Added template function whereRequires

Author: Ted Chen

README.md

@@ -134,6 +134,7 @@ Within those templates, the object emitted by docker-gen will have [this structu
 * *`trimSuffix $suffix $string`*: If `$suffix` is a suffix of `$string`, return `$string` with `$suffix` trimmed from the end. Otherwise, return `$string` unchanged.
 * *`where $containers $fieldPath $value`*: Filters an array of `RuntimeContainer` instances based on the values of a field path expression `$fieldPath`. A field path expression is a dot-delimited list of map keys or struct member names specifying the path from container to a nested value, which must be a string. Returns an array of containers having that value.
 * *`whereSomeMatch $containers $fieldPath $sep $values`*: Like `where`, but the string value specified by `$fieldPath` is first split by `$sep` into a list of strings. The comparison value is a string slice with possible matches. Returns containers which OR intersect these values.
+* *`whereRequires $containers $fieldPath $sep $values`*: Like `whereSomeMatch`, except all `$values` must exist in the `$fieldPath`.
 
 ===
 

template.go

@@ -92,6 +92,22 @@ func whereSomeMatch(entries []*RuntimeContainer, key, sep string, cmp []string)
 	return selection
 }
 
+// selects entries based on key.  Assumes key is delimited and breaks it apart before comparing
+func whereRequires(entries []*RuntimeContainer, key, sep string, cmp []string) []*RuntimeContainer {
+	selection := []*RuntimeContainer{}
+	req_count := len(cmp)
+	for _, v := range entries {
+		value := deepGet(*v, key)
+		if value != nil {
+			items := strings.Split(value.(string), sep)
+			if len(intersect(cmp, items)) == req_count {
+				selection = append(selection, v)
+			}
+		}
+	}
+	return selection
+}
+
 // hasPrefix returns whether a given string is a prefix of another string
 func hasPrefix(prefix, s string) bool {
 	return strings.HasPrefix(s, prefix)
@@ -269,6 +285,7 @@ func generateFile(config Config, containers Context) bool {
 		"trimSuffix":   trimSuffix,
 		"where":		where,
 		"whereSomeMatch": whereSomeMatch,
+		"whereRequires": whereRequires,
 	}).ParseFiles(templatePath)
 	if err != nil {
 		log.Fatalf("unable to parse template: %s", err)

template_test.go

@@ -266,6 +266,51 @@ func TestWhereSomeMatch(t *testing.T) {
 	}
 }
 
+func TestWhereRequires(t *testing.T) {
+	containers := []*RuntimeContainer{
+		&RuntimeContainer{
+			Env: map[string]string{
+				"VIRTUAL_HOST": "demo1.localhost",
+			},
+			ID: "1",
+		},
+		&RuntimeContainer{
+			Env: map[string]string{
+				"VIRTUAL_HOST": "demo2.localhost,demo4.localhost",
+			},
+			ID: "2",
+		},
+		&RuntimeContainer{
+			Env: map[string]string{
+				"VIRTUAL_HOST": "bar,demo3.localhost,foo",
+			},
+			ID: "3",
+		},
+		&RuntimeContainer{
+			Env: map[string]string{
+				"VIRTUAL_HOST": "demo2.localhost",
+			},
+			ID: "4",
+		},
+	}
+
+	if len(whereRequires(containers, "Env.VIRTUAL_HOST", ",", []string{"demo1.localhost"})) != 1 {
+		t.Fatalf("demo1.localhost expected 1 match")
+	}
+
+	if len(whereRequires(containers, "Env.VIRTUAL_HOST", ",", []string{"demo2.localhost", "lala"})) != 0 {
+		t.Fatalf("demo2.localhost,lala expected 0 matches")
+	}
+
+	if len(whereRequires(containers, "Env.VIRTUAL_HOST", ",", []string{"demo3.localhost"})) != 1 {
+		t.Fatalf("demo3.localhost expected 1 match")
+	}
+
+	if len(whereRequires(containers, "Env.NOEXIST", ",", []string{"demo3.localhost"})) != 0 {
+		t.Fatalf("NOEXIST demo3.localhost expected 0 match")
+	}
+}
+
 func TestHasPrefix(t *testing.T) {
 	const prefix = "tcp://"
 	const str = "tcp://127.0.0.1:2375"