improve regexp matching

Signed-off-by: Chanwit Kaewkasi <chanwit@gmail.com>

scheduler/filter/constraint.go

@@ -12,41 +12,79 @@ import (
 type ConstraintFilter struct {
 }
 
+func (f *ConstraintFilter) extractConstraints(env []string) map[string]string {
+	constraints := make(map[string]string)
+	for _, e := range env {
+		if strings.HasPrefix(e, "constraint:") {
+			constraint := strings.TrimPrefix(e, "constraint:")
+			parts := strings.SplitN(constraint, "=", 2)
+			constraints[strings.ToLower(parts[0])] = strings.ToLower(parts[1])
+		}
+	}
+	return constraints
+}
+
+// Create the regex for globbing (ex: ub*t* -> ^ub.*t.*$)
+// and match.
+func (f *ConstraintFilter) match(pattern, s string, useRegex bool) bool {
+	regex := pattern
+	if !useRegex {
+		regex = "^" + strings.Replace(pattern, "*", ".*", -1) + "$"
+	}
+	matched, err := regexp.MatchString(regex, strings.ToLower(s))
+	if err != nil {
+		log.Error(err)
+	}
+	return matched
+}
+
 func (f *ConstraintFilter) Filter(config *dockerclient.ContainerConfig, nodes []*cluster.Node) ([]*cluster.Node, error) {
 	constraints := extractEnv("constraint", config.Env)
 	for k, v := range constraints {
+
+		v0 := v
+
 		log.Debugf("matching constraint: %s=%s", k, v)
+
 		negate := false
+		useRegex := false
+
 		if strings.HasPrefix(v, "!") {
 			log.Debugf("negate detected")
 			v = strings.TrimPrefix(v, "!")
 			negate = true
 		}
+		if strings.HasPrefix(v, "/") && strings.HasSuffix(v, "/") {
+			log.Infof("regex detected")
+			v = strings.TrimPrefix(strings.TrimSuffix(v, "/"), "/")
+			useRegex = true
+		}
+
 		candidates := []*cluster.Node{}
 		for _, node := range nodes {
 			switch k {
 			case "node":
 				// "node" label is a special case pinning a container to a specific node.
+<<<<<<< HEAD
 				if match(v, node.ID) || match(v, node.Name) {
+=======
+				matchResult := f.match(v, node.ID, useRegex) || f.match(v, node.Name, useRegex)
+				if (negate && !matchResult) || (!negate && matchResult) {
+>>>>>>> improve regexp matching
 					candidates = append(candidates, node)
 				}
 			default:
 				// By default match the node labels.
 				if label, ok := node.Labels[k]; ok {
-					if negate {
-						if f.match(v, label) == false {
-							candidates = append(candidates, node)
-						}
-					} else {
-						if f.match(v, label) {
-							candidates = append(candidates, node)
-						}
+					matchResult := f.match(v, label, useRegex)
+					if (negate && !matchResult) || (!negate && matchResult) {
+						candidates = append(candidates, node)
 					}
 				}
 			}
 		}
 		if len(candidates) == 0 {
-			return nil, fmt.Errorf("unable to find a node that satisfies %s == %s", k, v)
+			return nil, fmt.Errorf("unable to find a node that satisfies %s = %s", k, v0)
 		}
 		nodes = candidates
 	}

scheduler/filter/constraint_test.go

@@ -40,7 +40,6 @@ func testFixtures() (nodes []*cluster.Node) {
 	return
 }
 
-/*
 func TestConstrainteFilter(t *testing.T) {
 	var (
 		f      = ConstraintFilter{}
@@ -113,9 +112,8 @@ func TestConstrainteFilter(t *testing.T) {
 	assert.NoError(t, err)
 	assert.Len(t, result, 2)
 }
-*/
 
-func TestConstraintNotExpression(t *testing.T) {
+func TestConstraintNotExpr(t *testing.T) {
 	var (
 		f      = ConstraintFilter{}
 		nodes  = testFixtures()
@@ -130,6 +128,20 @@ func TestConstraintNotExpression(t *testing.T) {
 	assert.NoError(t, err)
 	assert.Len(t, result, 2)
 
+	// Check not does_not_exist. All should be found
+	result, err = f.Filter(&dockerclient.ContainerConfig{
+		Env: []string{"constraint:name=!does_not_exist"},
+	}, nodes)
+	assert.NoError(t, err)
+	assert.Len(t, result, 3)
+
+	// Check name must not start with n
+	result, err = f.Filter(&dockerclient.ContainerConfig{
+		Env: []string{"constraint:name=!n*"},
+	}, nodes)
+	assert.Error(t, err)
+	assert.Len(t, result, 0)
+
 	// Check not with globber pattern
 	result, err = f.Filter(&dockerclient.ContainerConfig{
 		Env: []string{"constraint:region=!us*"},
@@ -138,3 +150,42 @@ func TestConstraintNotExpression(t *testing.T) {
 	assert.Len(t, result, 1)
 	assert.Equal(t, result[0].Labels["region"], "eu")
 }
+
+func TestConstraintRegExp(t *testing.T) {
+	var (
+		f      = ConstraintFilter{}
+		nodes  = testFixtures()
+		result []*cluster.Node
+		err    error
+	)
+
+	// Check with regular expression /node\d/ matches node{0..2}
+	result, err = f.Filter(&dockerclient.ContainerConfig{
+		Env: []string{`constraint:name=/node\d/`},
+	}, nodes)
+	assert.NoError(t, err)
+	assert.Len(t, result, 3)
+
+	// Check with regular expression /node\d/ matches node{0..2}
+	result, err = f.Filter(&dockerclient.ContainerConfig{
+		Env: []string{`constraint:name=/node[12]/`},
+	}, nodes)
+	assert.NoError(t, err)
+	assert.Len(t, result, 2)
+
+	// Check with regular expression ! and regexp /node[12]/ matches node[0]
+	result, err = f.Filter(&dockerclient.ContainerConfig{
+		Env: []string{`constraint:name=!/node[12]/`},
+	}, nodes)
+	assert.NoError(t, err)
+	assert.Len(t, result, 1)
+	assert.Equal(t, result[0], nodes[0])
+
+	// Validate node pinning by ! and regexp.
+	result, err = f.Filter(&dockerclient.ContainerConfig{
+		Env: []string{"constraint:node=!/node-[01]-id/"},
+	}, nodes)
+	assert.NoError(t, err)
+	assert.Len(t, result, 1)
+	assert.Equal(t, result[0], nodes[2])
+}