Bug#928938: cronic: Add option to report on return status only
Thanks for the clarification Dave. I definitely appreciate the problem of tools overusing stderr -- I've run into it, and much of my Cronic support email is about the problem. However, I don't thinking adding a global stderr suppression option is a good idea. Here's my reasons: Principle - Suppressing error output will miss important diagnostic messages. Not all stderr output is accompanied by an error-code. In particular, warnings are stderr output that don't prevent a tool from succeeding. Typical examples of warnings are deprecation warnings from interpreters/compilers, or security config warnings. Cronic should always assumes that any tool or script may succeed, but output warnings at any time. Social - I fear a global suppression option would quickly become the "recommended" usage for Cronic, which would defeat much of its utility. At the first sign of trouble, users will search around and find the global suppression option, rather then address the specific tool's problem. Practical - The extraneous stderr output can be suppressed locally in cron scripts by redirect the tool's stderr to stdout, or elsewhere. For example: gitlab-ctl ... 2>&1 Or the one-liner version with eval: cronic eval 'gitlab-ctl ... 2>&1' Of course, it is important to realize that one is kludging or bodging the problem here, and true warnings or errors may be missed. The only real solution is to fix the tool. At least by using the ugly "2>&1", the misbehaving tool is clearly marked. Cheers - Chuck
Bug#928938: cronic: Add option to report on return status only
On 15/05/2019 18:40, wrote: Hi all, Thanks for including me in the conversation. To start, I want to confirm that we are specifically taking about the debug-trace standard-error output of docker/gitlab/etc (typically activated with a -D/--debug option), and not the normal output of such programs? I ask because cronic has primitive support for ignoring debug-trace output on standard-error via the PS4 environment variable, so maybe a new option isn't needed? Or maybe the PS4 mechanism needs enhancing... Cheers - Chuck Hi Chuck, No, this isn't specifically-requested debug information. A command like "gitlab-ctl registry-garbage-collect -m" produce a whole lot of informational-level output on STDERR while returning a 0 error code. There's nothing you can pass to that script which will silence that, and it's the recommended / supported way of performing that garbage collection. Cheers, Dave -- Dave Page, Operations Team ManagerCodethink Ltd Telephone: +44 7762 840 4143rd Floor Dale House, 35 Dale Street http://www.codethink.co.uk/ Manchester M1 2HF, United Kingdom We respect your privacy. See https://www.codethink.co.uk/privacy.html
Bug#928938: cronic: Add option to report on return status only
Hi all, Thanks for including me in the conversation. To start, I want to confirm that we are specifically taking about the debug-trace standard-error output of docker/gitlab/etc (typically activated with a -D/--debug option), and not the normal output of such programs? I ask because cronic has primitive support for ignoring debug-trace output on standard-error via the PS4 environment variable, so maybe a new option isn't needed? Or maybe the PS4 mechanism needs enhancing... Cheers - Chuck
Bug#928938: cronic: Add option to report on return status only
Hi Dave Am 13.05.19 um 18:46 schrieb Dave Page: We have locally patched our cronic to support an option, -r, which will cause cronic to only generate a report if the return code is nonzero, even if there is STDERR output. We submit it for your consideration. Thank you very much for sharing your patch and the rationale for it. I've asked Chuck (CC), the upstream author, whether he wants to add this feature into his software. Let's see what he says. Kind regards, Daniel
Bug#928938: cronic: Add option to report on return status only
Package: cronic Version: 3-1 Severity: wishlist Tags: patch upstream Dear Maintainer, An increasing number of applications we use through cron are putting debug output on STDERR while returning 0 by default, and cannot be quietened. Examples include docker and gitlab maintenance We have locally patched our cronic to support an option, -r, which will cause cronic to only generate a report if the return code is nonzero, even if there is STDERR output. We submit it for your consideration. -- System Information: Debian Release: 9.9 APT prefers stable APT policy: (500, 'stable') Architecture: amd64 (x86_64) Foreign Architectures: i386 Kernel: Linux 4.9.0-9-amd64 (SMP w/4 CPU cores) Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8), LANGUAGE=en_GB:en (charmap=UTF-8) Shell: /bin/sh linked to /bin/dash Init: systemd (via /run/systemd/system) Versions of packages cronic depends on: ii bash 4.4-5 cronic recommends no packages. Versions of packages cronic suggests: ii cron 3.0pl1-128+deb9u1 -- no debconf information --- cronic.orig 2019-05-13 17:46:13.150590183 +0100 +++ cronic 2019-05-13 17:19:01.098080693 +0100 @@ -11,6 +11,18 @@ ERR=$TMP/cronic.err TRACE=$TMP/cronic.trace +CRONIC_RESULT_ONLY="" + +# Go over $@ to look for - parameters +while getopts r opt; do + case $opt in +r) + CRONIC_RESULT_ONLY="yes" + ;; + esac +done +shift "$((OPTIND-1))" + set +e "$@" >$OUT 2>$TRACE RESULT=$? @@ -24,7 +36,7 @@ ERR=$TRACE fi -if [ $RESULT -ne 0 -o -s "$ERR" ] +if [[ -n "$CRONIC_RESULT_ONLY" && $RESULT -ne 0 ]] || [[ -z "$CRONIC_RESULT_ONLY" && ( $RESULT -ne 0 || -s "$ERR" ) ]] then echo "Cronic detected failure or error output for the command:" echo "$@"
