environ

Documentation

Overview

Package environ is an environment variable manipulation library.

It couples the system's environment, represented as a []string of KEY[=VALUE] strings, into a key/value map and back.

Index

• func Join(k, v string) string
• func Split(v string) (key, value string)
• type Env
  • func FromCtx(ctx context.Context) Env
  • func New(s []string) Env
  • func System() Env
  • func (e Env) Clone() Env
  • func (e Env) Get(k string) (v string, ok bool)
  • func (e Env) GetEmpty(k string) string
  • func (e Env) Iter(cb func(k, v string) error) error
  • func (e Env) Len() int
  • func (e Env) Load(m map[string]string)
  • func (e Env) Map() map[string]string
  • func (e Env) Remove(k string) bool
  • func (e Env) RemoveMatch(fn func(k, v string) bool)
  • func (e Env) Set(k, v string)
  • func (e Env) SetEntry(entry string)
  • func (e Env) SetInCtx(ctx context.Context) context.Context
  • func (e Env) Sorted() []string
  • func (e Env) String() string
  • func (e Env) Update(other Env)

Functions

func Join

func Join(k, v string) string

Join creates an environment variable definition for the supplied key/value.

func Split

func Split(v string) (key, value string)

Split splits the supplied environment variable value into a key/value pair.

If v is of the form:

• KEY, returns (KEY, "")
• KEY=, returns (KEY, "")
• KEY=VALUE, returns (KEY, VALUE)

Types

type Env

type Env map[string]string

Env contains system environment variables. It preserves each environment variable verbatim (even if invalid).

Internally env is represented by a map of environment key to its "KEY=VALUE" value. Note that the value here is the full "KEY=VALUE", not just the VALUE part. This allows us to reconstitute the original environment string slice without reallocating all of its composite strings.

func FromCtx

func FromCtx(ctx context.Context) Env

FromCtx returns a copy of the current Env in `ctx`.

This is guaranteed to return a non-nil Env (i.e. it's always safe for assignment/manipulation)

If no Env has been set with With, this returns `System()`.

func New

func New(s []string) Env

New instantiates a new Env instance from the supplied set of environment KEY=VALUE strings using LoadSlice.

The environment is automatically configured with the local system's case insensitivity.

func System

func System() Env

System returns an Env instance instantiated with the current os.Environ values.

The environment is automatically configured with the local system's case insensitivity.

func (Env) Clone

func (e Env) Clone() Env

Clone creates a new Env instance that is identical to, but independent from, e.

If e is nil, returns nil. Otherwise returns a new (perhaps empty) Env.

func (Env) Get

func (e Env) Get(k string) (v string, ok bool)

Get returns the environment value for the supplied key.

If the value is defined, ok will be true and v will be set to its value (note that this can be empty if the environment has an empty value). If the value is not defined, ok will be false.

func (Env) GetEmpty

func (e Env) GetEmpty(k string) string

GetEmpty is the same as Get, except that instead of returning a separate boolean indicating the presence of a key, it will return an empty string if the key is missing.

func (Env) Iter

func (e Env) Iter(cb func(k, v string) error) error

Iter iterates through all of the key/value pairs in Env and invokes the supplied callback, cb, for each element.

If the callback returns error, iteration will stop immediately.

func (Env) Len

func (e Env) Len() int

Len returns the number of environment variables defined in e.

func (Env) Load

func (e Env) Load(m map[string]string)

Load adds environment variables defined in a key/value map to an existing environment.

func (Env) Map

func (e Env) Map() map[string]string

Map returns a map of the key/value values in the environment.

This is a clone of the contents of e; manipulating this map will not change the values in e.

If env is either nil or empty, returns nil.

func (Env) Remove

func (e Env) Remove(k string) bool

Remove removes a value from the environment, returning true if the value was present. If the value was missing, Remove returns false.

Remove is different from Set(k, "") in that Set persists the key with an empty value, while Remove removes it entirely.

func (Env) RemoveMatch

func (e Env) RemoveMatch(fn func(k, v string) bool)

RemoveMatch iterates over all keys and values in the environment, invoking the callback function, fn, for each key/value pair. If fn returns true, the key is removed from the environment.

func (Env) Set

func (e Env) Set(k, v string)

Set sets the supplied environment key and value.

func (Env) SetEntry

func (e Env) SetEntry(entry string)

SetEntry sets the supplied environment to a "KEY[=VALUE]" entry.

func (Env) SetInCtx

func (e Env) SetInCtx(ctx context.Context) context.Context

SetInCtx installs a copy of the Env into the context, which can be retrieved with `FromCtx`.

func (Env) Sorted

func (e Env) Sorted() []string

Sorted returns the contents of the environment, sorted by key.

func (Env) String

func (e Env) String() string

String returns debug representation of Env.

func (Env) Update

func (e Env) Update(other Env)

Update adds all key/value from other to the current environment. If there is a duplicate key, the value from other will overwrite the value from e.

Values from other will be sorted and added in alphabetic order. This means that if e is case insensitive and there are multiple keys in other that converge on the same case insensitive key, the one that is alphabetically highest will be added.