// Filter is exported
func (f *ConstraintFilter) Filter(config *cluster.ContainerConfig, nodes []*node.Node) ([]*node.Node, error) {
constraints, err := parseExprs(config.Constraints())
if err != nil {
return nil, err
}
for _, constraint := range constraints {
log.Debugf("matching constraint: %s %s %s", constraint.key, OPERATORS[constraint.operator], constraint.value)
candidates := []*node.Node{}
for _, node := range nodes {
switch constraint.key {
case "node":
// "node" label is a special case pinning a container to a specific node.
if constraint.Match(node.ID, node.Name) {
candidates = append(candidates, node)
}
default:
if constraint.Match(node.Labels[constraint.key]) {
candidates = append(candidates, node)
}
}
}
if len(candidates) == 0 {
if constraint.isSoft {
return nodes, nil
}
return nil, fmt.Errorf("unable to find a node that satisfies %s%s%s", constraint.key, OPERATORS[constraint.operator], constraint.value)
}
nodes = candidates
}
return nodes, nil
}
// GetFilters returns a list of the constraints found in the container config.
func (f *ConstraintFilter) GetFilters(config *cluster.ContainerConfig) ([]string, error) {
allConstraints := []string{}
constraints, err := parseExprs(config.Constraints())
if err != nil {
return nil, err
}
for _, constraint := range constraints {
allConstraints = append(allConstraints, fmt.Sprintf("%s%s%s", constraint.key, OPERATORS[constraint.operator], constraint.value))
}
return allConstraints, nil
}