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Commit 4a5e0e8e authored by Dag Erling Smørgrav's avatar Dag Erling Smørgrav
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Add an API for synthetic objects, and use it to implement negative 

caching of backend issues.

Brief summary:

 - moved http_msg array from cache_response.c to cache_http.c,
   introduced http_StatusMessage() lookup function

 - introduced http_Put{Protocol,Status,Response} to complement
   http_PrintfHeader().

 - introduced SYN_ErrorPage() in a new file, cache_synthetic.c.
   SYN_ErrorPage() populates the session's current object with the
   specified error code and a corresponding HTML error page; it is the
   caller's responsibility to ensure that the session has a suitable
   object (i.e. one that doesn't already have headers or a body)

 - rewrote RES_Error() to simply call SYN_ErrorPage() (with ttl = 0) and
   RES_WriteObj().

 - rewrote cnt_fetch() to use SYN_ErrorPage() to create a 503 page with
   a TTL of 30 seconds when Fetch() fails.

 - removed the call to RES_Error() in cache_backend.c; the error
   trickles back up to cnt_fetch() anyway.

Comments from review:

 - Memory allocation and pointer gymnastics for the header and body
   are duplicated all over the place (in new and pre-existing code)
   and should be centralized and hidden behind a suitable API.

 - The http_*() API needs refactoring, we shouldn't need four
   different functions to manipulate four different entries in the
   same array.


