add template function findSubmatch

Author: reddec

README.md

@@ -534,23 +534,29 @@ Additional "magic" vairables:
 #### Functions
 
 * [Sprig template utilities](http://masterminds.github.io/sprig/) available.
-* Custom functions:
-    * `getRootFile` (v1.2.1+) - (`{{getRootFile "myfile"}}`) get content of file with specific name in any of root
-      folders. Example:
-
-           Current working directory: /foo/bar/xyz
-           Looking for name: .gitignore
-           Will check (and return content):
-              /foo/bar/xyz/.gitignore
-              /foo/bar/.gitignore
-              /foo/.gitignore
-              /.gitignore
-
-      If nothing found - `ErrNotExists` returned
-    * `findRootFile` (v1.3.2+) - (`{{findRootFile "myfile"}}`) find path to file with specific name in any of root
-      folders. Same as `getRootFile` but instead of returning content it is returning path to file.
-    * `findRootDir` (v1.3.2+) - (`{{findRootDir "mydir"}}`) find path to directory with specific name in any of root
-      folders. Same as `findRootFile` but instead of looking for file it is looking for directory.
+  * Custom functions:
+      * `getRootFile` (v1.2.1+) - (`{{getRootFile "myfile"}}`) get content of file with specific name in any of root
+        folders. Example:
+
+             Current working directory: /foo/bar/xyz
+             Looking for name: .gitignore
+             Will check (and return content):
+                /foo/bar/xyz/.gitignore
+                /foo/bar/.gitignore
+                /foo/.gitignore
+                /.gitignore
+
+        If nothing found - `ErrNotExists` returned
+      * `findRootFile` (v1.3.2+) - (`{{findRootFile "myfile"}}`) find path to file with specific name in any of root
+        folders. Same as `getRootFile` but instead of returning content it is returning path to file.
+      * `findRootDir` (v1.3.2+) - (`{{findRootDir "mydir"}}`) find path to directory with specific name in any of root
+        folders. Same as `findRootFile` but instead of looking for file it is looking for directory.
+      * `findSubmatch` (v1.3.3+) - capture all regex groups with matching pattern. Example:
+            
+             Pattern: foo[ ]+([^ ]+)
+             Text: foo bar foo baz
+             Returns: [bar, baz]
+      
 
 #### Flow
 

internal/manifest.go

@@ -24,6 +24,7 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"regexp"
 	"strings"
 	"text/template"
 
@@ -297,6 +298,7 @@ func (r *renderContext) Render(value string) (string, error) {
 	funcMap["getRootFile"] = getRootFile(r.workDir)
 	funcMap["findRootFile"] = findRootFile(r.workDir)
 	funcMap["findRootDir"] = findRootDir(r.workDir)
+	funcMap["findSubmatch"] = findSubmatchAll
 	p, err := template.New("").Delims(r.open, r.close).Funcs(funcMap).Parse(value)
 	if err != nil {
 		return "", err
@@ -397,3 +399,22 @@ func findRootDir(root string) func(string) (string, error) {
 		}
 	}
 }
+
+// find all regex groups which matches pattern.
+//
+//     Pattern: foo[ ]+([^ ]+)
+//     Text: foo bar foo baz
+//     Returns: [bar, baz]
+//
+// Workaround for https://github.com/Masterminds/sprig/pull/298
+func findSubmatchAll(pattern string, text string) ([]string, error) {
+	p, err := regexp.Compile(pattern)
+	if err != nil {
+		return nil, err
+	}
+	var ans []string
+	for _, group := range p.FindAllStringSubmatch(text, -1) {
+		ans = append(ans, group[1:]...)
+	}
+	return ans, nil
+}

internal/manifest_test.go

@@ -17,6 +17,7 @@ limitations under the License.
 package internal
 
 import (
+	"fmt"
 	"os"
 	"path/filepath"
 	"testing"
@@ -64,3 +65,25 @@ func TestGetRootFile(t *testing.T) {
 		require.Contains(t, content, "module github.com/reddec/layout")
 	})
 }
+
+func TestSubmatch(t *testing.T) {
+	content := `
+foo bar
+
+foo barbaz
+bar=123,456
+`
+	t.Run("match groups", func(t *testing.T) {
+		matches, err := findSubmatchAll(`foo[ ]+(.+)`, content)
+		require.NoError(t, err)
+		require.Equal(t, []string{"bar", "barbaz"}, matches)
+	})
+}
+
+func ExampleFindSubmatch() {
+	pattern := `foo[ ]+([^ ]+)`
+	text := `foo bar foo baz`
+	out, _ := findSubmatchAll(pattern, text)
+	fmt.Println(out)
+	// output: [bar baz]
+}