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#define _POSIX_C_SOURCE 200809L
#include <netdb.h>
#include <netinet/in.h>
#include <poll.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#include "scrape.h"
#include "util.h"
#define BUF_INITIAL 1024
#define BUF_MAX 65536
#define MAX_LISTEN_SOCKETS 4
#define MAX_BACKLOG 16
struct scrape_req {
int socket;
cbuf *buf;
};
bool scrape_serve(const char *port, scrape_handler *handler, void *handler_ctx) {
struct scrape_req req;
struct pollfd fds[MAX_LISTEN_SOCKETS];
nfds_t nfds = 0;
int ret;
{
struct addrinfo hints = {
.ai_family = AF_UNSPEC,
.ai_socktype = SOCK_STREAM,
.ai_protocol = 0,
.ai_flags = AI_PASSIVE | AI_ADDRCONFIG,
};
struct addrinfo *addrs;
ret = getaddrinfo(0, port, &hints, &addrs);
if (ret != 0) {
fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(ret));
return false;
}
for (struct addrinfo *a = addrs; a && nfds < MAX_LISTEN_SOCKETS; a = a->ai_next) {
int s = socket(a->ai_family, a->ai_socktype, a->ai_protocol);
if (s == -1) {
perror("socket");
continue;
}
setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (int[]){1}, sizeof (int));
#if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY) && defined(AF_INET6)
if (a->ai_family == AF_INET6)
setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, (int[]){1}, sizeof (int));
#endif
ret = bind(s, a->ai_addr, a->ai_addrlen);
if (ret == -1) {
perror("bind");
close(s);
continue;
}
ret = listen(s, MAX_BACKLOG);
if (ret == -1) {
perror("listen");
close(s);
continue;
}
fds[nfds].fd = s;
fds[nfds].events = POLLIN;
nfds++;
}
}
if (nfds == 0) {
fprintf(stderr, "failed to bind any sockets");
return false;
}
req.buf = cbuf_alloc(BUF_INITIAL, BUF_MAX);
if (!req.buf) {
perror("cbuf_alloc");
for (nfds_t i = 0; i < nfds; i++)
close(fds[i].fd);
return false;
}
while (1) {
ret = poll(fds, nfds, -1);
if (ret == -1) {
perror("poll");
break;
}
for (nfds_t i = 0; i < nfds; i++) {
if (fds[i].revents == 0)
continue;
if (fds[i].revents != POLLIN) {
fprintf(stderr, "poll .revents = %d\n", fds[i].revents);
goto break_loop;
}
req.socket = accept(fds[i].fd, 0, 0);
if (req.socket == -1) {
perror("accept");
continue;
}
// TODO: HTTP stuff
handler(&req, handler_ctx);
close(req.socket);
}
}
break_loop:
for (nfds_t i = 0; i < nfds; i++)
close(fds[i].fd);
return false;
}
void scrape_write(scrape_req *req, const char *metric, const char *(*labels)[2], double value) {
cbuf_reset(req->buf);
cbuf_puts(req->buf, metric);
if (labels && (*labels)[0]) {
cbuf_putc(req->buf, '{');
for (const char *(*l)[2] = labels; (*l)[0]; l++) {
if (l != labels)
cbuf_putc(req->buf, ',');
cbuf_putf(req->buf, "%s=\"%s\"", (*l)[0], (*l)[1]);
}
cbuf_putc(req->buf, '}');
}
cbuf_putf(req->buf, " %.16g\n", value);
size_t buf_len;
const char *buf = cbuf_get(req->buf, &buf_len);
write_all(req->socket, buf, buf_len);
}
void scrape_write_raw(scrape_req *req, const void *buf, size_t len) {
write_all(req->socket, buf, len);
}
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