New constraints management.

Co-authored-by: Mathieu Lonjaret <mathieu.lonjaret@gmail.com>

pkg/provider/rancher/config.go

@@ -11,6 +11,7 @@ import (
 	"github.com/containous/traefik/pkg/config/label"
 	"github.com/containous/traefik/pkg/log"
 	"github.com/containous/traefik/pkg/provider"
+	"github.com/containous/traefik/pkg/provider/constraints"
 )
 
 func (p *Provider) buildConfiguration(ctx context.Context, services []rancherData) *config.Configuration {
@@ -120,10 +121,13 @@ func (p *Provider) keepService(ctx context.Context, service rancherData) bool {
 		return false
 	}
 
-	if ok, failingConstraint := p.MatchConstraints(service.ExtraConf.Tags); !ok {
-		if failingConstraint != nil {
-			logger.Debugf("service pruned by %q constraint", failingConstraint.String())
-		}
+	matches, err := constraints.Match(service.Labels, p.Constraints)
+	if err != nil {
+		logger.Error("Error matching constraints expression: %v", err)
+		return false
+	}
+	if !matches {
+		logger.Debugf("Service pruned by constraint expression: %q", p.Constraints)
 		return false
 	}
 

pkg/provider/rancher/config_test.go

@@ -5,7 +5,6 @@ import (
 	"testing"
 
 	"github.com/containous/traefik/pkg/config"
-	"github.com/containous/traefik/pkg/types"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -14,7 +13,7 @@ func Test_buildConfiguration(t *testing.T) {
 	testCases := []struct {
 		desc        string
 		containers  []rancherData
-		constraints []*types.Constraint
+		constraints string
 		expected    *config.Configuration
 	}{
 		{
@@ -330,13 +329,7 @@ func Test_buildConfiguration(t *testing.T) {
 					State:      "",
 				},
 			},
-			constraints: []*types.Constraint{
-				{
-					Key:       "tag",
-					MustMatch: true,
-					Value:     "bar",
-				},
-			},
+			constraints: `Label("traefik.tags", "bar")`,
 			expected: &config.Configuration{
 				TCP: &config.TCPConfiguration{
 					Routers:  map[string]*config.TCPRouter{},
@@ -363,13 +356,7 @@ func Test_buildConfiguration(t *testing.T) {
 					State:      "",
 				},
 			},
-			constraints: []*types.Constraint{
-				{
-					Key:       "tag",
-					MustMatch: true,
-					Value:     "foo",
-				},
-			},
+			constraints: `Label("traefik.tags", "foo")`,
 			expected: &config.Configuration{
 				TCP: &config.TCPConfiguration{
 					Routers:  map[string]*config.TCPRouter{},

pkg/provider/rancher/label.go

@@ -6,7 +6,6 @@ import (
 
 type configuration struct {
 	Enable bool
-	Tags   []string
 }
 
 func (p *Provider) getConfiguration(service rancherData) (configuration, error) {
@@ -14,7 +13,7 @@ func (p *Provider) getConfiguration(service rancherData) (configuration, error)
 		Enable: p.ExposedByDefault,
 	}
 
-	err := label.Decode(service.Labels, &conf, "traefik.rancher.", "traefik.enable", "traefik.tags")
+	err := label.Decode(service.Labels, &conf, "traefik.rancher.", "traefik.enable")
 	if err != nil {
 		return configuration{}, err
 	}

pkg/provider/rancher/rancher.go

@@ -40,8 +40,7 @@ var _ provider.Provider = (*Provider)(nil)
 
 // Provider holds configurations of the provider.
 type Provider struct {
-	provider.Constrainer `description:"List of constraints used to filter out some containers." export:"true"`
-
+	Constraints               string `description:"Constraints is an expression that Traefik matches against the container's labels to determine whether to create any route for that container." export:"true"`
 	Watch                     bool   `description:"Watch provider." export:"true"`
 	DefaultRule               string `description:"Default rule."`
 	ExposedByDefault          bool   `description:"Expose containers by default." export:"true"`