terraform/config/interpolate_funcs.go

880 lines
24 KiB
Go

package config
import (
"crypto/md5"
"crypto/sha1"
"crypto/sha256"
"encoding/base64"
"encoding/hex"
"encoding/json"
"errors"
"fmt"
"io/ioutil"
"net"
"regexp"
"sort"
"strconv"
"strings"
"github.com/apparentlymart/go-cidr/cidr"
"github.com/hashicorp/go-uuid"
"github.com/hashicorp/hil"
"github.com/hashicorp/hil/ast"
"github.com/mitchellh/go-homedir"
)
// stringSliceToVariableValue converts a string slice into the value
// required to be returned from interpolation functions which return
// TypeList.
func stringSliceToVariableValue(values []string) []ast.Variable {
output := make([]ast.Variable, len(values))
for index, value := range values {
output[index] = ast.Variable{
Type: ast.TypeString,
Value: value,
}
}
return output
}
func listVariableValueToStringSlice(values []ast.Variable) ([]string, error) {
output := make([]string, len(values))
for index, value := range values {
if value.Type != ast.TypeString {
return []string{}, fmt.Errorf("list has non-string element (%T)", value.Type.String())
}
output[index] = value.Value.(string)
}
return output, nil
}
// Funcs is the mapping of built-in functions for configuration.
func Funcs() map[string]ast.Function {
return map[string]ast.Function{
"base64decode": interpolationFuncBase64Decode(),
"base64encode": interpolationFuncBase64Encode(),
"base64sha256": interpolationFuncBase64Sha256(),
"cidrhost": interpolationFuncCidrHost(),
"cidrnetmask": interpolationFuncCidrNetmask(),
"cidrsubnet": interpolationFuncCidrSubnet(),
"coalesce": interpolationFuncCoalesce(),
"compact": interpolationFuncCompact(),
"concat": interpolationFuncConcat(),
"distinct": interpolationFuncDistinct(),
"element": interpolationFuncElement(),
"file": interpolationFuncFile(),
"format": interpolationFuncFormat(),
"formatlist": interpolationFuncFormatList(),
"index": interpolationFuncIndex(),
"join": interpolationFuncJoin(),
"jsonencode": interpolationFuncJSONEncode(),
"length": interpolationFuncLength(),
"lower": interpolationFuncLower(),
"md5": interpolationFuncMd5(),
"uuid": interpolationFuncUUID(),
"replace": interpolationFuncReplace(),
"sha1": interpolationFuncSha1(),
"sha256": interpolationFuncSha256(),
"signum": interpolationFuncSignum(),
"sort": interpolationFuncSort(),
"split": interpolationFuncSplit(),
"trimspace": interpolationFuncTrimSpace(),
"upper": interpolationFuncUpper(),
}
}
// interpolationFuncCompact strips a list of multi-variable values
// (e.g. as returned by "split") of any empty strings.
func interpolationFuncCompact() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeList},
ReturnType: ast.TypeList,
Variadic: false,
Callback: func(args []interface{}) (interface{}, error) {
inputList := args[0].([]ast.Variable)
var outputList []string
for _, val := range inputList {
if strVal, ok := val.Value.(string); ok {
if strVal == "" {
continue
}
outputList = append(outputList, strVal)
}
}
return stringSliceToVariableValue(outputList), nil
},
}
}
// interpolationFuncCidrHost implements the "cidrhost" function that
// fills in the host part of a CIDR range address to create a single
// host address
func interpolationFuncCidrHost() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{
ast.TypeString, // starting CIDR mask
ast.TypeInt, // host number to insert
},
ReturnType: ast.TypeString,
Variadic: false,
Callback: func(args []interface{}) (interface{}, error) {
hostNum := args[1].(int)
_, network, err := net.ParseCIDR(args[0].(string))
if err != nil {
return nil, fmt.Errorf("invalid CIDR expression: %s", err)
}
ip, err := cidr.Host(network, hostNum)
if err != nil {
return nil, err
}
return ip.String(), nil
},
}
}
// interpolationFuncCidrNetmask implements the "cidrnetmask" function
// that returns the subnet mask in IP address notation.
func interpolationFuncCidrNetmask() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{
ast.TypeString, // CIDR mask
},
ReturnType: ast.TypeString,
Variadic: false,
Callback: func(args []interface{}) (interface{}, error) {
_, network, err := net.ParseCIDR(args[0].(string))
if err != nil {
return nil, fmt.Errorf("invalid CIDR expression: %s", err)
}
return net.IP(network.Mask).String(), nil
},
}
}
// interpolationFuncCidrSubnet implements the "cidrsubnet" function that
// adds an additional subnet of the given length onto an existing
// IP block expressed in CIDR notation.
