envsubst

package module

v1.5.0 Latest Latest Go to latest Published: Aug 30, 2025 License: Apache-2.0 Imports: 10 Imported by: 3

Details

Valid go.mod file
Redistributable license
Tagged version
Stable version
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Repository

github.com/fluxcd/pkg

Links

Open Source Insights

README ¶

envsubst

github.com/fluxcd/pkg/envsubst is a Go package for expanding variables in a string using ${var} syntax. Includes support for bash string replacement functions.

This package is a fork of drone/envsubst.

Supported Functions

Expression	Meaning
`${var}`	Value of `$var`
`${#var}`	String length of `$var`
`${var^}`	Uppercase first character of `$var`
`${var^^}`	Uppercase all characters in `$var`
`${var,}`	Lowercase first character of `$var`
`${var,,}`	Lowercase all characters in `$var`
`${var:n}`	Offset `$var` `n` characters from start
`${var:n:len}`	Offset `$var` `n` characters with max length of `len`
`${var#pattern}`	Strip shortest `pattern` match from start
`${var##pattern}`	Strip longest `pattern` match from start
`${var%pattern}`	Strip shortest `pattern` match from end
`${var%%pattern}`	Strip longest `pattern` match from end
`${var-default}`	If `$var` is not set, evaluate expression as `$default`
`${var:-default}`	If `$var` is not set or is empty, evaluate expression as `$default`
`${var=default}`	If `$var` is not set, evaluate expression as `$default`
`${var:=default}`	If `$var` is not set or is empty, evaluate expression as `$default`
`${var/pattern/replacement}`	Replace as few `pattern` matches as possible with `replacement`
`${var//pattern/replacement}`	Replace as many `pattern` matches as possible with `replacement`
`${var/#pattern/replacement}`	Replace `pattern` match with `replacement` from `$var` start
`${var/%pattern/replacement}`	Replace `pattern` match with `replacement` from `$var` end

For a deeper reference, see bash-hackers or gnu pattern matching.

Unsupported Functions

${var+default}
${var:?default}
${var:+default}

Documentation ¶

Overview ¶

Package envsubst is a Go package for expanding variables in a string using `${var}` syntax. Includes support for bash string replacement functions.

Index ¶

func Eval(s string, mapping func(string) (string, bool)) (string, error)
func EvalEnv(s string, strict bool) (string, error)
func Getenv(s string) (string, bool)
type Template
- func Parse(s string) (t *Template, err error)
- func ParseFile(path string) (*Template, error)
- func (t *Template) Execute(mapping func(string) (string, bool)) (str string, err error)

Constants ¶

This section is empty.

Variables ¶

This section is empty.

Functions ¶

func Eval ¶

func Eval(s string, mapping func(string) (string, bool)) (string, error)

Eval replaces ${var} in the string based on the mapping function.

func EvalEnv ¶

func EvalEnv(s string, strict bool) (string, error)

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

func Getenv ¶

func Getenv(s string) (string, bool)

Types ¶

type Template ¶

type Template struct {
	// contains filtered or unexported fields
}

Template is the representation of a parsed shell format string.

func Parse ¶

func Parse(s string) (t *Template, err error)

Parse creates a new shell format template and parses the template definition from string s.

func ParseFile ¶

func ParseFile(path string) (*Template, error)

ParseFile creates a new shell format template and parses the template definition from the named file.

func (*Template) Execute ¶

func (t *Template) Execute(mapping func(string) (string, bool)) (str string, err error)

Execute applies a parsed template to the specified data mapping.

Source Files ¶

View all Source files

Directories ¶

Path	Synopsis
parse
path

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