Adds an md5sum function

Useful for computing md5sums of strings to be used in places
where sha256 is not supported.

docs/templating-language.md

@@ -65,6 +65,7 @@ provides the following functions:
   - [regexReplaceAll](#regexreplaceall)
   - [replaceAll](#replaceall)
   - [sha256Hex](#sha256hex)
+  - [md5sum](#md5sum)
   - [split](#split)
   - [timestamp](#timestamp)
   - [toJSON](#tojson)
@@ -1304,6 +1305,14 @@ Takes the argument as a string and compute the sha256_hex value
 {{ "bladibla" | sha256Hex }}
 ```
 
+### `md5sum`
+
+Takes a string input as an argument, and returns the hex-encoded md5 hash of the input.
+
+```liquid
+{{ "myString" | md5 }}
+```
+
 ### `split`
 
 Splits the given string on the provided separator:

template/funcs.go

@@ -2,6 +2,7 @@ package template
 
 import (
 	"bytes"
+	"crypto/md5"
 	"crypto/sha256"
 	"encoding/base64"
 	"encoding/hex"
@@ -1542,3 +1543,8 @@ func sha256Hex(item string) (string, error) {
 	output := hex.EncodeToString(h.Sum(nil))
 	return output, nil
 }
+
+// md5sum returns the md5 hash of a string
+func md5sum(item string) (string, error) {
+	return fmt.Sprintf("%x", md5.Sum([]byte(item))), nil
+}

template/funcs_test.go

@@ -234,3 +234,36 @@ func Test_sha256Hex(t *testing.T) {
 		})
 	}
 }
+
+func Test_md5sum(t *testing.T) {
+	type args struct {
+		item string
+	}
+	tests := []struct {
+		name    string
+		args    args
+		want    string
+		wantErr bool
+	}{
+		{
+			name: "Should return the proper string",
+			args: args{
+				item: "bladibla",
+			},
+			want:    "c6886abd136f7daece35aebb01f1b713",
+			wantErr: false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := md5sum(tt.args.item)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("md5sum() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if got != tt.want {
+				t.Errorf("md5sum() got = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

template/template.go

@@ -279,6 +279,7 @@ func funcMap(i *funcMapInput) template.FuncMap {
 		"regexMatch":      regexMatch,
 		"replaceAll":      replaceAll,
 		"sha256Hex":       sha256Hex,
+		"md5sum":          md5sum,
 		"timestamp":       timestamp,
 		"toLower":         toLower,
 		"toJSON":          toJSON,