng_recv(sock, &buf, &sz, NNG_FLAG_ALLOC)) == 0) {printf("%s: RECEIVED \"%s\"\n", name, buf);nng_free(buf, sz);}return (rv);
}int
send_recv(nng_socket sock, char* name)
{int rv;if ((rv = nng_setopt_ms(sock, NNG_OPT_RECVTIMEO, 100)) != 0) {fatal("nng_setopt_ms", rv);}for (;;) {recv_name(sock, name);Sleep(1);send_name(sock, name);}
}int
node0(const char* url)
{nng_socket sock;int rv;if ((rv = nng_pair0_open(&sock)) != 0) {fatal("nng_pair0_open", rv);}if ((rv = nng_listen(sock, url, NULL, 0)) != 0) {fatal("nng_listen", rv);}return (send_recv(sock, NODE0));
}int
node1(const char* url)
{nng_socket sock;int rv;Sleep(1);if ((rv = nng_pair0_open(&sock)) != 0) {fatal("nng_pair0_open", rv);}if ((rv = nng_dial(sock, url, NULL, 0)) != 0) {fatal("nng_dial", rv);}return (send_recv(sock, NODE1));
}int
main(int argc, char** argv)
{if ((argc > 1) && (strcmp(NODE0, argv[1]) == 0))return (node0(argv[2]));if ((argc > 1) && (strcmp(NODE1, argv[1]) == 0))return (node1(argv[2]));fprintf(stderr, "Usage: pair %s|%s <URL> <ARG> ...\n", NODE0, NODE1);return 1;
}

这里假设用的字符串是ASCII字符。

执行

pair node0 ipc:///tmp/pair.ipc & node0=$!
pair node1 ipc:///tmp/pair.ipc & node1=$!

输出

Pub/Sub (Topics & Broadcast)

单向广播

pubsub.cpp

#define _CRT_SECURE_NO_WARNINGS true
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
//#include <unistd.h>
#include <Windows.h>#include <nng/nng.h>
#include <nng/protocol/pubsub0/pub.h>
#include <nng/protocol/pubsub0/sub.h>#define SERVER "server"
#define CLIENT "client"void
fatal(const char* func, int rv)
{fprintf(stderr, "%s: %s\n", func, nng_strerror(rv));
}char*
date(void)
{time_t now = time(&now);struct tm* info = localtime(&now);char* text = asctime(info);text[strlen(text) - 1] = '\0'; // remove '\n'return (text);
}int
server(const char* url)
{nng_socket sock;int rv;if ((rv = nng_pub0_open(&sock)) != 0) {fatal("nng_pub0_open", rv);}if ((rv = nng_listen(sock, url, NULL, 0)) < 0) {fatal("nng_listen", rv);}for (;;) {char* d = date();printf("SERVER: PUBLISHING DATE %s\n", d);if ((rv = nng_send(sock, d, strlen(d) + 1, 0)) != 0) {fatal("nng_send", rv);}Sleep(1);}
}int
client(const char* url, const char* name)
{nng_socket sock;int rv;if ((rv = nng_sub0_open(&sock)) != 0) {fatal("nng_sub0_open", rv);}// subscribe to everything (empty means all topics)if ((rv = nng_setopt(sock, NNG_OPT_SUB_SUBSCRIBE, "", 0)) != 0) {fatal("nng_setopt", rv);}if ((rv = nng_dial(sock, url, NULL, 0)) != 0) {fatal("nng_dial", rv);}for (;;) {char* buf = NULL;size_t sz;if ((rv = nng_recv(sock, &buf, &sz, NNG_FLAG_ALLOC)) != 0) {fatal("nng_recv", rv);}printf("CLIENT (%s): RECEIVED %s\n", name, buf);nng_free(buf, sz);}
}int
main(const int argc, const char** argv)
{if ((argc >= 2) && (strcmp(SERVER, argv[1]) == 0))return (server(argv[2]));if ((argc >= 3) && (strcmp(CLIENT, argv[1]) == 0))return (client(argv[2], argv[3]));fprintf(stderr, "Usage: pubsub %s|%s <URL> <ARG> ...\n",SERVER, CLIENT);return 1;
}

执行

./pubsub server ipc:///tmp/pubsub.ipc & server=$! && sleep 1
./pubsub client ipc:///tmp/pubsub.ipc client0 & client0=$!
./pubsub client ipc:///tmp/pubsub.ipc client1 & client1=$!
./pubsub client ipc:///tmp/pubsub.ipc client2 & client2=$!

