Merge pull request #1760 from thevilledev/feature/hmac-sha256-function

Add function for HMAC SHA256
hashicorp · Jun 21, 2023 · 4d2281b · 4d2281b
2 parents a3e4db1 + 7899935
commit 4d2281b
Show file tree

Hide file tree

Showing 5 changed files with 69 additions and 0 deletions.
diff --git a/docs/templating-language.md b/docs/templating-language.md
@@ -74,6 +74,7 @@ provides the following functions:
   - [replaceAll](#replaceall)
   - [sha256Hex](#sha256hex)
   - [md5sum](#md5sum)
+  - [hmacSHA256Hex](#hmacSHA256hex)
   - [split](#split)
   - [splitToMap](#splitToMap)
   - [timestamp](#timestamp)
@@ -1498,6 +1499,20 @@ Takes a string input as an argument, and returns the hex-encoded md5 hash of the
 {{ "myString" | md5sum }}
 ```
 
+### `hmacSHA256Hex`
+
+Takes a key and a message as string inputs. Returns a hex-encoded HMAC-SHA256 hash with the given parameters.
+
+```golang
+{{ hmacSHA256Hex "somemessage" "somekey" }}
+```
+
+Or with a pipe function
+
+```golang
+{{ "somekey" | hmacSHA256Hex "somemessage" }}
+```
+
 ### `split`
 
 Splits the given string on the provided separator:

diff --git a/template/funcs.go b/template/funcs.go
@@ -5,6 +5,7 @@ package template
 
 import (
 	"bytes"
+	"crypto/hmac"
 	"crypto/md5"
 	"crypto/sha256"
 	"encoding/base64"
@@ -1720,6 +1721,14 @@ func md5sum(item string) (string, error) {
 	return fmt.Sprintf("%x", md5.Sum([]byte(item))), nil
 }
 
+// hmacSHA256Hex returns the HMAC-SHA256 hash in hexadecimal format of the
+// given message by using the provided key
+func hmacSHA256Hex(message, key string) (string, error) {
+	h := hmac.New(sha256.New, []byte(key))
+	h.Write([]byte(message))
+	return hex.EncodeToString(h.Sum(nil)), nil
+}
+
 // writeToFile writes the content to a file with permissions, username (or UID), group name (or GID),
 // and optional flags to select appending mode or add a newline.
 //

diff --git a/template/funcs_test.go b/template/funcs_test.go
@@ -268,3 +268,38 @@ func Test_md5sum(t *testing.T) {
 		})
 	}
 }
+
+func Test_hmacSHA256Hex(t *testing.T) {
+	type args struct {
+		message string
+		key     string
+	}
+	tests := []struct {
+		name    string
+		args    args
+		want    string
+		wantErr bool
+	}{
+		{
+			name: "Should return the proper string",
+			args: args{
+				message: "bladibla",
+				key:     "foobar",
+			},
+			want:    "82cd4c36fa45a1936e93d005ea2fd008350339bb9246a3ba0c8dfecb9d77155b",
+			wantErr: false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := hmacSHA256Hex(tt.args.message, tt.args.key)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("hmacSHA256Hex() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if got != tt.want {
+				t.Errorf("hmacSHA256Hex() got = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
diff --git a/template/template.go b/template/template.go
@@ -390,6 +390,7 @@ func funcMap(i *funcMapInput) template.FuncMap {
 		"replaceAll":            replaceAll,
 		"sha256Hex":             sha256Hex,
 		"md5sum":                md5sum,
+		"hmacSHA256Hex":         hmacSHA256Hex,
 		"timestamp":             timestamp,
 		"toLower":               toLower,
 		"toJSON":                toJSON,

diff --git a/template/template_test.go b/template/template_test.go
@@ -254,6 +254,15 @@ func TestTemplate_Execute(t *testing.T) {
 			"dGVzdGluZzEyMw==",
 			false,
 		},
+		{
+			"func_hmacSHA256Hex",
+			&NewTemplateInput{
+				Contents: `{{ hmacSHA256Hex "somemessage" "somekey" }}`,
+			},
+			nil,
+			"6116e95f2827172aa6ef8b22b883f6a77e966aefc129c6b8228ebd0aac74e98d",
+			false,
+		},
 		{
 			"func_datacenters",
 			&NewTemplateInput{