git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@1474 d4fa192b-c00b-0410-8231-f00ffab90ce4
parent 778fa5e3
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Showing with 283 additions and 133 deletions
bin/varnishd/Makefile.am
View file @ 4a5e0e8e
......@@ -24,6 +24,7 @@ varnishd_SOURCES = \
cache_pipe.c \
cache_response.c \
cache_session.c \
cache_synthetic.c \
cache_vcl.c \
cache_vrt.c \
cache_vrt_acl.c \
......
bin/varnishd/cache.h
View file @ 4a5e0e8e
......@@ -365,6 +365,7 @@ void HSH_Deref(struct object *o);
void HSH_Init(void);
/* cache_http.c */
const char *http_StatusMessage(int);
void HTTP_Init(void);
void http_ClrHeader(struct http *to);
void http_CopyHttp(struct http *to, struct http *fm);
......@@ -374,6 +375,9 @@ void http_CopyReq(struct worker *w, int fd, struct http *to, struct http *fm);
void http_CopyResp(struct worker *w, int fd, struct http *to, struct http *fm);
void http_SetResp(struct worker *w, int fd, struct http *to, const char *proto, const char *status, const char *response);
void http_FilterHeader(struct worker *w, int fd, struct http *to, struct http *fm, unsigned how);
void http_PutProtocol(struct worker *w, int fd, struct http *to, const char *protocol);
void http_PutStatus(struct worker *w, int fd, struct http *to, int status);
void http_PutResponse(struct worker *w, int fd, struct http *to, const char *response);
void http_PrintfHeader(struct worker *w, int fd, struct http *to, const char *fmt, ...);
void http_SetHeader(struct worker *w, int fd, struct http *to, const char *hdr);
void http_Setup(struct http *ht, void *space, unsigned len);
......@@ -437,6 +441,9 @@ void WSL_Flush(struct worker *w);
void RES_Error(struct sess *sp, int code, const char *reason);
void RES_WriteObj(struct sess *sp);
/* cache_synthetic.c */
void SYN_ErrorPage(struct sess *sp, int status, const char *reason, int ttl);
/* cache_vcl.c */
void VCL_Init(void);
void VCL_Refresh(struct VCL_conf **vcc);
......
bin/varnishd/cache_backend.c
View file @ 4a5e0e8e
......@@ -320,7 +320,6 @@ VBE_GetFd(struct sess *sp)
}
usleep(100000 * n);
}
RES_Error(sp, 503, "Backend did not respond.");
return (NULL);
}
......
bin/varnishd/cache_center.c
View file @ 4a5e0e8e
......@@ -286,26 +286,19 @@ static int
cnt_fetch(struct sess *sp)
{
if (Fetch(sp)) {
sp->obj->cacheable = 0;
HSH_Unbusy(sp->obj);
HSH_Deref(sp->obj);
sp->obj = NULL;
sp->step = STP_DONE;
RES_Error(sp, 503, NULL);
return (0);
}
SYN_ErrorPage(sp, 503, "Error talking to backend", 30);
} else {
RFC2616_cache_policy(sp, &sp->obj->http); /* XXX -> VCL */
RFC2616_cache_policy(sp, &sp->obj->http); /* XXX -> VCL */
VCL_fetch_method(sp);
VCL_fetch_method(sp);
if (sp->handling == VCL_RET_ERROR)
INCOMPL();
if (sp->handling == VCL_RET_ERROR)
INCOMPL();
if (sp->handling == VCL_RET_PASS)
sp->obj->pass = 1;
if (sp->handling == VCL_RET_PASS)
sp->obj->pass = 1;
}
sp->obj->cacheable = 1;
if (sp->obj->objhead != NULL) {
......
bin/varnishd/cache_http.c
View file @ 4a5e0e8e
......@@ -43,6 +43,10 @@
#include "shmlog.h"
#include "cache.h"
#ifndef HAVE_STRLCPY
#include <compat/strlcpy.h>
#endif
#define HTTPH(a, b, c, d, e, f, g) char b[] = "*" a ":";
#include "http_headers.h"
#undef HTTPH
......@@ -93,6 +97,68 @@ WSLH(struct worker *w, enum httptag t, unsigned xid, struct http *hp, int hdr)
WSLR(w, http2shmlog(hp, t), xid, hp->hd[hdr].b, hp->hd[hdr].e);
}
/*--------------------------------------------------------------------*/
/* List of canonical HTTP response code names from RFC2616 */