输出结果

SERVER: PUBLISHING DATE Sat Sep  7 17:40:11 2013
SERVER: PUBLISHING DATE Sat Sep  7 17:40:12 2013
SERVER: PUBLISHING DATE Sat Sep  7 17:40:13 2013
CLIENT (client2): RECEIVED Sat Sep  7 17:40:13 2013
CLIENT (client0): RECEIVED Sat Sep  7 17:40:13 2013
CLIENT (client1): RECEIVED Sat Sep  7 17:40:13 2013
SERVER: PUBLISHING DATE Sat Sep  7 17:40:14 2013
CLIENT (client2): RECEIVED Sat Sep  7 17:40:14 2013
CLIENT (client1): RECEIVED Sat Sep  7 17:40:14 2013
CLIENT (client0): RECEIVED Sat Sep  7 17:40:14 2013
SERVER: PUBLISHING DATE Sat Sep  7 17:40:15 2013
CLIENT (client1): RECEIVED Sat Sep  7 17:40:15 2013
CLIENT (client2): RECEIVED Sat Sep  7 17:40:15 2013
CLIENT (client0): RECEIVED Sat Sep  7 17:40:15 2013
SERVER: PUBLISHING DATE Sat Sep  7 17:40:16 2013
CLIENT (client1): RECEIVED Sat Sep  7 17:40:16 2013
CLIENT (client2): RECEIVED Sat Sep  7 17:40:16 2013
CLIENT (client0): RECEIVED Sat Sep  7 17:40:16 2013
Last updated 2018-02-15 00:01:10 UTC

Survey (Everybody Votes)

用于多节点表决或者服务发现。

survey.cpp

#define _CRT_SECURE_NO_WARNINGS true
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <Windows.h>#include <nng/nng.h>
#include <nng/protocol/survey0/survey.h>
#include <nng/protocol/survey0/respond.h>#define SERVER "server"
#define CLIENT "client"
#define DATE   "DATE"void
fatal(const char* func, int rv)
{fprintf(stderr, "%s: %s\n", func, nng_strerror(rv));exit(1);
}char*
date(void)
{time_t now = time(&now);struct tm* info = localtime(&now);char* text = asctime(info);text[strlen(text) - 1] = '\0'; // remove '\n'return (text);
}int
server(const char* url)
{nng_socket sock;int rv;if ((rv = nng_surveyor0_open(&sock)) != 0) {fatal("nng_surveyor0_open", rv);}if ((rv = nng_listen(sock, url, NULL, 0)) != 0) {fatal("nng_listen", rv);}for (;;) {printf("SERVER: SENDING DATE SURVEY REQUEST\n");if ((rv = nng_send(sock, (void *)DATE, strlen(DATE) + 1, 0)) != 0) {fatal("nng_send", rv);}for (;;) {char* buf = NULL;size_t sz;rv = nng_recv(sock, &buf, &sz, NNG_FLAG_ALLOC);if (rv == NNG_ETIMEDOUT) {break;}if (rv != 0) {fatal("nng_recv", rv);}printf("SERVER: RECEIVED \"%s\" SURVEY RESPONSE\n",buf);nng_free(buf, sz);}printf("SERVER: SURVEY COMPLETE\n");}
}int
client(const char* url, const char* name)
{nng_socket sock;int rv;if ((rv = nng_respondent0_open(&sock)) != 0) {fatal("nng_respondent0_open", rv);}if ((rv = nng_dial(sock, url, NULL, NNG_FLAG_NONBLOCK)) != 0) {fatal("nng_dial", rv);}for (;;) {char* buf = NULL;size_t sz;if ((rv = nng_recv(sock, &buf, &sz, NNG_FLAG_ALLOC)) == 0) {printf("CLIENT (%s): RECEIVED \"%s\" SURVEY REQUEST\n",name, buf);nng_free(buf, sz);char* d = date();printf("CLIENT (%s): SENDING DATE SURVEY RESPONSE\n",name);if ((rv = nng_send(sock, d, strlen(d) + 1, 0)) != 0) {fatal("nng_send", rv);}}}
}int
main(const int argc, const char** argv)
{if ((argc >= 2) && (strcmp(SERVER, argv[1]) == 0))return (server(argv[2]));if ((argc >= 3) && (strcmp(CLIENT, argv[1]) == 0))return (client(argv[2], argv[3]));fprintf(stderr, "Usage: survey %s|%s <URL> <ARG> ...\n",SERVER, CLIENT);return 1;
}

执行

urvey server ipc:///tmp/survey.ipc & server=$!
survey client ipc:///tmp/survey.ipc client0 & client0=$!
survey client ipc:///tmp/survey.ipc client1 & client1=$!
survey client ipc:///tmp/survey.ipc client2 & client2=$!

