/**
* pthread compatible routine that handles connections and processes
* whatever comes in on those.
*/
static void *
dispatch_runner(void *arg)
{
dispatcher *self = (dispatcher *)arg;
connection *conn;
int c;
self->metrics = 0;
self->blackholes = 0;
self->ticks = 0;
self->sleeps = 0;
self->prevmetrics = 0;
self->prevblackholes = 0;
self->prevticks = 0;
self->prevsleeps = 0;
if (self->type == LISTENER) {
struct pollfd ufds[sizeof(listeners) / sizeof(connection *)];
while (self->keep_running) {
for (c = 0; c < sizeof(listeners) / sizeof(connection *); c++) {
if (listeners[c] == NULL)
break;
ufds[c].fd = listeners[c]->sock;
ufds[c].events = POLLIN;
}
if (poll(ufds, c, 1000) > 0) {
for (--c; c >= 0; c--) {
if (ufds[c].revents & POLLIN) {
int client;
struct sockaddr addr;
socklen_t addrlen = sizeof(addr);
if ((client = accept(ufds[c].fd, &addr, &addrlen)) < 0)
{
logerr("dispatch: failed to "
"accept() new connection: %s\n",
strerror(errno));
dispatch_check_rlimit_and_warn();
continue;
}
if (dispatch_addconnection(client) == -1) {
close(client);
continue;
}
}
}
}
}
} else if (self->type == CONNECTION) {
int work;
struct timeval start, stop;
while (self->keep_running) {
work = 0;
if (self->route_refresh_pending) {
self->rtr = self->pending_rtr;
self->pending_rtr = NULL;
self->route_refresh_pending = 0;
self->hold = 0;
}
gettimeofday(&start, NULL);
pthread_rwlock_rdlock(&connectionslock);
for (c = 0; c < connectionslen; c++) {
conn = &(connections[c]);
/* atomically try to "claim" this connection */
if (!__sync_bool_compare_and_swap(&(conn->takenby), 0, self->id))
continue;
if (self->hold && !conn->isaggr) {
conn->takenby = 0;
continue;
}
work += dispatch_connection(conn, self, start);
}
pthread_rwlock_unlock(&connectionslock);
gettimeofday(&stop, NULL);
self->ticks += timediff(start, stop);
/* nothing done, avoid spinlocking */
if (self->keep_running && work == 0) {
gettimeofday(&start, NULL);
usleep((100 + (rand() % 200)) * 1000); /* 100ms - 300ms */
gettimeofday(&stop, NULL);
self->sleeps += timediff(start, stop);
}
}
} else {
logerr("huh? unknown self type!\n");
}
return NULL;
}
/**
* Reads from the queue and sends items to the remote server. This
* function is designed to be a thread. Data sending is attempted to be
* batched, but sent one by one to reduce loss on sending failure.
* A connection with the server is maintained for as long as there is
* data to be written. As soon as there is none, the connection is
* dropped if a timeout of DISCONNECT_WAIT_TIME exceeds.