func interpolationFuncCidrSubnet() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{
ast.TypeString, // starting CIDR mask
ast.TypeInt, // number of bits to extend the prefix
ast.TypeInt, // network number to append to the prefix
},
ReturnType: ast.TypeString,
Variadic: false,
Callback: func(args []interface{}) (interface{}, error) {
extraBits := args[1].(int)
subnetNum := args[2].(int)
_, network, err := net.ParseCIDR(args[0].(string))
if err != nil {
return nil, fmt.Errorf("invalid CIDR expression: %s", err)
}
// For portability with 32-bit systems where the subnet number
// will be a 32-bit int, we only allow extension of 32 bits in
// one call even if we're running on a 64-bit machine.
// (Of course, this is significant only for IPv6.)
if extraBits > 32 {
return nil, fmt.Errorf("may not extend prefix by more than 32 bits")
}
newNetwork, err := cidr.Subnet(network, extraBits, subnetNum)
if err != nil {
return nil, err
}
return newNetwork.String(), nil
},
}
}
// interpolationFuncCoalesce implements the "coalesce" function that
// returns the first non null / empty string from the provided input
func interpolationFuncCoalesce() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeString},
ReturnType: ast.TypeString,
Variadic: true,
VariadicType: ast.TypeString,
Callback: func(args []interface{}) (interface{}, error) {
if len(args) < 2 {
return nil, fmt.Errorf("must provide at least two arguments")
}
for _, arg := range args {
argument := arg.(string)
if argument != "" {
return argument, nil
}
}
return "", nil
},
}
}
// interpolationFuncConcat implements the "concat" function that
// concatenates multiple strings. This isn't actually necessary anymore
// since our language supports string concat natively, but for backwards
// compat we do this.
func interpolationFuncConcat() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeAny},
ReturnType: ast.TypeList,
Variadic: true,
VariadicType: ast.TypeAny,
Callback: func(args []interface{}) (interface{}, error) {
var finalListElements []string
for _, arg := range args {
// Append strings for backward compatibility
if argument, ok := arg.(string); ok {
finalListElements = append(finalListElements, argument)
continue
}
// Otherwise variables
if argument, ok := arg.([]ast.Variable); ok {
for _, element := range argument {
t := element.Type
switch t {
case ast.TypeString:
finalListElements = append(finalListElements, element.Value.(string))
default:
return nil, fmt.Errorf("concat() does not support lists of %s", t.Printable())
}
}
continue
}
return nil, fmt.Errorf("arguments to concat() must be a string or list of strings")
}
return stringSliceToVariableValue(finalListElements), nil
},
}
}
// interpolationFuncFile implements the "file" function that allows
// loading contents from a file.
func interpolationFuncFile() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeString},
ReturnType: ast.TypeString,
Callback: func(args []interface{}) (interface{}, error) {
path, err := homedir.Expand(args[0].(string))
if err != nil {
return "", err
}
data, err := ioutil.ReadFile(path)
if err != nil {
return "", err
}
return string(data), nil
},
}
}
// interpolationFuncFormat implements the "format" function that does
// string formatting.
func interpolationFuncFormat() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeString},
Variadic: true,
VariadicType: ast.TypeAny,
ReturnType: ast.TypeString,
Callback: func(args []interface{}) (interface{}, error) {
format := args[0].(string)
return fmt.Sprintf(format, args[1:]...), nil
},
}
}
// interpolationFuncFormatList implements the "formatlist" function that does
// string formatting on lists.
func interpolationFuncFormatList() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeAny},
Variadic: true,
VariadicType: ast.TypeAny,
ReturnType: ast.TypeList,
Callback: func(args []interface{}) (interface{}, error) {
// Make a copy of the variadic part of args
// to avoid modifying the original.
varargs := make([]interface{}, len(args)-1)
copy(varargs, args[1:])
// Convert arguments that are lists into slices.
