terraform/lang/funcs/collection.go

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package funcs
import (
"errors"
"fmt"
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"sort"
"github.com/zclconf/go-cty/cty"
"github.com/zclconf/go-cty/cty/convert"
"github.com/zclconf/go-cty/cty/function"
"github.com/zclconf/go-cty/cty/function/stdlib"
"github.com/zclconf/go-cty/cty/gocty"
)
var LengthFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "value",
Type: cty.DynamicPseudoType,
AllowDynamicType: true,
AllowUnknown: true,
},
},
Type: func(args []cty.Value) (cty.Type, error) {
collTy := args[0].Type()
switch {
case collTy == cty.String || collTy.IsTupleType() || collTy.IsObjectType() || collTy.IsListType() || collTy.IsMapType() || collTy.IsSetType() || collTy == cty.DynamicPseudoType:
return cty.Number, nil
default:
return cty.Number, errors.New("argument must be a string, a collection type, or a structural type")
}
},
Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
coll := args[0]
collTy := args[0].Type()
switch {
case collTy == cty.DynamicPseudoType:
return cty.UnknownVal(cty.Number), nil
case collTy.IsTupleType():
l := len(collTy.TupleElementTypes())
return cty.NumberIntVal(int64(l)), nil
case collTy.IsObjectType():
l := len(collTy.AttributeTypes())
return cty.NumberIntVal(int64(l)), nil
case collTy == cty.String:
// We'll delegate to the cty stdlib strlen function here, because
// it deals with all of the complexities of tokenizing unicode
// grapheme clusters.
return stdlib.Strlen(coll)
case collTy.IsListType() || collTy.IsSetType() || collTy.IsMapType():
return coll.Length(), nil
default:
// Should never happen, because of the checks in our Type func above
return cty.UnknownVal(cty.Number), errors.New("impossible value type for length(...)")
}
},
})
// CoalesceFunc constructs a function that takes any number of arguments and
// returns the first one that isn't empty. This function was copied from go-cty
// stdlib and modified so that it returns the first *non-empty* non-null element
// from a sequence, instead of merely the first non-null.
var CoalesceFunc = function.New(&function.Spec{
Params: []function.Parameter{},
VarParam: &function.Parameter{
Name: "vals",
Type: cty.DynamicPseudoType,
AllowUnknown: true,
AllowDynamicType: true,
AllowNull: true,
},
Type: func(args []cty.Value) (ret cty.Type, err error) {
argTypes := make([]cty.Type, len(args))
for i, val := range args {
argTypes[i] = val.Type()
}
retType, _ := convert.UnifyUnsafe(argTypes)
if retType == cty.NilType {
return cty.NilType, errors.New("all arguments must have the same type")
}
return retType, nil
},
Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
for _, argVal := range args {
// We already know this will succeed because of the checks in our Type func above
argVal, _ = convert.Convert(argVal, retType)
if !argVal.IsKnown() {
return cty.UnknownVal(retType), nil
}
if argVal.IsNull() {
continue
}
if retType == cty.String && argVal.RawEquals(cty.StringVal("")) {
continue
}
return argVal, nil
}
return cty.NilVal, errors.New("no non-null, non-empty-string arguments")
},
})
// IndexFunc constructs a function that finds the element index for a given value in a list.
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var IndexFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "list",
Type: cty.DynamicPseudoType,
},
{
Name: "value",
Type: cty.DynamicPseudoType,
},
},
Type: function.StaticReturnType(cty.Number),
Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
if !(args[0].Type().IsListType() || args[0].Type().IsTupleType()) {
return cty.NilVal, errors.New("argument must be a list or tuple")
}
if !args[0].IsKnown() {
return cty.UnknownVal(cty.Number), nil
}
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if args[0].LengthInt() == 0 { // Easy path
return cty.NilVal, errors.New("cannot search an empty list")
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}
for it := args[0].ElementIterator(); it.Next(); {
i, v := it.Element()
eq, err := stdlib.Equal(v, args[1])
if err != nil {
return cty.NilVal, err
}
if !eq.IsKnown() {
return cty.UnknownVal(cty.Number), nil
}
if eq.True() {
return i, nil
}
}
return cty.NilVal, errors.New("item not found")
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},
})
// Flatten until it's not a cty.List, and return whether the value is known.
