env functions

env.Getenv

Alias: getenv

Exposes the os.Getenv function.

Retrieves the value of the environment variable named by the key. If the variable is unset, but the same variable ending in _FILE is set, the contents of the file will be returned. Otherwise the provided default (or an empty string) is returned.

This is a more forgiving alternative to using .Env, since missing keys will return an empty string, instead of panicking.

The _FILE fallback is especially useful for use with 12-factor-style applications configurable only by environment variables, and especially in conjunction with features like Docker Secrets.

Example

$ gomplate -i 'Hello, {{env.Getenv "USER"}}'
Hello, hairyhenderson
$ gomplate -i 'Hey, {{getenv "FIRSTNAME" "you"}}!'
Hey, you!
$ echo "safe" > /tmp/mysecret
$ export SECRET_FILE=/tmp/mysecret
$ gomplate -i 'Your secret is {{getenv "SECRET"}}'
Your secret is safe

env.ExpandEnv

Exposes the os.ExpandEnv function.

Replaces ${var} or $var in the input string according to the values of the current environment variables. References to undefined variables are replaced by the empty string.

Like env.Getenv, the _FILE variant of a variable is used.

Example

$ gomplate -i '{{env.ExpandEnv "Hello $USER"}}'
Hello, hairyhenderson
$ gomplate -i 'Hey, {{env.ExpandEnv "Hey, ${FIRSTNAME}!"}}'
Hey, you!
$ echo "safe" > /tmp/mysecret
$ export SECRET_FILE=/tmp/mysecret
$ gomplate -i '{{env.ExpandEnv "Your secret is $SECRET"}}'
Your secret is safe
$ gomplate -i '{{env.ExpandEnv (file.Read "foo")}}
contents of file "foo"...