Enable backend to accept connection URL

backend/src/backend.cpp

@@ -14,9 +14,9 @@ class DronecodeSDKBackend::Impl {
     Impl() {}
     ~Impl() {}
 
-    void connect(const int mavlink_listen_port)
+    void connect(const std::string &connection_url)
     {
-        _connection_initiator.start(_dc, 14540);
+        _connection_initiator.start(_dc, connection_url);
         _connection_initiator.wait();
     }
 
@@ -41,9 +41,9 @@ void DronecodeSDKBackend::startGRPCServer()
 {
     _impl->startGRPCServer();
 }
-void DronecodeSDKBackend::connect(const int mavlink_listen_port)
+void DronecodeSDKBackend::connect(const std::string &connection_url)
 {
-    return _impl->connect(mavlink_listen_port);
+    return _impl->connect(connection_url);
 }
 void DronecodeSDKBackend::wait()
 {

backend/src/backend.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <memory>
+#include <string>
 
 namespace dronecode_sdk {
 namespace backend {
@@ -13,7 +14,7 @@ class DronecodeSDKBackend {
     DronecodeSDKBackend &operator=(DronecodeSDKBackend &&) = delete;
 
     void startGRPCServer();
-    void connect(const int mavlink_listen_port = 14540);
+    void connect(const std::string &connection_url = "udp://");
     void wait();
 
 private:

backend/src/backend_api.cpp

@@ -1,12 +1,12 @@
 #include "backend_api.h"
-
 #include "backend.h"
+#include <string>
 
-void runBackend(const int mavlink_listen_port, void (*onServerStarted)(void *), void *context)
+void runBackend(const char *connection_url, void (*onServerStarted)(void *), void *context)
 {
     dronecode_sdk::backend::DronecodeSDKBackend backend;
     backend.startGRPCServer();
-    backend.connect(mavlink_listen_port);
+    backend.connect(std::string(connection_url));
 
     if (onServerStarted != nullptr) {
         onServerStarted(context);

backend/src/backend_api.h

@@ -5,7 +5,7 @@ extern "C" {
 #endif
 
 __attribute__((visibility("default"))) void
-runBackend(int mavlink_listen_port, void (*onServerStarted)(void *), void *context);
+runBackend(const char *connection_url, void (*onServerStarted)(void *), void *context);
 
 #ifdef __cplusplus
 }

backend/src/connection_initiator.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <future>
+#include <string>
 
 #include "connection_result.h"
 #include "log.h"
@@ -13,14 +14,14 @@ template<typename DronecodeSDK> class ConnectionInitiator {
     ConnectionInitiator() {}
     ~ConnectionInitiator() {}
 
-    bool start(DronecodeSDK &dc, const int port)
+    bool start(DronecodeSDK &dc, const std::string &connection_url)
     {
         init_mutex();
         init_timeout_logging(dc);
 
         _discovery_future = wrapped_register_on_discover(dc);
 
-        if (!add_udp_connection(dc, port)) {
+        if (!add_any_connection(dc, connection_url)) {
             return false;
         }
 
@@ -38,9 +39,9 @@ template<typename DronecodeSDK> class ConnectionInitiator {
             [](uint64_t uuid) { LogInfo() << "System timed out [UUID: " << uuid << "]"; });
     }
 
-    bool add_udp_connection(DronecodeSDK &dc, const int port)
+    bool add_any_connection(DronecodeSDK &dc, const std::string &connection_url)
     {
-        dronecode_sdk::ConnectionResult connection_result = dc.add_udp_connection(port);
+        dronecode_sdk::ConnectionResult connection_result = dc.add_any_connection(connection_url);
 
         if (connection_result != ConnectionResult::SUCCESS) {
             LogErr() << "Connection failed: " << connection_result_str(connection_result);

backend/src/dronecode_sdk_server.cpp

@@ -1,6 +1,42 @@
 #include "backend_api.h"
+#include <iostream>
+#include <string>
+
+static void usage();
+
+static auto constexpr default_connection = "udp://:14540";
 