// Confirm along the way that all lists have the same length (n).
var n int
for i := 1; i < len(args); i++ {
s, ok := args[i].([]ast.Variable)
if !ok {
continue
}
parts, err := listVariableValueToStringSlice(s)
if err != nil {
return nil, err
}
// otherwise the list is sent down to be indexed
varargs[i-1] = parts
// Check length
if n == 0 {
// first list we've seen
n = len(parts)
continue
}
if n != len(parts) {
return nil, fmt.Errorf("format: mismatched list lengths: %d != %d", n, len(parts))
}
}
if n == 0 {
return nil, errors.New("no lists in arguments to formatlist")
}
// Do the formatting.
format := args[0].(string)
// Generate a list of formatted strings.
list := make([]string, n)
fmtargs := make([]interface{}, len(varargs))
for i := 0; i < n; i++ {
for j, arg := range varargs {
switch arg := arg.(type) {
default:
fmtargs[j] = arg
case []string:
fmtargs[j] = arg[i]
}
}
list[i] = fmt.Sprintf(format, fmtargs...)
}
return stringSliceToVariableValue(list), nil
},
}
}
// interpolationFuncIndex implements the "index" function that allows one to
// find the index of a specific element in a list
func interpolationFuncIndex() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeList, ast.TypeString},
ReturnType: ast.TypeInt,
Callback: func(args []interface{}) (interface{}, error) {
haystack := args[0].([]ast.Variable)
needle := args[1].(string)
for index, element := range haystack {
if needle == element.Value {
return index, nil
}
}
return nil, fmt.Errorf("Could not find '%s' in '%s'", needle, haystack)
},
}
}
// interpolationFuncDistinct implements the "distinct" function that
// removes duplicate elements from a list.
func interpolationFuncDistinct() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeList},
ReturnType: ast.TypeList,
Variadic: true,
VariadicType: ast.TypeList,
Callback: func(args []interface{}) (interface{}, error) {
var list []string
if len(args) != 1 {
return nil, fmt.Errorf("distinct() excepts only one argument.")
}
if argument, ok := args[0].([]ast.Variable); ok {
for _, element := range argument {
list = appendIfMissing(list, element.Value.(string))
}
}
return stringSliceToVariableValue(list), nil
},
}
}
// helper function to add an element to a list, if it does not already exsit
func appendIfMissing(slice []string, element string) []string {
for _, ele := range slice {
if ele == element {
return slice
}
}
return append(slice, element)
}
// interpolationFuncJoin implements the "join" function that allows
// multi-variable values to be joined by some character.
func interpolationFuncJoin() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeString},
Variadic: true,
VariadicType: ast.TypeList,
ReturnType: ast.TypeString,
Callback: func(args []interface{}) (interface{}, error) {
var list []string
if len(args) < 2 {
return nil, fmt.Errorf("not enough arguments to join()")
}
for _, arg := range args[1:] {
if parts, ok := arg.(ast.Variable); ok {
for _, part := range parts.Value.([]ast.Variable) {
list = append(list, part.Value.(string))
}
}
if parts, ok := arg.([]ast.Variable); ok {
for _, part := range parts {
list = append(list, part.Value.(string))
}
}
}
return strings.Join(list, args[0].(string)), nil
},
}
}
// interpolationFuncJSONEncode implements the "jsonencode" function that encodes
// a string, list, or map as its JSON representation. For now, values in the
// list or map may only be strings.
func interpolationFuncJSONEncode() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeAny},
ReturnType: ast.TypeString,
Callback: func(args []interface{}) (interface{}, error) {
var toEncode interface{}
switch typedArg := args[0].(type) {
case string:
toEncode = typedArg
case []ast.Variable:
// We preallocate the list here. Note that it's important that in
// the length 0 case, we have an empty list rather than nil, as
// they encode differently.
// XXX It would be nice to support arbitrarily nested data here. Is
// there an inverse of hil.InterfaceToVariable?
strings := make([]string, len(typedArg))
for i, v := range typedArg {
if v.Type != ast.TypeString {
return "", fmt.Errorf("list elements must be strings")
}
strings[i] = v.Value.(string)
}
toEncode = strings
case map[string]ast.Variable:
// XXX It would be nice to support arbitrarily nested data here. Is
// there an inverse of hil.InterfaceToVariable?
stringMap := make(map[string]string)
for k, v := range typedArg {
if v.Type != ast.TypeString {
return "", fmt.Errorf("map values must be strings")
}
stringMap[k] = v.Value.(string)
}
toEncode = stringMap
default:
return "", fmt.Errorf("unknown type for JSON encoding: %T", args[0])
}
jEnc, err := json.Marshal(toEncode)
if err != nil {
return "", fmt.Errorf("failed to encode JSON data '%s'", toEncode)
}
return string(jEnc), nil
},
}
}
// interpolationFuncReplace implements the "replace" function that does
// string replacement.
