boinc/sched_fcgi/feeder.C

221 lines
6.6 KiB
C

// The contents of this file are subject to the BOINC Public License
// Version 1.0 (the "License"); you may not use this file except in
// compliance with the License. You may obtain a copy of the License at
// http://boinc.berkeley.edu/license_1.0.txt
//
// Software distributed under the License is distributed on an "AS IS"
// basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
// License for the specific language governing rights and limitations
// under the License.
//
// The Original Code is the Berkeley Open Infrastructure for Network Computing.
//
// The Initial Developer of the Original Code is the SETI@home project.
// Portions created by the SETI@home project are Copyright (C) 2002
// University of California at Berkeley. All Rights Reserved.
//
// Contributor(s):
//
// feeder.C [-asynch]
//
// Creates a shared memory segment containing DB info,
// including results/workunits to send.
// This means that the scheduler CGI program doesn't have to
// access the DB to get this info.
//
// -asynch fork and run in a separate process
// TODO:
// - check for wu/results that don't get sent for a long time;
// generate a warning message
// - mechanism for rereading static tables (trigger file? signal?)
// Trigger file mechanism:
// The feeder program periodically checks for a file "feeder_trigger".
// It this file exists it contains a command to the feeder:
//
// <quit/> destroy shmem and exit
// <reread_db/> reread DB contents into existing shmem
//
// The feeder deletes the trigger file to indicate that it
// has completed the request.
#include <stdio.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef _USING_FCGI_
#include "/usr/local/include/fcgi_stdio.h"
#endif
#include "db.h"
#include "shmem.h"
#include "sched_shmem.h"
#define RESULTS_PER_ENUM 100
#define TRIGGER_FILENAME "feeder_trigger"
int check_trigger(SCHED_SHMEM* ssp) {
FILE* f;
char buf[256];
f = fopen(TRIGGER_FILENAME, "r");
if (!f) return 0;
fread(buf, 1, 256, f);
fclose(f);
if (!strcmp(buf, "<quit/>\n")) {
detach_shmem((void*)ssp);
destroy_shmem(BOINC_KEY);
unlink(TRIGGER_FILENAME);
exit(0);
} else if (!strcmp(buf, "<reread_db/>\n")) {
ssp->init();
ssp->scan_tables();
} else {
fprintf(stderr, "feeder: unknown command in trigger file: %s\n", buf);
}
unlink(TRIGGER_FILENAME);
return 0;
}
// Try keep the wu_results array filled.
// This is actually a little tricky.
// We use an enumerator.
// The inner loop scans the wu_result table,
// looking for empty slots and trying to fill them in.
// When the enumerator reaches the end, it is restarted;
// hopefully there will be some new workunits.
// There are two complications:
// - An enumeration may return results already in the array.
// So, for each result, we scan the entire array to make sure
// it's not there already. Can this be streamlined?
// - We must avoid excessive re-enumeration,
// especially when the number of results is less than the array size.
// Crude approach: if a "collision" (as above) occurred on
// a pass through the array, wait a long time (60 sec)
//
void feeder_loop(SCHED_SHMEM* ssp) {
int i, j, nadditions, ncollisions, retval;
RESULT result;
WORKUNIT wu;
bool no_wus, collision, restarted_enum;
while (1) {
nadditions = 0;
ncollisions = 0;
no_wus = false;
restarted_enum = false;
for (i=0; i<ssp->nwu_results; i++) {
if (!ssp->wu_results[i].present) {
retval = db_result_enum_to_send(result, RESULTS_PER_ENUM);
if (retval) {
// if we already restarted the enum on this pass,
// there's no point in doing it again.
//
if (restarted_enum) {
printf("feeder: already restarted enum\n");
break;
}
// restart the enumeration
//
restarted_enum = true;
retval = db_result_enum_to_send(result, RESULTS_PER_ENUM);
printf("feeder: restarting enumeration: %d\n", retval);
if (retval) {
no_wus = true;
break;
}
}
collision = false;
for (j=0; j<ssp->nwu_results; j++) {
if (ssp->wu_results[j].present
&& ssp->wu_results[j].result.id == result.id
) {
ncollisions++;
collision = true;
break;
}
}
if (!collision) {
printf("feeder: adding result %d\n", result.id);
retval = db_workunit(result.workunitid, wu);
if (retval) continue;
ssp->wu_results[i].result = result;
ssp->wu_results[i].workunit = wu;
ssp->wu_results[i].present = true;
nadditions++;
}
}
}
if (nadditions == 0) {
sleep(1);
} else {
printf("feeder: added %d results to array\n", nadditions);
}
if (no_wus) {
printf("feeder: no results available\n");
sleep(5);
}
if (ncollisions) {
printf("feeder: some results already in array - sleeping\n");
sleep(5);
}
check_trigger(ssp);
ssp->ready = true;
}
}
int main(int argc, char** argv) {
SCHED_SHMEM* ssp;
int i, retval;
bool asynch = false;
void* p;
for (i=1; i<argc; i++) {
if (!strcmp(argv[i], "-asynch")) {
asynch = true;
}
}
retval = destroy_shmem(BOINC_KEY);
if (retval) {
fprintf(stderr, "feeder: can't destroy shmem\n");
exit(1);
}
retval = create_shmem(BOINC_KEY, sizeof(SCHED_SHMEM), &p);
if (retval) {
fprintf(stderr, "feeder: can't create shmem\n");
exit(1);
}
ssp = (SCHED_SHMEM*)p;
ssp->init();
retval = db_open("boinc");
if (retval) {
fprintf(stderr, "feeder: db_open: %d\n", retval);
exit(1);
}
ssp->scan_tables();
printf(
"feeder: read\n"
"%d platforms\n"
"%d apps\n"
"%d app_versions\n",
ssp->nplatforms,
ssp->napps,
ssp->napp_versions
);
if (asynch) {
if (fork()==0) {
feeder_loop(ssp);
}
} else {
feeder_loop(ssp);
}
}