terraform/config/interpolate_funcs.go

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package config
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import (
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"bytes"
"encoding/base64"
"errors"
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"fmt"
"io/ioutil"
"net"
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"regexp"
"sort"
"strconv"
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"strings"
"github.com/apparentlymart/go-cidr/cidr"
"github.com/hashicorp/terraform/config/lang/ast"
"github.com/mitchellh/go-homedir"
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)
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// Funcs is the mapping of built-in functions for configuration.
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var Funcs map[string]ast.Function
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func init() {
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Funcs = map[string]ast.Function{
"cidrhost": interpolationFuncCidrHost(),
"cidrnetmask": interpolationFuncCidrNetmask(),
"cidrsubnet": interpolationFuncCidrSubnet(),
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"compact": interpolationFuncCompact(),
"concat": interpolationFuncConcat(),
"element": interpolationFuncElement(),
"file": interpolationFuncFile(),
"format": interpolationFuncFormat(),
"formatlist": interpolationFuncFormatList(),
"index": interpolationFuncIndex(),
"join": interpolationFuncJoin(),
"length": interpolationFuncLength(),
"lower": interpolationFuncLower(),
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"replace": interpolationFuncReplace(),
"split": interpolationFuncSplit(),
"base64encode": interpolationFuncBase64Encode(),
"base64decode": interpolationFuncBase64Decode(),
"upper": interpolationFuncUpper(),
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}
}
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// 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.TypeString},
ReturnType: ast.TypeString,
Variadic: false,
Callback: func(args []interface{}) (interface{}, error) {
if !IsStringList(args[0].(string)) {
return args[0].(string), nil
}
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return StringList(args[0].(string)).Compact().String(), nil
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},
}
}
// 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
},
}
}
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// 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.
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func interpolationFuncConcat() ast.Function {
return ast.Function{
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ArgTypes: []ast.Type{ast.TypeString},
ReturnType: ast.TypeString,
Variadic: true,
VariadicType: ast.TypeString,
Callback: func(args []interface{}) (interface{}, error) {
var b bytes.Buffer
var finalList []string
var isDeprecated = true
for _, arg := range args {
argument := arg.(string)
if len(argument) == 0 {
continue
}
if IsStringList(argument) {
isDeprecated = false
finalList = append(finalList, StringList(argument).Slice()...)
} else {
finalList = append(finalList, argument)
}
// Deprecated concat behaviour
b.WriteString(argument)
}
if isDeprecated {
return b.String(), nil
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}
return NewStringList(finalList).String(), nil
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},
}
}
// interpolationFuncFile implements the "file" function that allows
// loading contents from a file.
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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
},
}
}
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// interpolationFuncFormat implements the "format" function that does
// string formatting.
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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.TypeString},
Variadic: true,
VariadicType: ast.TypeAny,
ReturnType: ast.TypeString,
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].(string)
if !ok {
continue
}
if !IsStringList(s) {
continue
}
parts := StringList(s).Slice()
// 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 NewStringList(list).String(), 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.TypeString, ast.TypeString},
ReturnType: ast.TypeInt,
Callback: func(args []interface{}) (interface{}, error) {
haystack := StringList(args[0].(string)).Slice()
needle := args[1].(string)
for index, element := range haystack {
if needle == element {
return index, nil
}
}
return nil, fmt.Errorf("Could not find '%s' in '%s'", needle, haystack)
},
}
}
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// interpolationFuncJoin implements the "join" function that allows
// multi-variable values to be joined by some character.
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func interpolationFuncJoin() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeString, ast.TypeString},
ReturnType: ast.TypeString,
Callback: func(args []interface{}) (interface{}, error) {
var list []string
for _, arg := range args[1:] {
parts := StringList(arg.(string)).Slice()
list = append(list, parts...)
}
return strings.Join(list, args[0].(string)), nil
},
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}
}
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// 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] == '/' {
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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
},
}
}
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func interpolationFuncLength() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeString},
ReturnType: ast.TypeInt,
Variadic: false,
Callback: func(args []interface{}) (interface{}, error) {
if !IsStringList(args[0].(string)) {
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return len(args[0].(string)), nil
}
length := 0
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for _, arg := range args {
length += StringList(arg.(string)).Length()
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}
return length, nil
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},
}
}
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// 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.TypeString,
Callback: func(args []interface{}) (interface{}, error) {
sep := args[0].(string)
s := args[1].(string)
return NewStringList(strings.Split(s, sep)).String(), nil
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},
}
}
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// interpolationFuncLookup implements the "lookup" function that allows
// dynamic lookups of map types within a Terraform configuration.
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func interpolationFuncLookup(vs map[string]ast.Variable) ast.Function {
return ast.Function{
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ArgTypes: []ast.Type{ast.TypeString, ast.TypeString},
ReturnType: ast.TypeString,
Callback: func(args []interface{}) (interface{}, error) {
k := fmt.Sprintf("var.%s.%s", args[0].(string), args[1].(string))
v, ok := vs[k]
if !ok {
return "", fmt.Errorf(
"lookup in '%s' failed to find '%s'",
args[0].(string), args[1].(string))
}
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if v.Type != ast.TypeString {
return "", fmt.Errorf(
"lookup in '%s' for '%s' has bad type %s",
args[0].(string), args[1].(string), v.Type)
}
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return v.Value.(string), nil
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},
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}
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}
// 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.
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func interpolationFuncElement() ast.Function {
return ast.Function{
ArgTypes: []ast.Type{ast.TypeString, ast.TypeString},
ReturnType: ast.TypeString,
Callback: func(args []interface{}) (interface{}, error) {
list := StringList(args[0].(string))
index, err := strconv.Atoi(args[1].(string))
if err != nil {
return "", fmt.Errorf(
"invalid number for index, got %s", args[1])
}
v := list.Element(index)
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.TypeString},
ReturnType: ast.TypeString,
Callback: func(args []interface{}) (interface{}, error) {
// Prefix must include ending dot to be a map
prefix := fmt.Sprintf("var.%s.", args[0].(string))
keys := make([]string, 0, len(vs))
for k, _ := range vs {
if !strings.HasPrefix(k, prefix) {
continue
}
keys = append(keys, k[len(prefix):])
}
if len(keys) <= 0 {
return "", fmt.Errorf(
"failed to find map '%s'",
args[0].(string))
}
sort.Strings(keys)
return NewStringList(keys).String(), 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.TypeString},
ReturnType: ast.TypeString,
Callback: func(args []interface{}) (interface{}, error) {
// Prefix must include ending dot to be a map
prefix := fmt.Sprintf("var.%s.", args[0].(string))
keys := make([]string, 0, len(vs))
for k, _ := range vs {
if !strings.HasPrefix(k, prefix) {
continue
}
keys = append(keys, k)
}
if len(keys) <= 0 {
return "", fmt.Errorf(
"failed to find map '%s'",
args[0].(string))
}
sort.Strings(keys)
vals := make([]string, 0, len(keys))
for _, k := range keys {
v := vs[k]
if v.Type != ast.TypeString {
return "", fmt.Errorf("values(): %q has bad type %s", k, v.Type)
}
vals = append(vals, vs[k].Value.(string))
}
return NewStringList(vals).String(), 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
},
}
}
// 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
},
}
}