*/
static void *
server_queuereader(void *d)
{
server *self = (server *)d;
size_t len;
ssize_t slen;
const char **metric = self->batch;
struct timeval start, stop;
struct timeval timeout;
queue *squeue;
char idle = 0;
size_t *secpos = NULL;
*metric = NULL;
self->metrics = 0;
self->ticks = 0;
#define FAIL_WAIT_TIME 6 /* 6 * 250ms = 1.5s */
#define DISCONNECT_WAIT_TIME 12 /* 12 * 250ms = 3s */
#define LEN_CRITICAL(Q) (queue_free(Q) < self->bsize)
self->running = 1;
while (1) {
if (queue_len(self->queue) == 0) {
/* if we're idling, close the TCP connection, this allows us
* to reduce connections, while keeping the connection alive
* if we're writing a lot */
gettimeofday(&start, NULL);
if (self->ctype == CON_TCP && self->fd >= 0 &&
idle++ > DISCONNECT_WAIT_TIME)
{
close(self->fd);
self->fd = -1;
}
gettimeofday(&stop, NULL);
self->ticks += timediff(start, stop);
if (!self->keep_running)
break;
/* nothing to do, so slow down for a bit */
usleep((200 + (rand() % 100)) * 1000); /* 200ms - 300ms */
/* if we are in failure mode, keep checking if we can
* connect, this avoids unnecessary queue moves */
if (!self->failure)
/* it makes no sense to try and do something, so skip */
continue;
} else if (self->secondariescnt > 0 &&
(self->failure >= FAIL_WAIT_TIME ||
(!self->failover && LEN_CRITICAL(self->queue))))
{
size_t i;
gettimeofday(&start, NULL);
if (self->secondariescnt > 0) {
if (secpos == NULL) {
secpos = malloc(sizeof(size_t) * self->secondariescnt);
if (secpos == NULL) {
logerr("server: failed to allocate memory "
"for secpos\n");
gettimeofday(&stop, NULL);
self->ticks += timediff(start, stop);
continue;
}
for (i = 0; i < self->secondariescnt; i++)
secpos[i] = i;
}
if (!self->failover) {
/* randomise the failover list such that in the
* grand scheme of things we don't punish the first
* working server in the list to deal with all
* traffic meant for a now failing server */
for (i = 0; i < self->secondariescnt; i++) {
size_t n = rand() % (self->secondariescnt - i);
if (n != i) {
size_t t = secpos[n];
secpos[n] = secpos[i];
secpos[i] = t;
}
}
}
}
/* offload data from our queue to our secondaries
* when doing so, observe the following:
* - avoid nodes that are in failure mode
* - avoid nodes which queues are >= critical_len
* when no nodes remain given the above
* - send to nodes which queue size < critical_len
* where there are no such nodes
* - do nothing (we will overflow, since we can't send
* anywhere) */
*metric = NULL;
squeue = NULL;
for (i = 0; i < self->secondariescnt; i++) {
/* both conditions below make sure we skip ourself */
if (self->secondaries[secpos[i]]->failure)
continue;
squeue = self->secondaries[secpos[i]]->queue;
if (!self->failover && LEN_CRITICAL(squeue)) {
squeue = NULL;
continue;
}
if (*metric == NULL) {
/* send up to batch size of our queue to this queue */
len = queue_dequeue_vector(
self->batch, self->queue, self->bsize);
self->batch[len] = NULL;
metric = self->batch;
}
for (; *metric != NULL; metric++)
if (!queue_putback(squeue, *metric))
break;
/* try to put back stuff that didn't fit */
for (; *metric != NULL; metric++)
if (!queue_putback(self->queue, *metric))
break;
}
for (; *metric != NULL; metric++) {
if (mode & MODE_DEBUG)
logerr("dropping metric: %s", *metric);
free((char *)*metric);
self->dropped++;
}
gettimeofday(&stop, NULL);
self->ticks += timediff(start, stop);
if (squeue == NULL) {
/* we couldn't do anything, take it easy for a bit */
if (self->failure)
self->failure = 1;
if (!self->keep_running)
break;
usleep((200 + (rand() % 100)) * 1000); /* 200ms - 300ms */
}
} else if (self->failure) {
if (!self->keep_running)
break;
usleep((200 + (rand() % 100)) * 1000); /* 200ms - 300ms */
}
/* at this point we've got work to do, if we're instructed to
