MINOR: config: report when "monitor fail" rules are misplaced

"monitor-uri" may rely on "monitor fail" rules, which are processed
very early, immediately after the HTTP request is parsed and before
any http rulesets. It's not reported by the config parser when this
ruleset is misplaces, causing some configurations not to work like
users would expect. Let's just add the warning for a misplaced rule.
This commit is contained in:
Willy Tarreau 2017-12-01 18:25:08 +01:00
parent 7e351eefe5
commit 721d8e0286
2 changed files with 31 additions and 8 deletions

View File

@ -5255,12 +5255,14 @@ monitor-uri <uri>
version and all headers are ignored, but the request must at least be valid
at the HTTP level. This keyword may only be used with an HTTP-mode frontend.
Monitor requests are processed very early. It is not possible to block nor
divert them using ACLs. They cannot be logged either, and it is the intended
purpose. They are only used to report HAProxy's health to an upper component,
nothing more. However, it is possible to add any number of conditions using
"monitor fail" and ACLs so that the result can be adjusted to whatever check
can be imagined (most often the number of available servers in a backend).
Monitor requests are processed very early, just after the request is parsed
and even before any "http-request" or "block" rulesets. The only rulesets
applied before are the tcp-request ones. They cannot be logged either, and it
is the intended purpose. They are only used to report HAProxy's health to an
upper component, nothing more. However, it is possible to add any number of
conditions using "monitor fail" and ACLs so that the result can be adjusted
to whatever check can be imagined (most often the number of available servers
in a backend).
Example :
# Use /haproxy_test to report haproxy's status

View File

@ -406,6 +406,19 @@ int warnif_rule_after_tcp_cont(struct proxy *proxy, const char *file, int line,
return 0;
}
/* Report a warning if a rule is placed after a 'monitor fail' rule.
* Return 1 if the warning has been emitted, otherwise 0.
*/
int warnif_rule_after_monitor(struct proxy *proxy, const char *file, int line, const char *arg)
{
if (!LIST_ISEMPTY(&proxy->mon_fail_cond)) {
ha_warning("parsing [%s:%d] : a '%s' rule placed after a 'monitor fail' rule will still be processed before.\n",
file, line, arg);
return 1;
}
return 0;
}
/* Report a warning if a rule is placed after a 'block' rule.
* Return 1 if the warning has been emitted, otherwise 0.
*/
@ -532,13 +545,20 @@ int warnif_misplaced_block(struct proxy *proxy, const char *file, int line, cons
warnif_misplaced_http_req(proxy, file, line, arg);
}
/* report a warning if a "tcp request content" rule is dangerously placed */
int warnif_misplaced_tcp_cont(struct proxy *proxy, const char *file, int line, const char *arg)
/* report a warning if a block rule is dangerously placed */
int warnif_misplaced_monitor(struct proxy *proxy, const char *file, int line, const char *arg)
{
return warnif_rule_after_block(proxy, file, line, arg) ||
warnif_misplaced_block(proxy, file, line, arg);
}
/* report a warning if a "tcp request content" rule is dangerously placed */
int warnif_misplaced_tcp_cont(struct proxy *proxy, const char *file, int line, const char *arg)
{
return warnif_rule_after_monitor(proxy, file, line, arg) ||
warnif_misplaced_monitor(proxy, file, line, arg);
}
/* report a warning if a "tcp request session" rule is dangerously placed */
int warnif_misplaced_tcp_sess(struct proxy *proxy, const char *file, int line, const char *arg)
{
@ -5807,6 +5827,7 @@ int cfg_parse_listen(const char *file, int linenum, char **args, int kwm)
goto out;
}
err_code |= warnif_misplaced_monitor(curproxy, file, linenum, "monitor fail");
if ((cond = build_acl_cond(file, linenum, &curproxy->acl, curproxy, (const char **)args + 2, &errmsg)) == NULL) {
ha_alert("parsing [%s:%d] : error detected while parsing a '%s %s' condition : %s.\n",
file, linenum, args[0], args[1], errmsg);