Aliaksandr Valialkin 06f590ee63 lib/envtemplate: allow referring non-existing environment variables in config files and in command-line flags ...

A few users reported unexpected errors when environment variables referred other environment variables
at VictoriaMetrics startup. This resulted in the following fatal error on startup:

    cannot expand "..." env var value "...%{SOME_NON_EXISTING_ENV_VAR}..."

Fix this by leaving placeholders with non-existing env vars as is.
This improves the general usability of environment variables by VictoriaMetrics components
inside command-line flags and inside config files. User can easily notice placeholders with non-existing
environment variables by looking at the corresponding command-line flag or at the corresponding config option value.

While at it, replace duplicate docs about environment variables at the https://docs.victoriametrics.com/victoriametrics/cluster-victoriametrics/#environment-variables
with the link to the same docs at https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/#environment-variables .

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3999

2025-08-09 21:05:13 +02:00

..

envtemplate_test.go

lib/envtemplate: allow referring non-existing environment variables in config files and in command-line flags

2025-08-09 21:05:13 +02:00

envtemplate.go

lib/envtemplate: allow referring non-existing environment variables in config files and in command-line flags

2025-08-09 21:05:13 +02:00