Function envResolverWithCase

pkg/compose/envresolver.go:37–66

envResolverWithCase returns resolver for environment variables with the specified case-sensitive condition. Expected to be used with `MappingWithEquals.Resolve`. Updates in `environment` may not be reflected.

(environment map[string]string, caseInsensitive bool)

// Expected to be used with `MappingWithEquals.Resolve`.
// Updates in `environment` may not be reflected.
func envResolverWithCase(environment map[string]string, caseInsensitive bool) func(string) (string, bool) {
	if environment == nil {
		return func(s string) (string, bool) {
			return "", false
		}
	}
	if !caseInsensitive {
		return func(s string) (string, bool) {
			v, ok := environment[s]
			return v, ok
		}
	}
	// variable names must be treated case-insensitively.
	// Resolves in this way:
	// * Return the value if its name matches with the passed name case-sensitively.
	// * Otherwise, return the value if its lower-cased name matches lower-cased passed name.
	//     * The value is indefinite if multiple variable matches.
	loweredEnvironment := make(map[string]string, len(environment))
	for k, v := range environment {
		loweredEnvironment[strings.ToLower(k)] = v
	}
	return func(s string) (string, bool) {
		v, ok := environment[s]
		if ok {
			return v, ok
		}
		v, ok = loweredEnvironment[strings.ToLower(s)]
		return v, ok
	}
}