New constraints management.

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

pkg/provider/docker/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"
 	"github.com/docker/go-connections/nat"
 )
 
@@ -123,10 +124,13 @@ func (p *Provider) keepContainer(ctx context.Context, container dockerData) bool
 		return false
 	}
 
-	if ok, failingConstraint := p.MatchConstraints(container.ExtraConf.Tags); !ok {
-		if failingConstraint != nil {
-			logger.Debugf("Container pruned by %q constraint", failingConstraint.String())
-		}
+	matches, err := constraints.Match(container.Labels, p.Constraints)
+	if err != nil {
+		logger.Error("Error matching constraints expression: %v", err)
+		return false
+	}
+	if !matches {
+		logger.Debugf("Container pruned by constraint expression: %q", p.Constraints)
 		return false
 	}
 

pkg/provider/docker/config_test.go

@@ -6,7 +6,6 @@ import (
 	"testing"
 
 	"github.com/containous/traefik/pkg/config"
-	"github.com/containous/traefik/pkg/types"
 	docker "github.com/docker/docker/api/types"
 	"github.com/docker/docker/api/types/swarm"
 	"github.com/docker/go-connections/nat"
@@ -339,7 +338,7 @@ func Test_buildConfiguration(t *testing.T) {
 	testCases := []struct {
 		desc        string
 		containers  []dockerData
-		constraints []*types.Constraint
+		constraints string
 		expected    *config.Configuration
 	}{
 		{
@@ -1924,13 +1923,7 @@ func Test_buildConfiguration(t *testing.T) {
 					},
 				},
 			},
-			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{},
@@ -1965,13 +1958,7 @@ func Test_buildConfiguration(t *testing.T) {
 					},
 				},
 			},
-			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/docker/docker.go

@@ -45,7 +45,7 @@ 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"`
 	Endpoint                string           `description:"Docker server endpoint. Can be a tcp or a unix socket endpoint."`
 	DefaultRule             string           `description:"Default rule."`

pkg/provider/docker/label.go

@@ -14,7 +14,6 @@ const (
 // configuration Contains information from the labels that are globals (not related to the dynamic configuration) or specific to the provider.
 type configuration struct {
 	Enable bool
-	Tags   []string
 	Docker specificConfiguration
 }
 
@@ -31,7 +30,7 @@ func (p *Provider) getConfiguration(container dockerData) (configuration, error)
 		},
 	}
 
-	err := label.Decode(container.Labels, &conf, "traefik.docker.", "traefik.enable", "traefik.tags")
+	err := label.Decode(container.Labels, &conf, "traefik.docker.", "traefik.enable")
 	if err != nil {
 		return configuration{}, err
 	}