Summary

I'm happily working with Mattermost 3.5.0 (Build Hash: 3f19ccf1b1a6efdcc990cf8a0270ec4ffc0c6e22, Build Date: Tue Nov 15 18:55:53 UTC 2016), which is bundled with the most recent GitLab Omnibus (8.14.1). I've never used the CLI before, so I don't know if it worked in older releases.

Whenever I run the CLI with the -config option, I get the following error (it doesn't matter if i sudo or not):

$ sudo -u mattermost /opt/gitlab/embedded/bin/mattermost -config=/var/opt/gitlab/mattermost/config.json -version
[2016/12/01 14:00:57 CET] [EROR] Failed to load system translations for 'en' attempting to fall back to 'en'
panic: Failed to load system translations for 'en'

goroutine 1 [running]:
panic(0xb5c580, 0xc4204b5af0)
        /usr/local/go/src/runtime/panic.go:500 +0x1a1
github.com/mattermost/platform/utils.GetTranslationsBySystemLocale(0x0)
        /var/lib/jenkins/jobs/msr/jobs/platform-release/workspace/src/github.com/mattermost/platform/utils/i18n.go:50 +0x374
github.com/mattermost/platform/utils.InitTranslations(0xc4204b55f0, 0xc4204b5600, 0xc4204b5610)
        /var/lib/jenkins/jobs/msr/jobs/platform-release/workspace/src/github.com/mattermost/platform/utils/i18n.go:27 +0x54
main.main()
        /var/lib/jenkins/jobs/msr/jobs/platform-release/workspace/src/github.com/mattermost/platform/mattermost.go:114 +0xa4

If I run the command without the path to the config file it complains, obviously, it can't find the config file, but at least it doesn't panic:

$ sudo -u mattermost /opt/gitlab/embedded/bin/mattermost -version
[14:02:45 CET 2016/12/01] [EROR] (main.main:107) Unable to load mattermost configuration file:  utils.config.load_config.opening.panic

I don't know how Mattermost searches for its translation files, but in my understanding the files are there (again, it doesn't matter if I change the owner of the files):

$ ls -alh /opt/gitlab/embedded/service/mattermost/i18n
total 2.1M
drwxr-xr-x 2 root root 4.0K Nov 28 19:45 .
drwxrwxr-x 7 root root 4.0K Nov 28 19:45 ..
-rw-r--r-- 1 root root 187K Nov 28 17:22 de.json
-rw-r--r-- 1 root root 174K Nov 28 17:22 en.json
-rw-r--r-- 1 root root 190K Nov 28 17:22 es.json
-rw-r--r-- 1 root root 193K Nov 28 17:22 fr.json
-rw-r--r-- 1 root root 207K Nov 28 17:22 ja.json
-rw-r--r-- 1 root root 184K Nov 28 17:22 ko.json
-rw-r--r-- 1 root root 184K Nov 28 17:22 nl.json
-rw-r--r-- 1 root root 185K Nov 28 17:22 pt-BR.json
-rw-r--r-- 1 root root 236K Nov 28 17:22 ru.json
-rw-r--r-- 1 root root 166K Nov 28 17:22 zh_CN.json
-rw-r--r-- 1 root root 168K Nov 28 17:22 zh_TW.json

I've looked at the following issues, but they relate to much older versions of Mattermost and none of them brought up a solution that worked in this case:

• http://forum.mattermost.org/t/proper-cli-usage-in-gitlab/839
• http://forum.mattermost.org/t/found-workaround-cli-tool-still-crashing-and-throwing-errors-in-2-1-0/1132
• forum.mattermost.org/t/mattermost-init-script/2187 (sorry, I'm not allowed to post more than two links)

Steps to reproduce

1. install most recent GitLab Omnibus (8.14.1) on Ubuntu 14.04.5 LTS
2. fire the CLI with the path to the config file: sudo -u mattermost /opt/gitlab/embedded/bin/mattermost -config=/var/opt/gitlab/mattermost/config.json -help

EDIT: I forgot to mention, there are no log entries to this error. But just a few moments ago I've found a workaround in forum.mattermost.org/t/solved-how-to-authenticate-bots-using-the-api/2405/2