Adding directory for service framework

This commit was SVN r1906.

src/mca/service/service.h

@@ -0,0 +1,144 @@
+/*
+ * $HEADER$
+ */
+
+#ifndef MCA_SERVICE_H
+#define MCA_SERVICE_H
+
+#include "ompi_config.h"
+
+#include "mpi.h"
+#include "mca/mca.h"
+#include "mca/base/base.h"
+
+
+/**************************************************************************
+ * Service component
+ **************************************************************************/
+
+typedef const struct mca_service_module_1_0_0_t *(*mca_service_base_select_fn_t) (bool am_seed);
+
+/*
+ * Structure for service v1.0.0 components
+ * Chained to MCA v1.0.0
+ */
+struct mca_service_base_component_1_0_0_t {
+    mca_base_component_t dc_version;
+    mca_base_component_data_1_0_0_t dc_data;
+
+    /* Initialization / querying functions */
+
+    mca_service_base_select_fn_t dc_select;
+};
+typedef struct mca_service_base_component_1_0_0_t mca_service_base_component_1_0_0_t;
+
+
+/**************************************************************************
+ * Service module
+ **************************************************************************/
+
+typedef int (*mca_service_base_init_fn_t) (mca_service_base_module_t *self);
+typedef int (*mca_service_base_finalize_t) (mca_service_base_module_t *self);
+
+typedef int (*mca_service_base_poll_t) (mca_service_base_module_t *self);
+
+struct mca_service_base_module_1_0_0_t {
+
+    /* Init / finalize */
+
+    mca_service_base_init_fn_t dm_init;
+    mca_service_base_finalize_fn_t dm_finalize;
+
+    /* Polling */
+
+    mca_service_base_poll_fn_t dm_poll;
+};
+typedef struct mca_service_module_1_0_0_t mca_service_module_1_0_0_t;
+
+/*
+ * service services (i.e., components), and the initial events that
+ * will trigger scheduling them to run:
+ *
+ * Service              FD events    incoming OOB  timer  signals
+ * ------------------ -------------  ------------  -----  -------
+ * kenyad                 X (pipe)        X                  X
+ * i/o relaying           X               X
+ * inter-daemon comms     X
+ * inter-daemon hbeats    X                          X
+ *  ^^ may be same as inter-daemon comms? (a la lamd)
+ * name server                            X
+ * registry                               X
+ * pushing files                          X                       (future)
+ * routing oob                            X                       (future)
+ * incoming oob           X
+ * ------------------ -------------  ------------  -----  -------
+ *
+ * --> per converation w/ brian, do we need a pcm in here?  e.g.,
+       spawn daemons in rsh and bproc kinds of environments, so that
+       one daemon on bproc headnode acts as a proxy pcm...?
+   --> open question
+ *
+ * ***Assumption*** oob will be based on libevent, perhaps tcp or
+ *    perhaps only local named socket...is this a safe assumption?
+ *
+ * Initialization sequence:
+ *
+ * - find all service components
+ * - call select(); if non-NULL reply, keep, otherwise close/unloads
+ * - call init() on all modules
+ * - call poll() on all modules once.  poll() can do the following:
+ *   - post non-blocking oob receive with callback
+ *   - setup a fd and register with libevent with callback
+ *   - indicate that it wants to run after receiving a specific signal
+ *     (not in signal context -- will specify a callback that will be
+ *     invoked after return from signal context)
+ *   - request to be put on the end of the to-be-run queue
+ *   - request to run sometime after the end of a timeout
+ *   --> currently no other mechanisms for progress
+ * - post a non-blocking oob receive on a specific tag for shutdown
+ *
+ * The callback posted by the service for the shutdown message will
+ * simply set a global "time_to_shutdown" flag that will be noticed in
+ * the main event loop.
+ *
+ * Main event loop:
+ *
+ * Mainly a single threaded blocking progress on libevent (hence, it's
+ * blocking/asleep most of the time).  Main loop spins on calling the
+ * blocking libevent progress, checking for signal interrupts and
+ * calling the appropriate callbacks, and checking the global shutdown
+ * flag.  Something like this:
+ *
+ * do_init_stuff();
+ * while (1) {
+ *   // make progress on fd (including OOB) and timer events in here
+ *   err = blocking_libevent_progress();
+ *   // if one of the callbacks set the time_to_shutdown flag, then quit
+ *   if (time_to_shutdown) {
+ *     break;
+ *   } 
+ *   // if we were interrupted by a signal, invoke the callback that
+ *   // was registered for it
+ *   else if (err == interrupted_by_signal) {
+ *     call_handler_for_signal();
+ *   }
+ *   // see if there's anything on the to-be-run queue
+ *   foreach service (@to_be_run) {
+ *     service->poll();
+ *   }
+ * }
+ * do_finalize_stuff();
+ *
+ * open q: how to do oob sending from within the services?
+ */
+
+/*
+ * Macro for use in modules that are of type service v1.0.0
+ */
+#define MCA_SERVICE_BASE_VERSION_1_0_0 \
+  /* service v1.0 is chained to MCA v1.0 */ \
+  MCA_BASE_VERSION_1_0_0, \
+  /* service v1.0 */ \
+  "service", 1, 0, 0
+
+#endif                          /* MCA_SERVICE_H */