// We can flatten lists with unknown values, as long as they are not
// lists themselves.
func flattener(flattenList cty.Value) ([]cty.Value, bool) {
out := make([]cty.Value, 0)
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for it := flattenList.ElementIterator(); it.Next(); {
_, val := it.Element()
if val.Type().IsListType() || val.Type().IsSetType() || val.Type().IsTupleType() {
if !val.IsKnown() {
return out, false
}
res, known := flattener(val)
if !known {
return res, known
}
out = append(out, res...)
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} else {
out = append(out, val)
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}
}
return out, true
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}
// ListFunc constructs a function that takes an arbitrary number of arguments
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// and returns a list containing those values in the same order.
//
// This function is deprecated in Terraform v0.12
var ListFunc = function.New(&function.Spec{
Params: []function.Parameter{},
VarParam: &function.Parameter{
Name: "vals",
Type: cty.DynamicPseudoType,
AllowUnknown: true,
AllowDynamicType: true,
AllowNull: true,
},
Type: func(args []cty.Value) (ret cty.Type, err error) {
if len(args) == 0 {
return cty.NilType, errors.New("at least one argument is required")
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}
argTypes := make([]cty.Type, len(args))
for i, arg := range args {
argTypes[i] = arg.Type()
}
retType, _ := convert.UnifyUnsafe(argTypes)
if retType == cty.NilType {
return cty.NilType, errors.New("all arguments must have the same type")
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}
return cty.List(retType), nil
},
Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
newList := make([]cty.Value, 0, len(args))
for _, arg := range args {
// We already know this will succeed because of the checks in our Type func above
arg, _ = convert.Convert(arg, retType.ElementType())
newList = append(newList, arg)
}
return cty.ListVal(newList), nil
},
})
// LookupFunc constructs a function that performs dynamic lookups of map types.
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var LookupFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "inputMap",
Type: cty.DynamicPseudoType,
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},
{
Name: "key",
Type: cty.String,
},
},
VarParam: &function.Parameter{
Name: "default",
Type: cty.DynamicPseudoType,
AllowUnknown: true,
AllowDynamicType: true,
AllowNull: true,
},
Type: func(args []cty.Value) (ret cty.Type, err error) {
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if len(args) < 1 || len(args) > 3 {
return cty.NilType, fmt.Errorf("lookup() takes two or three arguments, got %d", len(args))
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}
ty := args[0].Type()
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switch {
case ty.IsObjectType():
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if !args[1].IsKnown() {
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return cty.DynamicPseudoType, nil
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}
key := args[1].AsString()
if ty.HasAttribute(key) {
return args[0].GetAttr(key).Type(), nil
} else if len(args) == 3 {
// if the key isn't found but a default is provided,
// return the default type
return args[2].Type(), nil
}
return cty.DynamicPseudoType, function.NewArgErrorf(0, "the given object has no attribute %q", key)
case ty.IsMapType():
if len(args) == 3 {
_, err = convert.Convert(args[2], ty.ElementType())
if err != nil {
return cty.NilType, function.NewArgErrorf(2, "the default value must have the same type as the map elements")
}
}
return ty.ElementType(), nil
default:
return cty.NilType, function.NewArgErrorf(0, "lookup() requires a map as the first argument")
}
},
Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
var defaultVal cty.Value
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defaultValueSet := false
if len(args) == 3 {
defaultVal = args[2]
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defaultValueSet = true
}
mapVar := args[0]
lookupKey := args[1].AsString()
if !mapVar.IsWhollyKnown() {
return cty.UnknownVal(retType), nil
}
if mapVar.Type().IsObjectType() {
if mapVar.Type().HasAttribute(lookupKey) {
return mapVar.GetAttr(lookupKey), nil
}
} else if mapVar.HasIndex(cty.StringVal(lookupKey)) == cty.True {
return mapVar.Index(cty.StringVal(lookupKey)), nil
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}
if defaultValueSet {
defaultVal, err = convert.Convert(defaultVal, retType)
if err != nil {
return cty.NilVal, err
}
return defaultVal, nil
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}
return cty.UnknownVal(cty.DynamicPseudoType), fmt.Errorf(
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"lookup failed to find '%s'", lookupKey)
},
})
// MapFunc constructs a function that takes an even number of arguments and
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// returns a map whose elements are constructed from consecutive pairs of arguments.
