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lang/funcs: New "uuidv5" function
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This generates name-based uuids, rather than pseudorandom uuids as with the
"uuid" function.
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lscheidler authored and apparentlymart committed Jun 7, 2019
1 parent d33c516 commit aa07806
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1 change: 1 addition & 0 deletions go.mod
Original file line number Diff line number Diff line change
Expand Up @@ -94,6 +94,7 @@ require (
github.com/pascaldekloe/goe v0.0.0-20180627143212-57f6aae5913c // indirect
github.com/pkg/errors v0.0.0-20170505043639-c605e284fe17 // indirect
github.com/posener/complete v1.2.1
github.com/satori/go.uuid v1.2.0
github.com/sean-/seed v0.0.0-20170313163322-e2103e2c3529 // indirect
github.com/sirupsen/logrus v1.1.1 // indirect
github.com/smartystreets/assertions v0.0.0-20180927180507-b2de0cb4f26d // indirect
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40 changes: 40 additions & 0 deletions lang/funcs/crypto.go
Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,7 @@ import (
"hash"

uuid "github.com/hashicorp/go-uuid"
uuidv5 "github.com/satori/go.uuid"
"github.com/zclconf/go-cty/cty"
"github.com/zclconf/go-cty/cty/function"
"github.com/zclconf/go-cty/cty/gocty"
Expand All @@ -32,6 +33,39 @@ var UUIDFunc = function.New(&function.Spec{
},
})

var UUIDV5Func = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "namespace",
Type: cty.String,
},
{
Name: "name",
Type: cty.String,
},
},
Type: function.StaticReturnType(cty.String),
Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
var namespace uuidv5.UUID
switch {
case args[0].AsString() == "dns":
namespace = uuidv5.NamespaceDNS
case args[0].AsString() == "url":
namespace = uuidv5.NamespaceURL
case args[0].AsString() == "oid":
namespace = uuidv5.NamespaceOID
case args[0].AsString() == "x500":
namespace = uuidv5.NamespaceX500
default:
if namespace, err = uuidv5.FromString(args[0].AsString()); err != nil {
return cty.UnknownVal(cty.String), fmt.Errorf("uuidv5() doesn't support namespace %s (%v)", args[0].AsString(), err)
}
}
val := args[1].AsString()
return cty.StringVal(uuidv5.NewV5(namespace, val).String()), nil
},
})

// Base64Sha256Func constructs a function that computes the SHA256 hash of a given string
// and encodes it with Base64.
var Base64Sha256Func = makeStringHashFunction(sha256.New, base64.StdEncoding.EncodeToString)
Expand Down Expand Up @@ -228,6 +262,12 @@ func UUID() (cty.Value, error) {
return UUIDFunc.Call(nil)
}

// UUIDV5 generates and returns a Type-5 UUID in the standard hexadecimal string
// format.
func UUIDV5(namespace cty.Value, name cty.Value) (cty.Value, error) {
return UUIDV5Func.Call([]cty.Value{namespace, name})
}

// Base64Sha256 computes the SHA256 hash of a given string and encodes it with
// Base64.
//
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65 changes: 65 additions & 0 deletions lang/funcs/crypto_test.go
Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,71 @@ func TestUUID(t *testing.T) {
}
}

func TestUUIDV5(t *testing.T) {
tests := []struct {
Namespace cty.Value
Name cty.Value
Want cty.Value
Err bool
}{
{
cty.StringVal("dns"),
cty.StringVal("tada"),
cty.StringVal("faa898db-9b9d-5b75-86a9-149e7bb8e3b8"),
false,
},
{
cty.StringVal("url"),
cty.StringVal("tada"),
cty.StringVal("2c1ff6b4-211f-577e-94de-d978b0caa16e"),
false,
},
{
cty.StringVal("oid"),
cty.StringVal("tada"),
cty.StringVal("61eeea26-5176-5288-87fc-232d6ed30d2f"),
false,
},
{
cty.StringVal("x500"),
cty.StringVal("tada"),
cty.StringVal("7e12415e-f7c9-57c3-9e43-52dc9950d264"),
false,
},
{
cty.StringVal("6ba7b810-9dad-11d1-80b4-00c04fd430c8"),
cty.StringVal("tada"),
cty.StringVal("faa898db-9b9d-5b75-86a9-149e7bb8e3b8"),
false,
},
{
cty.StringVal("tada"),
cty.StringVal("tada"),
cty.UnknownVal(cty.String),
true,
},
}

for _, test := range tests {
t.Run(fmt.Sprintf("uuidv5(%#v, %#v)", test.Namespace, test.Name), func(t *testing.T) {
got, err := UUIDV5(test.Namespace, test.Name)

if test.Err {
if err == nil {
t.Fatal("succeeded; want error")
}
return
} else if err != nil {
t.Fatalf("unexpected error: %s", err)
}

if !got.RawEquals(test.Want) {
t.Errorf("wrong result\ngot: %#v\nwant: %#v", got, test.Want)
}
})
}
}

func TestBase64Sha256(t *testing.T) {
tests := []struct {
String cty.Value
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1 change: 1 addition & 0 deletions lang/functions.go
Original file line number Diff line number Diff line change
Expand Up @@ -116,6 +116,7 @@ func (s *Scope) Functions() map[string]function.Function {
"upper": stdlib.UpperFunc,
"urlencode": funcs.URLEncodeFunc,
"uuid": funcs.UUIDFunc,
"uuidv5": funcs.UUIDV5Func,
"values": funcs.ValuesFunc,
"yamldecode": ctyyaml.YAMLDecodeFunc,
"yamlencode": ctyyaml.YAMLEncodeFunc,
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23 changes: 23 additions & 0 deletions lang/functions_test.go
Original file line number Diff line number Diff line change
Expand Up @@ -777,6 +777,29 @@ func TestFunctions(t *testing.T) {
},
},

