terraform/lang/funcs/string.go

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package funcs
import (
"fmt"
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"regexp"
"sort"
"strings"
"github.com/zclconf/go-cty/cty"
"github.com/zclconf/go-cty/cty/function"
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"github.com/zclconf/go-cty/cty/gocty"
)
var JoinFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "separator",
Type: cty.String,
},
},
VarParam: &function.Parameter{
Name: "lists",
Type: cty.List(cty.String),
},
Type: function.StaticReturnType(cty.String),
Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
sep := args[0].AsString()
listVals := args[1:]
if len(listVals) < 1 {
return cty.UnknownVal(cty.String), fmt.Errorf("at least one list is required")
}
l := 0
for _, list := range listVals {
if !list.IsWhollyKnown() {
return cty.UnknownVal(cty.String), nil
}
l += list.LengthInt()
}
items := make([]string, 0, l)
for ai, list := range listVals {
ei := 0
for it := list.ElementIterator(); it.Next(); {
_, val := it.Element()
if val.IsNull() {
if len(listVals) > 1 {
return cty.UnknownVal(cty.String), function.NewArgErrorf(ai+1, "element %d of list %d is null; cannot concatenate null values", ei, ai+1)
}
return cty.UnknownVal(cty.String), function.NewArgErrorf(ai+1, "element %d is null; cannot concatenate null values", ei)
}
items = append(items, val.AsString())
ei++
}
}
return cty.StringVal(strings.Join(items, sep)), nil
},
})
var SortFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "list",
Type: cty.List(cty.String),
},
},
Type: function.StaticReturnType(cty.List(cty.String)),
Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
listVal := args[0]
if !listVal.IsWhollyKnown() {
// If some of the element values aren't known yet then we
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// can't yet predict the order of the result.
return cty.UnknownVal(retType), nil
}
if listVal.LengthInt() == 0 { // Easy path
return listVal, nil
}
list := make([]string, 0, listVal.LengthInt())
for it := listVal.ElementIterator(); it.Next(); {
iv, v := it.Element()
if v.IsNull() {
return cty.UnknownVal(retType), fmt.Errorf("given list element %s is null; a null string cannot be sorted", iv.AsBigFloat().String())
}
list = append(list, v.AsString())
}
sort.Strings(list)
retVals := make([]cty.Value, len(list))
for i, s := range list {
retVals[i] = cty.StringVal(s)
}
return cty.ListVal(retVals), nil
},
})
var SplitFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "separator",
Type: cty.String,
},
{
Name: "str",
Type: cty.String,
},
},
Type: function.StaticReturnType(cty.List(cty.String)),
Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
sep := args[0].AsString()
str := args[1].AsString()
elems := strings.Split(str, sep)
elemVals := make([]cty.Value, len(elems))
for i, s := range elems {
elemVals[i] = cty.StringVal(s)
}
if len(elemVals) == 0 {
return cty.ListValEmpty(cty.String), nil
}
return cty.ListVal(elemVals), nil
},
})
// ChompFunc constructs a function that removes newline characters at the end of a string.
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var ChompFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "str",
Type: cty.String,
},
},
Type: function.StaticReturnType(cty.String),
Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
newlines := regexp.MustCompile(`(?:\r\n?|\n)*\z`)
return cty.StringVal(newlines.ReplaceAllString(args[0].AsString(), "")), nil
},
})
// IndentFunc constructs a function that adds a given number of spaces to the
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// beginnings of all but the first line in a given multi-line string.
var IndentFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "spaces",
Type: cty.Number,
},
{
Name: "str",
Type: cty.String,
},
},
Type: function.StaticReturnType(cty.String),
Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
var spaces int
if err := gocty.FromCtyValue(args[0], &spaces); err != nil {
return cty.UnknownVal(cty.String), err
}
data := args[1].AsString()
pad := strings.Repeat(" ", spaces)
return cty.StringVal(strings.Replace(data, "\n", "\n"+pad, -1)), nil
},
})
// ReplaceFunc constructs a function that searches a given string for another
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// given substring, and replaces each occurence with a given replacement string.
var ReplaceFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "str",
Type: cty.String,
},
{
Name: "substr",
Type: cty.String,
},
{
Name: "replace",
Type: cty.String,
},
},
Type: function.StaticReturnType(cty.String),
Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
str := args[0].AsString()
substr := args[1].AsString()
replace := args[2].AsString()
// We search/replace using a regexp if the string is surrounded
// in forward slashes.