func interpolationFuncReplace() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeString, ast.TypeString, ast.TypeString},
ReturnType: ast.TypeString,
Callback: func(args []interface{}) (interface{}, error) {
s := args[0].(string)
search := args[1].(string)
replace := args[2].(string)
// We search/replace using a regexp if the string is surrounded
// in forward slashes.
if len(search) > 1 && search[0] == '/' && search[len(search)-1] == '/' {
re, err := regexp.Compile(search[1 : len(search)-1])
if err != nil {
return nil, err
}
return re.ReplaceAllString(s, replace), nil
}
return strings.Replace(s, search, replace, -1), nil
},
}
}
func interpolationFuncLength() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeAny},
ReturnType: ast.TypeInt,
Variadic: false,
Callback: func(args []interface{}) (interface{}, error) {
subject := args[0]
switch typedSubject := subject.(type) {
case string:
return len(typedSubject), nil
case []ast.Variable:
return len(typedSubject), nil
}
return 0, fmt.Errorf("arguments to length() must be a string or list")
},
}
}
func interpolationFuncSignum() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeInt},
ReturnType: ast.TypeInt,
Variadic: false,
Callback: func(args []interface{}) (interface{}, error) {
num := args[0].(int)
switch {
case num < 0:
return -1, nil
case num > 0:
return +1, nil
default:
return 0, nil
}
},
}
}
// interpolationFuncSort sorts a list of a strings lexographically
func interpolationFuncSort() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeList},
ReturnType: ast.TypeList,
Variadic: false,
Callback: func(args []interface{}) (interface{}, error) {
inputList := args[0].([]ast.Variable)
// Ensure that all the list members are strings and
// create a string slice from them
members := make([]string, len(inputList))
for i, val := range inputList {
if val.Type != ast.TypeString {
return nil, fmt.Errorf(
"sort() may only be used with lists of strings - %s at index %d",
val.Type.String(), i)
}
members[i] = val.Value.(string)
}
sort.Strings(members)
return stringSliceToVariableValue(members), nil
},
}
}
// interpolationFuncSplit implements the "split" function that allows
// strings to split into multi-variable values
func interpolationFuncSplit() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeString, ast.TypeString},
ReturnType: ast.TypeList,
Callback: func(args []interface{}) (interface{}, error) {
sep := args[0].(string)
s := args[1].(string)
elements := strings.Split(s, sep)
return stringSliceToVariableValue(elements), nil
},
}
}
// interpolationFuncLookup implements the "lookup" function that allows
// dynamic lookups of map types within a Terraform configuration.
func interpolationFuncLookup(vs map[string]ast.Variable) ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeMap, ast.TypeString},
ReturnType: ast.TypeString,
Variadic: true,
VariadicType: ast.TypeString,
Callback: func(args []interface{}) (interface{}, error) {
defaultValue := ""
defaultValueSet := false
if len(args) > 2 {
defaultValue = args[2].(string)
defaultValueSet = true
}
if len(args) > 3 {
return "", fmt.Errorf("lookup() takes no more than three arguments")
}
index := args[1].(string)
mapVar := args[0].(map[string]ast.Variable)
v, ok := mapVar[index]
if !ok {
if defaultValueSet {
return defaultValue, nil
} else {
return "", fmt.Errorf(
"lookup failed to find '%s'",
args[1].(string))
}
}
if v.Type != ast.TypeString {
return "", fmt.Errorf(
"lookup for '%s' has bad type %s",
args[1].(string), v.Type)
}
return v.Value.(string), nil
},
}
}
// interpolationFuncElement implements the "element" function that allows
// a specific index to be looked up in a multi-variable value. Note that this will
// wrap if the index is larger than the number of elements in the multi-variable value.
func interpolationFuncElement() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeList, ast.TypeString},
ReturnType: ast.TypeString,
Callback: func(args []interface{}) (interface{}, error) {
list := args[0].([]ast.Variable)
if len(list) == 0 {
return nil, fmt.Errorf("element() may not be used with an empty list")
}
index, err := strconv.Atoi(args[1].(string))
if err != nil || index < 0 {
return "", fmt.Errorf(
"invalid number for index, got %s", args[1])
}
resolvedIndex := index % len(list)
v := list[resolvedIndex].Value
return v, nil
},
}
}
// interpolationFuncKeys implements the "keys" function that yields a list of
// keys of map types within a Terraform configuration.