static struct http_msg {
unsigned nbr;
const char *txt;
} http_msg[] = {
{ 101, "Switching Protocols" },
{ 200, "OK" },
{ 201, "Created" },
{ 202, "Accepted" },
{ 203, "Non-Authoritative Information" },
{ 204, "No Content" },
{ 205, "Reset Content" },
{ 206, "Partial Content" },
{ 300, "Multiple Choices" },
{ 301, "Moved Permanently" },
{ 302, "Found" },
{ 303, "See Other" },
{ 304, "Not Modified" },
{ 305, "Use Proxy" },
{ 306, "(Unused)" },
{ 307, "Temporary Redirect" },
{ 400, "Bad Request" },
{ 401, "Unauthorized" },
{ 402, "Payment Required" },
{ 403, "Forbidden" },
{ 404, "Not Found" },
{ 405, "Method Not Allowed" },
{ 406, "Not Acceptable" },
{ 407, "Proxy Authentication Required" },
{ 408, "Request Timeout" },
{ 409, "Conflict" },
{ 410, "Gone" },
{ 411, "Length Required" },
{ 412, "Precondition Failed" },
{ 413, "Request Entity Too Large" },
{ 414, "Request-URI Too Long" },
{ 415, "Unsupported Media Type" },
{ 416, "Requested Range Not Satisfiable" },
{ 417, "Expectation Failed" },
{ 500, "Internal Server Error" },
{ 501, "Not Implemented" },
{ 502, "Bad Gateway" },
{ 503, "Service Unavailable" },
{ 504, "Gateway Timeout" },
{ 505, "HTTP Version Not Supported" },
{ 0, NULL }
};
const char *
http_StatusMessage(int status)
{
struct http_msg *mp;
assert(status >= 100 && status <= 999);
for (mp = http_msg; mp->nbr != 0 && mp->nbr <= status; mp++)
if (mp->nbr == status)
return (mp->txt);
return ("Unknown Error");
}
/*--------------------------------------------------------------------*/
void
......@@ -816,6 +882,49 @@ http_SetHeader(struct worker *w, int fd, struct http *to, const char *hdr)
/*--------------------------------------------------------------------*/
void
http_PutProtocol(struct worker *w, int fd, struct http *to, const char *protocol)
{
int l;
CHECK_OBJ_NOTNULL(to, HTTP_MAGIC);
l = strlcpy(to->f, protocol, to->e - to->f);
xxxassert(to->f + l < to->e);
to->hd[HTTP_HDR_PROTO].b = to->f;
to->hd[HTTP_HDR_PROTO].e = to->f + l;
to->f += l + 1;
WSLH(w, HTTP_T_Protocol, fd, to, HTTP_HDR_PROTO);
}
void
http_PutStatus(struct worker *w, int fd, struct http *to, int status)
{
int l;
CHECK_OBJ_NOTNULL(to, HTTP_MAGIC);
assert(status >= 100 && status <= 999);
l = snprintf(to->f, to->e - to->f, "%d", status);
xxxassert(to->f + l < to->e);
to->hd[HTTP_HDR_STATUS].b = to->f;
to->hd[HTTP_HDR_STATUS].e = to->f + l;
to->f += l + 1;
WSLH(w, HTTP_T_Status, fd, to, HTTP_HDR_STATUS);
}
void
http_PutResponse(struct worker *w, int fd, struct http *to, const char *response)
{
int l;
CHECK_OBJ_NOTNULL(to, HTTP_MAGIC);
l = strlcpy(to->f, response, to->e - to->f);
xxxassert(to->f + l < to->e);
to->hd[HTTP_HDR_RESPONSE].b = to->f;
to->hd[HTTP_HDR_RESPONSE].e = to->f + l;
to->f += l + 1;
WSLH(w, HTTP_T_Response, fd, to, HTTP_HDR_RESPONSE);
}
void
http_PrintfHeader(struct worker *w, int fd, struct http *to, const char *fmt, ...)
{
......@@ -823,10 +932,11 @@ http_PrintfHeader(struct worker *w, int fd, struct http *to, const char *fmt, ..
unsigned l, n;
CHECK_OBJ_NOTNULL(to, HTTP_MAGIC);
va_start(ap, fmt);
l = to->e - to->f;
va_start(ap, fmt);
n = vsnprintf(to->f, l, fmt, ap);
if (n + 1 > l || to->nhd >= HTTP_HDR_MAX) {
va_end(ap);
if (n >= l || to->nhd >= HTTP_HDR_MAX) {
VSL_stats->losthdr++;
WSL(w, http2shmlog(to, HTTP_T_LostHeader), fd, "%s", to->f);
} else {
......@@ -837,7 +947,6 @@ http_PrintfHeader(struct worker *w, int fd, struct http *to, const char *fmt, ..
WSLH(w, HTTP_T_Header, fd, to, to->nhd);