* shut down, however, try to get everything out of the door
* (until we fail, see top of this loop) */
gettimeofday(&start, NULL);
/* try to connect */
if (self->fd < 0) {
if (self->ctype == CON_PIPE) {
int intconn[2];
if (pipe(intconn) < 0) {
if (!self->failure)
logerr("failed to create pipe: %s\n", strerror(errno));
self->failure += self->failure >= FAIL_WAIT_TIME ? 0 : 1;
continue;
}
dispatch_addconnection(intconn[0]);
self->fd = intconn[1];
} else if (self->ctype == CON_UDP) {
if ((self->fd = socket(self->saddr->ai_family,
self->saddr->ai_socktype,
self->saddr->ai_protocol)) < 0)
{
if (!self->failure)
logerr("failed to create udp socket: %s\n",
strerror(errno));
self->failure += self->failure >= FAIL_WAIT_TIME ? 0 : 1;
continue;
}
if (connect(self->fd,
self->saddr->ai_addr, self->saddr->ai_addrlen) < 0)
{
if (!self->failure)
logerr("failed to connect udp socket: %s\n",
strerror(errno));
close(self->fd);
self->fd = -1;
self->failure += self->failure >= FAIL_WAIT_TIME ? 0 : 1;
continue;
}
} else if (self->ctype == CON_FILE) {
if ((self->fd = open(self->ip,
O_WRONLY | O_APPEND | O_CREAT,
S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH)) < 0)
{
if (!self->failure)
logerr("failed to open file '%s': %s\n",
self->ip, strerror(errno));
self->failure += self->failure >= FAIL_WAIT_TIME ? 0 : 1;
continue;
}
} else {
int ret;
int args;
if ((self->fd = socket(self->saddr->ai_family,
self->saddr->ai_socktype,
self->saddr->ai_protocol)) < 0)
{
if (!self->failure)
logerr("failed to create socket: %s\n",
strerror(errno));
self->failure += self->failure >= FAIL_WAIT_TIME ? 0 : 1;
continue;
}
/* put socket in non-blocking mode such that we can
* poll() (time-out) on the connect() call */
args = fcntl(self->fd, F_GETFL, NULL);
(void) fcntl(self->fd, F_SETFL, args | O_NONBLOCK);
ret = connect(self->fd,
self->saddr->ai_addr, self->saddr->ai_addrlen);
if (ret < 0 && errno == EINPROGRESS) {
/* wait for connection to succeed if the OS thinks
* it can succeed */
struct pollfd ufds[1];
ufds[0].fd = self->fd;
ufds[0].events = POLLIN | POLLOUT;
ret = poll(ufds, 1, self->iotimeout + (rand() % 100));
if (ret == 0) {
/* time limit expired */
if (!self->failure)
logerr("failed to connect() to "
"%s:%u: Operation timed out\n",
self->ip, self->port);
close(self->fd);
self->fd = -1;
self->failure += self->failure >= FAIL_WAIT_TIME ? 0 : 1;
continue;
} else if (ret < 0) {
/* some select error occurred */
if (!self->failure)
logerr("failed to poll() for %s:%u: %s\n",
self->ip, self->port, strerror(errno));
close(self->fd);
self->fd = -1;
self->failure += self->failure >= FAIL_WAIT_TIME ? 0 : 1;
continue;
} else {
if (ufds[0].revents & POLLHUP) {
if (!self->failure)
logerr("failed to connect() for %s:%u: "
"Hangup\n", self->ip, self->port);
close(self->fd);
self->fd = -1;
self->failure += self->failure >= FAIL_WAIT_TIME ? 0 : 1;
continue;
}
}
} else if (ret < 0) {
if (!self->failure) {
logerr("failed to connect() to %s:%u: %s\n",
self->ip, self->port, strerror(errno));
dispatch_check_rlimit_and_warn();
}
close(self->fd);
self->fd = -1;
self->failure += self->failure >= FAIL_WAIT_TIME ? 0 : 1;
continue;
}
/* make socket blocking again */
(void) fcntl(self->fd, F_SETFL, args);
}
/* ensure we will break out of connections being stuck more
* quickly than the kernel would give up */
timeout.tv_sec = 10;
timeout.tv_usec = (rand() % 300) * 1000;
setsockopt(self->fd, SOL_SOCKET, SO_SNDTIMEO,
&timeout, sizeof(timeout));
#ifdef SO_NOSIGPIPE
setsockopt(self->fd, SOL_SOCKET, SO_NOSIGPIPE, NULL, 0);
#endif
}
/* send up to batch size */
len = queue_dequeue_vector(self->batch, self->queue, self->bsize);
self->batch[len] = NULL;
metric = self->batch;
if (len != 0 && !self->keep_running) {
/* be noisy during shutdown so we can track any slowing down
