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.

Added in gomplate v0.2.0

Usage

env.Getenv var [default]

Arguments

Examples

$ 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.Env

Returns a map of all environment variables. This is equivalent to .Env, but accessible via the env namespace.

Unlike env.Getenv, this does not read _FILE variants, and will fail when accessing a missing key.

This is useful when you want strict environment variable access without the _FILE fallback behavior.

Added in gomplate v5.1.0

Usage

env.Env

Examples

$ gomplate -i 'Hello, {{env.Env.USER}}'
Hello, hairyhenderson

$ gomplate -i '{{ env.Env.HOME }}'
/home/hairyhenderson

env.HasEnv

Returns true if the environment variable is set, false otherwise. This wraps the os.LookupEnv function.

Note that a variable set to an empty string is still considered “set”.

Added in gomplate v5.1.0

Usage

env.HasEnv var

var | env.HasEnv

Arguments

Examples

$ gomplate -i '{{if env.HasEnv "FOO"}}FOO is set{{else}}FOO is not set{{end}}'
FOO is not set
$ FOO=bar gomplate -i '{{if env.HasEnv "FOO"}}FOO is set{{else}}FOO is not set{{end}}'
FOO is set

$ EMPTY= gomplate -i '{{if env.HasEnv "EMPTY"}}EMPTY is set{{end}}'
EMPTY is set

$ gomplate -i '{{ "USER" | env.HasEnv }}'
true

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.

Added in gomplate v2.5.0

Usage

env.ExpandEnv input

Arguments

Examples

$ 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"...