to->nhd++;
}
va_end(ap);
}
/*--------------------------------------------------------------------*/
......
bin/varnishd/cache_response.c
View file @ 4a5e0e8e
......@@ -29,8 +29,6 @@
* $Id$
*/
#include <stdio.h> /* XXX: for NULL ?? */
#include <string.h> /* XXX: for NULL ?? */
#include <sys/types.h>
#include <sys/time.h>
......@@ -42,127 +40,28 @@
#include "heritage.h"
#include "cache.h"
/*--------------------------------------------------------------------*/
/* List of canonical HTTP response code names from RFC2616 */
static struct http_msg {
unsigned nbr;
const char *txt;
const char *reason;
} http_msg[] = {
{ 101, "Switching Protocols" },
{ 200, "OK" },
{ 201, "Created" },
{ 202, "Accepted" },
{ 203, "Non-Authoritative Information" },
{ 204, "No Content" },
{ 205, "Reset Content" },
{ 206, "Partial Content" },
{ 300, "Multiple Choices" },
{ 301, "Moved Permanently" },
{ 302, "Found" },
{ 303, "See Other" },
{ 304, "Not Modified" },
{ 305, "Use Proxy" },
{ 306, "(Unused)" },
{ 307, "Temporary Redirect" },
{ 400, "Bad Request" },
{ 401, "Unauthorized" },
{ 402, "Payment Required" },
{ 403, "Forbidden" },
{ 404, "Not Found" },
{ 405, "Method Not Allowed" },
{ 406, "Not Acceptable" },
{ 407, "Proxy Authentication Required" },
{ 408, "Request Timeout" },
{ 409, "Conflict" },
{ 410, "Gone" },
{ 411, "Length Required" },
{ 412, "Precondition Failed" },
{ 413, "Request Entity Too Large" },
{ 414, "Request-URI Too Long" },
{ 415, "Unsupported Media Type" },
{ 416, "Requested Range Not Satisfiable" },
{ 417, "Expectation Failed" },
{ 500, "Internal Server Error" },
{ 501, "Not Implemented" },
{ 502, "Bad Gateway" },
{ 503, "Service Unavailable" },
{ 504, "Gateway Timeout" },
{ 505, "HTTP Version Not Supported" },
{ 0, NULL }
};
/*--------------------------------------------------------------------*/
void
RES_Error(struct sess *sp, int code, const char *reason)
{
char buf[40];
struct vsb *sb;
struct http_msg *mp;
const char *msg;
assert(code >= 100 && code <= 999);
CHECK_OBJ_NOTNULL(sp, SESS_MAGIC);
clock_gettime(CLOCK_REALTIME, &sp->t_resp);
msg = "Unknown error";
for (mp = http_msg; mp->nbr != 0 && mp->nbr <= code; mp++) {
if (mp->nbr < code)
continue;
if (mp->nbr > code)
break;
msg = mp->txt;
if (reason == NULL)
reason = mp->reason;
break;
}
if (reason == NULL)
reason = msg;
AN(reason);
AN(msg);
/* get a pristine object */
HSH_Prealloc(sp);
sp->obj = sp->wrk->nobj;
sp->wrk->nobj = NULL;
sp->obj->busy = 1;
sb = vsb_new(NULL, NULL, 0, VSB_AUTOEXTEND);
XXXAN(sb);
/* synthesize error page and send it */
SYN_ErrorPage(sp, code, reason, 0);
RES_WriteObj(sp);
vsb_clear(sb);
vsb_printf(sb, "HTTP/1.1 %03d %s\r\n", code, msg);
TIM_format(sp->t_req.tv_sec, buf);
vsb_printf(sb, "Date: %s\r\n", buf);
vsb_cat(sb,
"Server: Varnish\r\n"
"Connection: close\r\n"
"Content-Type: text/html; charset=iso-8859-1\r\n"
"\r\n"
"<!DOCTYPE HTML PUBLIC \"-//IETF//DTD HTML 2.0//EN\">\r\n"
"<HTML>\r\n"
" <HEAD>\r\n");
vsb_printf(sb, " <TITLE>%03d %s</TITLE>\r\n", code, msg);
vsb_cat(sb,
" </HEAD>\r\n"
" <BODY>\r\n");
vsb_printf(sb, " <H1>Error %03d %s</H1>\r\n", code, msg);
vsb_printf(sb, " <P>%s</P>\r\n", reason);
vsb_printf(sb, " <H3>Guru Meditation:</H3>\r\n");
vsb_printf(sb, " <P>XID: %u</P>\r\n", sp->xid);
vsb_cat(sb,
" <I><A href=\"http://www.varnish-cache.org/\">Varnish</A></I>\r\n"
" </BODY>\r\n"
"</HTML>\r\n");
vsb_finish(sb);
WRK_Reset(sp->wrk, &sp->fd);
sp->wrk->acct.hdrbytes += WRK_Write(sp->wrk, vsb_data(sb), vsb_len(sb));
