envknob

Documentation

Overview

Package envknob provides access to environment-variable tweakable debug settings.

These are primarily knobs used by Tailscale developers during development or by users when instructed to by Tailscale developers when debugging something. They are not a stable interface and may be removed or any time.

A related package, control/controlknobs, are knobs that can be changed at runtime by the control plane. Sometimes both are used: an envknob for the default/explicit value, else falling back to the controlknob value.

Index

• func RegisterBool(envVar string) func() bool
• func String(envVar string) string

Functions

func RegisterBool

func RegisterBool(envVar string) func() bool

RegisterBool returns a func that gets the named environment variable, without a map lookup per call. It assumes that mutations happen via envknob.Setenv.

func String

func String(envVar string) string

String returns the named environment variable, using os.Getenv.

If the variable is non-empty, it's also tracked & logged as being an in-use knob.