Open xobotyi opened 1 month ago
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Thank you for raising this issue!
Upon investigation, it seems that environment variable prefixes and key replacers are not applied to configurations read from a dotenv file.
The merging with prefixes and key replacers is only applied when AutomaticEnv is used. AutomaticEnv monitors the OS environment variables, and on any subsequent call to viper.Get()
, it checks these environment variables, applying the merge and replacer functions as specified.
In contrast, when using ReadInConfig()
to load a dotenv file, Viper uses the in-built encoding Decoder. The configurations are read directly from the file, without applying the environment prefixes or key replacers. This is because ReadInConfig()
focuses on loading and decoding the file contents as-is, without integrating the environment-related settings from AutomaticEnv.
To summarize, environment variables are required if you need to apply environment prefixes and key replacers, as these are not automatically applied to configurations loaded from a dotenv file using ReadInConfig()
.
I understand, I've read the sources.
Main issue here that structures nesting, along with config format interopability simply won't work.
Mapsrtucture uses .
as nesting separator which, obviously won't happen within dotenv file.
Same for yaml-dotenv interop in such case switching format requires rewriting all configs (mapsrtucture tags), as yaml conventionally uses dash as words separator.
What I would expect, as said, dotenv file would be 1 to 1 compatible system envs replacement. Which is not the case now.
What I would suggest is to mirror automatic envs methods with ones that will be applied to dotenv files. Such approach will bring functionality to those who need it. Without breaking backwards compatibility.
Preflight Checklist
Viper Version
1.18.2
Go Version
1.22
Config Source
Files
Format
Dotenv
Repl.it link
No response
Code reproducing the issue
Expected Behavior
Dotenv files expected to be threated exactly as env variables
Actual Behavior
Neither env prefix, nor env key replacer not applied to configs being read from dotenv file
Steps To Reproduce
No response
Additional Information
example dotenv file content