diff options
author | Gordon Sim <gsim@apache.org> | 2008-11-07 14:08:29 +0000 |
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committer | Gordon Sim <gsim@apache.org> | 2008-11-07 14:08:29 +0000 |
commit | 53247faba484516d9c468b7ae7f514f32541295a (patch) | |
tree | 2a823dcf2f292479ba122a25a1fadec3837f9562 | |
parent | 0e0d76bedfb1f369ab0a71a62c931c13d66e0b7e (diff) | |
download | qpid-python-53247faba484516d9c468b7ae7f514f32541295a.tar.gz |
* Added some doxygen comments for FailoverManager
* Added means for application to alter the order in which urls are tried (or indeed the list of urls to try)
git-svn-id: https://svn.apache.org/repos/asf/incubator/qpid/trunk@712127 13f79535-47bb-0310-9956-ffa450edef68
-rw-r--r-- | qpid/cpp/examples/failover/declare_queues.cpp | 73 | ||||
-rw-r--r-- | qpid/cpp/examples/failover/resuming_receiver.cpp | 16 | ||||
-rw-r--r-- | qpid/cpp/src/qpid/client/FailoverManager.cpp | 10 | ||||
-rw-r--r-- | qpid/cpp/src/qpid/client/FailoverManager.h | 59 |
4 files changed, 101 insertions, 57 deletions
diff --git a/qpid/cpp/examples/failover/declare_queues.cpp b/qpid/cpp/examples/failover/declare_queues.cpp index 14e4a1e3cb..a677870c53 100644 --- a/qpid/cpp/examples/failover/declare_queues.cpp +++ b/qpid/cpp/examples/failover/declare_queues.cpp @@ -19,67 +19,40 @@ * */ -#include <qpid/client/FailoverConnection.h> +#include <qpid/client/FailoverManager.h> #include <qpid/client/Session.h> +#include <qpid/Exception.h> -#include <unistd.h> #include <cstdlib> #include <iostream> -#include <fstream> using namespace qpid::client; -using namespace qpid::framing; - using namespace std; - - - -int -main ( int argc, char ** argv) +int main(int argc, char ** argv) { - if ( argc < 3 ) - { - std::cerr << "Usage: ./declare_queues host cluster_port_file_name\n"; - std::cerr << "i.e. for host: 127.0.0.1\n"; - exit(1); - } - - const char * host = argv[1]; - int port = atoi(argv[2]); - - - try - { - FailoverConnection connection; - FailoverSession * session; - - connection.open ( host, port ); - session = connection.newSession(); - - session->queueDeclare ( "message_queue"); + ConnectionSettings settings; + if (argc > 1) settings.host = argv[1]; + if (argc > 2) settings.port = atoi(argv[2]); + + FailoverManager connection(settings); + try { + bool complete = false; + while (!complete) { + Session session = connection.connect().newSession(); + try { + session.queueDeclare(arg::queue="message_queue"); + complete = true; + } catch (const qpid::TransportFailure&) {} + } + connection.close(); + return 0; + } catch (const std::exception& error) { + std::cout << "Failed:" << error.what() << std::endl; + return 1; + } - /* - session->exchangeBind - ( arg::exchange="amq.direct", - arg::queue="message_queue", - arg::bindingKey="routing_key" - ); - * */ - session->exchangeBind ( "message_queue", - "amq.direct", - "routing_key" - ); - connection.close(); - return 0; - } - catch ( const std::exception& error ) - { - std::cout << error.what() << std::endl; - } - - return 1; } diff --git a/qpid/cpp/examples/failover/resuming_receiver.cpp b/qpid/cpp/examples/failover/resuming_receiver.cpp index 3c1df92ed1..d1886ce861 100644 --- a/qpid/cpp/examples/failover/resuming_receiver.cpp +++ b/qpid/cpp/examples/failover/resuming_receiver.cpp @@ -35,13 +35,16 @@ using namespace qpid::framing; using namespace std; -class Listener : public MessageListener, public FailoverManager::Command +class Listener : public MessageListener, + public FailoverManager::Command, + public FailoverManager::ReconnectionStrategy { public: Listener(); void received(Message& message); void execute(AsyncSession& session, bool isRetry); void check(); + void editUrlList(std::vector<Url>& urls); private: Subscription subscription; uint count; @@ -90,14 +93,23 @@ void Listener::execute(AsyncSession& session, bool isRetry) subs.run(); } +void Listener::editUrlList(std::vector<Url>& urls) +{ + /** + * A more realistic algorithm would be to search through the list + * for prefered hosts and ensure they come first in the list. + */ + if (urls.size() > 1) std::rotate(urls.begin(), urls.begin() + 1, urls.end()); +} + int main(int argc, char ** argv) { ConnectionSettings settings; if (argc > 1) settings.host = argv[1]; if (argc > 2) settings.port = atoi(argv[2]); - FailoverManager connection(settings); Listener listener; + FailoverManager connection(settings, &listener); try { connection.execute(listener); diff --git a/qpid/cpp/src/qpid/client/FailoverManager.cpp b/qpid/cpp/src/qpid/client/FailoverManager.cpp index 73c6bfc2de..ab9dbca70f 