Client/Server tweaks

README.md

@@ -17,6 +17,7 @@ ZeroEQ provides the following major features:
 * Publish events using zeroeq::Publisher
 * Subscribe to events using zeroeq::Subscriber
 * Web service APIs using zeroeq::http::Server using REST and JSON
+* Client-Server request-reply using zeroeq::Server and zeroeq::Client
 * Asynchronous, reliable transport using [ZeroMQ](http://www.zeromq.org)
 * Automatic publisher discovery using [Zeroconf](https://en.wikipedia.org/wiki/Zero-configuration_networking)
 * Serialization of events using [ZeroBuf](https://github.com/HBPVIS/ZeroBuf)

tests/common.h

@@ -16,6 +16,8 @@
 #ifdef _WIN32
 #include <process.h>
 #define getpid _getpid
+#define setenv(name, value, overwrite) _putenv_s(name, value)
+#define unsetenv(name) _putenv_s(name, nullptr)
 #else
 #include <sys/types.h>
 #include <unistd.h>

tests/publisher.cpp

@@ -14,11 +14,6 @@
 
 #include <servus/servus.h>
 
-#ifdef _MSC_VER
-#define setenv(name, value, overwrite) _putenv_s(name, value)
-#define unsetenv(name) _putenv_s(name, nullptr)
-#endif
-
 BOOST_AUTO_TEST_CASE(create_uri_publisher)
 {
     const zeroeq::Publisher publisher(zeroeq::URI(""));

tests/reqRep.cpp

@@ -10,6 +10,7 @@
 #include <servus/servus.h>
 #include <servus/uri.h>
 
+#include <atomic>
 #include <chrono>
 #include <thread>
 
@@ -320,6 +321,45 @@ BOOST_AUTO_TEST_CASE(two_servers)
     BOOST_CHECK(serverHandled);
 }
 
+BOOST_AUTO_TEST_CASE(envconnect)
+{
+    test::Echo echo("The quick brown fox");
+    const test::Echo reply("Jumped over the lazy dog");
+
+    zeroeq::Server server1(zeroeq::NULL_SESSION);
+    zeroeq::Server server2(zeroeq::NULL_SESSION);
+    std::string servers(server1.getURI().getHost() + ":" +
+                        std::to_string(int(server1.getURI().getPort())) + "," +
+                        server2.getURI().getHost() + ":" +
+                        std::to_string(int(server2.getURI().getPort())));
+    setenv("ZEROEQ_SERVERS", servers.c_str(), 1);
+
+    zeroeq::Client client;
+
+    bool handled1 = false;
+    bool handled2 = false;
+    std::thread thread1([&] { handled1 = runOnce(server1, echo, reply); });
+    std::thread thread2([&] { handled2 = runOnce(server2, echo, reply); });
+
+    size_t handled = 0;
+    const auto func = [&](const zeroeq::uint128_t&, const void*, size_t) {
+        ++handled;
+    };
+    client.request(echo, func);
+    client.request(echo, func);
+
+    BOOST_CHECK_EQUAL(handled, 0);
+    BOOST_CHECK(client.receive(TIMEOUT));
+    if (handled < 2)
+        BOOST_CHECK(client.receive(TIMEOUT));
+    BOOST_CHECK_EQUAL(handled, 2);
+
+    thread1.join();
+    thread2.join();
+    BOOST_CHECK(handled1);
+    BOOST_CHECK(handled2);
+}
+
 BOOST_AUTO_TEST_CASE(two_clients)
 {
     test::Echo echo("The quick brown fox");

zeroeq/client.cpp

@@ -23,6 +23,24 @@ class Client::Impl : public detail::Receiver
         , _servers(zmq_socket(getContext(), ZMQ_DEALER),
                    [](void* s) { ::zmq_close(s); })
     {
+        const char* serversEnv = getenv("ZEROEQ_SERVERS");
+        if (!serversEnv)
+            return;
+
+        std::string servers(serversEnv);
+        while (!servers.empty())
+        {
+            const size_t pos = servers.find(',');
+            const std::string server = servers.substr(0, pos);
+            servers = pos == std::string::npos ? std::string()
+                                               : servers.substr(pos + 1);
+
+            const auto& zmqURI = buildZmqURI(URI(server));
+            if (!addConnection(zmqURI))
+                ZEROEQTHROW(std::runtime_error("Cannot connect client to " +
+                                               zmqURI + ": " +
+                                               zmq_strerror(zmq_errno())));
+        }
     }
 
     explicit Impl(const URIs& uris)
@@ -38,11 +56,9 @@ class Client::Impl : public detail::Receiver
 
             const auto& zmqURI = buildZmqURI(uri);
             if (!addConnection(zmqURI))
-            {
                 ZEROEQTHROW(std::runtime_error("Cannot connect client to " +
                                                zmqURI + ": " +
                                                zmq_strerror(zmq_errno())));
-            }
         }
     }
 

zeroeq/client.h

@@ -38,6 +38,8 @@ class Client : public Receiver
      * Create a default client.
      *
      * Postconditions:
+     * - connects to all servers set in the comma-separated environment variable
+     *   ZEROEQ_SERVERS
      * - discovers servers on _zeroeq_rep._tcp ZeroConf service
      * - filters session \<username\> or ZEROEQ_SERVER_SESSION from environment
      *
@@ -49,6 +51,8 @@ class Client : public Receiver
      * Create a client which connects to servers from the given session.
      *
      * Postconditions:
+     * - connects to all servers set in the comma-separated environment variable
+     *   ZEROEQ_SERVERS
      * - discovers publishers on _zeroeq_rep._tcp ZeroConf service
      * - filters for given session
      *