//
// This function is deprecated in Terraform v0.12
var MapFunc = function.New(&function.Spec{
Params: []function.Parameter{},
VarParam: &function.Parameter{
Name: "vals",
Type: cty.DynamicPseudoType,
AllowUnknown: true,
AllowDynamicType: true,
AllowNull: true,
},
Type: func(args []cty.Value) (ret cty.Type, err error) {
if len(args) < 2 || len(args)%2 != 0 {
return cty.NilType, fmt.Errorf("map requires an even number of two or more arguments, got %d", len(args))
}
argTypes := make([]cty.Type, len(args)/2)
index := 0
for i := 0; i < len(args); i += 2 {
argTypes[index] = args[i+1].Type()
index++
}
valType, _ := convert.UnifyUnsafe(argTypes)
if valType == cty.NilType {
return cty.NilType, errors.New("all arguments must have the same type")
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}
return cty.Map(valType), nil
},
Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
for _, arg := range args {
if !arg.IsWhollyKnown() {
return cty.UnknownVal(retType), nil
}
}
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outputMap := make(map[string]cty.Value)
for i := 0; i < len(args); i += 2 {
keyVal, err := convert.Convert(args[i], cty.String)
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if err != nil {
return cty.NilVal, err
}
if keyVal.IsNull() {
return cty.NilVal, fmt.Errorf("argument %d is a null key", i+1)
}
key := keyVal.AsString()
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val := args[i+1]
var variable cty.Value
err = gocty.FromCtyValue(val, &variable)
if err != nil {
return cty.NilVal, err
}
// We already know this will succeed because of the checks in our Type func above
variable, _ = convert.Convert(variable, retType.ElementType())
// Check for duplicate keys
if _, ok := outputMap[key]; ok {
return cty.NilVal, fmt.Errorf("argument %d is a duplicate key: %q", i+1, key)
}
outputMap[key] = variable
}
return cty.MapVal(outputMap), nil
},
})
// MatchkeysFunc constructs a function that constructs a new list by taking a
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// subset of elements from one list whose indexes match the corresponding
// indexes of values in another list.
var MatchkeysFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "values",
Type: cty.List(cty.DynamicPseudoType),
},
{
Name: "keys",
Type: cty.List(cty.DynamicPseudoType),
},
{
Name: "searchset",
Type: cty.List(cty.DynamicPseudoType),
},
},
Type: func(args []cty.Value) (cty.Type, error) {
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ty, _ := convert.UnifyUnsafe([]cty.Type{args[1].Type(), args[2].Type()})
if ty == cty.NilType {
return cty.NilType, errors.New("keys and searchset must be of the same type")
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}
// the return type is based on args[0] (values)
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return args[0].Type(), nil
},
Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
if !args[0].IsKnown() {
return cty.UnknownVal(cty.List(retType.ElementType())), nil
}
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if args[0].LengthInt() != args[1].LengthInt() {
return cty.ListValEmpty(retType.ElementType()), errors.New("length of keys and values should be equal")
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}
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output := make([]cty.Value, 0)
values := args[0]
// Keys and searchset must be the same type.
// We can skip error checking here because we've already verified that
// they can be unified in the Type function
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ty, _ := convert.UnifyUnsafe([]cty.Type{args[1].Type(), args[2].Type()})
keys, _ := convert.Convert(args[1], ty)
searchset, _ := convert.Convert(args[2], ty)
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// if searchset is empty, return an empty list.