WRK_Flush(sp->wrk);
WSL(sp->wrk, SLT_TxStatus, sp->id, "%d", code);
WSL(sp->wrk, SLT_TxProtocol, sp->id, "HTTP/1.1");
WSL(sp->wrk, SLT_TxResponse, sp->id, msg);
vca_close_session(sp, reason);
vsb_delete(sb);
/* GC the error page */
HSH_Unbusy(sp->obj);
HSH_Deref(sp->obj);
sp->obj = NULL;
}
/*--------------------------------------------------------------------*/
static void
......
bin/varnishd/cache_synthetic.c 0 → 100644
View file @ 4a5e0e8e
/*-
* Copyright (c) 2007 Linpro AS
* All rights reserved.
*
* Author: Dag-Erling Smørgrav <des@linpro.no>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id$
*/
#include <sys/types.h>
#include <sys/time.h>
#include <stdlib.h>
#ifndef HAVE_CLOCK_GETTIME
#include "compat/clock_gettime.h"
#endif
#include "shmlog.h"
#include "heritage.h"
#include "cache.h"
/*
* Synthesize an error page. This assumes the session already has an
* object - if it doesn't, you need to either call HSH_Lookup(), or call
* HSH_Prealloc() and grab sp->obj->nobj, before calling this.
*/
void
SYN_ErrorPage(struct sess *sp, int status, const char *reason, int ttl)
{
struct storage *st;
struct object *o;
struct worker *w;
struct http *h;
struct vsb vsb;
const char *msg;
char date[40];
time_t now;
size_t len;
int fd;
assert(status >= 100 && status <= 999);
CHECK_OBJ_NOTNULL(sp, SESS_MAGIC);
CHECK_OBJ_NOTNULL(sp->wrk, WORKER_MAGIC);
CHECK_OBJ_NOTNULL(sp->obj, OBJECT_MAGIC);
CHECK_OBJ_NOTNULL(&sp->obj->http, HTTP_MAGIC);
assert(sp->obj->busy > 0);
/* shortcuts */
w = sp->wrk;
fd = sp->fd;
o = sp->obj;
h = &o->http;
time(&now);
/* look up HTTP response */
msg = http_StatusMessage(status);
if (reason == NULL)
reason = msg;
AN(reason);
AN(msg);
/* populate metadata */
o->response = status;
o->valid = 1;
o->entered = now;
o->ttl = now + ttl;
o->last_modified = now;
o->xid = sp->xid;
/* allocate space for body */
/* XXX what if the object already has a body? */
st = stevedore->alloc(stevedore, 1024);
XXXAN(st->stevedore);
TAILQ_INSERT_TAIL(&sp->obj->store, st, list);
/* generate body */
vsb_new(&vsb, (char *)st->ptr, st->space, VSB_FIXEDLEN);
vsb_printf(&vsb,
"<?xml version=\"1.0\" encoding=\"utf-8\"?>\n"
"<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Strict//EN\"\n"
" \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd\">\n"
"<html>\n"
" <head>\n"
" <title>%03d %s</title>\n", status, msg);
vsb_printf(&vsb,
" </head>\n"
" <body>\n"
" <h1>Error %03d %s</h1>\n", status, msg);
vsb_printf(&vsb,
" <p>%s</p>\n", reason);
vsb_printf(&vsb,
" <h3>Guru Meditation:</h3>\n"
" <p>XID: %u</p>\n", sp->xid);
vsb_printf(&vsb,
" <address><a href=\"http://www.varnish-cache.org/\">Varnish</a></address>\n"
" </body>\n"
"</html>\n");
vsb_finish(&vsb);
o->len = st->len = vsb_len(&vsb);
vsb_delete(&vsb);
/* allocate space for header */
/* XXX what if the object already has a header? */
h->v = h->s = calloc(len = 1024, 1);
XXXAN(h->s);
h->e = h->s + len;
/* generate header */
http_ClrHeader(h);
http_PutProtocol(w, fd, h, "HTTP/1.0"); /* XXX */
http_PutStatus(w, fd, h, status);
http_PutResponse(w, fd, h, msg);
TIM_format(now, date);
http_PrintfHeader(w, fd, h, "Date: %s", date);
http_PrintfHeader(w, fd, h, "Server: Varnish");
http_PrintfHeader(w, fd, h, "Retry-After: %ju", (uintmax_t)ttl);
http_PrintfHeader(w, fd, h, "Content-Type: text/html; charset=utf-8");
http_PrintfHeader(w, fd, h, "Content-Length: %u", o->len);
/* DO NOT generate X-Varnish header, RES_WriteObj will */
}
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