100644 --- a/qpid/cpp/src/qpid/client/FailoverManager.cpp +++ b/qpid/cpp/src/qpid/client/FailoverManager.cpp @@ -28,7 +28,8 @@ namespace client { using qpid::sys::Monitor; -FailoverManager::FailoverManager(const ConnectionSettings& s) : settings(s), state(IDLE) {} +FailoverManager::FailoverManager(const ConnectionSettings& s, + ReconnectionStrategy* rs) : settings(s), strategy(rs), state(IDLE) {} void FailoverManager::execute(Command& c) { @@ -38,11 +39,11 @@ void FailoverManager::execute(Command& c) try { AsyncSession session = connect().newSession(); c.execute(session, retry); - session.sync();//TODO: shouldn't be required, but seems there is a bug in session + session.sync();//TODO: shouldn't be required session.close(); completed = true; } catch(const TransportFailure&) { - retry = true; + retry = true; } } } @@ -86,6 +87,7 @@ Connection& FailoverManager::getConnection() void FailoverManager::attempt(Connection& c, ConnectionSettings s, std::vector<Url> urls) { Monitor::ScopedUnlock u(lock); + if (strategy) strategy->editUrlList(urls); if (urls.empty()) { attempt(c, s); } else { @@ -105,7 +107,9 @@ void FailoverManager::attempt(Connection& c, ConnectionSettings s, std::vector<U void FailoverManager::attempt(Connection& c, ConnectionSettings s) { try { + QPID_LOG(info, "Attempting to connect to " << s.host << " on " << s.port << "..."); c.open(s); + QPID_LOG(info, "Connected to " << s.host << " on " << s.port); } catch (const Exception& e) { QPID_LOG(info, "Could not connect to " << s.host << " on " << s.port << ": " << e.what()); } diff --git a/qpid/cpp/src/qpid/client/FailoverManager.h b/qpid/cpp/src/qpid/client/FailoverManager.h index d17b8371d0..5af2a8f994 100644 --- a/qpid/cpp/src/qpid/client/FailoverManager.h +++ b/qpid/cpp/src/qpid/client/FailoverManager.h @@ -38,21 +38,75 @@ struct CannotConnectException : qpid::Exception }; /** - * Utility to handle reconnection. + * Utility to manage failover. */ class FailoverManager { public: + /** + * Interface to implement for doing work that can be resumed on + * failover + */ struct Command { + /** + * This method will be called with isRetry=false when the + * command is first executed. The session to use for the work + * will be passed to the implementing class. If the connection + * fails while the execute call is in progress, the + * FailoverManager controlling the execution will re-establish + * a connection, open a new session and call back to the + * Command implementations execute method with the new session + * and isRetry=true. + */ virtual void execute(AsyncSession& session, bool isRetry) = 0; virtual ~Command() {} }; - FailoverManager(const ConnectionSettings& settings); + struct ReconnectionStrategy + { + /** + * This method is called by the FailoverManager prior to + * establishing a connection (or re-connection) and can be + * used if the application wishes to edit or re-order the list + * which will default to the list of known brokers for the + * last connection. + */ + virtual void editUrlList(std::vector<Url>& urls) = 0; + virtual ~ReconnectionStrategy() {} + }; + + /** + * Create a manager to control failover for a logical connection. + * + * @param settings the initial connection settings + * @param strategy optional stratgey callback allowing application + * to edit or reorder the list of urls to which reconnection is + * attempted + */ + FailoverManager(const ConnectionSettings& settings, ReconnectionStrategy* strategy = 0); + /** + * Return the current connection if open or attept to reconnect to + * the specified list of urls. If no list is specified the list of + * known brokers from the last connection will be used. If no list + * is specified and this is the first connect attempt, the host + * and port from the initial settings will be used. + */ Connection& connect(std::vector<Url> brokers = std::vector<Url>()); + /** + * Return the current connection whether open or not + */ Connection& getConnection(); + /** + * Close the current connection + */ void close(); + /** + * Reliably execute the specified command. This involves creating + * a session on which to carry out the work of the command, + * handling failover occuring while exeuting that command and + * re-starting the work. + */ void execute(Command&); private: enum State {IDLE, CONNECTING, CANT_CONNECT}; @@ -60,6 +114,7 @@ class FailoverManager qpid::sys::Monitor lock; Connection connection; ConnectionSettings settings; + ReconnectionStrategy* strategy; State state; void attempt(Connection&, ConnectionSettings settings, std::vector<Url> urls); |