mirror of https://github.com/docker/docs.git
68 lines
1.8 KiB
Go
68 lines
1.8 KiB
Go
package filter
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import (
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"fmt"
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"regexp"
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"strings"
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log "github.com/Sirupsen/logrus"
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"github.com/docker/swarm/cluster"
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"github.com/samalba/dockerclient"
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)
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// ConstraintFilter selects only nodes that match certain labels.
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type ConstraintFilter struct {
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}
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func (f *ConstraintFilter) extractConstraints(env []string) map[string]string {
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constraints := make(map[string]string)
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for _, e := range env {
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if strings.HasPrefix(e, "constraint:") {
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constraint := strings.TrimPrefix(e, "constraint:")
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parts := strings.SplitN(constraint, "=", 2)
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constraints[strings.ToLower(parts[0])] = strings.ToLower(parts[1])
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}
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}
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return constraints
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}
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// Create the regex for globbing (ex: ub*t* -> ^ub.*t.*$)
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// and match.
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func (f *ConstraintFilter) match(pattern, s string) bool {
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regex := "^" + strings.Replace(pattern, "*", ".*", -1) + "$"
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matched, err := regexp.MatchString(regex, strings.ToLower(s))
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if err != nil {
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log.Error(err)
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}
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return matched
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}
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func (f *ConstraintFilter) Filter(config *dockerclient.ContainerConfig, nodes []*cluster.Node) ([]*cluster.Node, error) {
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constraints := f.extractConstraints(config.Env)
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for k, v := range constraints {
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log.Debugf("matching constraint: %s=%s", k, v)
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candidates := []*cluster.Node{}
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for _, node := range nodes {
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switch k {
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case "node":
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// "node" label is a special case pinning a container to a specific node.
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if f.match(v, node.ID) || f.match(v, node.Name) {
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candidates = append(candidates, node)
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}
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default:
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// By default match the node labels.
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if label, ok := node.Labels[k]; ok {
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if f.match(v, label) {
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candidates = append(candidates, node)
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}
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}
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}
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}
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if len(candidates) == 0 {
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return nil, fmt.Errorf("unable to find a node that satisfies %s == %s", k, v)
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}
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nodes = candidates
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}
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return nodes, nil
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}
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