/** \defgroup process Process Management
- This collection of utilities provides help in managing daemon processes.
+ Future features:
+
+ \li Daemon manager watching the real daemon. Auto-restart, when the daemon fails
+
+ \li Provide access to the config console indirectly via the daemon manager. This allows to
+ connect to the daemon manager console even if the app is not running
+
+ \li For this to be efficient, the daemon manager must be it's own executable (e.g. senf-launch)
- \idea Add communication between parent and child process to daemonize() and add things like
- init_done(), failure() etc which allow the daemon process to tell the frontend of successful
- startup or failure. This probably means moving all the methods into a DaemonTools class (as
- statics or via a singleton). This would also allow for automatic pid file creation and
- removal (remove in global destructor).
+ \li auto-detect whether called from senf-launch or not
- \idea Add a DaemonProcess baseclass with init() and main() abstract members which wraps the
- startup process. DaeminProcess::run() would fork, call init(), create a pid file and then
- call main(). Exceptions during init()'s execution would be passed to the parent
- process. This is based on the above API.
+ \li when daemon is running, the console is transparently forwarded to the daemon. The daemon
+ however can still access the daemon manager as a subgroup
+
+ \li No idea, whether this is sensible: Make the daemon manager completely self-contained (not
+ dependent on any external OS support) by providing our own log-file rotation support.
+
+ This collection of utilities provides help in managing daemon processes.
\idea A closeall()/closemost() function which is useful when starting child processes. We'll use
getrlimit to now the biggest filehandle and close all of em. closemost() takes a number of
// Custom includes
#include <string>
+#include <boost/utility.hpp>
//#include "DaemonTools.mpp"
///////////////////////////////hh.p////////////////////////////////////////
namespace senf {
+ /** \brief Daemon process
+
+ This class provides the infrastructure to implement robust daemon processes. A daemon
+ process is implemented by deriving from senf::Daemon and implementing the necessary
+ (virtual) member functions.
+ \code
+ class MyDaemon : public senf::Daemon
+ {
+ void configure() {
+ // Set configuration parameters like daemonize(), pidFile() etc.
+ }
+
+ void init() {
+ // Initialize application. Setup all necessary objects. After init()
+ // has completed, is startup should not fail anymore
+ }
+
+ void run() {
+ // Main application code should be called here.
+ }
+ };
+ \endcode
+
+ The startup procedure is divided into three steps:
+ \li First, configure() is called. configure() should be as simple as possible. It just needs
+ to set the daemon parameters. No further setup should be done here.
+ \li init() is called after fork() but while still connected to the terminal. init() should
+ do all necessary application setup. Here, all configuration or user errors should be
+ detected and properly diagnosed.
+ \li After init() returns, the application will detach from the terminal. Now run() is called
+ to enter the application main loop.
+
+ Since there are times, where separating init() and run() into two separate functions is
+ difficult, instead of defining init() and run(), the member main() may be defined. This
+ member must call detach() as soon as initialization is completed to detach from the
+ foreground terminal.
+
+
+
+ \ingroup process
+ */
+ class Daemon : boost::noncopyable
+ {
+ public:
+ ///////////////////////////////////////////////////////////////////////////
+ // Types
+
+ /// Select standard stream to redirect
+ enum StdStream {
+ StdOut /** Standard output stream */
+ , StdErr /** Standard error stream */
+ , Both /** Both, standard output and error stream */
+ };
+
+ ///////////////////////////////////////////////////////////////////////////
+ ///\name Structors and default members
+ ///\{
+
+ virtual ~Daemon();
+
+ ///\}
+ ///\name Parameters
+ ///\{
+
+ void daemonize(bool); ///< Configure whether to run in fore- or background
+ bool daemon(); ///< \c true, if running as daemon
+
+ void consoleLog(std::string, StdStream which = Both); ///< Configure console log file
+ /**< May be called multiple times to set the log file
+ for stdout and stderr seperately. Any standard stream
+ not assigned to a log file will be redirected to
+ <tt>/dev/null</tt>.
+
+ When running in the foreground, the log files will be
+ ignored. */
+
+ void pidFile(std::string, bool unique = true); ///< Configure pid file
+
+ ///\}
+ ///\name Auxiliary helpers
+ ///\{
+
+ void detach(); ///< Detach into background now
+ /**< This is \e not the same as forking. The process will
+ already have forked into the background but until
+ detach() is called (either automatically after init()
+ returns or manually), the front end (foreground)
+ process will wait for the background process to ensure
+ successful startup. */
+
+ int argc(); ///< Access command line parameter count
+ char const ** argv(); ///< Access command line parameters
+
+ void fail(int code=1); ///< Terminate startup with failure
+
+ ///\}
+
+ int start(int argc, char const ** argv); ///< Called from main() to launch daemon.
+ /**< Normally not called directly but from the
+ \ref SENF_DAEMON_MAIN macro. */
+
+ protected:
+ Daemon();
+
+# ifdef DOXYGEN
+ protected:
+# else
+ private:
+# endif
+
+ virtual void configure(); ///< Called before forking to configure the daemon class
+ virtual void main(); ///< Called after forking to execute the main application
+ /**< The default implementation will call init(), detach()
+ and then run(). It is preferred to override init() and
+ run() if possible. */
+ virtual void init(); ///< Called to initialize the main application
+ /**< While init() is running, the application still is
+ connected to the controlling terminal. Error messages
+ will be shown to the user.
+
+ This member is only called, if the default main()
+ implementation is not overridden. */
+ virtual void run(); ///< Called to execute main application
+ /**< Called after detaching from the controlling
+ terminal.
+
+ This member is only called, if the default main()
+ implementation is not overridden. */
+ private:
+
+ void pidfileCreate();
+
+ int argc_;
+ char const ** argv_;
+
+ bool daemonize_;
+ int stdout_;
+ int stderr_;
+ std::string pidfile_;
+ bool unique_;
+
+ bool detached_;
+ };
+
+ /** \brief Provide \c main() function
+
+ This macro will provide a \c main() function to launch the daemon process defined in \a
+ klass. \a klass must be a class derived from senf::Daemon.
+
+ \ingroup process
+ */
+# define SENF_DAEMON_MAIN(klass) \
+ int main(int argc, char const ** argv) \
+ { \
+ klass instance; \
+ return instance.start(argc, argv); \
+ }
+
/// \addtogroup process
/// @{
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