if len(substr) > 1 && substr[0] == '/' && substr[len(substr)-1] == '/' {
re, err := regexp.Compile(substr[1 : len(substr)-1])
if err != nil {
return cty.UnknownVal(cty.String), err
}
return cty.StringVal(re.ReplaceAllString(str, replace)), nil
}
return cty.StringVal(strings.Replace(str, substr, replace, -1)), nil
},
})
// TitleFunc constructs a function that converts the first letter of each word
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// in the given string to uppercase.
var TitleFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "str",
Type: cty.String,
},
},
Type: function.StaticReturnType(cty.String),
Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
return cty.StringVal(strings.Title(args[0].AsString())), nil
},
})
// TrimSpaceFunc constructs a function that removes any space characters from
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// the start and end of the given string.
var TrimSpaceFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "str",
Type: cty.String,
},
},
Type: function.StaticReturnType(cty.String),
Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
return cty.StringVal(strings.TrimSpace(args[0].AsString())), nil
},
})
// TrimFunc constructs a function that removes the specified characters from
// the start and end of the given string.
var TrimFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "str",
Type: cty.String,
},
{
Name: "cutset",
Type: cty.String,
},
},
Type: function.StaticReturnType(cty.String),
Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
str := args[0].AsString()
cutset := args[1].AsString()
return cty.StringVal(strings.Trim(str, cutset)), nil
},
})
// TrimPrefixFunc constructs a function that removes the specified characters from
// the start the given string.
var TrimPrefixFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "str",
Type: cty.String,
},
{
Name: "prefix",
Type: cty.String,
},
},
Type: function.StaticReturnType(cty.String),
Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
str := args[0].AsString()
prefix := args[1].AsString()
return cty.StringVal(strings.TrimPrefix(str, prefix)), nil
},
})
// TrimSuffixFunc constructs a function that removes the specified characters from
// the end of the given string.
var TrimSuffixFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "str",
Type: cty.String,
},
{
Name: "suffix",
Type: cty.String,
},
},
Type: function.StaticReturnType(cty.String),
Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
str := args[0].AsString()
cutset := args[1].AsString()
return cty.StringVal(strings.TrimSuffix(str, cutset)), nil
},
})
// Join concatenates together the string elements of one or more lists with a
// given separator.
func Join(sep cty.Value, lists ...cty.Value) (cty.Value, error) {
args := make([]cty.Value, len(lists)+1)
args[0] = sep
copy(args[1:], lists)
return JoinFunc.Call(args)
}
// Sort re-orders the elements of a given list of strings so that they are
// in ascending lexicographical order.
func Sort(list cty.Value) (cty.Value, error) {
return SortFunc.Call([]cty.Value{list})
}
// Split divides a given string by a given separator, returning a list of
// strings containing the characters between the separator sequences.
func Split(sep, str cty.Value) (cty.Value, error) {
return SplitFunc.Call([]cty.Value{sep, str})
}
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// Chomp removes newline characters at the end of a string.
func Chomp(str cty.Value) (cty.Value, error) {
return ChompFunc.Call([]cty.Value{str})
}
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// Indent adds a given number of spaces to the beginnings of all but the first
// line in a given multi-line string.
func Indent(spaces, str cty.Value) (cty.Value, error) {
return IndentFunc.Call([]cty.Value{spaces, str})
}
// Replace searches a given string for another given substring,
// and replaces all occurences with a given replacement string.
func Replace(str, substr, replace cty.Value) (cty.Value, error) {
return ReplaceFunc.Call([]cty.Value{str, substr, replace})
}
// Title converts the first letter of each word in the given string to uppercase.
func Title(str cty.Value) (cty.Value, error) {
return TitleFunc.Call([]cty.Value{str})
}
// TrimSpace removes any space characters from the start and end of the given string.
func TrimSpace(str cty.Value) (cty.Value, error) {
return TrimSpaceFunc.Call([]cty.Value{str})
}
// Trim removes the specified characters from the start and end of the given string.
func Trim(str, cutset cty.Value) (cty.Value, error) {
return TrimFunc.Call([]cty.Value{str, cutset})
}
// TrimPrefix removes the specified prefix from the start of the given string.
func TrimPrefix(str, prefix cty.Value) (cty.Value, error) {
return TrimPrefixFunc.Call([]cty.Value{str, prefix})
}
// TrimSuffix removes the specified suffix from the end of the given string.
func TrimSuffix(str, suffix cty.Value) (cty.Value, error) {
return TrimSuffixFunc.Call([]cty.Value{str, suffix})
}