* servers, possibly preventing us to shut down */
logerr("shutting down %s:%u: waiting for %zu metrics\n",
self->ip, self->port, len + queue_len(self->queue));
}
if (len == 0 && self->failure) {
/* if we don't have anything to send, we have at least a
* connection succeed, so assume the server is up again,
* this is in particular important for recovering this
* node by probes, to avoid starvation of this server since
* its queue is possibly being offloaded to secondaries */
if (self->ctype != CON_UDP)
logerr("server %s:%u: OK after probe\n", self->ip, self->port);
self->failure = 0;
}
for (; *metric != NULL; metric++) {
len = strlen(*metric);
if ((slen = write(self->fd, *metric, len)) != len) {
/* not fully sent, or failure, close connection
* regardless so we don't get synchonisation problems,
* partially sent data is an error for us, since we use
* blocking sockets, and hence partial sent is
* indication of a failure */
if (self->ctype != CON_UDP && !self->failure)
logerr("failed to write() to %s:%u: %s\n",
self->ip, self->port,
(slen < 0 ? strerror(errno) : "uncomplete write"));
close(self->fd);
self->fd = -1;
self->failure += self->failure >= FAIL_WAIT_TIME ? 0 : 1;
/* put back stuff we couldn't process */
for (; *metric != NULL; metric++) {
if (!queue_putback(self->queue, *metric)) {
if (mode & MODE_DEBUG)
logerr("server %s:%u: dropping metric: %s",
self->ip, self->port, *metric);
free((char *)*metric);
self->dropped++;
}
}
break;
} else if (self->failure) {
if (self->ctype != CON_UDP)
logerr("server %s:%u: OK\n", self->ip, self->port);
self->failure = 0;
}
free((char *)*metric);
self->metrics++;
}
gettimeofday(&stop, NULL);
self->ticks += timediff(start, stop);
idle = 0;
}
self->running = 0;
if (self->fd >= 0)
close(self->fd);
return NULL;
}
/**
* pthread compatible routine that handles connections and processes
* whatever comes in on those.
*/
static void *
dispatch_runner(void *arg)
{
dispatcher *self = (dispatcher *)arg;
connection *conn;
int work;
int c;
self->metrics = 0;
self->ticks = 0;
self->state = SLEEPING;
if (self->type == LISTENER) {
fd_set fds;
int maxfd = -1;
struct timeval tv;
while (self->keep_running) {
FD_ZERO(&fds);
tv.tv_sec = 0;
tv.tv_usec = 250 * 1000; /* 250 ms */
for (c = 0; c < sizeof(listeners) / sizeof(connection *); c++) {
conn = listeners[c];
if (conn == NULL)
break;
FD_SET(conn->sock, &fds);
if (conn->sock > maxfd)
maxfd = conn->sock;
}
if (select(maxfd + 1, &fds, NULL, NULL, &tv) > 0) {
for (c = 0; c < sizeof(listeners) / sizeof(connection *); c++) {
conn = listeners[c];
if (conn == NULL)
break;
if (FD_ISSET(conn->sock, &fds)) {
int client;
struct sockaddr addr;
socklen_t addrlen = sizeof(addr);
if ((client = accept(conn->sock, &addr, &addrlen)) < 0)
{
logerr("dispatch: failed to "
"accept() new connection: %s\n",
strerror(errno));
dispatch_check_rlimit_and_warn();
continue;
}
if (dispatch_addconnection(client) == -1) {
close(client);
continue;
}
}
}
}
}
} else if (self->type == CONNECTION) {
while (self->keep_running) {
work = 0;
if (self->route_refresh_pending) {
self->routes = self->pending_routes;
self->pending_routes = NULL;
self->route_refresh_pending = 0;
}
pthread_rwlock_rdlock(&connectionslock);
for (c = 0; c < connectionslen; c++) {
conn = &(connections[c]);
/* atomically try to "claim" this connection */
if (!__sync_bool_compare_and_swap(&(conn->takenby), 0, self->id))
continue;
self->state = RUNNING;
work += dispatch_connection(conn, self);
}
pthread_rwlock_unlock(&connectionslock);
self->state = SLEEPING;
/* nothing done, avoid spinlocking */
if (self->keep_running && work == 0)
usleep((100 + (rand() % 200)) * 1000); /* 100ms - 300ms */
}
} else {
logerr("huh? unknown self type!\n");
}
return NULL;
}