terraform/tfdiags/config_traversals.go

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package tfdiags
import (
"bytes"
"fmt"
"strconv"
"github.com/zclconf/go-cty/cty"
)
// FormatCtyPath is a helper function to produce a user-friendly string
// representation of a cty.Path. The result uses a syntax similar to the
// HCL expression language in the hope of it being familiar to users.
func FormatCtyPath(path cty.Path) string {
var buf bytes.Buffer
for _, step := range path {
switch ts := step.(type) {
case cty.GetAttrStep:
fmt.Fprintf(&buf, ".%s", ts.Name)
case cty.IndexStep:
buf.WriteByte('[')
key := ts.Key
keyTy := key.Type()
switch {
case key.IsNull():
buf.WriteString("null")
case !key.IsKnown():
buf.WriteString("(not yet known)")
case keyTy == cty.Number:
bf := key.AsBigFloat()
buf.WriteString(bf.Text('g', -1))
case keyTy == cty.String:
buf.WriteString(strconv.Quote(key.AsString()))
default:
buf.WriteString("...")
}
buf.WriteByte(']')
}
}
return buf.String()
}
// FormatError is a helper function to produce a user-friendly string
// representation of certain special error types that we might want to
// include in diagnostic messages.
//
// This currently has special behavior only for cty.PathError, where a
// non-empty path is rendered in a HCL-like syntax as context.
func FormatError(err error) string {
perr, ok := err.(cty.PathError)
if !ok || len(perr.Path) == 0 {
return err.Error()
}
return fmt.Sprintf("%s: %s", FormatCtyPath(perr.Path), perr.Error())
}
// FormatErrorPrefixed is like FormatError except that it presents any path
// information after the given prefix string, which is assumed to contain
// an HCL syntax representation of the value that errors are relative to.
func FormatErrorPrefixed(err error, prefix string) string {
perr, ok := err.(cty.PathError)
if !ok || len(perr.Path) == 0 {
return fmt.Sprintf("%s: %s", prefix, err.Error())
}
return fmt.Sprintf("%s%s: %s", prefix, FormatCtyPath(perr.Path), perr.Error())
}