Remove BaseProvider

pkg/provider/constrainer.go

@@ -0,0 +1,27 @@
+package provider
+
+import "github.com/containous/traefik/pkg/types"
+
+// Constrainer Filter services by constraint, matching with Traefik tags.
+type Constrainer struct {
+	Constraints types.Constraints `description:"Filter services by constraint, matching with Traefik tags." export:"true"`
+}
+
+// MatchConstraints must match with EVERY single constraint
+// returns first constraint that do not match or nil.
+func (c *Constrainer) MatchConstraints(tags []string) (bool, *types.Constraint) {
+	// if there is no tags and no constraints, filtering is disabled
+	if len(tags) == 0 && len(c.Constraints) == 0 {
+		return true, nil
+	}
+
+	for _, constraint := range c.Constraints {
+		// xor: if ok and constraint.MustMatch are equal, then no tag is currently matching with the constraint
+		if ok := constraint.MatchConstraintWithAtLeastOneTag(tags); ok != constraint.MustMatch {
+			return false, constraint
+		}
+	}
+
+	// If no constraint or every constraints matching
+	return true, nil
+}