declare constants in golang using os.Getenv results in 'const initializer in os.Getenv("MY_SECRET") is not a constant' : <p>If I declare constants as the following I get the error 'const initializer in os.Getenv("MY_SECRET") is not a constant'. Why is this?</p>

<p>New to Go and I see the return type of Getenv is a string, but I don't understand why this wouldn't work as a constant. </p>

<pre><code>const (
    secret     = os.Getenv("MY_SECRET")
    key        = os.Getenv("MY_KEY")
)
</code></pre>
