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BUG/MINOR: checks: prevent http keep-alive with http-check expect

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Sbastien Rohaut reported that string negation in http-check expect didn't
work as expected.

The misbehaviour is caused by responses with HTTP keep-alive. When the
condition is not met, haproxy awaits more data until the buffer is full or the
connection is closed, resulting in a check timeout when "timeout check" is
lower than the keep-alive timeout on the server side.

In order to avoid the issue, when a "http-check expect" is used, haproxy will
ask the server to disable keep-alive by automatically appending a
"Connection: close" header to the request.
This commit is contained in:
Cyril Bont 2015-01-30 00:07:07 +01:00 committed by Willy Tarreau
parent aa435e7d7e
commit 32602d2361
2 changed files with 7 additions and 0 deletions
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4
doc/configuration.txt
View File

@ -2905,6 +2905,10 @@ http-check expect [!] <match> <pattern>
waste some CPU cycles, especially when regular expressions are used, and that
it is always better to focus the checks on smaller resources.
Also "http-check expect" doesn't support HTTP keep-alive. Keep in mind that it
will automatically append a "Connection: close" header, meaning that this
header should not be present in the request provided by "option httpchk".
Last, if "http-check expect" is combined with "http-check disable-on-404",
then this last one has precedence when the server responds with 404.

3
src/checks.c
View File

@ -1427,6 +1427,9 @@ static int connect_conn_chk(struct task *t)
else if ((check->type) == PR_O2_HTTP_CHK) {
if (s->proxy->options2 & PR_O2_CHK_SNDST)
bo_putblk(check->bo, trash.str, httpchk_build_status_header(s, trash.str, trash.size));
/* prevent HTTP keep-alive when "http-check expect" is used */
if (s->proxy->options2 & PR_O2_EXP_TYPE)
bo_putstr(check->bo, "Connection: close\r\n");
bo_putstr(check->bo, "\r\n");
*check->bo->p = '\0'; /* to make gdb output easier to read */
}