add a testcase for escape regexp

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

scheduler/filter/README.md

@@ -152,12 +152,13 @@ As you can see here, the containers were only scheduled on nodes with the redis
 Additionally, you can use a not (`!`) to negate and a regular expression in the form of `/regexp/` for specifying a constraint.
 For example,
 
-* `name=node1` will match nodes named with `node1`.
-* `name=!node1` will match all nodes, except `node1`.
-* `region=!us*` will match all nodes outside the regions prefixed with `us`.
-* `name=/node[12]/` will match nodes named `node1` and `node2`.
-* `name=/node\d/` will match all nodes named with `node` + 1 digit
-* `node=!/node-[01]-id/` will match all nodes, except those with ids `node-0-id` and `node-1-id`
+* `constraint:name=node1` will match nodes named with `node1`.
+* `constraint:name=!node1` will match all nodes, except `node1`.
+* `constraint:region=!us*` will match all nodes outside the regions prefixed with `us`.
+* `constraint:name=/node[12]/` will match nodes named `node1` and `node2`.
+* `constraint:name=/node\d/` will match all nodes named with `node` + 1 digit.
+* `constraint:node=!/node-[01]-id/` will match all nodes, except those with ids `node-0-id` and `node-1-id`.
+* `constraint:name=!/foo\[bar\]/` will match all nodes, except those with name `foo[bar]`. You can see the use of escape characters here.
 
 ## Port Filter
 

scheduler/filter/constraint_test.go

@@ -189,3 +189,38 @@ func TestConstraintRegExp(t *testing.T) {
 	assert.Len(t, result, 1)
 	assert.Equal(t, result[0], nodes[2])
 }
+
+func TestFilterRegExpWithEscape(t *testing.T) {
+	var (
+		f      = ConstraintFilter{}
+		nodes  = testFixtures()
+		result []*cluster.Node
+		err    error
+	)
+
+	// Prepare node with a strange name
+	node3 := cluster.NewNode("node-3")
+	node3.ID = "node-3-id"
+	node3.Name = "node-3-name"
+	node3.Labels = map[string]string{
+		"name":   "foo[bar]",
+		"group":  "2",
+		"region": "eu",
+	}
+	nodes = append(nodes, node3)
+
+	// Test filter with a strange name
+	result, err = f.Filter(&dockerclient.ContainerConfig{
+		Env: []string{`constraint:name=/foo\[bar\]/`},
+	}, nodes)
+	assert.NoError(t, err)
+	assert.Len(t, result, 1)
+	assert.Equal(t, result[0], nodes[3])
+
+	// Test ! filter with a strange name
+	result, err = f.Filter(&dockerclient.ContainerConfig{
+		Env: []string{`constraint:name=!/foo\[bar\]/`},
+	}, nodes)
+	assert.NoError(t, err)
+	assert.Len(t, result, 3)
+}