docs/scheduler/filter/constraint.go

67 lines
1.8 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) Filter(config *dockerclient.ContainerConfig, nodes []*cluster.Node) ([]*cluster.Node, error) {
constraints, err := extractEnv("constraint", config.Env)
if err != nil {
return nil, err
}
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
k, v, mode, useRegex := parse(k, v)
candidates := []*cluster.Node{}
for _, node := range nodes {
switch k {
case "node":
if mode == gte && node.ID >= v {
candidates = append(candidates, node)
} else if mode == lte && node.ID <= v {
candidates = append(candidates, node)
} else {
// "node" label is a special case pinning a container to a specific node.
matchResult := match(v, node.ID, useRegex) || match(v, node.Name, useRegex)
if (mode == neg && !matchResult) || (mode == equ && matchResult) {
candidates = append(candidates, node)
}
}
default:
// By default match the node labels.
if label, ok := node.Labels[k]; ok {
if mode == gte && label >= v {
candidates = append(candidates, node)
} else if mode == lte && label <= v {
candidates = append(candidates, node)
} else {
matchResult := match(v, label, useRegex)
if (mode == neg && !matchResult) || (mode == equ && 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
}