 int main(int argc, char **argv)
 {
-    runBackend(14540, nullptr, nullptr);
+    if (argc > 2) {
+        usage();
+        return 1;
+    }
+
+    if (argc == 2) {
+        const std::string positional_arg = argv[1];
+        if (positional_arg.compare("-h") == 0 || positional_arg.compare("--help") == 0) {
+            usage();
+            return 0;
+        }
+        runBackend(positional_arg.c_str(), nullptr, nullptr);
+    }
+
+    runBackend(default_connection, nullptr, nullptr);
+}
+
+void usage()
+{
+    std::cout << "Usage: backend_bin [-h | --help]" << std::endl
+              << "       backend_bin [Connection URL]" << std::endl
+              << std::endl
+              << "Connection URL format should be:" << std::endl
+              << "  Serial: serial:///path/to/serial/dev[:baudrate]" << std::endl
+              << "  UDP:    udp://[bind_host][:bind_port]" << std::endl
+              << "  TCP:    tcp://[server_host][:server_port]" << std::endl
+              << std::endl
+              << "For example to connect to SITL use: udp://:14540" << std::endl
+              << std::endl
+              << "Options:" << std::endl
+              << "  -h | --help : show this help" << std::endl;
 }

backend/test/connection_initiator_test.cpp

@@ -13,7 +13,7 @@ using event_callback_t = dronecode_sdk::testing::event_callback_t;
 using MockDronecodeSDK = NiceMock<dronecode_sdk::testing::MockDronecodeSDK>;
 using ConnectionInitiator = dronecode_sdk::backend::ConnectionInitiator<MockDronecodeSDK>;
 
-static constexpr auto ARBITRARY_PORT = 1291;
+static constexpr auto ARBITRARY_CONNECTION_URL = "udp://1291";
 static constexpr auto ARBITRARY_UUID = 1492;
 
 ACTION_P(SaveCallback, event_callback)
@@ -27,17 +27,17 @@ TEST(ConnectionInitiator, registerDiscoverIsCalledExactlyOnce)
     MockDronecodeSDK dc;
     EXPECT_CALL(dc, register_on_discover(_)).Times(1);
 
-    initiator.start(dc, ARBITRARY_PORT);
+    initiator.start(dc, ARBITRARY_CONNECTION_URL);
 }
 
 TEST(ConnectionInitiator, startAddsUDPConnection)
 {
     ConnectionInitiator initiator;
     MockDronecodeSDK dc;
 
-    EXPECT_CALL(dc, add_udp_connection(_));
+    EXPECT_CALL(dc, add_any_connection(_));
 
-    initiator.start(dc, ARBITRARY_PORT);
+    initiator.start(dc, ARBITRARY_CONNECTION_URL);
 }
 
 TEST(ConnectionInitiator, startHangsUntilSystemDiscovered)
@@ -48,7 +48,7 @@ TEST(ConnectionInitiator, startHangsUntilSystemDiscovered)
     EXPECT_CALL(dc, register_on_discover(_)).WillOnce(SaveCallback(&discover_callback));
 
     auto async_future = std::async(std::launch::async, [&initiator, &dc]() {
-        initiator.start(dc, ARBITRARY_PORT);
+        initiator.start(dc, ARBITRARY_CONNECTION_URL);
         initiator.wait();
     });
 
@@ -65,7 +65,7 @@ TEST(ConnectionInitiator, connectionDetectedIfDiscoverCallbackCalledBeforeWait)
     event_callback_t discover_callback;
     EXPECT_CALL(dc, register_on_discover(_)).WillOnce(SaveCallback(&discover_callback));
 
-    initiator.start(dc, ARBITRARY_PORT);
+    initiator.start(dc, ARBITRARY_CONNECTION_URL);
     discover_callback(ARBITRARY_UUID);
     initiator.wait();
 }
@@ -77,7 +77,7 @@ TEST(ConnectionInitiator, doesNotCrashIfDiscoverCallbackCalledMoreThanOnce)
     event_callback_t discover_callback;
     EXPECT_CALL(dc, register_on_discover(_)).WillOnce(SaveCallback(&discover_callback));
 
-    initiator.start(dc, ARBITRARY_PORT);
+    initiator.start(dc, ARBITRARY_CONNECTION_URL);
     discover_callback(ARBITRARY_UUID);
     discover_callback(ARBITRARY_UUID);
 }

core/mocks/dronecode_sdk_mock.h

@@ -1,3 +1,4 @@
+#include <string>
 #include <gmock/gmock.h>
 
 #include "connection_result.h"
@@ -9,7 +10,7 @@ typedef std::function<void(uint64_t uuid)> event_callback_t;
 
 class MockDronecodeSDK {
 public:
-    MOCK_CONST_METHOD1(add_udp_connection, ConnectionResult(int local_port_number)){};
+    MOCK_CONST_METHOD1(add_any_connection, ConnectionResult(const std::string &)){};
     MOCK_CONST_METHOD1(register_on_discover, void(event_callback_t)){};
     MOCK_CONST_METHOD1(register_on_timeout, void(event_callback_t)){};
 };