forked from dotenv
A sample project using Dotenv would look like this:
extern crate dotenv_rs;
use dotenv_rs::dotenv;
use std::env;
fn main() {
dotenv().ok();
for (key, value) in env::vars() {
println!("{}: {}", key, value);
}
dotenv_with_prefix(&String::from("Test")).ok();
for (key, value) in env::vars() {
println!("{}: {}", key, value);
}
}It's possible to reuse variables in the .env file using $VARIABLE syntax.
The syntax and rules are similar to bash ones, here's the example:
VAR=one
VAR_2=two
# Non-existing values are replaced with an empty string
RESULT=$NOPE #value: '' (empty string)
# All the letters after $ symbol are treated as the variable name to replace
RESULT=$VAR #value: 'one'
# Double quotes do not affect the substitution
RESULT="$VAR" #value: 'one'
# Different syntax, same result
RESULT=${VAR} #value: 'one'
# Curly braces are useful in cases when we need to use a variable with non-alphanumeric name
RESULT=$VAR_2 #value: 'one_2' since $ with no curly braces stops after first non-alphanumeric symbol
RESULT=${VAR_2} #value: 'two'
# The replacement can be escaped with either single quotes or a backslash:
RESULT='$VAR' #value: '$VAR'
RESULT=\$VAR #value: '$VAR'
# Environment variables are used in the substutution and always override the local variables
RESULT=$PATH #value: the contents of the $PATH environment variable
PATH="My local variable value"
RESULT=$PATH #value: the contents of the $PATH environment variable, even though the local variable is definedDotenv will parse the file, substituting the variables the way it's described in the comments.
Add dotenv_codegen to your dependencies, and add the following to the top of
your crate:
#[macro_use]
extern crate dotenv_codegen;Then, in your crate:
fn main() {
println!("{}", dotenv!("MEANING_OF_LIFE"));
}
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