if searchset.LengthInt() == 0 {
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return cty.ListValEmpty(retType.ElementType()), nil
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}
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if !values.IsWhollyKnown() || !keys.IsWhollyKnown() {
return cty.UnknownVal(retType), nil
}
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i := 0
for it := keys.ElementIterator(); it.Next(); {
_, key := it.Element()
for iter := searchset.ElementIterator(); iter.Next(); {
_, search := iter.Element()
eq, err := stdlib.Equal(key, search)
if err != nil {
return cty.NilVal, err
}
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if !eq.IsKnown() {
return cty.ListValEmpty(retType.ElementType()), nil
}
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if eq.True() {
v := values.Index(cty.NumberIntVal(int64(i)))
output = append(output, v)
break
}
}
i++
}
// if we haven't matched any key, then output is an empty list.
if len(output) == 0 {
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return cty.ListValEmpty(retType.ElementType()), nil
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}
return cty.ListVal(output), nil
},
})
// TransposeFunc constructs a function that takes a map of lists of strings and
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// swaps the keys and values to produce a new map of lists of strings.
var TransposeFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "values",
Type: cty.Map(cty.List(cty.String)),
},
},
Type: function.StaticReturnType(cty.Map(cty.List(cty.String))),
Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
inputMap := args[0]
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if !inputMap.IsWhollyKnown() {
return cty.UnknownVal(retType), nil
}
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outputMap := make(map[string]cty.Value)
tmpMap := make(map[string][]string)
for it := inputMap.ElementIterator(); it.Next(); {
inKey, inVal := it.Element()
for iter := inVal.ElementIterator(); iter.Next(); {
_, val := iter.Element()
if !val.Type().Equals(cty.String) {
return cty.MapValEmpty(cty.List(cty.String)), errors.New("input must be a map of lists of strings")
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}
outKey := val.AsString()
if _, ok := tmpMap[outKey]; !ok {
tmpMap[outKey] = make([]string, 0)
}
outVal := tmpMap[outKey]
outVal = append(outVal, inKey.AsString())
sort.Strings(outVal)
tmpMap[outKey] = outVal
}
}
for outKey, outVal := range tmpMap {
values := make([]cty.Value, 0)
for _, v := range outVal {
values = append(values, cty.StringVal(v))
}
outputMap[outKey] = cty.ListVal(values)
}
if len(outputMap) == 0 {
return cty.MapValEmpty(cty.List(cty.String)), nil
}
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return cty.MapVal(outputMap), nil
},
})
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// helper function to add an element to a list, if it does not already exist
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func appendIfMissing(slice []cty.Value, element cty.Value) ([]cty.Value, error) {
for _, ele := range slice {
eq, err := stdlib.Equal(ele, element)
if err != nil {
return slice, err
}
if eq.True() {
return slice, nil
}
}
return append(slice, element), nil
}
// Length returns the number of elements in the given collection or number of
// Unicode characters in the given string.
func Length(collection cty.Value) (cty.Value, error) {
return LengthFunc.Call([]cty.Value{collection})
}
// Coalesce takes any number of arguments and returns the first one that isn't empty.
func Coalesce(args ...cty.Value) (cty.Value, error) {
return CoalesceFunc.Call(args)
}
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// Index finds the element index for a given value in a list.
func Index(list, value cty.Value) (cty.Value, error) {
return IndexFunc.Call([]cty.Value{list, value})
}
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// List takes any number of list arguments and returns a list containing those
// values in the same order.
func List(args ...cty.Value) (cty.Value, error) {
return ListFunc.Call(args)
}
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// Lookup performs a dynamic lookup into a map.
// There are two required arguments, map and key, plus an optional default,
// which is a value to return if no key is found in map.
func Lookup(args ...cty.Value) (cty.Value, error) {
return LookupFunc.Call(args)
}
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// Map takes an even number of arguments and returns a map whose elements are constructed
// from consecutive pairs of arguments.
func Map(args ...cty.Value) (cty.Value, error) {
return MapFunc.Call(args)
}
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// Matchkeys constructs a new list by taking a subset of elements from one list
// whose indexes match the corresponding indexes of values in another list.
func Matchkeys(values, keys, searchset cty.Value) (cty.Value, error) {
return MatchkeysFunc.Call([]cty.Value{values, keys, searchset})
}
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// Transpose takes a map of lists of strings and swaps the keys and values to
// produce a new map of lists of strings.
func Transpose(values cty.Value) (cty.Value, error) {
return TransposeFunc.Call([]cty.Value{values})
}