tree 8902b789e0bd9ebc5b16b8a3b9be4a48cbce8b69
parent 9fa1f4e310ec37ff36023440d8a823e1c4ffb33b
author Christopher Faulet <cfaulet@haproxy.com> 1591337936 +0200
committer Christopher Faulet <cfaulet@haproxy.com> 1591348300 +0200

BUG/MEDIUM: contrib/prometheus-exporter: Properly set flags to dump metrics

When the metrics are dumped, in the main function promex_dump_metrics(), the
appctx flags are set before entering in a new scope, among others things to know
which metrics names and descriptions to use. But, those flags are not restored
when the dump is interrupted because of a full output buffer. If this happens
after the dump of global metrics, it may only lead to extra #TYPE and #HELP
lines. But if this happens during the dump of global metrics, the following
dumps of frontends, backends and servers metrics use names and descriptions of
global ones with the unmatching indexes. This first leads to unexisting metrics
names. For instance, "haproxy_frontend_nbproc". But also to out-of-bound
accesses to name and description arrays because there are more stats fields than
info fields.

It is easy to reproduce the bug using small buffers, setting tune.bufsize to
8192 for instance.

This patch should fix the issue #666. It must be backported as far as 2.0.

(cherry picked from commit efde955bdb7b7479267cfcd823cce26bb3f5c4d3)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit 797d1df519d1780fa27992adc038a73ef466f9fe)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>