docs/scheduler/filter/constraint.go

98 lines
2.6 KiB
Go

package filter
import (
"fmt"
log "github.com/Sirupsen/logrus"
"github.com/docker/swarm/cluster"
"github.com/samalba/dockerclient"
)
// ConstraintFilter selects only nodes that match certain labels.
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, 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 {
log.Debugf("matching constraint: %s=%s", k, v)
// keep the original for display in case of error
v0 := v
k0 := k
negate := false
if strings.HasPrefix(v, "!") {
log.Debugf("negate detected in value")
v = strings.TrimPrefix(v, "!")
negate = true
} else if strings.HasSuffix(k, "!") {
log.Debugf("negate detected in key")
k = strings.TrimSuffix(k, "!")
negate = true
}
useRegex := false
if strings.HasPrefix(v, "/") && strings.HasSuffix(v, "/") {
log.Debugf("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 {
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", k0, v0)
}
nodes = candidates
}
return nodes, nil
}