输出结果

SERVER: SENDING DATE SURVEY REQUEST
SERVER: SURVEY COMPLETE
SERVER: SENDING DATE SURVEY REQUEST
CLIENT (client2): RECEIVED "DATE" SURVEY REQUEST
CLIENT (client0): RECEIVED "DATE" SURVEY REQUEST
CLIENT (client1): RECEIVED "DATE" SURVEY REQUEST
CLIENT (client2): SENDING DATE SURVEY RESPONSE
CLIENT (client1): SENDING DATE SURVEY RESPONSE
CLIENT (client0): SENDING DATE SURVEY RESPONSE
SERVER: RECEIVED "Tue Jan  9 11:33:40 2018" SURVEY RESPONSE
SERVER: RECEIVED "Tue Jan  9 11:33:40 2018" SURVEY RESPONSE
SERVER: RECEIVED "Tue Jan  9 11:33:40 2018" SURVEY RESPONSE
SERVER: SURVEY COMPLETE
SERVER: SENDING DATE SURVEY REQUEST
CLIENT (client2): RECEIVED "DATE" SURVEY REQUEST
CLIENT (client2): SENDING DATE SURVEY RESPONSE
CLIENT (client0): RECEIVED "DATE" SURVEY REQUEST
CLIENT (client0): SENDING DATE SURVEY RESPONSE
CLIENT (client1): RECEIVED "DATE" SURVEY REQUEST
CLIENT (client1): SENDING DATE SURVEY RESPONSE
SERVER: RECEIVED "Tue Jan  9 11:33:41 2018" SURVEY RESPONSE
SERVER: RECEIVED "Tue Jan  9 11:33:41 2018" SURVEY RESPONSE
SERVER: RECEIVED "Tue Jan  9 11:33:41 2018" SURVEY RESPONSE

Bus (Routing)

网状连接通信，每个加入节点都可以发送/接受广播消息。

bus.cpp

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <Windows.h>#include <nng/nng.h>
#include <nng/protocol/bus0/bus.h>void
fatal(const char* func, int rv)
{fprintf(stderr, "%s: %s\n", func, nng_strerror(rv));exit(1);
}int
node(int argc, char** argv)
{nng_socket sock;int rv;size_t sz;if ((rv = nng_bus0_open(&sock)) != 0) {fatal("nng_bus0_open", rv);}if ((rv = nng_listen(sock, argv[2], NULL, 0)) != 0) {fatal("nng_listen", rv);}Sleep(3000); // wait for peers to bindif (argc >= 3) {for (int x = 3; x < argc; x++) {if ((rv = nng_dial(sock, argv[x], NULL, 0)) != 0) {fatal("nng_dial", rv);}}}Sleep(1000); // wait for connects to establish// SENDsz = strlen(argv[1]) + 1; // '\0' tooprintf("%s: SENDING '%s' ONTO BUS\n", argv[1], argv[1]);if ((rv = nng_send(sock, argv[1], sz, 0)) != 0) {fatal("nng_send", rv);}// RECVfor (;;) {char* buf = NULL;size_t sz;if ((rv = nng_recv(sock, &buf, &sz, NNG_FLAG_ALLOC)) != 0) {if (rv == NNG_ETIMEDOUT) {fatal("nng_recv", rv);}}printf("%s: RECEIVED '%s' FROM BUS\n", argv[1], buf);nng_free(buf, sz);}nng_close(sock);return (0);
}int
main(int argc, char** argv)
{if (argc >= 3) {return (node(argc, argv));}fprintf(stderr, "Usage: bus <NODE_NAME> <URL> <URL> ...\n");return 1;
}

执行

bus node0 ipc:///tmp/node0.ipc ipc:///tmp/node1.ipc ipc:///tmp/node2.ipc & node0=$!
bus node1 ipc:///tmp/node1.ipc ipc:///tmp/node2.ipc ipc:///tmp/node3.ipc & node1=$!
bus node2 ipc:///tmp/node2.ipc ipc:///tmp/node3.ipc & node2=$!
bus node3 ipc:///tmp/node3.ipc ipc:///tmp/node0.ipc & node3=$!

输出

node0: SENDING 'node0' ONTO BUS
node1: SENDING 'node1' ONTO BUS
node2: SENDING 'node2' ONTO BUS
node3: SENDING 'node3' ONTO BUS
node0: RECEIVED 'node1' FROM BUS
node0: RECEIVED 'node2' FROM BUS
node0: RECEIVED 'node3' FROM BUS
node1: RECEIVED 'node0' FROM BUS
node1: RECEIVED 'node2' FROM BUS
node1: RECEIVED 'node3' FROM BUS
node2: RECEIVED 'node0' FROM BUS
node2: RECEIVED 'node1' FROM BUS
node2: RECEIVED 'node3' FROM BUS
node3: RECEIVED 'node0' FROM BUS
node3: RECEIVED 'node1' FROM BUS
node3: RECEIVED 'node2' FROM BUS