Bug#1010054: prometheus-blackbox-exporter: ignores --log.level= commandline flag

[Tobias Klausmann]

Package: prometheus-blackbox-exporter
Version: 0.19.0-2
Severity: normal

Dear Maintainer,

This is essentially the same bug as #1002729, and likely caused by
broken vendoring.

-- System Information:
Debian Release: bookworm/sid
APT prefers testing
APT policy: (500, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 5.16.0-6-amd64 (SMP w/12 CPU threads; PREEMPT)
Locale: LANG=C.UTF-8, LC_CTYPE=C.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages prometheus-blackbox-exporter depends on:
ii adduser 3.121
ii debconf [debconf-2.0] 1.5.79
ii init-system-helpers 1.62
ii libc6 2.33-7
ii libcap2-bin 1:2.44-1

prometheus-blackbox-exporter recommends no packages.

prometheus-blackbox-exporter suggests no packages.

-- Configuration Files:
/etc/prometheus/blackbox.yml changed:
modules:
http_2xx:
prober: http
http:
http_post_2xx:
prober: http
http:
method: POST
tcp_connect:
prober: tcp
pop3s_banner:
prober: tcp
tcp:
query_response:
- expect: "^+OK"
tls: true
tls_config:
insecure_skip_verify: false
ssh_banner:
prober: tcp
tcp:
query_response:
- expect: "^SSH-2.0-"
irc_banner:
prober: tcp
tcp:
query_response:
- send: "NICK prober"
- send: "USER prober prober prober :prober"
- expect: "PING :([^ ]+)"
send: "PONG ${1}"
- expect: "^:[^ ]+ 001"
icmp:
prober: icmp


-- debconf information:
prometheus-blackbox-exporter/want_cap_net_raw: false

[Daniel Swarbrick]

Looking at the changes for prometheus/common v0.26.0, I see:

- Replace go-kit/kit/log with go-kit/log

This just jogged my memory as to what the issue is. For whatever reason, the log level is not set correctly if the exporter still uses go-kit/kit/log (instead of the newer go-kit/log) and is built with prometheus/common v0.26.0 or later.

blackbox_exporter v0.19.0 still uses go-kit/kit/log, so the options are either to patch that in Debian to use go-kit/log, or update to blackbox_exporter v0.20.0, which uses the latter.

On Tue, May 10, 2022 at 8:08 PM Daniel Swarbrick <daniel.s...@ionos.com> wrote:

Several months ago I encountered the same bug with prometheus-smokeping-prober, and fixed it, but my brain is a bit foggy right now as to what the root cause was.

However, for prometheus-blackbox-exporter at least, the --log.level flag is respected so long as you build / run it with the dependency versions specified by go.mod - up until using prometheus/common v0.26.0 or later - at which point the --log.level flag is no longer honoured. This version number sticks in my mind from the smokeping_prober bug too.

I will follow up with more information shortly.

[Daniel Swarbrick]