"uuidv5": {
{
`uuidv5("dns", "tada")`,
cty.StringVal("faa898db-9b9d-5b75-86a9-149e7bb8e3b8"),
},
{
`uuidv5("url", "tada")`,
cty.StringVal("2c1ff6b4-211f-577e-94de-d978b0caa16e"),
},
{
`uuidv5("oid", "tada")`,
cty.StringVal("61eeea26-5176-5288-87fc-232d6ed30d2f"),
},
{
`uuidv5("x500", "tada")`,
cty.StringVal("7e12415e-f7c9-57c3-9e43-52dc9950d264"),
},
{
`uuidv5("6ba7b810-9dad-11d1-80b4-00c04fd430c8", "tada")`,
cty.StringVal("faa898db-9b9d-5b75-86a9-149e7bb8e3b8"),
},
},

"values": {
{
`values({"hello"="world", "what's"="up"})`,
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4 changes: 4 additions & 0 deletions website/docs/configuration/functions/uuid.html.md
Original file line number Diff line number Diff line change
Expand Up @@ -38,3 +38,7 @@ equivalent randomness to the `uuid` function.
> uuid()
b5ee72a3-54dd-c4b8-551c-4bdc0204cedb
```

## Related Functions

* [`uuidv5`](./uuidv5.html), which generates name-based UUIDs.
85 changes: 85 additions & 0 deletions website/docs/configuration/functions/uuidv5.html.md
Original file line number Diff line number Diff line change
@@ -0,0 +1,85 @@
---
layout: "functions"
page_title: "uuidv5 - Functions - Configuration Language"
sidebar_current: "docs-funcs-crypto-uuidv5"
description: |-
The uuidv5 function generates a uuid v5 string representation of the value in the specified namespace.
---

# `uuidv5` Function

-> **Note:** This page is about Terraform 0.12 and later. For Terraform 0.11 and
earlier, see
[0.11 Configuration Language: Interpolation Syntax](../../configuration-0-11/interpolation.html).

`uuidv5` generates a _name-based_ UUID, as described in
[RFC 4122 section 4.3](https://tools.ietf.org/html/rfc4122#section-4.3),
also known as a "version 5" UUID.

```
uuidv5(namespace, name)
```

Unlike the pseudo-random UUIDs generated by
[`uuid`](./uuid.html), name-based UUIDs derive from namespace and an name,
producing the same UUID value every time if the namespace and name are
unchanged.

Name-based UUID namespaces are themselves UUIDs, but for readability this
function accepts some keywords as aliases for the namespaces that were
assigned by RFC 4122:

| Keyword | Namespace ID | Name format |
| ------- | ------------ | ----------- |
| `"dns"` | `6ba7b810-9dad-11d1-80b4-00c04fd430c8` | A fully-qualified DNS domain name. |
| `"url"` | `6ba7b811-9dad-11d1-80b4-00c04fd430c8` | Any valid URL as defined in [RFC 3986](https://tools.ietf.org/html/rfc3986). |
| `"oid"` | `6ba7b812-9dad-11d1-80b4-00c04fd430c8` | An [ISO/IEC object identifier](https://oidref.com/) |
| `"x500"` | `6ba7b814-9dad-11d1-80b4-00c04fd430c8` | [X.500 Distinguished Name](https://tools.ietf.org/html/rfc1779) |

To use any other namespace not included in the above table, pass its assigned
namespace ID directly in the first argument in the usual UUID string format.

## Examples

Use the namespace keywords where possible, to make the intent more obvious to
a future reader:

```
> uuidv5("dns", "www.terraform.io")
a5008fae-b28c-5ba5-96cd-82b4c53552d6
> uuidv5("url", "https://www.terraform.io/")
9db6f67c-dd95-5ea0-aa5b-e70e5c5f7cf5
> uuidv5("oid", "1.3.6.1.4")
af9d40a5-7a36-5c07-b23a-851cd99fbfa5
> uuidv5("x500", "CN=Example,C=GB")
84e09961-4aa4-57f8-95b7-03edb1073253
```

The namespace keywords treated as equivalent to their corresponding namespace
UUIDs, and in some special cases it may be more appropriate to use the
UUID form:

```
> uuidv5("6ba7b810-9dad-11d1-80b4-00c04fd430c8", "www.terraform.io")
a5008fae-b28c-5ba5-96cd-82b4c53552d6
```

If you wish to use a namespace defined outside of RFC 4122, using the namespace
UUID is required because no corresponding keyword is available:

```
> uuidv5("743ac3c0-3bf7-4a5b-9e6c-59360447c757", "LIBS:diskfont.library")
ede1a974-df7e-5f17-84b9-76208818b2c8
```

When using raw UUID namespaces, consider including a comment alongside the
expression that indicates which namespace this repressents in a
human-significant manner, such as by reference to the standard that
defined it.

## Related Functions

* [`uuid`](./uuid.html), which generates pseudorandom UUIDs.
4 changes: 4 additions & 0 deletions website/layouts/functions.erb
Original file line number Diff line number Diff line change
Expand Up @@ -386,6 +386,10 @@
<a href="/docs/configuration/functions/uuid.html">uuid</a>
</li>

<li>
<a href="/docs/configuration/functions/uuidv5.html">uuidv5</a>
</li>

</ul>
</li>

Expand Down

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