databricks-cli/libs/dyn/dynvar/ref.go

74 lines
1.8 KiB
Go

package dynvar
import (
"regexp"
"github.com/databricks/cli/libs/dyn"
)
var re = regexp.MustCompile(`\$\{([a-zA-Z]+([-_]?[a-zA-Z0-9]+)*(\.[a-zA-Z]+([-_]?[a-zA-Z0-9]+)*(\[[0-9]+\])*)*(\[[0-9]+\])*)\}`)
// ref represents a variable reference.
// It is a string [dyn.Value] contained in a larger [dyn.Value].
// Its path within the containing [dyn.Value] is also stored.
type ref struct {
// Original value.
value dyn.Value
// String value in the original [dyn.Value].
str string
// Matches of the variable reference in the string.
matches [][]string
}
// newRef returns a new ref if the given [dyn.Value] contains a string
// with one or more variable references. It returns false if the given
// [dyn.Value] does not contain variable references.
//
// Examples of a valid variable references:
// - "${a.b}"
// - "${a.b.c}"
// - "${a} ${b} ${c}"
func newRef(v dyn.Value) (ref, bool) {
s, ok := v.AsString()
if !ok {
return ref{}, false
}
// Check if the string contains any variable references.
m := re.FindAllStringSubmatch(s, -1)
if len(m) == 0 {
return ref{}, false
}
return ref{
value: v,
str: s,
matches: m,
}, true
}
// isPure returns true if the variable reference contains a single
// variable reference and nothing more. We need this so we can
// interpolate values of non-string types (i.e. it can be substituted).
func (v ref) isPure() bool {
// Need single match, equal to the incoming string.
if len(v.matches) == 0 || len(v.matches[0]) == 0 {
panic("invalid variable reference; expect at least one match")
}
return v.matches[0][0] == v.str
}
func (v ref) references() []string {
var out []string
for _, m := range v.matches {
out = append(out, m[1])
}
return out
}
func IsPureVariableReference(s string) bool {
return len(s) > 0 && re.FindString(s) == s
}