func interpolationFuncKeys(vs map[string]ast.Variable) ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeMap},
ReturnType: ast.TypeList,
Callback: func(args []interface{}) (interface{}, error) {
mapVar := args[0].(map[string]ast.Variable)
keys := make([]string, 0)
for k, _ := range mapVar {
keys = append(keys, k)
}
sort.Strings(keys)
//Keys are guaranteed to be strings
return stringSliceToVariableValue(keys), nil
},
}
}
// interpolationFuncValues implements the "values" function that yields a list of
// keys of map types within a Terraform configuration.
func interpolationFuncValues(vs map[string]ast.Variable) ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeMap},
ReturnType: ast.TypeList,
Callback: func(args []interface{}) (interface{}, error) {
mapVar := args[0].(map[string]ast.Variable)
keys := make([]string, 0)
for k, _ := range mapVar {
keys = append(keys, k)
}
sort.Strings(keys)
values := make([]string, len(keys))
for index, key := range keys {
if value, ok := mapVar[key].Value.(string); ok {
values[index] = value
} else {
return "", fmt.Errorf("values(): %q has element with bad type %s",
key, mapVar[key].Type)
}
}
variable, err := hil.InterfaceToVariable(values)
if err != nil {
return nil, err
}
return variable.Value, nil
},
}
}
// interpolationFuncBase64Encode implements the "base64encode" function that
// allows Base64 encoding.
func interpolationFuncBase64Encode() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeString},
ReturnType: ast.TypeString,
Callback: func(args []interface{}) (interface{}, error) {
s := args[0].(string)
return base64.StdEncoding.EncodeToString([]byte(s)), nil
},
}
}
// interpolationFuncBase64Decode implements the "base64decode" function that
// allows Base64 decoding.
func interpolationFuncBase64Decode() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeString},
ReturnType: ast.TypeString,
Callback: func(args []interface{}) (interface{}, error) {
s := args[0].(string)
sDec, err := base64.StdEncoding.DecodeString(s)
if err != nil {
return "", fmt.Errorf("failed to decode base64 data '%s'", s)
}
return string(sDec), nil
},
}
}
// interpolationFuncLower implements the "lower" function that does
// string lower casing.
func interpolationFuncLower() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeString},
ReturnType: ast.TypeString,
Callback: func(args []interface{}) (interface{}, error) {
toLower := args[0].(string)
return strings.ToLower(toLower), nil
},
}
}
func interpolationFuncMd5() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeString},
ReturnType: ast.TypeString,
Callback: func(args []interface{}) (interface{}, error) {
s := args[0].(string)
h := md5.New()
h.Write([]byte(s))
hash := hex.EncodeToString(h.Sum(nil))
return hash, nil
},
}
}
// interpolationFuncUpper implements the "upper" function that does
// string upper casing.
func interpolationFuncUpper() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeString},
ReturnType: ast.TypeString,
Callback: func(args []interface{}) (interface{}, error) {
toUpper := args[0].(string)
return strings.ToUpper(toUpper), nil
},
}
}
func interpolationFuncSha1() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeString},
ReturnType: ast.TypeString,
Callback: func(args []interface{}) (interface{}, error) {
s := args[0].(string)
h := sha1.New()
h.Write([]byte(s))
hash := hex.EncodeToString(h.Sum(nil))
return hash, nil
},
}
}
// hexadecimal representation of sha256 sum
func interpolationFuncSha256() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeString},
ReturnType: ast.TypeString,
Callback: func(args []interface{}) (interface{}, error) {
s := args[0].(string)
h := sha256.New()
h.Write([]byte(s))
hash := hex.EncodeToString(h.Sum(nil))
return hash, nil
},
}
}
func interpolationFuncTrimSpace() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeString},
ReturnType: ast.TypeString,
Callback: func(args []interface{}) (interface{}, error) {
trimSpace := args[0].(string)
return strings.TrimSpace(trimSpace), nil
},
}
}
func interpolationFuncBase64Sha256() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeString},
ReturnType: ast.TypeString,
Callback: func(args []interface{}) (interface{}, error) {
s := args[0].(string)
h := sha256.New()
h.Write([]byte(s))
shaSum := h.Sum(nil)
encoded := base64.StdEncoding.EncodeToString(shaSum[:])
return encoded, nil
},
}
}
func interpolationFuncUUID() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{},
ReturnType: ast.TypeString,
Callback: func(args []interface{}) (interface{}, error) {
return uuid.GenerateUUID()
},
}
}